The cystic fibrosis gene, IgE and IgG4.

We decided to survey a geographically defined population of cystic fibrosis patients 
and parents living in Avon County, England. By examining the obligate 
heterozygotes (the parents), we would be able to assess the influence 
of the CF gene without the presence of the disease. There 
is an increase in immediate hypersensitivity to A. fumigatus in CF 
patients but not their parents. This increased sensitivity is probably IgE-mediated 
and a secondary effect of lung damage. There is no evidence 
that the CF gene produces a generalised increase in skin reactivity 
(atopy), serum IgE or serum IgG4 in the heterozygotes. They are 
not therefore likely to develop asthma. 