Differential expression of CD25 and HC2 antigens on subtypes of acute myeloid leukemias.

The presence of CD25 and HC2 antigens in 66 different patients with acute myeloid leukemia (AML) was investigated. The expression of both antigens was observed in 32% of AML cells. Dual fluorescence staining experiments performed in 5 AML patient cells showed that CD25 and HC2 antigens were simultaneously expressed in a single cell. The expression of both antigens was mainly observed in the M4 and M5 subtypes of AML. Although immunopurified IL-2 was able to block the binding of anti-CD25 monoclonal antibody to the AML cells, the IL-2 receptor did not appear to be functional.