Autoantibodies against complement proteins in patients with antiphospholipid syndrome: Prevalence and clinical associations

Abstract

Seventy‐seven patients with antiphospholipid syndrome were tested for autoantibodies against C1q, C3, FB, FH, and C4bp. Fifty‐seven patients had at least one anti‐complement antibody. IgM anti‐FH positivity was associated with thrombosis when anti‐C3 and anti‐FB were, negatively or positively, associated with various noncriteria manifestations of antiphospholipid syndrome.