Immune system changes in cytapheresis donors.

In vitro measurements of several variables of the immune system were made in 21 healthy donors who had been subjected to frequent cytapheresis an a group of whole blood donor controls matched for age and sex. Significant changes noted in the apheresis donors compared to controls included a 23 percent lower mean absolute lymphocyte count (p less than .01), a 25 percent lower mean T cell count (p less than .01), and a 46 percent lower mean B cell count (p less than .001). Serum protein changes included a 27 percent lower mean gamma globulin level (p less than .01), and 14 percent lower mean IgG level (p less than .05) in the apheresis donors when compared to the control group. The possible implications of these findings are discussed, and we suggest that donors undergoing multiple cytapheresis procedures be closely monitored to determine the safe donation frequency.