Side-chain-specific lymphocyte responses in workers with occupational allergy induced by penicillins

Eight workers with clinically diagnosed or suspected occupational allergy caused by penicillins were studied by the lymphocyte transformation test (LTT) and by skin test. The majority of the workers handled bacampicillin, some of them had been in contact with benzylpenicillin and one worked with azidocillin only. Six workers had eczema and 2 workers suffered from rhinitis only. Lymphocytes from workers with bacampicillin-induced symptoms responded to this drug in vitro by an increased 3H-thymidine incorporation and by lymphoblastogenesis. Bacampicillin-specific allergy had been confirmed by positive patch test in 5 workers. Lymphocytes from bacampicillin-allergic workers did not respond to other penicillins such as benzylpenicillin or azidocillin in vitro. However, such penicillins were antigenic in vitro since lymphocytes from an azidocillin patch test positive worker proliferated on exposure to azidocillin in vitro. The findings at the cellular level were further supported by the specificity of the skin test. Thus, bacampicillin patch test positive workers had a negative skin reaction to benzylpenicillin. In conclusion, these data suggest the role of penicillin side chains in the sensitization process underlying occupational allergy to penicillins. LTT can be used as a tool for studying antigenic specificities involved in a sensitization process leading to penicillin allergy.