Depression of cellular immunity after open-heart surgery

Using a whole blood test system we investigated cell-mediated immunity in 45 patients undergoing open-heart surgery. The peripheral blood lymphocytes were stimulated with the nonspecific mitogens phytohemagglutinin, concanavalin A and pokeweed mitogen, one bacterial recall antigen, tuberculin PPD, and one viral antigen, herpes simplex virus. The patients were tested three times: pre-operatively, and seven days and 2 wks post-operatively. There were no significant differences between a control group of healthy blood donors and the patient group tested preoperatively. However, seven days after operation we observed a clear decrease of the reactions to all stimulants. Two weeks after operation there was an increase of lymphocyte proliferation data in regard to tuberculin PPD and herpes simplex virus. Concerning the nonspecific mitogens PHA and PWM, there was only a tendency of an increase. We believe that two weeks after operation is too short an interval to notice a full normalization of the cellular immune functions. In comparison with the conventional system of isolated lymphocytes, the whole blood technique is advantageous in investigating cell-mediated immunity, particularly if the patient groups are large.