That CFTR mutations regulate Th1/Th2 balance was further evident by Muller et al. studies which demonstrated that intra-tracheal delivery of recombinant truncated CFTR reduces levels of Th2-cytokines and IgE antibody in CFTR-deficient mouse model of ABPA [46]. This evidence concerns the gene IGHE and allergic bronchopulmonary aspergillosis.