Haemolysis in Patients with Chronic Lymphocytic Leukaemia during Extracorporeal Irradiation of the Blood

Erythrocyte destruction was studied in six patients with chronic lymphocytic leukaemia treated with extracorporeal irradiation of the blood (ECI). Before treatment all patients were anaemic. 51Cr‐labelling showed an apparent half‐life of 14 to 19 days indicating a reduced erythrocyte life span. 59Fe‐data were suggestive of random destruction of erythrocytes in four of the six patients. During the later part of the ECI period considerable reticulocytosis developed, and increased disappearance rate of 51Cr‐label was evident after a mean cumulative erythrocyte dose between 18,500 and 34,000 rads had been reached. This indicates the occurrence of haemolysis which was most pronounced in the one patient with a slightly positive Coombs' test. The 59Fe‐curves were either unaffected by the irradiation or showed only minor effects; since labelling was performed immediately before treatment, this indicates that young erythrocytes are less radiosensitive.