Apoptosis in acute myeloblastic leukemia: follow-up study on trephine biopsies of the bone marrow

A clinicopathological study on 87 adult patients presenting with "de novo" acute myeloblastic leukemia (AML) was performed to assess the rate of apoptosis before and during chemotherapy and its predictive impact on clinical course. Evaluation included trephine biopsies of the bone marrow and the situ end-labeling technic (ISEL) for the identification of programmed cell death in large and intact hemopoietic tissue areas. In comparison with a control group of 21 patients without any hematological disorder, morphometric analysis revealed no significantly different numbers of apoptotic cells in AML at the onset of disease and following sequential examinations at intervals ranging between 10 to 19 months. Moreover, the incidence of programmed cell death was not associated with the subgroups of the FAB classification and statistics failed to show a relationship with survival or remission status. In conclusion, these findings are in keeping with the assumption that apoptosis occurs with the same frequency in recovering normal hemopoiesis in complete or partial remission, in manifest AML and relapse. In the latter conditions, enhancement of proliferation is not associated with an increase in the apoptotic index.