Augmentation of interleukin-2 production after cardiac operations in patients treated with erythropoietin.

It has been reported recently that cardiac operations can be followed by a transient impairment of cell-mediated immunity. In this study we examined indices of cell-mediated immunity in patients undergoing cardiac operations. Twenty-five of the patients received erythropoietin (200 U/kg) daily for 2 weeks before and after operation, and 30 matched control patients did not receive erythropoietin. On postoperative day 1, the numbers of total T cells and helper/inducer T cells were significantly higher in erythropoietin-treated patients than in control patients. The ability of patients' cells to make interleukin-2 in vitro increased after erythropoietin injection in the preoperative period. By postoperative day 1, erythropoietin-treated patients exhibited a fall in interleukin-2 production that was significantly less than that in control patients; levels increased by day 2 to a mean value twice that of the preoperative baseline and more than four times the corresponding mean level in the control groups, and levels returned to the baseline range by postoperative day 14. Levels of interleukin-2 production in erythropoietin-treated patients were significantly higher than those in control patients at each interval tested through postoperative day 7. These findings indicate that erythropoietin treatment not only augmented levels of circulating erythrocytes but also improved indices of cell-mediated immunity. Although the mechanism responsible for this effect remains to be determined, the finding suggests that erythropoietin might help to ameliorate or prevent the impairment of immune function that can occur after cardiac operations.