PROGNOSTIC VALUE OF CELL MARKER ANALYSIS IN DE-NOVO ACUTE MYELOID-LEUKEMIA

Clinical and cytologic characteristics were correlated to immunologic markersin 154 patients with newly diagnosed acute myeloid leukemia (AM L). The panel of monoclonal antibodies (MoAbs) was selected to identif y differentiation-associated antigens of both the myeloid and the lymp hoid lineages (CD13, CD33, CD14, CD15, CD7, CD34, CD10, HLA-DR, CD19, CD2, CD5, TdT). The expression of multidrug resistance P-glycoprotein (P-170) was also evaluated in 117 patients. Differences in antigenic e xpression was observed among the various French-American-British (FAB) subgroups. HLA-DR was poorly expressed on the blasts of acutepromyelo cytic leukemia (M3), and was always found in FAB M5. CD34 was detectab le in all MO cases and only in one M3 (p < 0.001). Lymphoid-associated antigens were positive in 74 cases (48.1%). In particular, CD7 was fo und in 49 patients (31.8%), and TdT in 30 (21.3%), 15 samples displayi ng coexpression of these two antigens. The incidence of CD7+ cases was particularly elevated in MO and M5 AML (p = 0.005). It significantly correlated with the expression of CD34,HLA-DR, P-170 (p < 0.001, p = 0 .018 and p = 0.034 respectively), and with a leukocyte count > 50 x 10 (9)/I (p = 0.038). Sixty-nine (59%) samples demonstrated P-170 positiv ity. Again, this phenotype was particularly expressedin the poorly dif ferentiated forms (M5, M0 and M1) and showed significant correlation w ith the immaturity markers CD34, CD7 and HLA-DR (p = 0.013, p = 0.022 and p = .001, respectively). Expression of individual antigens correla ted with prognosis. Refractoriness to first line therapy was associate d with CD7 expression (p = 0.002) and P-170 (p = 0.001). The CD7 marke r was also significantly associated with a very low overall survival ( p < 0.001) and continuous complete remission (p < 0.001). CD14 express ion also significantly predicted lowersurvival rates (p = 0.033). The combination (CD7+ CD14+) identified a subset of patients with a partic ularly adverse outcome. The prognostic value of CD7 expression, alone or in combination with other markers, was confirmed in multivariate an alysis.