Immunocytochemical Studies on Platelets. The Demonstration of a Common Antigen in Human Platelets and Megakaryocytes

By means of the fluorescent antibody technic of Coons and Kaplan it was possible to demonstrate a common antigenic structure in human platelets and megakaryocytes, both in nonthrombocytopenic cases and in cases with idiopathic thrombocytopenic purpura. Direct evidence for a marked increase in the number of platelets in the spleens of two cases of idiopathic thrombocytopenia is given. The pathogenetic significance of this finding is discussed. It is concluded that the fluorescent antibody technic is a valuable tool for the chemical and morphologic study of platelets and megakaryocytes both in tissues and smears.