Heterogeneous expression of dipeptidyl-amino-peptidase (DAP IV) in T-cell chronic lymphocytic leukemia.

The reactivity for the enzyme dipeptidyl-amino-peptidase IV (DAP IV) has been correlated, in 8 cases of T-cell chronic lymphocytic leukemia (T-CLL), with the cellular phenotype as well as the morphological and clinical behaviour of disease. A highly reproducible correspondence between the 'helper' phenotype (OKT4+/Fc mu-R+) and DAP IV expression was observed in cases with aggressive disease, whereas the cases with OKT8+/Fc mu-R+ phenotype was characterized by a favorable prognosis, LGL (large granular lymphocyte) morphology, and were virtually negative for DAP IV.