THE SIGNIFICANCE OF TRILINEAGE MYELODYSPLASIA IN DE-NOVO ACUTE MYELOBLASTIC-LEUKEMIA - CLINICAL AND LABORATORY FEATURES

A prospective study was undertaken to elucidate the clinical and labor atory differences between tie novo acute myeloid leukemia (AML) and AM L with trilineage myelodysplasia (AML-TMDS). One hundred and seven pat ients with AML were diagnosed at the University Hospital between Janua ry 1987 and July 1992, and were followed until July 1995. TMDS was ide ntified in 17 of them (16%). With regard to age and sex distribution n o difference was found between AML patients with and without TMDS (p = 0.43, p = 0.54, respectively). The duration of symptoms at presentati on in AML-TMDS was similar to those observed in de novo AML (p = 0.29) . Hemoglobin values and platelet counts were similar in both groups of patients (p = 0.45, p = 0.44, respectively). However, peripheral whit e blood cell and neutrophil counts, as well as blast counts in AML-TMD S patients were lower than those observed in AML without TMDS patients (p < 0.001 for all of them). Bone marrow blast counts in de novo AML were higher than the values observed in AML-TMDS patients (p < 0.001). TMDS occurred predominantly in M2 and M6 FAB types, and was absent in the M3 type. Bone marrow histology showed no particular feature that could be of diagnostic relevance. The remission rates were similar in both groups of patients (p = 0.55). The same was true for the probabil ity of disease-free survival and overall survival during the period of study (p = 0.50, p = 0.33, respectively). These results suggest that: 1) in AML-TMDS patients, leukemia transformation occurs in a more und ifferentiated pluripotent stem cell, leading to a dysplastic residual hemopoiesis besides the blast proliferation; 2) the incidence of TMDS in our group of patients did not influence the clinical outcome after treatment of the disease.