Anti-phospholipase A2 receptor positive membranous nephropathy: investigating the link between electron microscopy stages and clinical outcome.

This retrospective, observational study sought to examine the relationship between Ehrenreich-Churg electron microscopy (EM) stages and long-term outcomes in anti-PLA2R membranous nephropathy (MN). Seventy-one patients with anti-PLA2R MN (median titer 185.7RU/mL) were followed for a median of 46 months, with end-stage kidney disease (ESKD) as the primary endpoint, and response to treatment as a secondary endpoint. Patients were grouped into stages I-II (41 patients) and stages III-IV (30 patients) for analytical purposes. Notably, the III-IV group demonstrated a lower eGFR, lower anti-PLA2R titer, but a higher chronicity score. Kaplan-Meier analysis showed shorter mean kidney survival time in stages III-IV compared to I-II (p 0.03). However, multivariate analysis using Cox regression indicated that Ehrenreich-Churg stages did not significantly influence kidney survival, but lower eGFR at diagnosis and higher histopathological chronicity score did. Remission was achieved by 64% of patients and no relationship between Ehrenreich-Churg stages and treatment response was found. The only identified risk factor for not achieving remission was the severity of hyposerinemia at diagnosis. In conclusion, while EM stages III-IV are associated with more chronic lesions and stages I-II with more active immunologic disease, the histological chronicity score seems to be a stronger predictor of long-term outcomes.