Cystic fibrosis heterozygosity in the pathogenesis of allergy

47% of cystic fibrosis (C.F.) heterozygotes had positive prick skin tests of 1 or more of 9 antigens and 53% had histories of allergic disease, both occurring significantly more often than in a control group. Since 1 in 20 of the population are C.F. carriers, this would contribute to allergy in the community.