Functional expression of Fas (CD95) in acute myeloid leukemia cells in the context of CD34 and CD38 expression: Possible correlation with sensitivity to chemotherapy

Abstract

Clinical studies of bone marrow transplantation (BMT) suggest that the immune system contributes to the eradication of acute myeloid leukemia (AML). A recent study also showed that the Fas (CD95/APO1) mediates apoptotic signal from cytotoxic T lymphocytes. Sixty-four patients with AML were studied for the expression of Fas in the context of CD34 and CD38 coexpression. The clinical relevance of Fas expression and function on AML was also investigated. Fas was expressed on 2% to 98% of AML cells (2% to 20% in 11 patients, 20% to 50% in 20 patients, 50% to 80% in 24 patients, and 80% to 98% in nine patients). Only 44.4% of patients with AML M1 (French-American- British [FAB] classification) were Fas+ (≤20% of leukemia cells expressed Fas), whereas 89.1% of patients with AML M2, M3, M4, M5 were Fas+ (P < .06). We conclude that the majority of AML cells exhibit variable expression of Fas, and apoptosis could be induced by anti-Fas MoAb in some cases. Our results suggest the Fas- mediated apoptosis may be clinically relevant, whereas the issue of clonogenic leukemia cells and Fas expression needs further studies.