Expression of CD 25 (Tac antigen) in lymphoid leukemias and non-Hodgkin lymphomas

A monoclonal antibody to IL2 receptor Tac/CD 25 antigen was included in the phenotyping panel of 92 leukemic proliferations. Spontaneous expression of this molecule was observed in one disorder of T-phenotype only, but in 75% of B-chronic lymphocytic leukemia (CLL) and on cells from B-cell leukemic lymphomas. These findings provide further evidence for a non-T-cell restriction of IL2 receptor and raise the question of multiple gene derepression in hematologic disorders of B-lineage.