Abstract
Adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities were measured with the lymphocyte fraction from patients with various lymphoproliferative disorders. The ratio of ADA activity to PNP activity (ADA/PNP) was high in T-cell malignancies including T-cell chronic lymphocytic leukemia, adult T-cell leukemia, Sézary syndrome and T-cell lymphosarcoma and one case with null cell lymphosarcoma. The values determined in other lymphoproliferative disorders and nonlymphocytic leukemias were low and equivalent to the values (<1) obtained in nomal controls. These results suggest that undifferentiated T-cells have high ADA/PNP ratios and higher values indicate more undifferentiated T-cell malignancies.
