Host defense mechanisms in surgical patients: effect of surgery and trauma.

Numerous experimental and clinical studies have documented that trauma-including surgery-alters the immune response, and that the response is a function of the magnitude of the injury or operation. The abnormalities seen after surgical operations on humans or animals include decreased antibody response, decreased neutrophil chemotaxis, decreased delayed-type hypersensitivity reaction, abnormal neutrophil adherence, serum immunosuppressive factors, decreased fibronectin levels, reduced serum opsonic activity, and reduced efficacy of interleukin-2. These abnormalities involve all aspects of the host defense mechanisms, both the cellular and humoral mediators and the specific and nonspecific immune responses. The capacity to control these responses in surgical patients may have important clinical applications.