MAST-CELL TRYPTASE IN ANESTHETIC ANAPHYLACTOID REACTIONS

Increased concentrations of mast cell tryptase are a highly sensitive indicator of anaphylactic reactions during anaesthesia. We obtained se rum specimens from 350 patients after possible anaphylactic reactions during anaesthesia. Serum was collected from patients in our own insti tution (27), and transported by mail and courier from other hospitals in response to a request in the medical literature (323). Concentratio ns of mast cell tryptase were measured in 416 specimens. Intradermal t esting was performed in 217 patients and radioimmunoassay for drug-spe cific antibodies with serum in 198 patients. Mast cell tryptase concen trations were increased in 158 patients, equivocal in 10 and not incre ased in 182. There was a significant difference in the incidence of po sitive intradermal tests, radioimmunoassay tests and evidence of an Ig E-mediated reaction in patients whose mast cell tryptase concentration s were increased. Seven of 143 patients whose mast cell tryptase conce ntrations were not increased at appropriate sampling times had positiv e tests for IgE antibodies, and in 33 of 158 patients with increased m ast cell tryptase concentrations no IgE antibodies were detected. We c onclude that increased mast cell tryptase concentrations are a valuabl e indicator of an anaphylactic reaction during anaesthesia. Their pres ence favours an IgE-mediated cause but does not always distinguish bet ween anaphylactoid and anaphylactoid reactions, and patients in whom m ast cell tryptase concentrations are not increased still require skin testing.