Two MPGN patients were reported with FH-autoantibodies inhibiting the cofactor activity of FH and C3b cleavage by FI [22,25], and three out of eight FH-autoantibodies from patients with AP-mediated glomerulopathies impaired, but not completely inhibited FH cofactor function [23]. Here, FH is linked to primary membranoproliferative glomerulonephritis.