HYDROXYCHLOROQUINE REVERSES THROMBOGENIC PROPERTIES OF ANTIPHOSPHOLIPID ANTIBODIES IN MICE

Background Previous studies have demonstrated that human monoclonal an d polyclonal anticardiolipin antibodies have thrombogenic properties i n vivo. Using such a model in which these antibodies have been shown t o increase both the size of an induced thrombus and the duration of ti me in which such a clot lasts, we investigated whether hydroxychloroqu ine alters the dynamics of such thrombus formation. Methods and Result s Three groups of nine mice were injected with purified immunoglobulin G (IgG) from a patient with the antiphospholipid syndrome (IgG-APS) a nd then fed with hydroxychloroquine at various doses (100, 6, and 3 mg /kg body wt). Three control groups of mice were also studied, includin g mice injected with IgG-APS and then fed with placebo, as well as two other groups injected with IgG from normal human serum and fed either hydroxychloroquine or placebo. A standardized thrombogenic injury was subsequently induced in the femoral vein of each mouse and the area ( size) of thrombus measured as well as the total period of time that th rombus was present. Mice treated with hydroxychloroquine and IgG-APS s howed significantly smaller thrombi that persisted for a shorter perio d of time compared with animals treated with IgG-APS and placebo. Conc lusions Hydroxychloroquine significantly diminished both thrombus size and total time of thrombus formation in mice previously injected with IgG-APS.