C3 and IgA glomerulonephritis: In the present study, C3 glomerular expression was found to be more pronounced in PMN with crescent bodies, considering the involvement of C3 in crescent body formation in IgA nephropathy and the presence of complement response activation in the latter [20]; whereas previous studies found that there may be local dysregulation of glomerular complement in the formation of crescent bodies in small-vessel vasculitis [21, 22], we consider that complement response may contribute to crescent body formation in PMN, However, the exact mechanism needs to be further investigated.