Transformation delay of lymphocytes in patients undergoing radiation therapy.

Two types of assay systems to measure the effect of radiation on immune competence are described. The first, transformation, is measured by blast formation or uptake and incorporation of tritiated thymidine by lumphocytes. This measure is affected by a number of known cell responses to radiation such as division delay and delay in DNA synthesis. The second, called Bactec, is designed to measure lymphocyte metabolic acitivty. Data gathered on 37 patients with lung cancer show that the Bactec system provides a better index of the patient's immune status before and after radiation therapy.