Suppressive effects of thiopental and halothane on specific arms of the immune response.

The effect of thiopental, halothane and surgery on specific arms of the immune response of normal mice was studied. These experiments represent the first step in localizing a potentially correctable anesthesia/surgery-induced defect in immune reactivity which may be involved with postoperative increases in tumor growth. The delayed-type hypersensitivity (DTH) response of mice to 2,4-dinitrochlorobenzene (DNCB) was studied. Combinations of induction and inhalation anesthesia and surgery were administered at various phases of the immune response to DNCB. Thiopental impaired the afferent response while halothane impaired the efferent response. When the agents were combined, both arms of the immune response were suppressed. A surgical procedure, in most experiments, did not produce a greater immunosuppression than thiopental and halothane. The administration of an immunorestorative agent, thiabendazole, returned reactivity to normal levels. Thiopental and halothane either affect different immune cell populations or they affect different functions of a cell population active in both arms of the DTH response. In relation to tumor growth, the degree of suppression may not be as significant as the cell population impaired.