C3 and primary membranoproliferative glomerulonephritis: Pre-transplant low complement, monoclonal gammopathy [1,53,82], C3 nephritic factor, and genetic abnormalities (CFH, CFI, MCP) [53,84,89,90] are risk factors. Other factors include young age, crescents in original biopsy, low BMI [10,85], shorter dialysis duration before kidney transplantation [87], and prior graft loss from MPGN [10].