T helper 2 response in allergic bronchopulmonary aspergillosis is not driven by specific Aspergillus antigens.

Allergic bronchopulmonary aspergillosis (ABPA) is characterized by an allergic immunological response to Aspergillus fumigatus. In this study, we investigated whether certain Aspergillus antigens are more allergenic than others, as was postulated previously. We stimulated peripheral blood mononuclear cells from patients with ABPA with the classically described A. fumigatus allergens Aspf1, Aspf2, Aspf3, and Aspf4, as well as two other Aspergillus antigens, Crf1 and Catalase1. Activated CD4+ T cells displayed a T helper 2 phenotype with the production of IL-4 in response to stimulation with several of these different antigens. Immune responses were not limited to the classically described A. fumigatus allergens. In healthy individuals, we demonstrated a similar recognition profile to the different antigens, but in contrast the activated CD4+ T cells exerted a T helper 1 phenotype and mainly produced IFN-γ after stimulation with A. fumigatus antigens. In conclusion, irrespective of the A. fumigatus antigen, the T-cell immune response in patients with ABPA is skewed to a T helper 2 cytokine secretion profile.