Platelet Size and Kinetics in Hereditary and Acquired Thrombocytopenia

Abstract

Measurements of platelet size and life-0 span were obtained to classify a variety of thrombocytopenic states. The mean size index in idiopathic thrombocytopenic purpura was significantly increased, whereas platelets in the Wiskott–Aldrich syndrome were small. The platelet defect in a family characterized by thrombocytopenia, sex-linked recessive inheritance, small platelet size and shortened platelet life-span closely resembled that of the Wiskott–Aldrich syndrome, but only mild eczema was present and immunologic abnormalities were absent. In a second family, thrombocytopenia was associated with increased platelet size suggesting a young cell population similar to idiopathic thrombocytopenic purpura. However, autologous platelet life-span was normal. Size measurements are thus useful in the classification of thrombocytopenias. Although in acquired conditions increased platelet size suggests a young platelet population, in hereditary disease platelet size is determined more by the nature of the intrinsic platelet defect than by mean cell age.