MBL2 and systemic lupus erythematosus: For example, autoantibodies against factor B have been detected in C3 glomerulopathy and membranoproliferative glomerulonephritis (MPGN) (88, 89), antibodies against factor I in aHUS (90), antibodies against MBL in rheumatoid arthritis (91), and antibodies against ficolins in SLE (92, 93).