Halothane-induced suppression of cell-mediated immunity in normal and tumor-bearing C3Hf/He mice.

The present investigation was designed to demonstrate whether depression of cell-mediated immunity in tumor-bearing hosts is potentiated by halothane anesthesia. Both the in vivo and in vitro effects of halothane anesthesia on splenic lymphocytes from normal and tumor-bearing C3Hf/He mice were examined by lymphocyte transformation. The stimulation index (SI) of lymphocytes from normal C3Hf/He mice exposed to 1.5% halothane/98.5% oxygen anesthesia was significantly less than that of lymphocytes from normal C23Hf/He mice exposed to oxygen (SI of 25.3 and 33.6, respectively) (p < 0.001). Lymphocytes from tumor-bearing C3Hf/He mice demonstrated the greatest degree of immunosuppression by halothane when compared to those of normal (non-tumor-bearing) mice. That the tumor was the principal immunosuppressive factor was demonstraed by the SI of 34.6 for the non-tumor-bearing mouse lymphocytes and 4.1 for those of the mice with fibrosarcomas (p < 0.001). Lymphocytes from tumor-bearing hosts exposed to 1.5% halothane anesthesia demonstrated diminished lymphocyte transformation compared with those from control (tumor-bearing) mice exposed to oxygen (SI of 1.7 and 4.4, respectively) (p < 0.001). In both tumor-bearing and normal mice, there was a significant suppression of the cell-mediated immune response when the animals were exposed to halothane compared to exposure to oxygen. Results of this investigation demonstrate that halothane anesthesia potentiates the suppression of cell-mediated immunity observed in tumor-bearing hosts.