Lymphocyte function in the critically ill surgical patient.

Lymphocyte function is commonly altered in critical ill surgical patients. There is controversy whether or not formation of antibodies is impaired; however, cellular immune responses are routinely depressed. Patients who have suffered major surgical or accidental trauma or burns frequently become anergic. Their lymphocytes respond poorly to mitogenic or antigenic stimulation, and serum factors suppressive of lymphocyte activation appear. Mechanisms underlying these abnormalities remain to be defined.