Abstract:

Ｏｂｊｅｃｔｉｖｅ：To analyze clinicopathological and renal prognostic features of postinfectious glomerulonephritis with isolated C3 deposition(C3PIGN).
Ｍｅｔｈｏｄｏｌｏｇｙ：postinfectious glomerulonephritis(PIGN)and C3 glomerulonephritis(C3GN)diagnosed by renal biopsy from 2009 to 2015 were enrolled in this study.
Ｒｅｓｕｌｔｓ：(1)43 cases of PIGN with C3 deposition(C3PIGN)，46 cases of PIGN with Ig and C3 deposition(Ig+C3PIGN)and 52 cases of C3GN were included in this study.(2)In comparison with Ig+C3PIGN,C3PIGN group has lower rates of nephrotic range proteinuria,hypoalbuminemia,crescents,tubular atrophic interstitial fibrosis(IFTA),mesangial and subendothelial electron dense deposits.(3)In comparison with C3GN,C3PIGN group has higher proportion of children,shorter duration of disease,higher rates of microscopic hematuria and lower rates of nephrotic range proteinuria and hypoalbuminemia.The proportion of global sclerosis,IFTA,hyaline degeneration of arteries and mesangial and subendothelial electron dense deposits were lower in C3PIGN group.However,There were no differences in complement C3 fragment deposition between two groups.(4)32 patients with C3PIGN recovered completely within 1 year and 7 patients presented with persistented proteinuria and/or hematuria,among which 5 patients gradually turned negative,while 2 patients did not go to remission,suggesting that there is an imbalance in the alternative pathway of complement activation,consistent with the diagnosis of C3GN.
Ｃｏｎｃｌｕｓｉｏｎ：
Compared with Ig+C3PIGN and C3GN,the clinical and histopathological changes of C3PIGN were mild,but the same C3 fragment was deposited in glomeruli of both C3PIGN and C3GN.Longterm followup of patients with C3PIGN should be performed in order to detect C3GN patients who are clinically diagnosed as “C3PIGN” with infection as the cause.