Identification by immunoblotting of three halothane-induced liver microsomal polypeptide antigens recognized by antibodies in sera from patients with halothane-associated hepatitis.

Previous studies have demonstrated that sera from patients with severe liver damage after halothane anesthesia ("halothane hepatitis") contain antibodies reacting with novel antigenic determinants expressed on hepatocytes from rabbits exposed previously to halothane. To determine the structure of the halothane-induced antigen(s), immunoblotting experiments were performed using patient sera and rabbit liver subcellular fractions. Three polypeptide antigens (Mr 100,000, 76,000 and 57,000) expressed in liver fractions from animals sacrificed 16 hr after exposure to 1% halothane in oxygen for 45 min, but not in fractions from unexposed animals, were identified. Analysis of fractions prepared by differential and sucrose density gradient centrifugation, and characterized by enzyme marker analysis, localized all three antigens to a microsomal subfraction relatively enriched in glucose-6-phosphatase activity, therefore, presumably derived from the endoplasmic reticulum. Antibodies to these antigens were detected in 19 of 24 sera from patients with halothane hepatitis, and four distinct patterns of antibody specificity were observed: 100,000 + 76,000 (seven patients), 100,000 alone (seven patients), 76,000 alone (three patients) and 57,000 alone (two patients). Such antibodies were not detectable in sera from 24 normal blood donors or 36 control patients. Thus, halothane induces expression of three distinct polypeptide antigens in liver, and patients with halothane hepatitis differ in patterns of recognition of these antigens by circulating antibodies.