Lymphocyte sub-populations following splenic irradiation in patients with chronic lymphocytic leukaemia

Four patients with chronic lymphocytic leukaemia were treated with splenic irradiation, 100 rads per week for 10 weeks. No patient had received prior therapy of any kind. All patients showed an excellent clinical response in terms of decrease in lymphocyte count in blood and bone marrow and decrease in lymph node and spleen size. B and T cell populations returned to normal in all patients as did the ratio of TG to TM cells. Two patients showed an increase in IgM levels, but the overall pattern of immunoglobulins showed no consistent change following treatment. No toxicity was incurred during treatment. We conclude that splenic irradiation is a safe and effective treatment of previously untreated patients with CLL and is associated with a return to normal of lymphocyte sub-populations. The role of the abnormal T cell population in the pathogenesis of the hypoimmunoglobulinaemia remains unclear.