Amplification of thrombus size as a function of the quantity of anti–β2-GP1 autoantibody infusion. Anti–β2-GP1 autoantibodies from patient A or patient C at various doses were infused into wild-type mice 5 minutes before laser-induced arteriolar wall injury. Fab fragments of rat monoclonal anti–mouse CD41 antibody conjugated to Alexa 647 or rat monoclonal anti–mouse CD42 antibody conjugated to Dylight 649 were also infused to allow fluorescence detection of the platelet thrombus. (A) Representative images of the fluorescence signal associated with platelets (red) within the context of the bright-field histology are presented after vessel injury in mice treated with anti–β2-GP1 autoantibodies from patient A. (B) The median integrated platelet fluorescence (F Platelet) as a function of time in 3 separate mice after infusion of 0 μg (n = 22 thrombi), 3 μg (n = 25 thrombi), or 10 μg (n = 25) of anti–β2-GP1 autoantibodies derived from patient A. (C) The median integrated platelet fluorescence (F Platelet) as a function of time in 3 separate mice after infusion of 0 μg (n = 25 thrombi), 1.5 μg (n = 30 thrombi), 3 μg (n = 28 thrombi), 6 μg (n = 29 thrombi), 10 μg (n = 29 thrombi), and 65 μg (n = 24 thrombi) of anti–β2-GP1 autoantibodies derived from patient C. a indicates 0 μg; b, 1.5 μg; c, 3 μg; d, 6 μg; e, 7 μg; f, 10 μg; and g, 65 μg.
