DIAGNOSIS OF IGE-DEPENDENT ANAPHYLAXIS TO NEUROMUSCULAR BLOCKING-DRUGS, THIOPENTONE AND OPIOIDS

Although allergenic cross-reactivity of neuromuscular blocking drugs ( NMBDs) is recognised clinically and has been firmly established at the serological and immunochemical levels, interpretation of in vitro inh ibition findings for clinical purposes is not always straightforward. Points to be taken into account when considering serum IgE direct bind ing and inhibition results and when determining which NMBDs a patient may be sensitive to, include the relationship between in vitro potenci es and clinical findings and the nature of the drug solid phase used f or testing. It should also be remembered that the stimulating antigeni c source for the patients' NMBD-reactive IgE antibodies is almost alwa ys unknown. A comparison of skin and IgE radioimmunoassay (RIA) tests for NMBDs in 29 patients is presented and difficulties involved in int erpreting the results of both tests are discussed. Methods for increas ing the detection of NMBD-reactive IgE antibodies are outlined. In scr eening sera of patients for IgE antibodies to thiopentone and morphine as well as NMBDs, multiple drug reactivities have been detected in a few subjects. Attention is drawn to defects in the existing thiopenton e RIA although it is clear that the test is specific in patients who r eact to the drug. Addition of the serum tryptase assay to skin tests a nd IgE RIAs for NMBDs, thiopentone and morphine provides a powerful co mbination of diagnostic tests for the investigation of anaphylactoid r eactions to anaesthetic drugs.