IMPAIRED B LYMPHOCYTE FUNCTION DURING OPEN-HEART SURGERY Effects of Anaesthesia and Surgery

B lymphocyte function m vitro was measured in patients undergoing open-heart surgery. Conventional balanced anaesthesia, or high-dose fentanyl anaesthesia was used. Pokeweed mitogen (PWM) induced lymphocyte transformation was depressed at the end of the operation, but the response to formalinized Stapkylococcus aurtut Cowan I (StaCw) was not. The numbers of immunoglobulin producing and secreting cells measured by an indirect protein A plaque-forming cell assay decreased after PWM-stimulation, but remained unchanged after StaCw stimulation at the end of the operation. IgG, IgM and IgA secretion by PWM- and StaCw-stimulated lymphocytes, into the culture medium, was depressed in the period after operation. Depressed immnrw functions occurred after open-heart surgery, but not in association with anaesthesia alone before surgery. The decreases were not mediated by hydrocortisone-sensitive suppressor cells. Minor differences between the two anaesthetic techniques were found in lymphocyte proliferative responses. Anaesthesia and surgery affect the immune defence mechanisms, but it has been shown that anaesthesia per se has either none, or only minor immunological effects. In contrast, surgical trauma can cause im