SERA FROM PATIENTS WITH HALOTHANE HEPATITIS CONTAIN ANTIBODIES TO HALOTHANE-INDUCED LIVER ANTIGENS WHICH ARE NOT DETECTABLE BY IMMUNOBLOTTING

In previous studies, immune responses to novel, halothane-induced hepa tic antigens have been implicated in the mechanism of halothane hepati tis. Experiments performed using the technique of immunoblotting have indicated that the halothane-induced antigens comprise a group of halo thane metabolite-modified microsomal proteins (trifluoroacetylated pro teins). tn the present report, we describe detection of an additional and quite distinct group of halothane-induced antigens. The novel halo thane-induced antigens were expressed in microsomal fractions from riv ers of halothane-treated rats and could be detected by enzyme-linked i mmunosorbent assay (ELISA), but not by immunoblotting. In contrast to the major trifluoroacetyl-protein antigens detectable by immunoblottin g, which were soluble in buffer containing 0.1% sodium deoxycholate, t he novel antigens detectable by ELISA were not soluble in 0.1% sodium deoxycholate but were soluble in 2% sodium deoxycholate. Expression of the novel antigens was reduced markedly when rats were treated with d euterated halothane, in place of halothane. This suggests that their e xpression requires metabolism of halothane via the same oxidative, cyt ochrome P450-mediated pathway known to be responsible for generation o f the antigens detectable by immunoblotting. Both the antigens detecta ble by ELISA and the antigens detected by immunoblotting were expresse d slowly in livers of halothane-treated rats and were long-lived. Over all, these results indicate that the technique of immunoblotting is of limited value for detection and characterization of antigens involved in immune-mediated adverse drug reactions.