Increased T-lymphocyte numbers in chronic granulocytic leukemia before treatment.

We measured the numbers of B- and T-lymphocytes in the peripheral blood of 40 patients with chronic granulocytic leukemia (CGL) at different stages in the chronic or stable phase of the disease. In untreated patients and in treated patients with relatively high leukocyte counts, T-cell numbers were increased: in the majority of cases this increase involved both "helper" (OKT4+) and "suppressor" (OKT8+) cells. B-cell numbers were normal. Patients whose leukocyte counts had been restored to normal by treatment with cytotoxic drugs had normal T-cell numbers, but B-cell numbers were reduced in comparison with normal persons. We conclude that untreated CGL is usually associated with a T-cell lymphocytosis that can be reversed by chemotherapy. The excess of T-lymphocytes in the blood before treatment is probably an immunological response to the neoplastic proliferation, but the possibility that some T-lymphocytes might be involved in the malignant clone cannot be excluded.