Platelet function in chronic leukemias.

Bleeding time, clot retraction, platelet factor 3 availability and platelet aggregation in response to ADP, epinephrine, collagen and ristocetin were studied in 12 cases of chronic leukemia which included eight of chronic myeloid leukemia, two of chronic lymphatic leukemia and two of CLL related disorders. One or more abnormalities in platelet function were detected in all the cases. Among the cases of CML, bleeding time was prolonged in one, clot retraction was impaired in one and PF3 availability was decreased in one case. Defects in platelet aggregation were variable. Among the cases of CLL and CLL related disorders, bleeding time was prolonged in two, clot retraction was impaired in one and PF3 availability was decreased in three cases. Platelet aggregation responses were significantly impaired in all the cases.