Clinical significance of glomerular C3 deposition in primary membranous nephropathy.

Abstract

We aimed to investigate the effects of glomerular C3 deposition on clinical, histopathological features, and outcomes of patients with primary membranous nephropathy (MN). A total of 261 patients with biopsy-proven primary MN, who were on follow up for at least 6months, were included in the study. The patients were grouped according to their C3 immunostaining in kidney biopsy samples at the time of diagnosis: Low intensity [LI; (C3 1 +)] and high intensity [HI; (C3 2 + or C3 3 +)]. The primary outcome was the development of kidney failure. Complete (CR) or partial remission (PR) was defined as secondary outcome. Sixteen patients reached the primary outcome after a median follow-up of 33.8months. Patients in the high intensitygroup (119 cases)had lower eGFR and higher proteinuria at admission and last follow-up compared to patients in the low intensity group(142 cases). Also, more patients in the high intensitygroup reached the primary outcome compared to patients in the low intensitygroup: twelve patients (10.1%) in the high intensitygroup and four patients (2.8%) in the low intensitygroup reached the primary outcome (p = 0.015). Kaplan-Meier analysis demonstrated that patients in the high intensitygroup had a higher risk for kidney failure(p = 0.02). In multivariate logistic regression analysis, high intensityC3 deposition and initial estimated glomerular filtration rate (eGFR) indepenentlypredicted primary outcome. Extensive glomerular C3 deposition is a predictor of kidney failure in patients with MN.