Complete homozygous deficiency of CFHR1. A) Plasma samples of patients and healthy controls were separated on 12% SDS-PAGE, transferred to a PVDF membrane, and analyzed by Western blotting using a mouse monoclonal antibody against FH (C18/3) that identifies FH (150 kDa) and the two differently glycosylated forms of CFHR1α and CFHR1β (37 and 42 kDa). Plasma samples of healthy controls are shown in lanes 8 and 9. CFHR1 positive patients were found for aHUS (lane 2), RA (lane 4), SLE (lane 6) and LA+ (lane 7). Patients with total CFHR1 deficiency are shown for aHUS (lane 1), RA (lane 3) and SLE (lane 5). Lane 10 shows purified FH. B) Complete CFHR1 deficiency in whole patient groups (including FH-autoantibody positive and negative patients) determined using Western blotting. C) Complete CFHR1 deficiency in FH-autoantibody positive individuals in different disease and control groups. Numbers indicated above bars in the panel C represent number of CFHR1 deficient patients vs. total number of patients positive for FH-autoantibodies.