Cerebrospinal Fluid β2-Microglobulin as a Diagnostic Biomarker in Central Nervous System Lymphoma: a Single-Center Retrospective Analysis

Cerebrospinal Fluid β2-Microglobulin as a Diagnostic Biomarker in Central Nervous System Lymphoma: a Single-Center Retrospective Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cerebrospinal Fluid β2-Microglobulin as a Diagnostic Biomarker in Central Nervous System Lymphoma: a Single-Center Retrospective Analysis Yijun Fan, Yuyang Huang, Wenwen Zheng, Zhouzhou Su, Jun Hu, Shunzong Yuan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7657007/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Nov, 2025 Read the published version in Annals of Hematology → Version 1 posted 8 You are reading this latest preprint version Abstract This retrospective cohort study investigated the diagnostic and prognostic significance of cerebrospinal fluid (CSF) β2-microglobulin (β2-M) in 1,349 patients hospitalized between January 2018 and August 2024. Patients were categorized into lymphoma, leukemia, solid tumor, and other disease cohorts, with additional stratification by central nervous system (CNS) involvement. CSF β2-M concentrations were markedly elevated in CNS lymphoma (CNSL) relative to all comparator groups (p < 0.001). A cutoff value of 1.85 mg/L discriminated CNSL from non-CNS-involved lymphoma with high diagnostic accuracy (AUC 0.939), yielding 89.7% sensitivity and 85.7% specificity. Longitudinal assessment further demonstrated that dynamic CSF β2-M trajectories correlated with therapeutic response and relapse risk ( p = 0.009 for complete remission; p = 0.006 for relapse), underscoring its utility as a monitoring biomarker. Collectively, these findings establish CSF β2-microglobulin as a reliable, accessible, and cost-effective biomarker for both diagnosis and prognostic evaluation in CNSL. Central nervous system lymphoma β2-microglobulin cerebrospinal fluid diagnostic biomarker Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Central nervous system lymphoma (CNSL) is a rare but aggressive subtype of extranodal non-Hodgkin lymphoma, accounting for nearly 3% to 4% of all CNS tumors [ 1 ]. CNSL can be divided into primary and secondary CNSL (PCNSL and SCNSL) based on tumor cells involving the brain, eyes, meninges, or spinal cord without or with evidence of systemic disease. For SCNSL, the diagnosis can be easily achieved by combining non-brain biopsy pathology and radiographic imaging patterns. However, for PCNSL, in most time, the only way to obtain a definitive diagnosis is histopathological confirmation after invasive brain biopsy [ 1 ]. Particularly, deep-seated lesions often preclude safe sampling, and their invasiveness carries substantial risks, including intracranial hemorrhage, cerebral edema, and seizures [ 2 ]. Although a positive finding in other samples, such as cerebrospinal fluid (CSF) and vitreous biopsy, to some extent can avoid the need for a surgical operation, a safer and less invasive diagnostic method for CNSL has not been established yet. CSF assessment and intrathecal chemotherapy are routine operations for CNSL in some practice centers [ 3 ]. Several outstanding studies have demonstrated that interleukin-10 (IL-10), the C-X-C motif chemokine ligand 13 (CXCL13), and circulating tumor DNA (ctDNA) in CSF are reliable markers for adjuvant diagnosis of CNSL, but lack universal applicability due to methodological complexity or inconsistent diagnostic thresholds [ 4 , 5 ]. Consequently, a widely suitable biomarker in the CSF for the diagnosis of patients with CNSL is still an unmet need [ 6 ]. β2-microglobulin (β2-M), an 11.8-kDa subunit of major histocompatibility complex class I (MHC-I) molecules, is detectable in multiple body fluids including CSF, serum, and urine [ 7 ]. Elevated CSF β2-M levels are consistently observed in diverse CNS pathologies, including neoplastic, inflammatory, and neuroimmune disorders, with particularly marked elevations in CNSL [ 4 , 8 – 10 ]. Mavligit et al. [ 11 ] first identified elevated CSF β2-M with a mean level of 4.2 ± 0.6 mg/L in CNSL patients. Recent studies proposed CSF β2-M cut-offs at 2.4 mg/L (CNSL vs. tumors) [ 12 ] and 2.056 mg/L (PCNSL vs. other CNS malignancies/inflammation) [ 13 ] for differential diagnosis. However, these previous findings are limited by small cohort sizes and a lack of validation across heterogeneous CNS diseases. And due to longitudinal variations, there is a lack of standardized detection methods for β2-M. To address these gaps, herein we conducted a large-scale retrospective study to assess the diagnostic value of CSF β2-M in CNSL. 2. Methods 2.1 Study population Between January 2018 and August 2024, CSF and serum β2-M reports were retrieved from 1,349 individuals with confirmed or suspected CNS diseases presenting at the Fifth Medical Center of the People's Liberation Army General Hospital. Because all data used for analysis were collected from routine medical procedures without affecting clinical care, institutional review board approval was waived. The study complied with the World Medical Association Declaration of Helsinki concerning the ethical conduct of research involving human subjects. Informed consent was obtained from all participants before inclusion. Patients were stratified into four major cohorts based on disease diagnosis: lymphoma, leukemia, solid tumor, and other diseases (Fig. 1 ). Within the lymphoma cohort, patients were further classified based on CNS involvement into CNSL and non-CNS lymphoma (NCNSL), with CNSL including diffuse large B-cell lymphoma (DLBCL, n = 41), NK/T-cell lymphomas (n = 2), peripheral T-cell lymphomas (n = 3), Burkitt lymphomas (n = 2), and unclassified B-cell lymphoma (n = 1). Similarly, in the leukemia cohort, patients were divided into CNS leukemia and non-CNS leukemia. The solid tumor cohort contained CNS solid tumors and non-CNS solid tumors, CNS solid tumors comprised gliomas (n = 2), meningioma (n = 2), and lung (n = 32), spine (n = 1), cervix (n = 1), breast (n = 16), or gastric (n = 4) cancer metastases. Other disease cohort included CNS infectious diseases, CNS miscellaneous diseases, and non-CNS-involved diseases. 2.2 Sample measurement β2-M concentrations in CSF and serum samples were measured through immunoturbidimetric assay performed on automatic biochemistry analyzers HITACHI Labospect 008AS or HITACHI 7600 − 110 (Tokyo, Japan). Measurements were conducted on the same day or within three days after sample collection. Total protein and glucose levels in CSF were also assessed in the combination package on the same analyzers when β2-M was measured. IL-10 concentrations in CSF were determined with a commercial IL-10 reagent kit (Siemens Healthcare Diagnostics Products Ltd., Gwynedd, UK) via an automated chemiluminescence immunoassay on the Immulite 1000 Analyzer (Siemens Healthcare Diagnostics Inc., NJ, USA). The limits of detection were 0.2 mg/L for β2-M and 5 pg/mL for IL-10, respectively. 2.3 Statistical analysis All statistical analyses were conducted using GraphPad Prism software (version 10.0). Continuous variables are presented as median (range). Comparisons between two groups were performed using the Mann–Whitney U test or chi-square test, while the Kruskal–Wallis test was used for comparisons across multiple groups. The relationship between CSF β2-M and serum β2-M levels was assessed by Spearman’s rank correlation. For post hoc pairwise comparisons, the Bonferroni correction was applied using the Dunn test function from the FSA package. Diagnostic performance was assessed by calculating the area under the receiver operating characteristic (ROC) curve. A two-sided p-value of less than 0.05 was considered statistically significant. 3. Results 3.1 Utility of CSF β2-M as a CNSL Biomarker Firstly, we compared CSF β2-M levels of patients with CNSL to patients with other CNS involved conditions (Table 1). In the CNSL group, the median CSF β2-M concentration was 3.0 (range, 1.2-13.5) mg/L, significantly higher than other groups ( p < 0.001 for CNS leukemia, CNS solid tumor, and CNS miscellaneous diseases; p = 0.095 for CNS infectious diseases ). In contrast, a comparison of CSF total protein (TP) levels between CNSL, CNS leukemia, CNS solid tumor, and CNS infectious disease patients revealed no significance ( p = 0.312). Critically, serum β2-M concentrations of CNSL demonstrated considerable overlap across other groups, confirming its inability to discriminate CNSL from other CNS-involved tumors. We also found that CSF β2-M levels were significantly higher in patients with CNS involvement by hematopoietic malignancies compared with CNS non-involvement (median: CNSL vs. NCNSL: 3.0 mg/L vs. 1.2 mg/L; CNS leukemia vs. non-CNS leukemia: 1.6 mg/L vs. 1.1 mg/L; both p < 0.001) (Figs. 2a, b). However, the difference between patients with CNS involvement by solid tumor and CNS non-involvement was not significant. (median: CNS solid tumor vs. non-CNS solid tumor: 1.8 mg/L vs. 1.6 mg/L, p = 0.286) (Fig. 2c). Furthermore, Serum β2-M levels were significantly lower in patients with CNS involvement by both lymphoma (median: CNSL vs. NCNSL: 1.5 mg/L vs. 2.2 mg/L, p < 0.001) and solid tumor cohorts (median: CNS solid tumor vs. non-CNS solid tumor: 1.3 mg/L vs. 2.2 mg/L, p < 0.001). And no significant difference was observed in serum β2-M levels between CNS leukemia and Non-CNS leukemia (median: CNS leukemia vs. non-CNS leukemia: 1.8 mg/L vs. 1.8 mg/L, p = 0.776) (Figs. 2d-f). Table 1 Baseline characteristics and laborator y markers in each groups.Data are presented as median (range) Group Sex, male/female, No.(%) Age, y CSF TP, g/L CSF β2M, mg/L Serum β2-M, mg/L CNSL (n = 49) 32/17 (65/35) 58 (29, 75) 0.70 (0.27, 5.25) 3.0 (1.2, 13.5) 1.5 (0.7, 4.5) PCNSL (n = 31) 20/11 (65/35) 56 (33, 75) 0.57 (0.27, 2.98) 2.7 (1.3, 13.5) 1.2(0.7, 2.2) SCNSL (n = 18) 12/9 (57/43) 61 (29, 74) 0.84 (0.4, 5.25) 3.2 (1.2, 11.2) 1.8 (1.3, 4.5) NCNSL (n = 428) 268/160 (63/37) 51 (12, 90) 0.36 (0.11, 5.20) 1.2 (0.4, 5.1) 2.2 (0.7, 12.1) CNS leukemia (n = 43) 27/16 (63/37) 39 (16, 71) 0.61 (0.18, 5.59) 1.6 (0.5, 6.8) 1.8 (0.8, 4.6) Non-CNS leukemia (n = 541) 309/232 (57/43) 40 (11, 78) 0.35 (0.14, 16.60) 1.1 (0.5, 3.4) 1.8 (0.6, 10.0) CNS solid tumor (n = 58) 19/39 (33/67) 52 (31, 75) 0.56 (0.23, 3.75) 1.8 (0.7, 7.6) 1.3 (0.6, 3.3) Non-CNS Solid Tumor (n = 13) 5/8 (38/62) 49 (36, 74) 0.43 (0.13, 3.51) 1.6 (0.8, 3.0) 2.2 (1.2, 7.5) CNS infectious diseases (n = 50) 34/16 (68/32) 11 (0, 75) 0.60 (0.15, 5.50) 2.3 (0.3, 21.5) 2.4 (0.7, 8.1) CNS miscellaneous diseases (n = 90) 52/38 (58/42) 51 (0, 98) 0.44 (0.10, 2.25) 1.7 (0.3, 7.1) 1.9 (0.6, 24.8) Non-CNS-Involved Diseases (n = 77) 51/26 (34/66) 0 (0, 68) 0.63 (0.13, 3.13) 1.7 (0.5, 5.8) 2.6 (1.1, 5.3) Abbreviations: CNSL, central nervous system lymphoma; PCNSL, primary CNSL; SCNSL, secondary CNSL; NCNSL, non-CNS lymphoma; β2-M, β2-microglobulin. 3.2 Diagnostic Performance of CSF β2-M in patients with CNSL We then performed ROC analysis and found that a CSF β2-M threshold of 1.85 mg/L could distinguish CNSL from NCNSL with an area under the curve (AUC) of 0.939 ( p < 0.001), sensitivity of 89.7%, and specificity of 85.7%. In contrast, CSF β2-M showed lower diagnostic accuracy for differentiating CNS leukemia from non-CNS leukemia (AUC: 0.685, p < 0.001) and CNS solid tumor from non-CNS solid tumor (AUC: 0.596, p = 0.281), underscoring its specificity for CNSL (Fig. 3a). Due to limited routine clinical use, CSF IL-10 levels were available for only 217 patients. CSF IL-10 concentrations were significantly elevated in CNSL compared to NCNSL (median: CNSL vs. NCNSL: 9.62 pg/mL (range, 5-1000) vs. 5 pg/mL (range, 5-49.2), p < 0.001) (Fig. 3b). ROC analysis yielded an AUC of 0.765 for CSF IL-10, with a sensitivity of 54.3% and specificity of 98.4% at an optimal cutoff of 5.745 pg/mL. When combined, CSF β2-M and IL-10 improved diagnostic accuracy further, achieving an AUC of 0.952, sensitivity of 91.4%, and specificity of 88.5%. This combined biomarker panel outperformed IL-10 alone in detecting CNSL ( p < 0.001) (Fig. 3c). 3. 3 Correlation Between CSF and Serum β2-M While seminal work by Starmans et al. reported dissociation between serum and CSF β2-M levels in neuroinfectious diseases [14], this relationship in CNS malignancies—particularly CNSL—remains largely unexplored. We found that in patients with CNS non-involvement, β2-M levels were significantly higher in serum than in CSF (NCNSL, p < 0.001;non-CNS leukemia, p < 0.001; non-CNS solid tumor, p = 0.021; non-CNS-involved disease, p < 0.001) (Table 1). In contrast, in patients with CNS involvement by malignancies, β2-M levels were significantly higher in CSF than in serum (CNSL, p < 0.001; CNS solid tumor, p = 0.049; CNS Leukemia, p = 0.557) (Table 1). Particularly, the difference of β2-M levels between CSF and serum in patients with CNSL was the most significant. β2-M level in CSF was nearly doubled as that in serum. A weak negative correlation between CSF and serum β2-M levels was observed in CNSL patients (r =–0.036, p = 0.807), whereas NCNSL patients exhibited a moderate positive correlation (r = 0.410, p < 0.001) (Fig. 4a). PCNSL showed lower serum β2-M levels than SCNSL (median: PCNSL vs. SCNSL: 1.2 mg/L vs. 1.8 mg/L, p < 0.001), while CSF β2-M levels showed no difference between PCNSL and SCNSL groups (median: PCNSL vs. SCNSL:2.7 mg/L vs. 3.2 mg/L, p = 0.237) (Fig. 4b). These findings suggested local CNS production of β2-M independent of systemic disease. 3. 4 CSF β2-M Dynamics Indicate Treatment Efficacy in CNSL All 35 patients diagnosed with CNSL were treated with intrathecal methotrexate chemotherapy after hospital admission. CSF β2-M concentrations were assessed at multiple timepoints during the treatment course (Figs. 5a-c). In complete responders (CR, n = 19), CSF β2-M levels showed a significant downward trend, with a reduction of nearly half from baseline after treatment (median: 2.9 mg/L vs. 1.4 mg/L, pre-treatment vs. CR, p = 0.009). Conversely, progressive disease (PD, n = 6) was associated with persistently elevated levels (median: 2.2 mg/L vs. 2.35 mg/L, pre-treatment vs. PD, p = 0.701). Among 10 relapsed patients—3 with partial response (PR) and 7 with CR prior to relapse—CSF β2-M levels significantly increased from remission levels to relapse state (median: 1.3 → 3.3 mg/L, response vs. relapse, p = 0.006), and decreased to 1.9 mg/L after retreatment (relapse vs. post-treatment, p = 0.055). 4. Discussion In this study, we found that the β2-M level of CSF was significantly higher than that of serum in patients with CNSL. On the contrary, β2-M level of CSF was significantly lower than that of serum in patients without evident CNS diseases or in patients with NCNSL. Meanwhile, in CSF, β2-M levels demonstrated a dynamic high-low-high model as patients with CNSL experienced the pattern of emergence-regression-relapse. Therefore. for the first time, these data indicated that local lymphoma cell-originated β2-M in the brain might be a main source for its elevation in the CSF of patients with CNSL. CSF β2-M should be a suitable marker for diagnostic and prognostic evaluation of patients with CNSL. This work substantiates decades of research establishing CSF β2-M as a CNSL biomarker. Our large cohort confirms its diagnostic robustness across modern methodologies. Crucially, we demonstrate that 1.85 mg/L is the optimal diagnostic threshold, outperforming historical cutoffs like Kersten's 1.6 mg/L (AUC = 0.77, sensitivity = 81%, specificity = 68%) and Ernerudh's 1.9 mg/L (sensitivity = 71%, specificity = 67%; AUC not reported) [15,16]. This precision stems from our rigorous exclusion of confounders and large sample size. β2-M can be measured by various immunochemical assays, including immunoturbidimetric assay, radioimmunoassay, and enzyme-linked immunoassay (ELISA). Importantly, despite assay variations, CSF β2-M in CNSL consistently ranges 2–4 mg/L, underscoring the methodological robustness of β2-M as a CNSL biomarker across detection platforms [11,12,16-18]. Our findings demonstrated CSF β2-M Levels were significantly elevated in CNSL compared to cerebral leukemia, metastatic brain tumors, or CNS infections. Crucially, this distinction was not observed for CSF total protein or serum β2-M levels, highlighting the unique diagnostic value of CSF β2-M in differentiating CNSL from these key intracranial pathologies. Similar to the phenomenon observed in viral meningitis/encephalitis research—where CSF β2-M levels are significantly elevated without correlation to serum levels—we also identified a marked dissociation between CSF and serum β2-MG concentrations in patients with CNSL. [19]. This discrepancy further supports the hypothesis of localized intrathecal synthesis of β2-M within the CNS. Notably, no correlation was found between CSF and serum β2-M in CNSL, which stands in striking contrast to the moderate positive correlation observed in NCNSL. More importantly, despite significantly elevated serum β2-M levels in SCNSL, their CSF β2-M concentrations remained comparable to those in PCNSL. These findings collectively suggest that the increase in CSF β2-M in CNSL likely originates from local production by malignant lymphoid cells or the tumor microenvironment within the CNS compartment, rather than passive diffusion from the systemic circulation, underscoring its value as a marker of localized immunological and neoplastic activity. Compared to emerging biomarkers, CSF β2-M offers unmatched clinical utility. Although IL-10/IL-6 ratios >1 demonstrate diagnostic value in differentiating CNSL from infectious conditions [20,21], IL-10 quantification suffers from substantial methodological variability: reported thresholds range from 3 to 21.77 pg/mL of CNSL across ELISA, electrochemiluminescence immunoassay (ECLIA), and cytometric bead array (CBA) platforms [12,20-22]. These techniques require specialized instrumentation, prolonged turnaround times, and high costs. In contrast, β2-M detection via latex immunoturbidimetric assays is cost-effective, reproducible, and technically straightforward [23]. Similarly, while concurrent detection of MYD88 L265P and elevated IL-10 yields 94% sensitivity and 98% specificity (AUC=0.96) [24], PCR-based assays remain inaccessible in resource-limited settings. Furthermore, our data confirm β2-M's superior sensitivity to IL-10 (89.7% vs. 54.3%). When CSF β2-M and IL-10 were combined, diagnostic accuracy improved further (AUC=0.952), supporting the potential utility of this biomarker panel. Thus, β2-M represents the most pragmatic frontline test. The "high-low-high" dynamic model revealed significant monitoring potential. At relapse, CSF β2-M levels increased significantly by 1.5-fold; at subsequent post-relapse treatment, CSF β2-M levels showed a trending reduction. Furthermore, the reduction of CSF β2-M levels in complete responder group reached statistical significance, supporting CSF β2-M's prognostic utility in CNSL. Though this trend aligns with historical reports of β2-M's prognostic value [17-18,25-26], validation is needed in prospective trials with standardized protocols prior to clinical adoption. Our study has limitations. The retrospective single-center design may introduce selection bias. Subtype analyses (e.g., T-cell, NK/T-cell, B-cell lymphoma) were precluded by small sample sizes. Prognostic assessment was confounded by treatment variability, and serial sampling was insufficient for reliable monitoring of dynamic changes. Future studies should explore integrated biomarker algorithms combining CSF β2-M with chemokines and ctDNA to enhance diagnostic precision [27-29]. 5. Conclusion CSF β2-M remains a crucial biomarker for CNS lymphomas, supported by decades of global research and methodological consistency. Its cost-effectiveness, rapid detection, and diagnostic utility position it as an indispensable tool. Future prospective multicenter studies and combinations of multiple biomarkers are needed to validate these findings and optimize early intervention strategies for patients with CNS lymphoma. Declarations The authors’ declarations regarding competing interests, funding, ethics approval, informed consent, data availability, and author contributions are provided on the title page. Acknowledgements: We appreciate all patients and clinical staff who contributed to this study in the Fifth Medical Center of PLA General Hospital. Competing Interests : All authors declare no conflicts of interest. Funding: This work was supported by National Natural Science Foundation of China (NSFC), Grant No. 82170230. Ethics Approval: Ethical approval for this retrospective study was waived by the Ethics Committee of the Fifth Medical Center of PLA General Hospital because the analysis used exclusively anonymized data obtained from routine clinical care. Informed Consent: Informed consent was obtained from all individual participants included in the study. Data Availability: The raw data supporting the conclusions of this article will be made available by the authors upon reasonable request. Author Contributions: Y.F. and Y.H. contributed equally to this work. Both participated in the research design, data collection, data analysis, and writing of the manuscript. W.Z., Z.S. and J.H. participated in the sample detection and data collection. S.Y. conceived, designed and supervised all aspects of the study, guided manuscript preparation and revision. All authors reviewed the manuscript and approved the final version for submission. References Morell AA, Shah AH, Cavallo C, et al. Diagnosis of primary central nervous system lymphoma: a systematic review of the utility of CSF screening and the role of early brain biopsy. Neurooncol Pract 2019;6:415-423. https://doi.org/10.1093/nop/npz015 Khatab S, Spliet W, Woerdeman PA. Frameless image-guided stereotactic brain biopsies: emphasis on diagnostic yield. Acta Neurochir (Wien) 2014;156:1441-1450. https://doi.org/10.1007/s00701-014-2145-2 Ferreri AJM. How I treat primary CNS lymphoma. Blood 2011;118:510-522. https://doi.org/10.1182/blood-2011-03-321349 Maeyama M, Sasayama T, Tanaka K, et al. Multi-marker algorithms based on CXCL13, IL-10, sIL-2 receptor, and β2-microglobulin in cerebrospinal fluid to diagnose CNS lymphoma. Cancer Med 2020;9:4114-4125. https://doi.org/10.1002/cam4.3048 Rimelen V, Ahle G, Pencreach E, et al. Tumor cell-free DNA detection in CSF for prima-ry CNS lymphoma diagnosis. Acta Neuropathol Commun 2019;7:1-3. https://doi.org/10.1186/s40478-019-0692-8 Grommes C, DeAngelis LM. Primary CNS lymphoma. J Clin Oncol 2017;35:2410-2418. https://doi.org/10.1200/JCO.2017.72.7602 Bjorkman PJ, Saper MA, Samraoui B, et al. Structure of the human class I histocompatibility antigen, HLA-A2. Nature 1987;329:506-512. https://doi.org/10.1038/329506a0 Haarmann A, Hähnel L, Schuhmann MK, et al. Age-adjusted CSF β2-microglobulin and lactate are increased and ACE is decreased in patients with multiple sclerosis, but only lactate correlates with clinical disease duration and severity. J Neuroimmunol 2018;323:19-27. https://doi.org/10.1016/j.jneuroim.2018.07.001 Lenzlinger PM, Hans VH, Jöller-Jemelka HI, et al. Markers for cell-mediated immune response are elevated in cerebrospinal fluid and serum after severe traumatic brain injury in humans. J Neurotrauma 2001;18:479-489. https://doi.org/10.1089/089771501300227288 Svatoňová J, Bořecká K, Adam P, et al. Beta2-microglobulin as a diagnostic marker in c-erebrospinal fluid: a follow-up study. Dis Markers 2014;2014:495402. https://doi.org/10.1155/2014/495402 Mavligit GM, Stuckey SE, Cabanillas FF, et al. Diagnosis of leukemia or lymphoma in the central nervous system by beta2-microglobulin determination. N Engl J Med 1980;303:718-722. https://doi.org/10.1056/NEJM198009253031302 Sasagawa Y, Akai T, Tachibana O, et al. Diagnostic value of interleukin-10 in cerebrospinal fluid for diffuse large B-cell lymphoma of the central nervous system. J Neurooncol 2015;121:177-183. https://doi.org/10.1007/s11060-014-1622-z Sasayama T, Nakamizo S, Nishihara M, et al. Cerebrospinal fluid interleukin-10 is a potentially useful biomarker in immunocompetent primary central nervous system lymphoma (PCNSL). Neuro Oncol 2012;14:368-380. https://doi.org/10.1093/neuonc/nor203 Starmans JJ, Vos J, Van der Helm HJ. The beta 2-microglobulin content of the cerebrosp-inal fluid in neurological disease. J Neurol Sci 1977;33:45-49. https://doi.org/10.1016/0022-510x(77)90180-0 Kersten MJ, Evers LM, Dellemijn PL, et al. Elevation of cerebrospinal fluid soluble CD27 levels in patients with meningeal localization of lymphoid malignancies. Blood 1996;87:1985-1989. https://doi.org/10.1182/blood.V87.5.1985.1985 Ernerudh J, Olsson T, Berlin G, et al. Cerebrospinal fluid immunoglobulins and beta 2-microglobulin in lymphoproliferative and other neoplastic diseases of the central nervous system. Arch Neurol 1987;44:915-920. https://doi.org/10.1001/archneur.1987.00520210017012 Bertucci A, Boucard C, Harlay V, et al. Prognostic value of Beta 2-Microglobulinin in cerebrospinal fluid in primary central nervous system lymphoma. J Neurol Sci 2024;457. https://doi.org/10.1016/j.jns.2023.122847 Hansen PB, Kjeldsen L, Dalhoff K, et al. Cerebrospinal fluid beta-2-microglobulin in adult patients with acute leukemia or lymphoma: a useful marker in early diagnosis and moni-toring of CNS-involvement. Acta Neurol Scand 1992;85:224-227. https://doi.org/10.1111/j.1600-0404.1992.tb04033.x Zhang MZ, Shi QG, Xu XY, et al. Elevated levels of β2-microglobulin in cerebrospinal fluid in adult patients with viral encephalitis/meningitis. Clin Biochem 2024;125:110719. https://doi.org/10.1016/j.clinbiochem.2024.110719 Nguyen-Them L, Costopoulos M, Tanguy ML, et al. The CSF IL-10 concentration is an effective diagnostic marker in immunocompetent primary CNS lymphoma and a potential prognostic biomarker in treatment-responsive patients. Eur J Cancer 2016;61:69-76. https://doi.org/10.1016/j.ejca.2016.03.080 Song Y, Zhang W, Zhang L, et al. Cerebrospinal fluid IL-10 and IL-10/IL-6 as accurate diagnostic biomarkers for primary central nervous system large B-cell lymphoma. Sci Rep 2016;6:38671. https://doi.org/10.1038/srep38671 Mabray MC, Barajas RF, Villanueva-Meyer JE, et al. The combined performance of ADC, CSF CXC chemokine ligand 13, and CSF interleukin 10 in the diagnosis of central nervous system lymphoma. AJNR Am J Neuroradiol 2016;37:74-79. https://doi.org/10.3174/ajnr.A4450 Ning K, Chai H, Cui Y, et al. Fast detection of β2 microglobulin in patient blood by a handhold centrifugal microfluidic device. Sens Actuators B Chem 2022;373:132737. https://doi.org/10. 1016/j.snb.2022.132737 Ferreri AJM, Calimeri T, Lopedote P, et al. MYD88 L265P mutation and interleukin-10 detection in cerebrospinal fluid are highly specific discriminating markers in patients with primary central nervous system lymphoma: results from a prospective study. Br J Haematol 2021;193:497-505. https://doi.org/10.1111/bjh.17357 Yao ML, Chen TM, Li P. Cerebrospinal Fluid β2-Microglobulin for Prognostic Evaluation of Patients with Central Nervous System Infiltration in Acute Lymphoblastic Leukemia. Z-hongguo Shi Yan Xue Ye Xue Za Zhi 2022;30:113-118. https://doi.org/10.19746/j.cnki.issn.1009-2137.2022.01.018 Oberg G, Hällgren R, Venge P. Beta 2-microglobulin, lysozyme and lactoferrin in cerebrospinal fluid in patients with lymphoma or leukaemia: relationship to CNS involvement and the effect of prophylactic intrathecal treatment with methotrexate. Br J Haematol 1987;66:315-322. https://doi.org/10.1111/j.1365-2141.1987.tb06916.x Dogliotti I, Jiménez C, Varettoni M, et al. Diagnostics in Waldenström’s macroglobulinemia: a consensus statement of the European Consortium for Waldenström’s Macroglobulinemia. Leukemia 2023;37:388-395. https://doi.org/10.1038/s41375-022-01762-3 Yamagishi Y, Sasaki N, Nakano Y, et al. Liquid biopsy of cerebrospinal fluid for MYD88 L265P mutation is useful for diagnosis of central nervous system lymphoma. Cancer Sci 2021;112:4702-4710. https://doi.org/10.1111/cas.15133 Gupta M, Burns EJ, Georgantas NZ, et al. A rapid genotyping panel for detection of primary central nervous system lymphoma. Blood 2021;138:382-386. https://doi.org/10.1182/blood.20 20010137 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 10 Nov, 2025 Read the published version in Annals of Hematology → Version 1 posted Editorial decision: Revision requested 01 Oct, 2025 Reviews received at journal 30 Sep, 2025 Reviewers agreed at journal 27 Sep, 2025 Reviewers agreed at journal 24 Sep, 2025 Reviewers invited by journal 24 Sep, 2025 Editor assigned by journal 23 Sep, 2025 Submission checks completed at journal 23 Sep, 2025 First submitted to journal 19 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7657007","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":523334300,"identity":"c189c465-c1b3-4ed9-80d4-4066d69198cc","order_by":0,"name":"Yijun Fan","email":"","orcid":"","institution":"the Fifth Medical Center of PLA General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yijun","middleName":"","lastName":"Fan","suffix":""},{"id":523334303,"identity":"3b3be7ef-3f25-42db-97bf-582e9554f9a9","order_by":1,"name":"Yuyang Huang","email":"","orcid":"","institution":"the Fifth Medical Center of PLA General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuyang","middleName":"","lastName":"Huang","suffix":""},{"id":523334307,"identity":"23bc5b9a-9eac-4783-9f2d-33b2f0466531","order_by":2,"name":"Wenwen Zheng","email":"","orcid":"","institution":"the Fifth Medical Center of PLA General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Wenwen","middleName":"","lastName":"Zheng","suffix":""},{"id":523334308,"identity":"0557aeeb-3ed6-4492-ac5f-da526931e648","order_by":3,"name":"Zhouzhou Su","email":"","orcid":"","institution":"Karolinska Institute","correspondingAuthor":false,"prefix":"","firstName":"Zhouzhou","middleName":"","lastName":"Su","suffix":""},{"id":523334309,"identity":"ae70e3f3-aa76-4d07-9ac5-82811e7858e0","order_by":4,"name":"Jun Hu","email":"","orcid":"","institution":"Southwest Hospital, Third Military Medical University (Army Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Hu","suffix":""},{"id":523334313,"identity":"33b8ccb0-4f7b-41fe-9383-ffea7e182ae6","order_by":5,"name":"Shunzong Yuan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYLACxgYo44OBjRxpWhhnFKQZk6aFmefD4USCqg1uJD97+HPH4Tz59t7Dr20MmBMY2A8f3YBfS5q5Me+Zw8WMPefSrHMM2PIYeNLSbuDXkmAmzdh2OLFZIsfMOMeAp5hBgseMgJb0b5I/gVraQFosDCQSGwhryTGT4AVq6ZHIMX7MYGBAWIvkmTdl0rxt6YkzeM6YMfYYJBizEfIL3/H0bUCHWSfOb+8x/vDjz385fvbDx/BqUTiAYLNJgEl8ykFAvgHBZv5ASPUoGAWjYBSMTAAAHxRLRRDw6RoAAAAASUVORK5CYII=","orcid":"","institution":"the Fifth Medical Center of PLA General Hospital","correspondingAuthor":true,"prefix":"","firstName":"Shunzong","middleName":"","lastName":"Yuan","suffix":""}],"badges":[],"createdAt":"2025-09-19 09:38:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7657007/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7657007/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00277-025-06719-x","type":"published","date":"2025-11-10T15:58:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":92861703,"identity":"ecad3783-36dc-45aa-94d2-46078e94a5b5","added_by":"auto","created_at":"2025-10-06 12:23:57","extension":"tif","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2616514,"visible":true,"origin":"","legend":"","description":"","filename":"Fig1.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/bf522b40113115e25c1fd004.tif"},{"id":92859827,"identity":"a04c9ef2-886c-4ff0-9183-c208d87104f8","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11325860,"visible":true,"origin":"","legend":"","description":"","filename":"SubmissionMaterialsManuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/d640c6c1e2a73fc6997e8d9f.docx"},{"id":92859820,"identity":"cc579a4d-da10-4ca5-9b31-747576fa81c7","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2934072,"visible":true,"origin":"","legend":"","description":"","filename":"Fig2.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/10b79de4e33e6d704385fa20.tif"},{"id":92859816,"identity":"017355f5-7332-45e2-b8c7-faf63b4ad85c","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1416092,"visible":true,"origin":"","legend":"","description":"","filename":"Fig3.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/d35708e9b8f18433f3176b3d.tif"},{"id":92860870,"identity":"fb8055f7-0fce-4d18-bd69-361024e4efd7","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"tif","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1376916,"visible":true,"origin":"","legend":"","description":"","filename":"Fig4.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/06583bdce27dec9b21a7bbee.tif"},{"id":92859824,"identity":"ff8514b9-1f18-462c-94c2-619c2174609b","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2924492,"visible":true,"origin":"","legend":"","description":"","filename":"Fig5.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/923b0c352d76181cea0b6f20.tif"},{"id":92859815,"identity":"6cd0ac13-cd4e-473d-ac2e-d622e34297da","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"json","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7034,"visible":true,"origin":"","legend":"","description":"","filename":"fc7fefa92cbd494baa673613895d275f.json","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/3c32994c670defcbdf4d32c1.json"},{"id":92859819,"identity":"6b67bc0f-2b0f-4551-9b44-614af7885a68","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"xml","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":92188,"visible":true,"origin":"","legend":"","description":"","filename":"fc7fefa92cbd494baa673613895d275f1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/271b45de02b87d4d29779bde.xml"},{"id":92859813,"identity":"b59d466e-877b-4047-a082-8a1013a0357e","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2616514,"visible":true,"origin":"","legend":"","description":"","filename":"Fig1.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/dfb11e88a24ee26d5567aa12.tif"},{"id":92861709,"identity":"6f403610-2526-4fff-a6c7-bce2ce81ba51","added_by":"auto","created_at":"2025-10-06 12:23:57","extension":"tif","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2934072,"visible":true,"origin":"","legend":"","description":"","filename":"Fig2.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/93b6fe6eeda02e9d9e92856e.tif"},{"id":92859833,"identity":"173c68a5-01de-4811-bbba-5ee3622b2b83","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1416092,"visible":true,"origin":"","legend":"","description":"","filename":"Fig3.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/6bce77fbe9e83a6e7a3d4588.tif"},{"id":92859823,"identity":"53121ab6-d3f8-47e4-bab5-9b67145ac0f4","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"tif","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1376916,"visible":true,"origin":"","legend":"","description":"","filename":"Fig4.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/1b739bdb117bd5e89c6b7fc1.tif"},{"id":92861704,"identity":"d71c51b4-1867-4d89-9edc-05e1c7c4c69b","added_by":"auto","created_at":"2025-10-06 12:23:57","extension":"tif","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2924492,"visible":true,"origin":"","legend":"","description":"","filename":"Fig5.tiff.tif","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/6e7a20b46880809299323c0e.tif"},{"id":92859830,"identity":"c67a77f5-7488-4929-95f1-42e189b39ec0","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"jpeg","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2616514,"visible":true,"origin":"","legend":"","description":"","filename":"Fig1.tiff.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/d9b16d8afb0237c0084618be.jpeg"},{"id":92859834,"identity":"87e6a769-45a9-479c-b4f3-46f071577a9d","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"jpeg","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2934072,"visible":true,"origin":"","legend":"","description":"","filename":"Fig2.tiff.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/6a64563a26af5639adfe4117.jpeg"},{"id":92861711,"identity":"0bb83129-f648-4fb3-98bb-fb3b35512895","added_by":"auto","created_at":"2025-10-06 12:23:57","extension":"jpeg","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1416092,"visible":true,"origin":"","legend":"","description":"","filename":"Fig3.tiff.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/04f823d320b660d966cd5d32.jpeg"},{"id":92860875,"identity":"074d6b09-3b27-42b5-99f4-db9496045d3d","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"jpeg","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1376916,"visible":true,"origin":"","legend":"","description":"","filename":"Fig4.tiff.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/c2bfc8d1a67888b697874f0f.jpeg"},{"id":92860873,"identity":"070e4d7d-f6b5-4ca3-beb2-284fc4ad6315","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"jpeg","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2924492,"visible":true,"origin":"","legend":"","description":"","filename":"Fig5.tiff.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/b2f619040838aac5d0fff958.jpeg"},{"id":92859840,"identity":"8357f7e5-cd03-4609-b336-c39c606e41ad","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":472180,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig1.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/816629f6049132de24c13446.png"},{"id":92862059,"identity":"fd0edae8-f392-4b77-bfce-9ffb1d2fa7e8","added_by":"auto","created_at":"2025-10-06 12:31:57","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":446899,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig2.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/10451727e8aaa4aeb2672676.png"},{"id":92860879,"identity":"c8720ecd-eddd-4281-8a45-3c840217d1c2","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":231097,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig3.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/a4c014d73c80ef51a091e25a.png"},{"id":92859835,"identity":"9dbaa279-1115-47b1-96fd-525a78349658","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":223637,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig4.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/646da4700c4387e4b96b7792.png"},{"id":92859832,"identity":"719b7e9e-b4c1-49e9-b427-744b6ee673a0","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":390627,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig5.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/0c69612154e46433c0c7d405.png"},{"id":92860878,"identity":"c11180ed-1bbc-4bf6-b697-82e766980d3d","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":472180,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/535ae32159e84bae3ebf7524.png"},{"id":92862060,"identity":"d793aee1-ce8c-4e14-a526-20ca570231a5","added_by":"auto","created_at":"2025-10-06 12:31:57","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":446899,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/e91f784d46fac3739b8cc09a.png"},{"id":92859842,"identity":"ecd6fbd0-8c88-40da-82d3-7f651990398a","added_by":"auto","created_at":"2025-10-06 12:07:58","extension":"png","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":231097,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/998ff4e6015bc420d8f1ba4b.png"},{"id":92859825,"identity":"28f7c6ed-751f-4b2e-bbc3-0417980e037d","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"png","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":223637,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/51eb167fc62336b91234b6c7.png"},{"id":92859831,"identity":"a71bd6ab-50ad-4d83-a780-c21e4b834512","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"png","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":390627,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/29d279860971a5f0af500284.png"},{"id":92860881,"identity":"2ee5623b-816b-47e0-a7b2-a4f0507e1233","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"xml","order_by":28,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":93311,"visible":true,"origin":"","legend":"","description":"","filename":"fc7fefa92cbd494baa673613895d275f1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/660f68a1fdafe510a380e241.xml"},{"id":92859837,"identity":"7480a399-1674-4d17-a814-cd577d085b28","added_by":"auto","created_at":"2025-10-06 12:07:57","extension":"html","order_by":29,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":102850,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/f2cb795821e89c80af075883.html"},{"id":92859807,"identity":"fab80abd-b2e7-43eb-b876-10fa1ac9f4b7","added_by":"auto","created_at":"2025-10-06 12:07:56","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44104,"visible":true,"origin":"","legend":"\u003cp\u003ePatient enrollment and stratification. CNSL, central nervous system lymphoma; NCNSL, non-CNS lymphoma.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/1dbd50f5fe317eece9c6663e.png"},{"id":92860864,"identity":"76c4e1db-a2d2-4e4b-a1c2-f7983b5f9c64","added_by":"auto","created_at":"2025-10-06 12:15:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":79155,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of β2-microglobulin (β2-M) levels across different patient groups in cerebrospinal fluid (CSF) and serum, respectively. Comparison of CSF β2-M levels between patients with CNSL and NCNSL (a), CNS leukemia and non-CNS leukemia (b), CNS solid tumors and non-CNS solid tumors (c); Comparison of serum β2-M levels between patients with CNSL and NCNSL (d), CNS leukemia and non-CNS leukemia (e), CNS solid tumors and non-CNS solid tumors (f)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/d273d1ec0220cb56c718c3b7.png"},{"id":92860866,"identity":"3420601e-7544-4e3d-80e2-3d7fa125f9e9","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":46646,"visible":true,"origin":"","legend":"\u003cp\u003eDiagnostic performance of CSF biomarkers for distinguishing CNSL from NCNSL. (a) ROC curve analysis of CSF β2-M in discriminating CNSL from NCNSL, CNS leukemia from non-CNS leukemia, and CNS solid tumor from non-CNS solid tumor. (b) CSF interleukin-10 (IL-10) levels in patients with CNSL compared to NCNSL. (c) ROC analysis comparing the diagnostic accuracy of CSF β2-M, CSF IL-10, and β2-M + IL-10 for distinguishing CNSL from NCNSL\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/75e8b415c1806c673bb9ae05.png"},{"id":92859808,"identity":"2eb279ae-015e-4d8c-8304-8ee836846d7c","added_by":"auto","created_at":"2025-10-06 12:07:56","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":40068,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of CSF and serum β2-M correlation and comparison in patients with CNSL or NCNSL. (a) Analysis of CSF and serum β2-M correlation in patients with CNSLand NCNSL. (b) Comparison of CSF and serum β2-M levels in patients withprimary (PCNSL) and secondary CNSL (SCNSL)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/0898cb09af6cb707ec2f0803.png"},{"id":92860868,"identity":"104bb579-c065-47ac-86da-961ef5c46e6f","added_by":"auto","created_at":"2025-10-06 12:15:57","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":112509,"visible":true,"origin":"","legend":"\u003cp\u003eCSF β2-M level changes after treatment. CSF β2-M level changes in patients with CNSL treated with first-line therapy are shown before treatment and after treatmentin complete response (CR) (a) and progression disease (PD) (b).Dynamic CSF β2-M level changes in patients with CNSL treated with first-line and rescue therapies are shown before treatment and in response, relapse, and re-response after treatment (c)\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/b12e43657ce70bf852a44bda.png"},{"id":96105215,"identity":"d5f2f6e5-8252-4187-8b44-394d4fa3627a","added_by":"auto","created_at":"2025-11-17 16:10:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":833213,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7657007/v1/a156c265-51bc-4cd9-a614-4da2fcea8f3a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cerebrospinal Fluid β2-Microglobulin as a Diagnostic Biomarker in Central Nervous System Lymphoma: a Single-Center Retrospective Analysis","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eCentral nervous system lymphoma (CNSL) is a rare but aggressive subtype of extranodal non-Hodgkin lymphoma, accounting for nearly 3% to 4% of all CNS tumors [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. CNSL can be divided into primary and secondary CNSL (PCNSL and SCNSL) based on tumor cells involving the brain, eyes, meninges, or spinal cord without or with evidence of systemic disease. For SCNSL, the diagnosis can be easily achieved by combining non-brain biopsy pathology and radiographic imaging patterns. However, for PCNSL, in most time, the only way to obtain a definitive diagnosis is histopathological confirmation after invasive brain biopsy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Particularly, deep-seated lesions often preclude safe sampling, and their invasiveness carries substantial risks, including intracranial hemorrhage, cerebral edema, and seizures [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although a positive finding in other samples, such as cerebrospinal fluid (CSF) and vitreous biopsy, to some extent can avoid the need for a surgical operation, a safer and less invasive diagnostic method for CNSL has not been established yet. CSF assessment and intrathecal chemotherapy are routine operations for CNSL in some practice centers [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Several outstanding studies have demonstrated that interleukin-10 (IL-10), the C-X-C motif chemokine ligand 13 (CXCL13), and circulating tumor DNA (ctDNA) in CSF are reliable markers for adjuvant diagnosis of CNSL, but lack universal applicability due to methodological complexity or inconsistent diagnostic thresholds [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Consequently, a widely suitable biomarker in the CSF for the diagnosis of patients with CNSL is still an unmet need [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eβ2-microglobulin (β2-M), an 11.8-kDa subunit of major histocompatibility complex class I (MHC-I) molecules, is detectable in multiple body fluids including CSF, serum, and urine [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Elevated CSF β2-M levels are consistently observed in diverse CNS pathologies, including neoplastic, inflammatory, and neuroimmune disorders, with particularly marked elevations in CNSL [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Mavligit et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] first identified elevated CSF β2-M with a mean level of 4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mg/L in CNSL patients. Recent studies proposed CSF β2-M cut-offs at 2.4 mg/L (CNSL vs. tumors) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and 2.056 mg/L (PCNSL vs. other CNS malignancies/inflammation) [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] for differential diagnosis. However, these previous findings are limited by small cohort sizes and a lack of validation across heterogeneous CNS diseases. And due to longitudinal variations, there is a lack of standardized detection methods for β2-M. To address these gaps, herein we conducted a large-scale retrospective study to assess the diagnostic value of CSF β2-M in CNSL.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Study population\u003c/h2\u003e\u003cp\u003eBetween January 2018 and August 2024, CSF and serum β2-M reports were retrieved from 1,349 individuals with confirmed or suspected CNS diseases presenting at the Fifth Medical Center of the People's Liberation Army General Hospital. Because all data used for analysis were collected from routine medical procedures without affecting clinical care, institutional review board approval was waived. The study complied with the World Medical Association Declaration of Helsinki concerning the ethical conduct of research involving human subjects. Informed consent was obtained from all participants before inclusion.\u003c/p\u003e\u003cp\u003ePatients were stratified into four major cohorts based on disease diagnosis: lymphoma, leukemia, solid tumor, and other diseases (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Within the lymphoma cohort, patients were further classified based on CNS involvement into CNSL and non-CNS lymphoma (NCNSL), with CNSL including diffuse large B-cell lymphoma (DLBCL, n\u0026thinsp;=\u0026thinsp;41), NK/T-cell lymphomas (n\u0026thinsp;=\u0026thinsp;2), peripheral T-cell lymphomas (n\u0026thinsp;=\u0026thinsp;3), Burkitt lymphomas (n\u0026thinsp;=\u0026thinsp;2), and unclassified B-cell lymphoma (n\u0026thinsp;=\u0026thinsp;1). Similarly, in the leukemia cohort, patients were divided into CNS leukemia and non-CNS leukemia. The solid tumor cohort contained CNS solid tumors and non-CNS solid tumors, CNS solid tumors comprised gliomas (n\u0026thinsp;=\u0026thinsp;2), meningioma (n\u0026thinsp;=\u0026thinsp;2), and lung (n\u0026thinsp;=\u0026thinsp;32), spine (n\u0026thinsp;=\u0026thinsp;1), cervix (n\u0026thinsp;=\u0026thinsp;1), breast (n\u0026thinsp;=\u0026thinsp;16), or gastric (n\u0026thinsp;=\u0026thinsp;4) cancer metastases. Other disease cohort included CNS infectious diseases, CNS miscellaneous diseases, and non-CNS-involved diseases.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Sample measurement\u003c/h2\u003e\u003cp\u003eβ2-M concentrations in CSF and serum samples were measured through immunoturbidimetric assay performed on automatic biochemistry analyzers HITACHI Labospect 008AS or HITACHI 7600\u0026thinsp;\u0026minus;\u0026thinsp;110 (Tokyo, Japan). Measurements were conducted on the same day or within three days after sample collection. Total protein and glucose levels in CSF were also assessed in the combination package on the same analyzers when β2-M was measured. IL-10 concentrations in CSF were determined with a commercial IL-10 reagent kit (Siemens Healthcare Diagnostics Products Ltd., Gwynedd, UK) via an automated chemiluminescence immunoassay on the Immulite 1000 Analyzer (Siemens Healthcare Diagnostics Inc., NJ, USA). The limits of detection were 0.2 mg/L for β2-M and 5 pg/mL for IL-10, respectively.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Statistical analysis\u003c/h2\u003e\u003cp\u003eAll statistical analyses were conducted using GraphPad Prism software (version 10.0). Continuous variables are presented as median (range). Comparisons between two groups were performed using the Mann\u0026ndash;Whitney U test or chi-square test, while the Kruskal\u0026ndash;Wallis test was used for comparisons across multiple groups. The relationship between CSF β2-M and serum β2-M levels was assessed by Spearman\u0026rsquo;s rank correlation. For post hoc pairwise comparisons, the Bonferroni correction was applied using the Dunn test function from the FSA package. Diagnostic performance was assessed by calculating the area under the receiver operating characteristic (ROC) curve. A two-sided p-value of less than 0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003e3.1 Utility of CSF \u0026beta;2-M as a CNSL Biomarker\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFirstly, we compared CSF \u0026beta;2-M levels of patients with CNSL to patients with other CNS involved conditions (Table 1). In the CNSL group, the median CSF \u0026beta;2-M concentration was 3.0 (range, 1.2-13.5) mg/L, significantly higher than other groups (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001 for CNS leukemia, CNS solid tumor, and CNS miscellaneous diseases; \u003cem\u003ep\u003c/em\u003e = 0.095 for CNS infectious diseases ). In contrast, a comparison of CSF total protein (TP) levels between CNSL, CNS leukemia, CNS solid tumor, and CNS infectious disease patients revealed no significance (\u003cem\u003ep\u003c/em\u003e = 0.312). Critically, serum \u0026beta;2-M concentrations of CNSL demonstrated considerable overlap across other groups, confirming its inability to discriminate CNSL from other CNS-involved tumors. We also found that CSF \u0026beta;2-M levels were significantly higher in patients with CNS involvement by hematopoietic malignancies compared with CNS non-involvement (median: CNSL vs. NCNSL: 3.0 mg/L vs. 1.2 mg/L; CNS leukemia vs. non-CNS leukemia: 1.6 mg/L vs. 1.1 mg/L; both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) (Figs. 2a, b). However, the difference between patients with CNS involvement by solid tumor and CNS non-involvement was not significant. (median: CNS solid tumor vs. non-CNS solid tumor: 1.8 mg/L vs. 1.6 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.286) (Fig. 2c). Furthermore, Serum \u0026beta;2-M levels were significantly lower in patients with CNS involvement by both lymphoma (median: CNSL vs. NCNSL: 1.5 mg/L vs. 2.2 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) and solid tumor cohorts (median: CNS solid tumor vs. non-CNS solid tumor: 1.3 mg/L vs. 2.2 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001). And no significant difference was observed in serum \u0026beta;2-M levels between CNS leukemia and Non-CNS leukemia (median: CNS leukemia vs. non-CNS leukemia: 1.8 mg/L vs. 1.8 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.776) (Figs. 2d-f).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Baseline characteristics and laborator y markers in each groups.Data are presented as median (range)\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"105%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003eSex, male/female, No.(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003eAge, y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003eCSF TP, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003eCSF \u0026beta;2M, mg/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003eSerum \u0026beta;2-M, mg/L\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eCNSL (n = 49)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e32/17 (65/35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e58 (29, 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.70 (0.27, 5.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e3.0 (1.2, 13.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.5 (0.7, 4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003ePCNSL (n = 31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e20/11 (65/35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e56 (33, 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.57 (0.27, 2.98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e2.7 (1.3, 13.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.2(0.7, 2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eSCNSL (n = 18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e12/9 (57/43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e61 (29, 74)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.84 (0.4, 5.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e3.2 (1.2, 11.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.8 (1.3, 4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eNCNSL (n = 428)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e268/160 (63/37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e51 (12, 90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.36 (0.11, 5.20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.2 (0.4, 5.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.2 (0.7, 12.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eCNS leukemia (n = 43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e27/16 (63/37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e39 (16, 71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.61 (0.18, 5.59)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.6 (0.5, 6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.8 (0.8, 4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eNon-CNS leukemia\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(n = 541)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e309/232 (57/43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e40 (11, 78)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.35 (0.14, 16.60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.1 (0.5, 3.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.8 (0.6, 10.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eCNS solid tumor\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(n = 58)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e19/39 (33/67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e52 (31, 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.56 (0.23, 3.75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.8 (0.7, 7.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.3 (0.6, 3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eNon-CNS Solid Tumor\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(n = 13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e5/8 (38/62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e49 (36, 74)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.43 (0.13, 3.51)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.6 (0.8, 3.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.2 (1.2, 7.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eCNS infectious diseases\u003c/p\u003e\n \u003cp\u003e(n = 50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e34/16 (68/32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e11 (0, 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.60 (0.15, 5.50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e2.3 (0.3, 21.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.4 (0.7, 8.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eCNS miscellaneous diseases\u003c/p\u003e\n \u003cp\u003e(n = 90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e52/38 (58/42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e51 (0, 98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.44 (0.10, 2.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.7 (0.3, 7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.9 (0.6, 24.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 27px;\"\u003e\n \u003cp\u003eNon-CNS-Involved Diseases\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(n = 77)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9px;\"\u003e\n \u003cp\u003e51/26 (34/66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e0 (0, 68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.63 (0.13, 3.13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.7 (0.5, 5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.6 (1.1, 5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp skip=\"true\"\u003eAbbreviations: CNSL, central nervous system lymphoma; PCNSL, primary CNSL; SCNSL, secondary CNSL; NCNSL, non-CNS lymphoma; \u0026beta;2-M, \u0026beta;2-microglobulin.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Diagnostic Performance of CSF \u0026beta;2-M in patients with CNSL\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe then performed ROC analysis and found that a CSF \u0026beta;2-M threshold of 1.85 mg/L could distinguish CNSL from NCNSL with an area under the curve (AUC) of 0.939 (\u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001), sensitivity of 89.7%, and specificity of 85.7%. In contrast, CSF \u0026beta;2-M showed lower diagnostic accuracy for differentiating CNS leukemia from non-CNS leukemia (AUC: 0.685, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) and CNS solid tumor from non-CNS solid tumor (AUC: 0.596, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.281), underscoring its specificity for CNSL (Fig. 3a). Due to limited routine clinical use, CSF IL-10 levels were available for only 217 patients. CSF IL-10 concentrations were significantly elevated in CNSL compared to NCNSL (median: CNSL vs. NCNSL: 9.62 pg/mL (range, 5-1000) vs. 5 pg/mL (range, 5-49.2), \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) (Fig. 3b). ROC analysis yielded an AUC of 0.765 for CSF IL-10, with a sensitivity of 54.3% and specificity of 98.4% at an optimal cutoff of 5.745 pg/mL. When combined, CSF \u0026beta;2-M and IL-10 improved diagnostic accuracy further, achieving an AUC of 0.952, sensitivity of 91.4%, and specificity of 88.5%. This combined biomarker panel outperformed IL-10 alone in detecting CNSL (\u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) (Fig. 3c).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.\u003c/strong\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Correlation Between CSF and Serum \u0026beta;2-M\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhile seminal work by Starmans et al. reported dissociation between serum and CSF \u0026beta;2-M levels in neuroinfectious diseases [14], this relationship in CNS malignancies\u0026mdash;particularly CNSL\u0026mdash;remains largely unexplored. We found that in patients with CNS non-involvement, \u0026beta;2-M levels were significantly higher in serum than in CSF (NCNSL, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001;non-CNS leukemia, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001; non-CNS solid tumor, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.021; non-CNS-involved disease, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) (Table 1). In contrast, in patients with CNS involvement by malignancies, \u0026beta;2-M levels were significantly higher in CSF than in serum (CNSL, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001; CNS solid tumor, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.049; CNS Leukemia, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.557) (Table 1). Particularly, the difference of \u0026beta;2-M levels between CSF and serum in patients with CNSL was the most significant. \u0026beta;2-M level in CSF was nearly doubled as that in serum. A weak negative correlation between CSF and serum \u0026beta;2-M levels was observed in CNSL patients (r =\u0026ndash;0.036, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.807), whereas NCNSL patients exhibited a moderate positive correlation (r = 0.410, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001) (Fig. 4a). PCNSL showed lower serum \u0026beta;2-M levels than SCNSL (median: PCNSL vs. SCNSL: 1.2 mg/L vs. 1.8 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001), while CSF \u0026beta;2-M levels showed no difference between PCNSL and SCNSL groups (median: PCNSL vs. SCNSL:2.7 mg/L vs. 3.2 mg/L, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.237) (Fig. 4b). These findings suggested local CNS production of \u0026beta;2-M independent of systemic disease.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.\u003c/strong\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;CSF \u0026beta;2-M Dynamics Indicate Treatment Efficacy in CNSL\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll 35 patients diagnosed with CNSL were treated with intrathecal methotrexate chemotherapy after hospital admission. CSF \u0026beta;2-M concentrations were assessed at multiple timepoints during the treatment course (Figs. 5a-c). In complete responders (CR, n = 19), CSF \u0026beta;2-M levels showed a significant downward trend, with a reduction of nearly half from baseline after treatment (median: 2.9 mg/L vs. 1.4 mg/L, pre-treatment vs. CR, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.009). Conversely, progressive disease (PD, n = 6) was associated with persistently elevated levels (median: 2.2 mg/L vs. 2.35 mg/L, pre-treatment vs. PD, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.701). Among 10 relapsed patients\u0026mdash;3 with partial response (PR) and 7 with CR prior to relapse\u0026mdash;CSF \u0026beta;2-M levels significantly increased from remission levels to relapse state (median: 1.3 \u0026rarr; 3.3 mg/L, response vs. relapse, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.006), and decreased to 1.9 mg/L after retreatment (relapse vs. post-treatment, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e= 0.055).\u003c/p\u003e"},{"header":"4.\tDiscussion","content":"\u003cp\u003eIn this study, we found that the \u0026beta;2-M level of CSF was significantly higher than that of serum in patients with CNSL. On the contrary, \u0026beta;2-M level of CSF was significantly lower than that of serum in patients without evident CNS diseases or in patients with NCNSL. Meanwhile, in CSF, \u0026beta;2-M levels demonstrated a dynamic high-low-high model as patients with CNSL experienced the pattern of emergence-regression-relapse. Therefore. for the first time, these data indicated that local lymphoma cell-originated \u0026beta;2-M in the brain might be a main source for its elevation in the CSF of patients with CNSL. CSF \u0026beta;2-M should be a suitable marker for diagnostic and prognostic evaluation of patients with CNSL.\u003c/p\u003e\n\u003cp\u003eThis work substantiates decades of research establishing CSF \u0026beta;2-M as a CNSL biomarker. Our large cohort confirms its diagnostic robustness across modern methodologies. Crucially, we demonstrate that 1.85 mg/L is the optimal diagnostic threshold, outperforming historical cutoffs like Kersten\u0026apos;s 1.6 mg/L (AUC = 0.77, sensitivity = 81%, specificity = 68%) and Ernerudh\u0026apos;s 1.9 mg/L (sensitivity = 71%, specificity = 67%; AUC not reported) [15,16]. This precision stems from our rigorous exclusion of confounders and large sample size. \u0026beta;2-M can be measured by various immunochemical assays, including immunoturbidimetric assay, radioimmunoassay, and enzyme-linked immunoassay (ELISA). Importantly, despite assay variations, CSF \u0026beta;2-M in CNSL consistently ranges 2\u0026ndash;4 mg/L, underscoring the methodological robustness of \u0026beta;2-M as a CNSL biomarker across detection platforms [11,12,16-18]. Our findings demonstrated CSF \u0026beta;2-M Levels were significantly elevated in CNSL compared to cerebral leukemia, metastatic brain tumors, or CNS infections. Crucially, this distinction was not observed for CSF total protein or serum \u0026beta;2-M levels, highlighting the unique diagnostic value of CSF \u0026beta;2-M in differentiating CNSL from these key intracranial pathologies.\u003c/p\u003e\n\u003cp\u003eSimilar to the phenomenon observed in viral meningitis/encephalitis research\u0026mdash;where CSF \u0026beta;2-M levels are significantly elevated without correlation to serum levels\u0026mdash;we also identified a marked dissociation between CSF and serum \u0026beta;2-MG concentrations in patients with CNSL. [19]. This discrepancy further supports the hypothesis of localized intrathecal synthesis of \u0026beta;2-M within the CNS. Notably, no correlation was found between CSF and serum \u0026beta;2-M in CNSL, which stands in striking contrast to the moderate positive correlation observed in NCNSL. More importantly, despite significantly elevated serum \u0026beta;2-M levels in SCNSL, their CSF \u0026beta;2-M concentrations remained comparable to those in PCNSL. These findings collectively suggest that the increase in CSF \u0026beta;2-M in CNSL likely originates from local production by malignant lymphoid cells or the tumor microenvironment within the CNS compartment, rather than passive diffusion from the systemic circulation, underscoring its value as a marker of localized immunological and neoplastic activity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompared to emerging biomarkers, CSF \u0026beta;2-M offers unmatched clinical utility. Although IL-10/IL-6 ratios \u0026gt;1 demonstrate diagnostic value in differentiating CNSL from infectious conditions [20,21], IL-10 quantification suffers from substantial methodological variability: reported thresholds range from 3 to 21.77 pg/mL of CNSL across ELISA, electrochemiluminescence immunoassay (ECLIA), and cytometric bead array (CBA) platforms [12,20-22]. These techniques require specialized instrumentation, prolonged turnaround times, and high costs. In contrast, \u0026beta;2-M detection via latex immunoturbidimetric assays is cost-effective, reproducible, and technically straightforward [23]. Similarly, while concurrent detection of MYD88 L265P and elevated IL-10 yields 94% sensitivity and 98% specificity (AUC=0.96) [24], PCR-based assays remain inaccessible in resource-limited settings. Furthermore, our data confirm \u0026beta;2-M\u0026apos;s superior sensitivity to IL-10 (89.7% vs. 54.3%). When CSF \u0026beta;2-M and IL-10 were combined, diagnostic accuracy improved further (AUC=0.952), supporting the potential utility of this biomarker panel. Thus, \u0026beta;2-M represents the most pragmatic frontline test.\u003c/p\u003e\n\u003cp\u003eThe \u0026quot;high-low-high\u0026quot; dynamic model revealed significant monitoring potential. At relapse, CSF \u0026beta;2-M levels increased significantly by 1.5-fold; at subsequent post-relapse treatment, CSF \u0026beta;2-M levels showed a trending reduction. Furthermore, the reduction of CSF \u0026beta;2-M levels in complete responder group reached statistical significance, supporting CSF \u0026beta;2-M\u0026apos;s prognostic utility in CNSL. Though this trend aligns with historical reports of \u0026beta;2-M\u0026apos;s prognostic value [17-18,25-26], validation is needed in prospective trials with standardized protocols prior to clinical adoption.\u003c/p\u003e\n\u003cp\u003eOur study has limitations. The retrospective single-center design may introduce selection bias. Subtype analyses (e.g., T-cell, NK/T-cell, B-cell lymphoma) were precluded by small sample sizes. Prognostic assessment was confounded by treatment variability, and serial sampling was insufficient for reliable monitoring of dynamic changes. Future studies should explore integrated biomarker algorithms combining CSF \u0026beta;2-M with chemokines and ctDNA to enhance diagnostic precision [27-29].\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eCSF β2-M remains a crucial biomarker for CNS lymphomas, supported by decades of global research and methodological consistency. Its cost-effectiveness, rapid detection, and diagnostic utility position it as an indispensable tool. Future prospective multicenter studies and combinations of multiple biomarkers are needed to validate these findings and optimize early intervention strategies for patients with CNS lymphoma.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp skip=\"true\"\u003eThe authors\u0026rsquo; declarations regarding competing interests, funding, ethics approval, informed consent, data availability, and author contributions are provided on the title page.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003eWe appreciate all patients and clinical staff who contributed to this study in the Fifth Medical Center of PLA General Hospital.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003eAll authors declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This work was supported by National Natural Science Foundation of China (NSFC), Grant No. 82170230.\u003c/p\u003e\n\u003cp skip=\"true\"\u003e\u003cstrong\u003eEthics Approval:\u003c/strong\u003e Ethical approval for this retrospective study was waived by the Ethics Committee of the Fifth Medical Center of PLA General Hospital because the analysis used exclusively anonymized data obtained from routine clinical care.\u003c/p\u003e\n\u003cp skip=\"true\"\u003e\u003cstrong\u003eInformed Consent:\u003c/strong\u003eInformed consent was obtained from all individual participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u0026nbsp;\u003c/strong\u003eThe raw data supporting the conclusions of this article will be made available by the authors upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u0026nbsp;\u003c/strong\u003eY.F. and Y.H. contributed equally to this work. Both participated in the research design, data collection, data analysis, and writing of the manuscript. W.Z., Z.S. and J.H. participated in the sample detection and data collection. S.Y. conceived, designed and supervised all aspects of the study, guided manuscript preparation and revision. All authors reviewed the manuscript and approved the final version for submission.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMorell AA, Shah AH, Cavallo C, et al. Diagnosis of primary central nervous system lymphoma: a systematic review of the utility of CSF screening and the role of early brain biopsy. Neurooncol Pract 2019;6:415-423. https://doi.org/10.1093/nop/npz015\u003c/li\u003e\n\u003cli\u003eKhatab S, Spliet W, Woerdeman PA. Frameless image-guided stereotactic brain biopsies: emphasis on diagnostic yield. Acta Neurochir (Wien) 2014;156:1441-1450. https://doi.org/10.1007/s00701-014-2145-2\u003c/li\u003e\n\u003cli\u003eFerreri AJM. How I treat primary CNS lymphoma. Blood 2011;118:510-522. https://doi.org/10.1182/blood-2011-03-321349\u003c/li\u003e\n\u003cli\u003eMaeyama M, Sasayama T, Tanaka K, et al. Multi-marker algorithms based on CXCL13, IL-10, sIL-2 receptor, and \u0026beta;2-microglobulin in cerebrospinal fluid to diagnose CNS lymphoma. Cancer Med 2020;9:4114-4125. https://doi.org/10.1002/cam4.3048\u003c/li\u003e\n\u003cli\u003eRimelen V, Ahle G, Pencreach E, et al. Tumor cell-free DNA detection in CSF for prima-ry CNS lymphoma diagnosis. Acta Neuropathol Commun 2019;7:1-3. https://doi.org/10.1186/s40478-019-0692-8\u003c/li\u003e\n\u003cli\u003eGrommes C, DeAngelis LM. Primary CNS lymphoma. J Clin Oncol 2017;35:2410-2418. https://doi.org/10.1200/JCO.2017.72.7602\u003c/li\u003e\n\u003cli\u003eBjorkman PJ, Saper MA, Samraoui B, et al. Structure of the human class I histocompatibility antigen, HLA-A2. Nature 1987;329:506-512. https://doi.org/10.1038/329506a0\u003c/li\u003e\n\u003cli\u003eHaarmann A, H\u0026auml;hnel L, Schuhmann MK, et al. Age-adjusted CSF \u0026beta;2-microglobulin and lactate are increased and ACE is decreased in patients with multiple sclerosis, but only lactate correlates with clinical disease duration and severity. J Neuroimmunol 2018;323:19-27. https://doi.org/10.1016/j.jneuroim.2018.07.001\u003c/li\u003e\n\u003cli\u003eLenzlinger PM, Hans VH, J\u0026ouml;ller-Jemelka HI, et al. Markers for cell-mediated immune response are elevated in cerebrospinal fluid and serum after severe traumatic brain injury in humans. J Neurotrauma 2001;18:479-489. https://doi.org/10.1089/089771501300227288\u003c/li\u003e\n\u003cli\u003eSvatoňov\u0026aacute; J, Bořeck\u0026aacute; K, Adam P, et al. Beta2-microglobulin as a diagnostic marker in c-erebrospinal fluid: a follow-up study. Dis Markers 2014;2014:495402. https://doi.org/10.1155/2014/495402\u003c/li\u003e\n\u003cli\u003eMavligit GM, Stuckey SE, Cabanillas FF, et al. Diagnosis of leukemia or lymphoma in the central nervous system by beta2-microglobulin determination. N Engl J Med 1980;303:718-722. https://doi.org/10.1056/NEJM198009253031302\u003c/li\u003e\n\u003cli\u003eSasagawa Y, Akai T, Tachibana O, et al. Diagnostic value of interleukin-10 in cerebrospinal fluid for diffuse large B-cell lymphoma of the central nervous system. J Neurooncol 2015;121:177-183. https://doi.org/10.1007/s11060-014-1622-z\u003c/li\u003e\n\u003cli\u003eSasayama T, Nakamizo S, Nishihara M, et al. Cerebrospinal fluid interleukin-10 is a potentially useful biomarker in immunocompetent primary central nervous system lymphoma (PCNSL). Neuro Oncol 2012;14:368-380. https://doi.org/10.1093/neuonc/nor203\u003c/li\u003e\n\u003cli\u003eStarmans JJ, Vos J, Van der Helm HJ. The beta 2-microglobulin content of the cerebrosp-inal fluid in neurological disease. J Neurol Sci 1977;33:45-49. https://doi.org/10.1016/0022-510x(77)90180-0\u003c/li\u003e\n\u003cli\u003eKersten MJ, Evers LM, Dellemijn PL, et al. Elevation of cerebrospinal fluid soluble CD27 levels in patients with meningeal localization of lymphoid malignancies. Blood 1996;87:1985-1989. https://doi.org/10.1182/blood.V87.5.1985.1985\u003c/li\u003e\n\u003cli\u003eErnerudh J, Olsson T, Berlin G, et al. Cerebrospinal fluid immunoglobulins and beta 2-microglobulin in lymphoproliferative and other neoplastic diseases of the central nervous system. Arch Neurol 1987;44:915-920. https://doi.org/10.1001/archneur.1987.00520210017012\u003c/li\u003e\n\u003cli\u003eBertucci A, Boucard C, Harlay V, et al. Prognostic value of Beta 2-Microglobulinin in cerebrospinal fluid in primary central nervous system lymphoma. J Neurol Sci 2024;457. https://doi.org/10.1016/j.jns.2023.122847\u003c/li\u003e\n\u003cli\u003eHansen PB, Kjeldsen L, Dalhoff K, et al. Cerebrospinal fluid beta-2-microglobulin in adult patients with acute leukemia or lymphoma: a useful marker in early diagnosis and moni-toring of CNS-involvement. Acta Neurol Scand 1992;85:224-227. https://doi.org/10.1111/j.1600-0404.1992.tb04033.x\u003c/li\u003e\n\u003cli\u003eZhang MZ, Shi QG, Xu XY, et al. Elevated levels of \u0026beta;2-microglobulin in cerebrospinal fluid in adult patients with viral encephalitis/meningitis. Clin Biochem 2024;125:110719. https://doi.org/10.1016/j.clinbiochem.2024.110719\u003c/li\u003e\n\u003cli\u003eNguyen-Them L, Costopoulos M, Tanguy ML, et al. The CSF IL-10 concentration is an effective diagnostic marker in immunocompetent primary CNS lymphoma and a potential prognostic biomarker in treatment-responsive patients. Eur J Cancer 2016;61:69-76. https://doi.org/10.1016/j.ejca.2016.03.080\u003c/li\u003e\n\u003cli\u003eSong Y, Zhang W, Zhang L, et al. Cerebrospinal fluid IL-10 and IL-10/IL-6 as accurate diagnostic biomarkers for primary central nervous system large B-cell lymphoma. Sci Rep 2016;6:38671. https://doi.org/10.1038/srep38671\u003c/li\u003e\n\u003cli\u003eMabray MC, Barajas RF, Villanueva-Meyer JE, et al. The combined performance of ADC, CSF CXC chemokine ligand 13, and CSF interleukin 10 in the diagnosis of central nervous system lymphoma. AJNR Am J Neuroradiol 2016;37:74-79. https://doi.org/10.3174/ajnr.A4450\u003c/li\u003e\n\u003cli\u003eNing K, Chai H, Cui Y, et al. Fast detection of \u0026beta;2 microglobulin in patient blood by a handhold centrifugal microfluidic device. Sens Actuators B Chem 2022;373:132737. https://doi.org/10. 1016/j.snb.2022.132737\u003c/li\u003e\n\u003cli\u003eFerreri AJM, Calimeri T, Lopedote P, et al. MYD88 L265P mutation and interleukin-10 detection in cerebrospinal fluid are highly specific discriminating markers in patients with primary central nervous system lymphoma: results from a prospective study. Br J Haematol 2021;193:497-505. https://doi.org/10.1111/bjh.17357\u003c/li\u003e\n\u003cli\u003eYao ML, Chen TM, Li P. Cerebrospinal Fluid \u0026beta;2-Microglobulin for Prognostic Evaluation of Patients with Central Nervous System Infiltration in Acute Lymphoblastic Leukemia. Z-hongguo Shi Yan Xue Ye Xue Za Zhi 2022;30:113-118. https://doi.org/10.19746/j.cnki.issn.1009-2137.2022.01.018\u003c/li\u003e\n\u003cli\u003eOberg G, H\u0026auml;llgren R, Venge P. Beta 2-microglobulin, lysozyme and lactoferrin in cerebrospinal fluid in patients with lymphoma or leukaemia: relationship to CNS involvement and the effect of prophylactic intrathecal treatment with methotrexate. Br J Haematol 1987;66:315-322. https://doi.org/10.1111/j.1365-2141.1987.tb06916.x\u003c/li\u003e\n\u003cli\u003eDogliotti I, Jim\u0026eacute;nez C, Varettoni M, et al. Diagnostics in Waldenstr\u0026ouml;m\u0026rsquo;s macroglobulinemia: a consensus statement of the European Consortium for Waldenstr\u0026ouml;m\u0026rsquo;s Macroglobulinemia. Leukemia 2023;37:388-395. https://doi.org/10.1038/s41375-022-01762-3\u003c/li\u003e\n\u003cli\u003eYamagishi Y, Sasaki N, Nakano Y, et al. Liquid biopsy of cerebrospinal fluid for MYD88 L265P mutation is useful for diagnosis of central nervous system lymphoma. Cancer Sci 2021;112:4702-4710. https://doi.org/10.1111/cas.15133\u003c/li\u003e\n\u003cli\u003eGupta M, Burns EJ, Georgantas NZ, et al. A rapid genotyping panel for detection of primary central nervous system lymphoma. Blood 2021;138:382-386. https://doi.org/10.1182/blood.20 20010137\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"annals-of-hematology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aohe","sideBox":"Learn more about [Annals of Hematology](http://link.springer.com/journal/277)","snPcode":"277","submissionUrl":"https://submission.nature.com/new-submission/277/3","title":"Annals of Hematology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Central nervous system lymphoma, β2-microglobulin, cerebrospinal fluid, diagnostic biomarker","lastPublishedDoi":"10.21203/rs.3.rs-7657007/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7657007/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis retrospective cohort study investigated the diagnostic and prognostic significance of cerebrospinal fluid (CSF) β2-microglobulin (β2-M) in 1,349 patients hospitalized between January 2018 and August 2024. Patients were categorized into lymphoma, leukemia, solid tumor, and other disease cohorts, with additional stratification by central nervous system (CNS) involvement. CSF β2-M concentrations were markedly elevated in CNS lymphoma (CNSL) relative to all comparator groups (p \u0026lt; 0.001). A cutoff value of 1.85 mg/L discriminated CNSL from non-CNS-involved lymphoma with high diagnostic accuracy (AUC 0.939), yielding 89.7% sensitivity and 85.7% specificity. Longitudinal assessment further demonstrated that dynamic CSF β2-M trajectories correlated with therapeutic response and relapse risk (\u003cem\u003ep\u003c/em\u003e = 0.009 for complete remission; \u003cem\u003ep\u003c/em\u003e = 0.006 for relapse), underscoring its utility as a monitoring biomarker. Collectively, these findings establish CSF β2-microglobulin as a reliable, accessible, and cost-effective biomarker for both diagnosis and prognostic evaluation in CNSL.\u003c/p\u003e","manuscriptTitle":"Cerebrospinal Fluid β2-Microglobulin as a Diagnostic Biomarker in Central Nervous System Lymphoma: a Single-Center Retrospective Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-06 12:07:52","doi":"10.21203/rs.3.rs-7657007/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-01T11:00:52+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-30T20:02:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"239049600509804295399560126060639210029","date":"2025-09-27T18:24:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"129221876169982842648131824340641156178","date":"2025-09-24T15:33:02+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-24T08:03:57+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-23T15:14:25+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-23T15:13:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Annals of Hematology","date":"2025-09-19T09:29:07+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"annals-of-hematology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aohe","sideBox":"Learn more about [Annals of Hematology](http://link.springer.com/journal/277)","snPcode":"277","submissionUrl":"https://submission.nature.com/new-submission/277/3","title":"Annals of Hematology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7c7fc302-03de-48f0-8b31-30b7a1ff4bbc","owner":[],"postedDate":"October 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T16:05:37+00:00","versionOfRecord":{"articleIdentity":"rs-7657007","link":"https://doi.org/10.1007/s00277-025-06719-x","journal":{"identity":"annals-of-hematology","isVorOnly":false,"title":"Annals of Hematology"},"publishedOn":"2025-11-10 15:58:00","publishedOnDateReadable":"November 10th, 2025"},"versionCreatedAt":"2025-10-06 12:07:52","video":"","vorDoi":"10.1007/s00277-025-06719-x","vorDoiUrl":"https://doi.org/10.1007/s00277-025-06719-x","workflowStages":[]},"version":"v1","identity":"rs-7657007","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7657007","identity":"rs-7657007","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}