RETINOIC ACID-DEPENDENT GENE TRANSACTIVATION BY PML-RAR · WITHOUT

APL is a distinct subtype of acute myeloid leukemia char-acterized by the severe alteration of hemostasis at the onset, that is accentuated after the introduction of chemotherapy. Modern treatment with retinoic acid has permitted a better management of APL related coagulopathy. This study eval-uates the hemoststic parametres in 31 APL patients with relapse. Clinical examination showed a greater incidence of severe hemorrhagic syndrome at onset compared with the moment of relapse. Biological data showed superior values of hemoglobin, circulating leukemia cells and platelets at relapse compared with the initial data. At the same time, coagulation parameters (fibrinogen, APTT, AP, TQ, TMF, FDP) where less altered at relapse than at onset. On the oth-er hand, the incidence of severe hemorrhagic complications is greater during the treatment of relapse with 25,8 % deaths caused by cerebral hemorrhage. Coagulation data showed the predominence of severe coagulopathy and a slower nor-malization of coagulation parameters and platelets at relapse. This data suggest the possible action of different mechanisms in the pathogenesis of APL related coagulopa-thy at onset and during relapse, that might by an explana-tion for the severe course of coagulopathy at relapse. WORKSHOP I