Extracorporeal irradiation of the blood in humans: effects upon erythrocyte survival.

By LEWIS M. SCHIFFEII, HAII0u L. knar’s, AIIJUN D. CIIANANA, EUGENE P. CRoNKITE, MICHAEL L. GREENBERG, HORTON A. JOHNsoN, J AMES S. ROBERTSON AND PIERRE A. STIIYCKMANS T HE FIRST SUCCESSF’UL EXPERIMENTS utilizing extracorporeal irradiation of the blood ( ECIB ) to deplete the body of lymphocytes were performed by Cronkite et al. using the cow as an experimental animal.1’m It soon became evident that continuous prolonged ECIB produced hemolytic anemia and hemoglobinuria. Thus, despite the fact that erythrocytes arc more radioresistant than leukocytes, it was shown that sufficient irradiation shortens their lifespan and produces hemolysis. Mathematical analysis designed to measure the accumulated dose distribution to the erythrocytes indicated that hemoglobinemia did not occur to any significant extent until at least 25 per cent of the circulating erythrocytes received over 100,000 rads. Further studies on bovine erythrocyte survival after in vitro gamma irradiation have been performed4 and will be considered later. The clinical application of ECIB in human beings as a method of reducing lymphocyte populations of the body and for destroying leukemic leukocytes has been initiated by at least two other groups besides ollrselves.5,h In view of the interest expressed by many investigators in the potential uses, amid possible harmful effects, of ECIB, it was considered important to explore the effects of large doses of irradiation upon