Allergological examination of cystic fibrosis patients with skin reactions during carbenicillin treatment.

Sixteen of 84 cystic fibrosis patients developed skin manifestations during intensive carbenicillin therapy. The possibility of allergic drug reactions was examined. None of the patients showed any significant levels of antibodies of IgE, IgG or IgM classes against carbenicillin and different penicilloyl determinants as recorded with RAST, sandwich-radioimmunoassay and double antibody assay. The leukocytes of the patients did not release histamine on in vitro provocation with carbenicillin. Furthermore, none of the patients responded to prick test or to peroral penicillin provocation. The negative findings indicated that the recorded reactions were most probably not due to antibody-mediated allergy of type I or type III.