Quinidine - Induced Thrombocytopenia and Leukopenia : Demonstration and Characterization of Distinct Antiplatelet

A patient with the rare syndrome of simultaneous quinidine-induced thrombocytopenia and leukopenia was studied. A quinidine-dependent antiplatelet antibody was detected in her serum by platelet aggregometry and by indirect platelet-suspension immunofluorescence. A drugdependent antileukocyte antibody was demonstrated by leukoagglutination and by granulocyte immunofluorescence. Both antibodies were found to belong to the lgG class by immunofluorescence using monospecific antisera. There appeared to be two distinct antibodies. since the antibody eluted off sensitized platelets reacted only with platelets and that eluted off sensitized granulocytes