New morphological findings on platelets in Bernard-Soulier syndrome

Bernard-Soulier Syndrome is characterized morphologically by many giant platelets in the peripheral blood. However, the mechanism of large platelet production has not yet been clarified. Our electron microscopic examinations revealed that some platelets have two or three definite circumferential bundles of microtubules, whereas no pathological findings were obtained in the liberation of platelets from megakaryocytes by light microscopy. From these observations, we consider that the giant platelets of Bernard-Soulier Syndrome are formed by fusion of two or three platelets while they are circulating in the peripheral blood stream.