C4A and IgA glomerulonephritis: Regarding the role of complement components in IgA nephropathy, we calculated its centrality values:c3 (0.11), complement factor h (0.05), c4 (0.02), anti c1q autoantibody (0), c1q (0), c3a receptor (0), c3b inactivator (0), c3bi receptor (0), c3c (0), c4a (0), c4d (0), c5b-9 (0).