The effect of glomerular c3 deposition on renal outcome in patients with membranous nephropathy: data of the tsn-gold study

Abstract Background and Aims We aimed to evaluate the effect of glomerular C3 deposits on clinical and laboratory findings and outcome in patients with idiopathic membranous nephropathy (MN) included in the Primary Glomerular Diseases Study of Turkish Society of Nephrology Glomerular Diseases Study Group (TSN-GOLD). Method The data of 1595 patients with MN in the database has been evaluated. 114 patients were excluded due to lack of data about C3 staining, 54 patients due to secondary MN and 523 due to lack of data about the follow-up. Patients with glomerular C3 deposits were compared with those with no C3 staining. Results Glomerular C3 deposits were detected in kidney biopsy specimens of 601 patients of the 888 patients analysed. The demographic data, clinical and laboratory findings at the time of diagnosis of C3 (+) and C3 (-) groups are presented in Table 1. They were similar except serum albumin level that was lower in C3 (+) group. Subepithelial deposits and interstitial fibrosis was more prominent, IgG, Kappa and Lambda staining more intense, positivity for C1q and IgA was more frequent in C3 (+) group (Table 2). The study groups were similar regarding remission rates after the first imuunosuppressive treatment (p = 0.582). 155 patients (25.8%) had partial, 152 (25.3%) had complete remission while no remission was detected in 92 patients (15.3%) in C3 (+) group. 69 patients (24.0%) had partial and 81 patients (28.2%) had complete remission; 40 patients (13.9%) had no remission in C3 (-) group. The relapse rates were 17.6% and 19.9% in C3 (+) and C3 (-) groups (p = 0.360). The percentage of patients who died or needed renal replacement therapy (RRT) were higher C3 (+) group (p = 0.013) (Figure 1). Conclusion Need for RRT and mortality is higher in patients with C3 deposition showing the importance of C3 deposition in the prognosis of MN. More prominent interstitial fibrosis may be related with the worse outcome.