Positive immediate skin tests in cystic fibrosis: a possible role for Pseudomonas infection.

A review was made of the medical records of 49 patients from whose sputum mucoid Pseudomonas aeruginosa had been isolated over a 20-month period. This showed that 31 of 42 had positive immediate skin prick tests to common antigens. 21 had positive reactions to Aspergillus fumigatus antigens and 23 had precipitins to A. fumigatus antigen. 36 patients had had frequent courses of antibiotics and airway obstruction was present in 47. These results have prompted the hypothesis that the positive skin test reactions in patients with cystic fibrosis may in part be explained by the abundance of fungal and bacterial antigens that occur in the respiratory tract of these patients. The former antigens sensitize the immunoglobulin E producing cells whilst the latter exert an adjuvant action and facilitate this.