C3 and vasculitis: Recently, analysis for common gene variants in the CFH/CFHR1-CFHR5 gene cluster detected CFB, C3, and CD46 (MCP) genes, along with determination of plasma levels for C3, C4, FH, FHR-1/2/5, FB properdin, in 102 individuals with ANCA-vasculitis (54 active and the remaining in remission off immunosuppression).