Development and use of three new radioallergosorbent tests in the diagnosis of penicillin allergy.

The synthesis and characterisation of three novel reagents for use in the radioallergosorbent test (RAST) for the diagnosis of penicillin allergy are described. The antigenic determinants involved are the benzyl penicillanyl, thiol-linked benzyl penicillenate and thiol-linked penicillamine. These reagents, and also one specific for the benzyl penicilloyl group, have been used to evaluate the sea of subjects suspected of suffering from penicillin allergy and to explore the aetiology of the respiratory dyspnoea experienced by some workers exposed to penicillin-containing dusts. The use of these reagents, while confirming the importance of the penicilloyl or major determinant of penicillin allergy, has shown that there is heterogeneity in the IgE response of penicillin-allergic patients and some patients have IgE antibody specific for one or more of the new determinants only. These reagents will, therefore, increase diagnostic capabilities. Their use has also confirmed that the disorder induced by occupational exposure to penicillins is not primarily mediated by IgE antibody specific for allergenic determinants represented by any of the available reagents.

The development and validation of radioallergosorbent tests for the detection of specific human IgE antibody directed against laboratory animal urinary proteins.

Radioallergosorbent tests (RAST) using urinary proteins from mice, rats, guinea pigs and rabbits have been developed and used in the diagnosis of laboratory animal allergy (LAA). Of the 273 subjects tested, 15 had been previously diagnosed as laboratory animal allergic and 8 of these (53%) gave one or more positive RAST results. Of the 258 symptom-free individuals, only 9 (3.5%) had one or more positive RAST. Of these 9, 7 had previously worked with animals or had occupational exposure to the appropriate species; the remaining 2 individuals had only some pet exposure. RAST was, therefore, of value in the diagnosis of LAA. During the development of these RAST assays, several sources of potential error were identified. Modest titres of total IgE (600 IU/ml and above) were found to influence the specific RAST index observed and lead to false positive results. The presence of human IgG antibody specific for rabbit serum proteins was also identified in four sera, and was responsible for interference in the rabbit urinary protein RAST system.