Amplification of fibrin generation and platelet thrombus accumulation as a function of the quantity of anti–β2-GP1 autoantibody infusion. Anti–β2-GP1 autoantibodies from patient B at various doses were infused into wild-type mice 5-15 minutes before laser-induced arteriolar wall injury. Fab fragments of rat monoclonal anti–mouse CD42 antibody conjugated to Dylight 649 and mouse anti–human fibrin monoclonal antibodies labeled with Alexa 488 were also infused to allow fluorescence detection of the platelet thrombus and fibrin. (A) Representative images of the fluorescence signal associated with platelets (red) and fibrin (green) over 180 seconds after vessel injury are for mice treated with anti–β2-GP1 autoantibodies from patient B. Yellow represents merge. (B) The median integrated platelet fluorescence (F Platelet; top panel) and the median integrated fibrin fluorescence (F Fibrin; bottom panel) as a function of time in 3 to 5 mice after infusion of 0 μg (n = 25 thrombi), 3 μg (n = 23 thrombi), 7 μg (n = 19), or 10 μg (n = 24) of anti–β2-GP1 autoantibodies derived from patient B. a indicates 0 μg; c, 3 μg; e, 7 μg; and f, 10 μg.
