Correlation of glomerular mannose-binding lectin deposition with the clinicopathology and prognosis of PLA2R-associated membranous nephropathy

Mannose-binding lectin (MBL) and autoantibody IgG4 staining against the phospholipase A2 receptor (PLA2R)were correlated. To enquire into the pathogenic effect of MBL in IMN as well as its relevance to clinicopathology and prognosis.Patients with IMN in 2021–2022 at our hospital were divided into positive and negative groups based on glomerular MBL immunofluorescence results and anti-PLA2R antibody characterization, and their clinical, pathological and follow-up data were evaluated.Among 39 patients with IMN, the positive rates of glomerular MBL and IgG4 deposition and serum anti-PLA2R antibodies were 31 (79.5%), 37 (100%) and 26 (70.3%), respectively. There were no notable differences in clinical and pathological features between the MBL-positive and negative groups of patients, but there were differences in IgG4 expression in the renal tissues (p < 0.05). There were no notable differences in MBL deposition between IMN patients grouped qualitatively by blood PLA2R antibodies. Renal tissue MBL was highly expressed (79.5%) and C1q was lowly expressed (15.38%). Kaplan-Meier analysis of clinical remission was similar in both groups. In multivariate COX regression analysis adjusted for sex, age, serum anti-PLA2R antibody concentration and blood pressure, MBL deposition (HR, 0.776; 95% CI, 0.311–1.939; p = 0.587) was not associated with IMN remission in the MBL-negative compared with the positive group.Renal tissue MBL characterization correlates with IgG4 and anti-PLA2R antibodies are involved in the pathogenesis of IMN through the induction of complement activation by the complement agglutinin pathway. No significant clinical, pathological or prognostic differences between patients with positive and negative MBL deposits were found in the study.