Relationship between in vitro and in vivo radiosensitivity of lymphocytes in chronic lymphocytic leukemia

A significant positive correlation was obtained between the in vitro radiosensitivity of the blood lymphocytes of patients with chronic lymphocytic leukemia (CLL) and the in vivo response of the total leukocyte count subsequent to radiation therapy. Four types of equations were used to represent and measure the effect of in vitro X-irradiation on lymphocytes from CLL patients and measure the response of patients to a course of radiotherapy. For the in vivo analysis we used data from 10 patients who were routinely treated with a total of 16 courses of radiation therapy. The total leukocyte count showed a uniform exponential decline during a course of therapy. According to the literature, about 25% of all CLL patients and about 50% of CLL patients with advanced disease are resistant to chemotherapy. The equations and indices of the present study may be useful to diagnose CLL patients who are prone to be resistant to chemotherapy.