RECURRENT VENOUS THROMBOSIS AS THE PRESENTING MANIFESTATION OF ACUTE LYMPHOCYTIC-LEUKEMIA - LEUKEMIC-CELL PROCOAGULANT ACTIVITY IS NOT RESPONSIBLE FOR THE HYPERCOAGULABLE STATE

The association of cancer with clinical abnormalities of blood coagula tion, including superficial thrombophlebitis, deep vein thrombosis (DV T), and disseminated intravascular coagulation (DIC) is well-known, pa rticularly in patients with solid tumors and acute promyelocytic leuke mia (APL). Less commonly appreciated is the potential for the developm ent of venous thromboembolic disease (TED) in patients with acute lymp hocytic leukemia (ALL). Multiple mechanisms have been implicated for t he activation of coagulation in these patients, with an emphasis on th e contribution made by the procoagulant properties of the tumor cells themselves. We present two cases of patients with pre-B cell ALL, both of whom developed recurrent TED as the presenting manifestation of th eir leukemia and/or heralding relapse. The blast cells from one of the patients were studied for the presence of procoagulant activity (PCA) and by Northern blot analysis for tissue factor (TF) messenger RNA (m RNA). Neither PCA nor TF mRNA could be identified in highly purified p opulations of the lymphoblast cells. We conclude that recurrent TED ca n be a manifestation of ALL and that mechanisms other than the release of tumor cell procoagulants should be sought to explain the pathogene sis of thrombosis in some patients. (C) Wiley-Liss, Inc.