Abstract:

Abstract Objective: To investigate the clinicopathologic features and the prognosis in patients with C3 glomerulopathy (C3G). Methodology: Fifty four cases with C3G were enrolled into this retrospective study. They were divided into two subtypes: C3 glomerulonephritis (C3GN, n=39) and dense deposit disease (DDD, n=15). Their clinicopathologic data and prognosis were investigated and compared. Results: They were 32 males and 22 females with an average age of 31.7±16.1 years old. They presented nephrotic syndrome in 44.4%, the low level of serum complement C3 in 81.5% and a higher titer of antistreptolysin-O (ASO) in 61%. They also showed multiple histologic patterns of glomerulopathy, such as membrane proliferative glomerulonephritis in 61.1% and mesangial proliferative in 27.8%. Immunohistology examinations showed that bright staining for C3 was evident within capillary wall in 98.1% patients and in the mesangium in 63% patients. 32 (59.3%) cases were accompanied by the deposition of immunoglobulin. Compared with C3GN, those with DDD were younger (P=0.011), the similar level of surem complement C3, lower level of serum albumin and fewer accompanied by hypertension (P=0.031). More patients with DDD showed membrane proliferative and crescentic glomerulonephritis and presented C3 deposition within renal tubular basement membrance and interstitial vascular wall (P<0.001), besides mesangium and capillary wall. Electron microscopy identified hyperosmiophilic dense deposits mainly occupying the lamina densa of the glomerular basement membrane, tubular basement membrane and Bowman’s capsule in DDD group, while intramembranous, mesangial, subepithelial and subendothelial deposits were found in C3GN. There was no difference in the cumulative incidence of poor renal outcome between two groups. Conclusion: We have described the histopathologic findings among the largest cohort of patients with C3G in Asian. Patients with C3G presented surem complement C3 below normal, mainly C3 deposit by immunofluoresence and confirmed by electron microscopy.

Key words: C3G, DDD, C3GN, clinicopathologic features, prognosis