Reversible inhibition of natural killer cell activity by volatile anaesthetic agents in vitro.

NK cell cytotoxicity against the erythroleukaemia cell line K562 was studied, during and after the in vitro exposure to clinically-used concentrations of the general anaesthetic agents nitrous oxide, halothane and enflurane. Each of these agents produced a dose-dependent reduction in cytotoxicity. At approximately equipotent doses nitrous oxide produced less suppression than either halothane or enflurane whilst the combination of nitrous oxide with enflurane resulted in an additive suppressive effect. Cytotoxicity was not completely inhibited even by doses up to 12 MAC h. Reversibility of this suppression was demonstrated as cytotoxicity returned to normal within 1 h of the withdrawal of the anaesthetic. Therefore, postoperative immunity, mediated by NK cell cytotoxicity, is unlikely to be significantly depressed following anaesthesia with the agents investigated.