Depression of lymphocyte responses after surgical trauma.

The peripheral blood lymphocyte responses to phytohaemagglutinin, pokeweed mitogen and tuberculin were investigated in 21 patients undergoing major surgical operations. Responsiveness to all three stimulants fell post-operatively, and the extent of the fall was related to the degree of operative trauma (arbitrarily assessed) but not to the length of the operation. These findings suggested that reduced responsiveness was due to trauma, or a reaction to it (possibly the increased levels of plasma cortisol found post-operatively, or release of an inhibitory substance from damaged tissue) rather than to the anaesthetic or to a redistribution of lymphocyte sub-populations. The hypothesis that reduced lymphocyte responsiveness was due to raised plasma cortisol levels was tested by exposing peripheral blood leucocytes to cortisol and phytohaemagglutinin the findings did not support this hypothesis.