C5AR1 and vasculitis: The serum anti-C5aR antibody levels in the membranous nephropathy group (n = 18) (p < 0.001), focal and segmental glomerulosclerosis group (n = 25) (p < 0.001), IgA nephropathy group (n = 14) (p = 0.002), mesangial proliferative (non-IgA) glomerulonephritis group (n = 6) (p = 0.008), control group (n = 22) (p < 0.001), c-ANCA vasculitis group (n = 40) (p < 0.001), and p-ANCA vasculitis group (n = 16) (p = 0.006) were all lower than the serum anti-C5aR antibody levels in the lupus nephritis group (n = 17) (Figure 3).