Surface marker expression in adult acute myeloid leukaemia: correlations with initial characteristics, morphology and response to therapy.

The clinical significance of surface markers was investigated in 145 cases of acute myeloid (AML) or undifferentiated leukaemia (AUL), using a panel of six monoclonal antibodies directed to NHL-30.5 antigen (expressed on poorly differentiated myeloid cells), CD13, CD14, CD15, CD33 and CD34 antigens. Expression of CD14 was correlated with higher leucocyte count, higher serum lactate dehydrogenase level and presentation with extramedullary disease. There was no strict correlation with the French-American-British classification. However, the expression of CD14 was associated with monocytic subtypes. CD15 was mainly expressed in M2 and M3 subtypes, and NHL-30.5 and CD34 antigens in AUL and M1 leukaemias. All patients were treated with the same intensive induction treatment. Staining by three antibodies had a prognostic value. The complete remission (CR) rates were 38% (26/68) in NHL-30.5-positive versus 75% (62/77) in NHL-30.5-negative cases (P less than 10(-5), 50% (37/74) in CD34-positive versus 72% (51/71) in CD34-negative cases (P = 0.007) and 70% (77/110) in CD15-positive versus 31% (11/35) in CD15-negative cases (P less than 10(-4). Expression of NHL-30.5 and CD34 antigen was associated with shorter survival (P less than 10(-3) and P less than 10(-2) respectively), whereas survival was longer in CD15-positive cases (P less than 10(-3). In multivariate analysis, expression of NHL-30.5 antigen, absence of CD15, and high LDH level were associated with poor survival. CR duration was not influenced by any of the factors studied, including antigen expression. These results suggest that leukaemias with less differentiated phenotype have a lower response rate to induction treatment.