Qualitative platelet abnormalities in a patient with chronic idiopathic thrombocytopenic purpura (ITP).

Abstract

Summary A patient is described with active, chronic idiopathic thrombocytopenic purpura (ITP) and qualitative platelet abnormalities. An antiplatelet factor was demonstrated by the reduced survival of both autologous and isolo-gous platelets, and its identification as antibody suggested by positive tests for antiplatelet antibody. The major abnormalities of platelet function were reduced platelet adhesion in vivo and to glass, and reduced platelet aggregation with ADP, Ristocetin and collagen. ADP-induced aggregation of normal platelets was reduced by prior incubation of the normal platelets with the patient's platelet-poor plasma (PPP). It is suggested that abnormal platelet function in ITP may be an index of antibody activity, a determinant of premature platelet removal by the reticulo-endothelial system (RES) and a contributing factor to impaired haemostasis.