Changes in peripheral blood leukocyte counts, lymphocyte subpopulations, and in vitro transformation after heart valve replacement. Effects of oxygenator type and postoperative parenteral nutrition.

We studied the effects of elective open-heart surgery with cardiopulmonary bypass on peripheral blood leukocyte counts, lymphocyte subpopulations, and in vitro transformation in 21 patients with heart valve disease. Peripheral blood showed significant neutrophilia with increases in the number of stab cells for up to 14 days postoperatively. In contrast, total lymphocyte count and the number of lymphocyte subclasses, as characterized by E, EA, and EAC rosette formation and surface membrane immunoglobulin markers, were significantly diminished on the second but not on the seventh postoperative day. Significant increases in the relative amount of atypical lymphocytes, characterized by both morphology and autoradiography, occurred for up to 14 days postoperatively. The transformation response of lymphocytes to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) was significantly decreased 2 days postoperatively, but values greater than the preoperative level were seen again 5 days later. The mixed lymphocyte culture (MLC) response was significantly decreased on the second day postoperatively, but returned to the preoperative level 5 days later. The stimulatory ability of lymphocytes in MLC and their response to purified tuberculoprotein were significantly lower than normal for up to 14 days after the operation. There were no differences in the changes of these parameters between patients perfused with bubble and membrane oxygenators, or between patients given conventional fluid therapy (approximately 6 kcal, per kilogram of body weight per day) and parenteral nutrition (approximately 40 kcal. per kilogram of body weight per day) for 4 days postoperatively. The results show a significant decline of lymphocyte count and impairment of their function immediately after open-heart surgery. The oxygenator type and the postoperative parenteral nutrition have no effect on these changes.