Complement activation in thrombotic APS and CAPS. (A) Complement activation indicated by a positive mHam assay was detected in 35.6% of patients with APS and 85.7% of those with CAPS, compared with only 6.8% patients with SLE (P < .001). The percentage of patients with a positive mHam assay also increased in a triple-positive aPL profile (positive for lupus anticoagulant and anti-β2GPI and anti-cardiolipin antibodies) (B) and recurrent thrombosis (C). P values refer to the χ² test for trend in all cases.