A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody

A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody | 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 Case Report A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody Xia Zhang, Ling Zeng, Xingyu Du, Tao Liang, Benhai Yao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6684433/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract We report a case of autoimmune encephalitis with cerebellar ataxia as the main manifestation. The main clinical manifestation of the patient was persistent vertigo with headache. Plain and enhanced MRI of the head suggested multiple lesions in bilateral cerebellar hemispheres and right temporo-occipital lobe. Examinations of the nervous system: Romberg test, finger-to-nose test, and heel-knee-shin test were positive; paraneoplastic syndrome-related antibody test in blood and cerebrospinal fluid showed that anti CV2 antibody was positive. Diagnosis: Autoimmune encephalitis with anti CV2 antibody. The symptoms improved after regular intravenous infusion of cyclophosphamide combined with hormone treatment. Anti CV2 antibody can cause subacute cerebellar degeneration. Therefore, when cerebellar ataxia is the main clinical manifestation of patients and imaging indicates cerebellar lesions, it is necessary to consider the possibility of autoimmune encephalitis with anti CV2 antibody. Autoimmune encephalitis Anti CV2 antibody Cerebellar ataxia Leukoencephalopathy chronic cericitis Figures Figure 1 Introduction Autoimmune encephalitis with anti–CV2 antibody is a rare form of autoimmune encephalitis in which patients test positive for anti-CV2 antibody in peripheral blood or cerebrospinal fluid, and the clinical manifestations are mainly limbic encephalitis, ataxia as a prominent manifestation is rare. Furthermore, more than 80% of this disease can be combined with tumors, small cell lung cancer and thymoma are the mainstay, immunotherapy is the main treatment plan. We report a case of anti-CV2 antibody autoimmune encephalitis with cerebellar ataxia as the main clinical manifestation in the Department of Neurology of the Affiliated Hospital of Zunyi Medical University, with case characteristics, auxiliary examination, treatment plan and prognosis, so as to increase clinicians' awareness of the disease and to allow early diagnosis and treatment when similar cases are encountered. Case report The patient was a 22-year-old female who presented with vertigo with unsteadiness in walking, which gradually worsened. 27 days later, she developed a severe headache with nausea and non-jet vomiting, which was accompanied by gastric contents. Neurological physical examination showed positive finger-nose test, heel-knee-shin test and closed-eye difficulty sign. Routine cerebrospinal fluid examination after lumbar puncture showed elevated white blood cell count and protein quantification (Table 1 ), and cranial CT angiography showed no abnormalities. Cranial MRI (April 13, 2019) showed multiple lesions in the bilateral cerebellar hemispheres and the right temporo-occipital lobe on plain scan and enhancement, considering chronic infectious lesions (tuberculosis possibility), tumors in the right cerebellar hemisphere could not be excluded, cerebral softening foci, and cerebral atrophy; cranial MRI spectral imaging (MRS) showed elevated Cho peaks and decreased NAA peaks in the lesion area, with a maximum Ch/NAA of approximately 2.93 (Fig. 1 A-E). The diagnosis of intracranial multiple lesions was initially considered, and the nature of the lesions was not determined, so treatment with antiviral, inflammation suppression, and diagnostic antituberculosis therapy was given. The results of the four viral tests (cytomegalovirus, rubella virus, herpes simplex virus, and EBV) were negative; the female tumor-associated antigen and antinuclear antibody tests showed no abnormalities; the third-generation thyrotropin (TSH) in the thyroid function test was 0.403 µIU/mL (normal value 0.55–4.78 µIU/mL); the 24-hour electroencephalogram showed no abnormalities. Several ultrasonographies (thyroid, breast, abdomen, urinary tract, gynecology) showed no significant abnormalities; lumbar puncture was repeated for cerebrospinal fluid-related tests (Table 1 ); anti-CV2 antibody test (blood and cerebrospinal fluid) was positive for autoimmune encephalitis and paraneoplastic syndrome-related antibodies, so the diagnosis was autoimmune encephalitis with anti-CV2 antibody. Anti-tuberculosis and viral drugs were discontinued, and cyclophosphamide 1g was added as an intravenous infusion (750mg/m2) to suppress the immune response. After active treatment the patient's vertigo and headache improved and she was able to walk normally. After discharge, the patient was instructed to take oral prednisone tablets 50mg qd (reduced by 1 tablet every 2 weeks) and to use cyclophosphamide (1g/1 time/month regularly). Table 1 Results of cerebrospinal fluid examination of patients at different time point time No. pressure appearance WBC N L CSFTP 2019.4.15 2019.4.23 2019.7.16 1 2 3 120 180 210 colorless and clear light yellow and clear colorless and clear 450 53 0 0.12 0.20 / 0.88 0.80 / 601 292 288 Note: Cerebrospinal fluid pressure (80∼180 mmH20), white blood cell count (WBC, 0∼5×106/L), neutrophils (N), lymphocytes (L), and cerebrospinal fluid protein quantification (CSFTP, 150∼450 mg/L). Cerebrospinal fluid smear did not showed bacteria, acid-resistant bacilli, or cryptococcal spores, and cerebrospinal fluid exfoliated cells did not show tumor cells. "/": unclassified. On July 10, 2019, the patient had headache and distension with dizziness and nausea at the follow-up visit, no fever, vomiting, and convulsions, and she could walk as normal people. A third cerebrospinal fluid examination (Table 1 ) was completed; a repeat cranial MRI (July 18, 2019) with plain scan, enhancement and MRS revealed a reduced foci of right cerebellar enhancement compared to April 13, 2019. The patient's headache, dizziness, and nausea were considered to be related to high cerebral pressure and were treated with dehydration to lower cranial pressure and immunosuppression. On September 30, 2019 the patient was seen in our gynecology outpatient clinic for vulvar pruritus and completed a histopathological biopsy of the cervix showing chronic cervicitis with localized high-grade phosphoepithelial lesions (HSIL, CIN grade III), which was not treated. A repeat cranial MRI (October 23, 2019) plain and enhanced examination compared with the previous one (July 18, 2019) showed increased cerebellar strengthening foci; MRS showed slightly reduced Cho and Cr and NAA peaks in the cerebellar strengthening nodules, which were non-tumor lesions. One month later, the patient underwent cervical conization at a local hospital, and the pathology suggested inflammatory lesions. The patient's condition recurred and immunotherapy was continued. The patient had severe nausea and vomiting adverse reactions during the 11th and 12th cyclophosphamide intravenous infusions, the cause of which was considered to be the patient's intolerance; the total amount of cyclophosphamide had reached 12 g, but the intracranial lesions were still present, and to prevent disease relapse, mortification with mortification (500 m, orally, twice a day) was added to suppress immunotherapy. A repeat cranial MRI (July 13, 2020) plain, enhanced and MRS examination showed a reduced cerebellar lesion compared with the previous one (October 23, 2019). The patient's condition was stable, and the original treatment plan was continued. 28 September 2021, the cranial MRI plain scan, enhancement and MRS examination did not show significant changes compared with the last (13 July 2020) film, and the tumor spectrum was visible in the right temporal lobe. However, the patient had no relevant clinical manifestations, and the thyroid, breast, abdomen, gynecology and chest CT examinations were all abnormal on review at the local hospital. Combined with the patient's condition and cranial MRI results, the possibility of tumor nature was temporarily ruled out for his intracranial multiple lesions. The patient was followed up on March 28, 2022, with no special discomfort and normal walking, and the patient stopped the mortification of mortification on his own. The patient was followed up on February 6, 2023, at 32 weeks of gestation, and the fetus was delivered prematurely due to renal calculi, fluid retention and infection. The patient and the newborn were healthy. Discussion Autoimmune encephalitis (AE), which is also known as autoimmune-mediated limbic encephalitis, is an autoimmune disorder clinically characterized by memory impairment, behavior changes, and seizures. It usually affects the limbic system, brainstem, and cerebellum 1 . Combining tumors is called paraneoplastic AE, Paraneoplastic AE consistent with borderline encephalitis is called paraneoplastic borderline encephalitis 2 . An epidemiological study of AE showing an incidence of 0.8/100,000 person-years and prevalence of 13.7/100,000 3 . AE is classified according to the location of nerve cell antigens can be divided into the following two categories: Antibodies against intracellular antigens include Hu, Yo, Ri, Ma2, CV2, Amphiphysin, Anna-3, Tr, PCA-2, GAD, etc, which are significantly correlated with clinical symptoms of the nervous system and potential tumors. Antibodies against cell surface antigen, NMDAR, LGI1, GABABR, AMPAR, CASPR2, DPPX, IgLON5, etc 2 , 4 . Among them, anti-CV2 autoimmune encephalitis is a rare form of autoimmune encephalitis. Its incidence 0.7/100,000 person-years 2 . In 1996, Honnorat et al, found that anti-CV2 antibodies specifically recognized protein antigens with a relative molecular weight of 66 000 in the cytoplasm of oligodendrocyte subsets of rat brain stem, cerebellum and spinal cord white matter 5 . The CV2 antibody can specifically recognize CRMP-5. anti-CV2 antibody expressed in the cerebellum, hippocampus, thalamus, peripheral neurons, spinal cord, retina, and in SCLCs 6 , 7 . Most frequently anti-CV2/CRMP5 antibodies cause subacute cerebellar degeneration, followed by encephalomyelitis, limbic encephalitis, optic neuritis and retinopathy 8 . The clinical presentations with anti-CV2 antibody include cerebellar ataxia, chorea, peripheral and autonomic neuropathies, myelopathy, optic neuritis, and retinitis, involuntary movements, mental and behavioral abnormalities, hypomnesia, convulsions, olfactory disorders, Parkinson-like symptoms, Myasthenia syndrome (Lambert-Eaton myasthenic syndrome, LEMS and myasthenia gravis, MG) 6 , 9 – 13 ,Anti-CV2 is commonly found in SCLC (small cell lung cancer), thymoma, breast cancer and other tumors, as well as on Hodgkin's lymphoma, head and neck tumor, bronchial cancer, prostate cancer, testicular cancer, gastrointestinal stromal tumor, oophoroma, High-grade ovarian serous carcinoma, Uterine sarcoma, Squamous cell carcinoma of the tongue, Ovarian adenocarcinoma, Neuroendocrine carcinoma, Kidney cancer 5 , 14 – 19 . In this case, no obvious tumor was found during the follow-up, but the patient was admitted to the gynecological clinic due to pruritus of the vulva, and cervical histopathological biopsy showed chronic cervicitis with local high-grade phosphoid intraepithelial lesions (HSIL, CIN ⅲ). After that, cervical conization was performed in the local hospital, and inflammatory lesions were considered in postoperative pathology. In this case, the diagnosis of tuberculous meningitis and viral encephalitis was considered, and antiviral and anti-tuberculosis treatments were given. The results of anti-CV2 antibody in blood and cerebrospinal fluid were positive, and the diagnosis of autoimmune encephalitis with anti-CV2 antibody was established. Antiviral and tuberculosis drug therapy was stopped, and hormone and immunosuppressive therapy were still used. Cerebrospinal fluid did not support tuberculous meningitis after review, and the intracranial lesions were shrinking, so tuberculous meningitis and viral encephalitis could be excluded. Combined with the pathological results of the cervix, it was speculated that the etiology might be related to local high-grade phosphoid epithelial lesions of the cervix. Cheng YW et al reported abnormal signals in bilateral basal ganglia, right temporal lobe and midbrain on brain MRI. MRI showed patchy enhancement in bilateral basal ganglia thalamus, right temporal lobe and midbrain 20 . There may also be abnormal signals in hippocampus, white matter, cortex and subcortical, cerebellum and spinal cord, brain atrophy, and a small part of MRI enhancement can be enhanced 11 , 21 – 23 . Clinically, it is rare to involve the brain, cerebellum and brainstem at the same time. The lesions reported in this case involved the brain lobes and cerebellum. MRI enhancement showed enhanced foci and brain atrophy. The imaging findings were consistent with those reported in the literature. Slow wave, epileptic discharge and normal EEG; Most cerebrospinal fluid showed increased leukocyte count and/or protein 20 . The cases reported in this paper are consistent with the literature. Serum and or cerebrospinal fluid anti CV2 antibody positive can be diagnosed. The treatment of autoimmune encephalitis is mainly immunotherapy. The patient was treated with hormone in the early stage, and the clinical symptoms were slightly relieved and the intracranial lesions were reduced. The disease fluctuated after diagnosis. Cyclophosphamide was given after diagnosis, and the symptoms of vertigo and ataxia disappeared. However, recurrent headache, dizziness and vomiting occurred, and head MRI lesions tended to increase. Gynecological examination revealed local high-grade phosphoid intraepithelial lesions of the cervix, and cervical conization was performed. Cyclophosphoacyl (750mg/m2) was given regularly once a month, with a total amount of 12g. During the last two times, the patient had severe nausea, vomiting and other gastrointestinal reactions, which could not be tolerated. Considering the repeated fluctuation of the patient's condition during treatment, mycophenolate mofetil (1.0g/ day) was added to the treatment. The patient's condition was stable and no tumor was found during the follow-up for 2 years. Declarations Ethics approval and consent to participate Institutional Review Board (IRB) approval was unnecessary because this article is a case report. Consent for publication Written informed consent for the publication of the patient's identifiable data and clinical images was obtained from the patient and their family. Competing interests The authors declare that they have no competing interests. Funding This work was supported by grants from the Zunyi City Science and Technology Plan Project (ZunKehe HZ (2022) No. 250), science and technology research of Chinese medicine and ethnic medicine science in Guizhou Administration of Traditional Chinese Medicine (QZYY-2021-006), and Science and Technology Fund Project of Guizhou Provincial Health and Health Commission (gzwkj2023-005). Author Contribution LZ andXZ share first authorship. LZ,XZ designed and wrote this article and analyzed and interpretated its data. XD ,TLwrote part of this article, BY helped with proofreading. All authors contributed to be the article and approved the final version Acknowledgments We are grateful to the patient and their family for their cooperation and consent to share their medical information. They provided verbal and written consent for this work, but no IRB approval was necessary because this article is a case report. Their support was essential to the completion of this report and We would like to thank Zunyi Science and Technology and Big Data Bureau, Guizhou Administration of Traditional Chinese Medicine and Guizhou Provincial Health and Health Commission. Availability of data and materials The data that support the current study are available from the corresponding author on reasonable request. Data Availability Statement The original contributions presented in the study are included in the article, further inquires can be directed to the corresponding authors. References Jammoul A, Li Y, Rae-Grant A. Autoantibody-mediated encephalitis: Not just paraneoplastic, not just limbic, and not untreatable [J]. Cleve Clin J Med, 2016, 83(1): 43-53. Graus F, Titulaer MJ, Balu R , et al. A clinical approach to diagnosis of autoimmune encephalitis [J]. Lancet Neurol, 2016, 15(4): 391-404. Dubey D, Pittock SJ, Kelly CR , et al. Autoimmune encephalitis epidemiology and a comparison to infectious encephalitis [J]. Ann Neurol, 2018, 83(1): 166-177. Dalmau J, Rosenfeld MR. Paraneoplastic syndromes of the CNS [J]. Lancet Neurol, 2008, 7(4): 327-340. Honnorat J, Antoine JC, Derrington E , et al. Antibodies to a subpopulation of glial cells and a 66 kDa developmental protein in patients with paraneoplastic neurological syndromes [J]. J Neurol Neurosurg Psychiatry, 1996, 61(3): 270-278. Yu Z, Kryzer TJ, Griesmann GE , et al. CRMP-5 neuronal autoantibody: marker of lung cancer and thymoma-related autoimmunity [J]. Ann Neurol, 2001, 49(2): 146-154. Ricard D, Rogemond V, Charrier E , et al. Isolation and expression pattern of human Unc-33-like phosphoprotein 6/collapsin response mediator protein 5 (Ulip6/CRMP5): coexistence with Ulip2/CRMP2 in Sema3a- sensitive oligodendrocytes [J]. J Neurosci, 2001, 21(18): 7203-7214. Waldvogel HJ, Baer K, Eady E , et al. Differential localization of gamma-aminobutyric acid type A and glycine receptor subunits and gephyrin in the human pons, medulla oblongata and uppermost cervical segment of the spinal cord: an immunohistochemical study [J]. J Comp Neurol, 2010, 518(3): 305-328. Dubey D, Lennon VA, Gadoth A , et al. Autoimmune CRMP5 neuropathy phenotype and outcome defined from 105 cases [J]. Neurology, 2018, 90(2): e103-e110. Graus F, Delattre JY, Antoine JC , et al. Recommended diagnostic criteria for paraneoplastic neurological syndromes [J]. J Neurol Neurosurg Psychiatry, 2004, 75(8): 1135-1140. Wu X, Wang H, Xu G , et al. Anti-CV2 Autoimmune Encephalitis With Parkinson-Like Symptoms and Bilateral Leukoencephalopathy-A Case Report [J]. Front Neurol, 2019, 10: 1064. Song J, Zhang Y, Lang Y , et al. Parkinsonism and dysautonomia with anti-CV2/CRMP5 associated paraneoplastic neurological syndromes mimicking multiple system atrophy: a case report [J]. BMC Neurol, 2021, 21(1): 408. Honnorat J, Cartalat-Carel S, Ricard D , et al. Onco-neural antibodies and tumour type determine survival and neurological symptoms in paraneoplastic neurological syndromes with Hu or CV2/CRMP5 antibodies [J]. J Neurol Neurosurg Psychiatry, 2009, 80(4): 412-416. Yan J, Chen Z, Liang Y , et al. Anti-CV2/CRMP5 antibody-positive paraneoplastic neurological syndromes with chronic intestinal pseudo-obstruction in a small-cell lung cancer patient: a case report and literature review [J]. J Int Med Res, 2020, 48(12): 300060520974466. Juárez-Vignon Whaley JJ, Carrera-Muiños A, Hernandez-Gutierrez KG , et al. Paraneoplastic Cerebellar Degeneration with Anti-CV2/CRMP5 Antibodies in Ovarian Cancer: Case Report and Review of the Literature [J]. Case Rep Oncol, 2021, 14(3): 1799-1805. Vernino S, Tuite P, Adler CH , et al. Paraneoplastic chorea associated with CRMP-5 neuronal antibody and lung carcinoma [J]. Ann Neurol, 2002, 51(5): 625-630. Kellinghaus C, Kraus J, Blaes F , et al. CRMP-5-autoantibodies in testicular cancer associated with limbic encephalitis and choreiform dyskinesias [J]. Eur Neurol, 2007, 57(4): 241-243. Maramattom BV. Paraneoplastic CRMP-5 basal ganglionitis and limbic encephalitis in an elderly Indian lady [J]. Neurol India, 2013, 61(5): 534-535. Totland C, Haugen M, Vedeler C. CRMP5 Antibodies-Diagnostic Challenges [J]. Front Neurol, 2021, 12: 729075. 程艳伟, 刘亢丁, 刘珊 , et al. 抗CV2自身免疫性脑炎一例并文献复习 [J]. 中华神经科杂志, 2018, 51(5): 376-381. Xia J, Yin X, Zhu M , et al. Autoimmune encephalitis positive for both anti-γ-aminobutyric acid B receptor and anticollapsin response-mediator protein 5 antibodies: A case report [J]. Medicine, 2018, 97(3): e9574. Fadda L, Floris G, Polizzi L , et al. Pulvinar sign in a case of anti-CV2 encephalitis [J]. J Neurol Sci, 2018, 393: 69-71. Flabeau O, Laurent C, Schneider S , et al. Spinal cord tractopathy in paraneoplastic anti-CV2/CRMP5 myelitis responsive to plasma exchange [J]. Rev Neurol (Paris), 2022, 178(3): 280-282. Additional Declarations No competing interests reported. Supplementary Files Table1.jpg graphicabstract.pptx Cite Share Download PDF Status: Posted Version 1 posted 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-6684433","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":476752499,"identity":"e350f02e-e2d3-43e1-9792-b715e2a40ccb","order_by":0,"name":"Xia Zhang","email":"","orcid":"","institution":"Affiliated Hospital of Zunyi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xia","middleName":"","lastName":"Zhang","suffix":""},{"id":476752501,"identity":"37b14211-bb88-499d-8dc4-ae16fb4e982b","order_by":1,"name":"Ling Zeng","email":"","orcid":"","institution":"Affiliated Hospital of Zunyi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ling","middleName":"","lastName":"Zeng","suffix":""},{"id":476752502,"identity":"0c9057cb-34eb-4800-a821-0dd6f50f7c3b","order_by":2,"name":"Xingyu Du","email":"","orcid":"","institution":"Affiliated Hospital of Zunyi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xingyu","middleName":"","lastName":"Du","suffix":""},{"id":476752503,"identity":"0f7d5754-3bfe-4193-928e-31bda1857619","order_by":3,"name":"Tao Liang","email":"","orcid":"","institution":"Affiliated Hospital of Zunyi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Tao","middleName":"","lastName":"Liang","suffix":""},{"id":476752504,"identity":"94840c2e-2376-4c5b-a98c-7681ae1e0e0b","order_by":4,"name":"Benhai Yao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACfoYDyQ8+GNTU97M3EKlFsvHAM8MZBccYZ/YcIFKLweGDD6R5PjAzbriRQKzLjh1OMOYxYGOWnPl44w2GGptogjoYe44lPJxjIMPGL51WbMFwLC23gZAWZokzCQZvDNh4JGfnmEkwNhwmrIVN/v0HCR4DZgmDm2eI1MLDcCBBEqjFwOAGD5FaJBgOpBnOMDiWINkD9EsCMX6xPwCKyj81Cfzshzfe+FBjQ1gLMjCQSCBFOUQLqTpGwSgYBaNgZAAAiVVD94uiItsAAAAASUVORK5CYII=","orcid":"","institution":"Affiliated Hospital of Zunyi Medical University","correspondingAuthor":true,"prefix":"","firstName":"Benhai","middleName":"","lastName":"Yao","suffix":""}],"badges":[],"createdAt":"2025-05-17 04:38:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6684433/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6684433/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85649538,"identity":"62da44f3-7261-4fe8-8095-becac8826288","added_by":"auto","created_at":"2025-06-30 08:59:10","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":8177749,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDynamic changes of the patient's cranial MRI \u003c/strong\u003eThe cranial MRI presentation on April 13, 2019: (A, B) FLAIR showed that right temporo-occipital lobe, bilateral cerebellar hemispheres demonstrating lamellar, patchy long T2 signal with blurred margin, shallow cerebral sulcus and gyrus around the lesion, brain parenchymal atrophy; (C) enhancement scan showed part of the lesion enhancement in cerebrum, and adjacent meningeal enhancement; (D, E) MRS showed that cerebellar lesion area Cho peak elevated, NAA peak decreased, and the Ch/NAA was approximately 2.93 at most. MRI cranial manifestation on July 18, 2019: (F, G) FLAIR showed that right temporo-occipital lobe, bilateral cerebellar hemispheres demonstrating lamellar, patchy long T2 signal, brain sulcus enlargement, and brain parenchyma atrophy; (H) enhancement scan showed right cerebellar lesion point-like enhancement and adjacent meningeal enhancement, compared with the image on April 13, 2019 right cerebellar enhancement foci reduced; (I, J) MRS showed cerebellar lesion area Cho peak decreased, NAA peak decreased, and the Ch/NAA maximum about 0.73. Cranial MRI manifestation on October 23, 2019: (K, L) FLAIR showed right temporo-occipital lobe, cerebellar earth demonstrating lamellar long T2 signal, and right temporo-occipital lobe and cerebellar hemisphere atrophy; (M) enhancement scan showed cerebellar earth strengthening, compared with July 18, 2019 image cerebellar lesion enlargement; (N, O) MRS showed Cho, Cr, and NAA peaks were reduced in the cerebellar lesion area. On July 13, 2020, the cranial MRI: (P, K) FLAIR showed right temporo-occipital lobe and cerebellum demonstrating lamellar long T2 signal, and the right temporo-occipital lobe and cerebellar hemisphere atrophied; (R) enhanced scan showed cerebellar enhancement, and the cerebellar lesion was reduced, compared with the image on October 23, 2019; (S, T) MRS showed the nerve tissue necrosis at the right temporal occipital lobe lesion was severe. The cranial MRI on September 28, 2021,: (U, V) FLAIR showed the right temporo-occipital lobe and cerebellum demonstrating lamellar long T2 signal, and the right temporo-occipital lobe and cerebellar hemisphere atrophied; (W) enhanced scan showed cerebellar enhancement, and no significant change compared with the image on July 13, 2020; (X, Y) MRS showed right temporal lobe demonstrating relative increase of Cho peak, increase of Cho/NAA ratio, which ratio maximum was 2.96, severe neurological tissue necrosis at the lesion, and tumor spectral lines were seen in the right temporal lobe.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6684433/v1/3f8e08227986c8d7557615de.jpg"},{"id":98622549,"identity":"c0069a00-aa18-472a-98c7-20927bcfdab4","added_by":"auto","created_at":"2025-12-19 16:57:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8593777,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6684433/v1/88ca3eea-49f3-4748-923d-1e965fe7e298.pdf"},{"id":85647872,"identity":"ffbdddaf-b49d-4e04-8ad7-f6194c7f6674","added_by":"auto","created_at":"2025-06-30 08:51:09","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":971023,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6684433/v1/070e38007f36171a6ec5f441.jpg"},{"id":85647883,"identity":"9ea89ac4-6716-425f-89c4-332414daa31d","added_by":"auto","created_at":"2025-06-30 08:51:11","extension":"pptx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":2058170,"visible":true,"origin":"","legend":"","description":"","filename":"graphicabstract.pptx","url":"https://assets-eu.researchsquare.com/files/rs-6684433/v1/79fab3f83c448db5b37c4d56.pptx"}],"financialInterests":"No competing interests reported.","formattedTitle":"A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAutoimmune encephalitis with anti\u0026ndash;CV2 antibody is a rare form of autoimmune encephalitis in which patients test positive for anti-CV2 antibody in peripheral blood or cerebrospinal fluid, and the clinical manifestations are mainly limbic encephalitis, ataxia as a prominent manifestation is rare. Furthermore, more than 80% of this disease can be combined with tumors, small cell lung cancer and thymoma are the mainstay, immunotherapy is the main treatment plan. We report a case of anti-CV2 antibody autoimmune encephalitis with cerebellar ataxia as the main clinical manifestation in the Department of Neurology of the Affiliated Hospital of Zunyi Medical University, with case characteristics, auxiliary examination, treatment plan and prognosis, so as to increase clinicians' awareness of the disease and to allow early diagnosis and treatment when similar cases are encountered.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eThe patient was a 22-year-old female who presented with vertigo with unsteadiness in walking, which gradually worsened. 27 days later, she developed a severe headache with nausea and non-jet vomiting, which was accompanied by gastric contents. Neurological physical examination showed positive finger-nose test, heel-knee-shin test and closed-eye difficulty sign. Routine cerebrospinal fluid examination after lumbar puncture showed elevated white blood cell count and protein quantification (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), and cranial CT angiography showed no abnormalities. Cranial MRI (April 13, 2019) showed multiple lesions in the bilateral cerebellar hemispheres and the right temporo-occipital lobe on plain scan and enhancement, considering chronic infectious lesions (tuberculosis possibility), tumors in the right cerebellar hemisphere could not be excluded, cerebral softening foci, and cerebral atrophy; cranial MRI spectral imaging (MRS) showed elevated Cho peaks and decreased NAA peaks in the lesion area, with a maximum Ch/NAA of approximately 2.93 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA-E). The diagnosis of intracranial multiple lesions was initially considered, and the nature of the lesions was not determined, so treatment with antiviral, inflammation suppression, and diagnostic antituberculosis therapy was given. The results of the four viral tests (cytomegalovirus, rubella virus, herpes simplex virus, and EBV) were negative; the female tumor-associated antigen and antinuclear antibody tests showed no abnormalities; the third-generation thyrotropin (TSH) in the thyroid function test was 0.403 \u0026micro;IU/mL (normal value 0.55\u0026ndash;4.78 \u0026micro;IU/mL); the 24-hour electroencephalogram showed no abnormalities. Several ultrasonographies (thyroid, breast, abdomen, urinary tract, gynecology) showed no significant abnormalities; lumbar puncture was repeated for cerebrospinal fluid-related tests (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e); anti-CV2 antibody test (blood and cerebrospinal fluid) was positive for autoimmune encephalitis and paraneoplastic syndrome-related antibodies, so the diagnosis was autoimmune encephalitis with anti-CV2 antibody. Anti-tuberculosis and viral drugs were discontinued, and cyclophosphamide 1g was added as an intravenous infusion (750mg/m2) to suppress the immune response. After active treatment the patient's vertigo and headache improved and she was able to walk normally. After discharge, the patient was instructed to take oral prednisone tablets 50mg qd (reduced by 1 tablet every 2 weeks) and to use cyclophosphamide (1g/1 time/month regularly).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResults of cerebrospinal fluid examination of patients at different time point\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003etime\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003epressure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eappearance\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWBC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCSFTP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2019.4.15\u003c/p\u003e \u003cp\u003e2019.4.23\u003c/p\u003e \u003cp\u003e2019.7.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e2\u003c/p\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e120\u003c/p\u003e \u003cp\u003e180\u003c/p\u003e \u003cp\u003e210\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecolorless and clear\u003c/p\u003e \u003cp\u003elight yellow and clear\u003c/p\u003e \u003cp\u003ecolorless and clear\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e450\u003c/p\u003e \u003cp\u003e53\u003c/p\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003cp\u003e0.20\u003c/p\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.88\u003c/p\u003e \u003cp\u003e0.80\u003c/p\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e601\u003c/p\u003e \u003cp\u003e292\u003c/p\u003e \u003cp\u003e288\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eNote: Cerebrospinal fluid pressure (80\u0026sim;180 mmH20), white blood cell count (WBC, 0\u0026sim;5\u0026times;106/L), neutrophils (N), lymphocytes (L), and cerebrospinal fluid protein quantification (CSFTP, 150\u0026sim;450 mg/L). Cerebrospinal fluid smear did not showed bacteria, acid-resistant bacilli, or cryptococcal spores, and cerebrospinal fluid exfoliated cells did not show tumor cells. \"/\": unclassified.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOn July 10, 2019, the patient had headache and distension with dizziness and nausea at the follow-up visit, no fever, vomiting, and convulsions, and she could walk as normal people. A third cerebrospinal fluid examination (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) was completed; a repeat cranial MRI (July 18, 2019) with plain scan, enhancement and MRS revealed a reduced foci of right cerebellar enhancement compared to April 13, 2019. The patient's headache, dizziness, and nausea were considered to be related to high cerebral pressure and were treated with dehydration to lower cranial pressure and immunosuppression.\u003c/p\u003e \u003cp\u003eOn September 30, 2019 the patient was seen in our gynecology outpatient clinic for vulvar pruritus and completed a histopathological biopsy of the cervix showing chronic cervicitis with localized high-grade phosphoepithelial lesions (HSIL, CIN grade III), which was not treated. A repeat cranial MRI (October 23, 2019) plain and enhanced examination compared with the previous one (July 18, 2019) showed increased cerebellar strengthening foci; MRS showed slightly reduced Cho and Cr and NAA peaks in the cerebellar strengthening nodules, which were non-tumor lesions. One month later, the patient underwent cervical conization at a local hospital, and the pathology suggested inflammatory lesions. The patient's condition recurred and immunotherapy was continued. The patient had severe nausea and vomiting adverse reactions during the 11th and 12th cyclophosphamide intravenous infusions, the cause of which was considered to be the patient's intolerance; the total amount of cyclophosphamide had reached 12 g, but the intracranial lesions were still present, and to prevent disease relapse, mortification with mortification (500 m, orally, twice a day) was added to suppress immunotherapy.\u003c/p\u003e \u003cp\u003eA repeat cranial MRI (July 13, 2020) plain, enhanced and MRS examination showed a reduced cerebellar lesion compared with the previous one (October 23, 2019). The patient's condition was stable, and the original treatment plan was continued. 28 September 2021, the cranial MRI plain scan, enhancement and MRS examination did not show significant changes compared with the last (13 July 2020) film, and the tumor spectrum was visible in the right temporal lobe. However, the patient had no relevant clinical manifestations, and the thyroid, breast, abdomen, gynecology and chest CT examinations were all abnormal on review at the local hospital. Combined with the patient's condition and cranial MRI results, the possibility of tumor nature was temporarily ruled out for his intracranial multiple lesions. The patient was followed up on March 28, 2022, with no special discomfort and normal walking, and the patient stopped the mortification of mortification on his own. The patient was followed up on February 6, 2023, at 32 weeks of gestation, and the fetus was delivered prematurely due to renal calculi, fluid retention and infection. The patient and the newborn were healthy.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAutoimmune encephalitis (AE), which is also known as autoimmune-mediated limbic encephalitis, is an autoimmune disorder clinically characterized by memory impairment, behavior changes, and seizures. It usually affects the limbic system, brainstem, and cerebellum\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Combining tumors is called paraneoplastic AE, Paraneoplastic AE consistent with borderline encephalitis is called paraneoplastic borderline encephalitis \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. An epidemiological study of AE showing an incidence of 0.8/100,000 person-years and prevalence of 13.7/100,000 \u003csup\u003e3\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAE is classified according to the location of nerve cell antigens can be divided into the following two categories: Antibodies against intracellular antigens include Hu, Yo, Ri, Ma2, CV2, Amphiphysin, Anna-3, Tr, PCA-2, GAD, etc, which are significantly correlated with clinical symptoms of the nervous system and potential tumors. Antibodies against cell surface antigen, NMDAR, LGI1, GABABR, AMPAR, CASPR2, DPPX, IgLON5, etc \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAmong them, anti-CV2 autoimmune encephalitis is a rare form of autoimmune encephalitis. Its incidence 0.7/100,000 person-years\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. In 1996, Honnorat et al, found that anti-CV2 antibodies specifically recognized protein antigens with a relative molecular weight of 66 000 in the cytoplasm of oligodendrocyte subsets of rat brain stem, cerebellum and spinal cord white matter \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. The CV2 antibody can specifically recognize CRMP-5. anti-CV2 antibody expressed in the cerebellum, hippocampus, thalamus, peripheral neurons, spinal cord, retina, and in SCLCs \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMost frequently anti-CV2/CRMP5 antibodies cause subacute cerebellar degeneration, followed by encephalomyelitis, limbic encephalitis, optic neuritis and retinopathy \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. The clinical presentations with anti-CV2 antibody include cerebellar ataxia, chorea, peripheral and autonomic neuropathies, myelopathy, optic neuritis, and retinitis, involuntary movements, mental and behavioral abnormalities, hypomnesia, convulsions, olfactory disorders, Parkinson-like symptoms, Myasthenia syndrome (Lambert-Eaton myasthenic syndrome, LEMS and myasthenia gravis, MG) \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR10 CR11 CR12\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e,Anti-CV2 is commonly found in SCLC (small cell lung cancer), thymoma, breast cancer and other tumors, as well as on Hodgkin's lymphoma, head and neck tumor, bronchial cancer, prostate cancer, testicular cancer, gastrointestinal stromal tumor, oophoroma, High-grade ovarian serous carcinoma, Uterine sarcoma, Squamous cell carcinoma of the tongue, Ovarian adenocarcinoma, Neuroendocrine carcinoma, Kidney cancer \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn this case, no obvious tumor was found during the follow-up, but the patient was admitted to the gynecological clinic due to pruritus of the vulva, and cervical histopathological biopsy showed chronic cervicitis with local high-grade phosphoid intraepithelial lesions (HSIL, CIN ⅲ). After that, cervical conization was performed in the local hospital, and inflammatory lesions were considered in postoperative pathology. In this case, the diagnosis of tuberculous meningitis and viral encephalitis was considered, and antiviral and anti-tuberculosis treatments were given. The results of anti-CV2 antibody in blood and cerebrospinal fluid were positive, and the diagnosis of autoimmune encephalitis with anti-CV2 antibody was established. Antiviral and tuberculosis drug therapy was stopped, and hormone and immunosuppressive therapy were still used. Cerebrospinal fluid did not support tuberculous meningitis after review, and the intracranial lesions were shrinking, so tuberculous meningitis and viral encephalitis could be excluded. Combined with the pathological results of the cervix, it was speculated that the etiology might be related to local high-grade phosphoid epithelial lesions of the cervix.\u003c/p\u003e \u003cp\u003eCheng YW et al reported abnormal signals in bilateral basal ganglia, right temporal lobe and midbrain on brain MRI. MRI showed patchy enhancement in bilateral basal ganglia thalamus, right temporal lobe and midbrain\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. There may also be abnormal signals in hippocampus, white matter, cortex and subcortical, cerebellum and spinal cord, brain atrophy, and a small part of MRI enhancement can be enhanced \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Clinically, it is rare to involve the brain, cerebellum and brainstem at the same time. The lesions reported in this case involved the brain lobes and cerebellum. MRI enhancement showed enhanced foci and brain atrophy. The imaging findings were consistent with those reported in the literature. Slow wave, epileptic discharge and normal EEG; Most cerebrospinal fluid showed increased leukocyte count and/or protein\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. The cases reported in this paper are consistent with the literature. Serum and or cerebrospinal fluid anti CV2 antibody positive can be diagnosed.\u003c/p\u003e \u003cp\u003eThe treatment of autoimmune encephalitis is mainly immunotherapy. The patient was treated with hormone in the early stage, and the clinical symptoms were slightly relieved and the intracranial lesions were reduced. The disease fluctuated after diagnosis. Cyclophosphamide was given after diagnosis, and the symptoms of vertigo and ataxia disappeared. However, recurrent headache, dizziness and vomiting occurred, and head MRI lesions tended to increase. Gynecological examination revealed local high-grade phosphoid intraepithelial lesions of the cervix, and cervical conization was performed. Cyclophosphoacyl (750mg/m2) was given regularly once a month, with a total amount of 12g. During the last two times, the patient had severe nausea, vomiting and other gastrointestinal reactions, which could not be tolerated. Considering the repeated fluctuation of the patient's condition during treatment, mycophenolate mofetil (1.0g/ day) was added to the treatment. The patient's condition was stable and no tumor was found during the follow-up for 2 years.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003eInstitutional Review Board (IRB) approval was unnecessary because this article is a case report.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003e Written informed consent for the publication of the patient's identifiable data and clinical images was obtained from the patient and their family.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis work was supported by grants from the Zunyi City Science and Technology Plan Project (ZunKehe HZ (2022) No. 250), science and technology research of Chinese medicine and ethnic medicine science in Guizhou Administration of Traditional Chinese Medicine (QZYY-2021-006), and Science and Technology Fund Project of Guizhou Provincial Health and Health Commission (gzwkj2023-005).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eLZ andXZ share first authorship. LZ,XZ designed and wrote this article and analyzed and interpretated its data. XD ,TLwrote part of this article, BY helped with proofreading. All authors contributed to be the article and approved the final version\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe are grateful to the patient and their family for their cooperation and consent to share their medical information. They provided verbal and written consent for this work, but no IRB approval was necessary because this article is a case report. Their support was essential to the completion of this report and We would like to thank Zunyi Science and Technology and Big Data Bureau, Guizhou Administration of Traditional Chinese Medicine and Guizhou Provincial Health and Health Commission.\u003c/p\u003e\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e \u003cp\u003eThe data that support the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\u003ch2\u003eData Availability Statement\u003c/h2\u003e \u003cp\u003eThe original contributions presented in the study are included in the article, further inquires can be directed to the corresponding authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJammoul A, Li Y, Rae-Grant A. Autoantibody-mediated encephalitis: Not just paraneoplastic, not just limbic, and not untreatable [J]. 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Rev Neurol (Paris), 2022, 178(3): 280-282.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Autoimmune encephalitis, Anti CV2 antibody, Cerebellar ataxia, Leukoencephalopathy, chronic cericitis","lastPublishedDoi":"10.21203/rs.3.rs-6684433/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6684433/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWe report a case of autoimmune encephalitis with cerebellar ataxia as the main manifestation. The main clinical manifestation of the patient was persistent vertigo with headache. Plain and enhanced MRI of the head suggested multiple lesions in bilateral cerebellar hemispheres and right temporo-occipital lobe. Examinations of the nervous system: Romberg test, finger-to-nose test, and heel-knee-shin test were positive; paraneoplastic syndrome-related antibody test in blood and cerebrospinal fluid showed that anti CV2 antibody was positive. Diagnosis: Autoimmune encephalitis with anti CV2 antibody. The symptoms improved after regular intravenous infusion of cyclophosphamide combined with hormone treatment. Anti CV2 antibody can cause subacute cerebellar degeneration. Therefore, when cerebellar ataxia is the main clinical manifestation of patients and imaging indicates cerebellar lesions, it is necessary to consider the possibility of autoimmune encephalitis with anti CV2 antibody.\u003c/p\u003e","manuscriptTitle":"A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-30 08:51:03","doi":"10.21203/rs.3.rs-6684433/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"15f4abe5-367c-4acb-9e6e-a6f260309d84","owner":[],"postedDate":"June 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-17T06:54:45+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-30 08:51:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6684433","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6684433","identity":"rs-6684433","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}