AF exposure: Increased BALF cell numbers (especially eosinophils), IgE, Th2 cytokines and AHR. Th2 cytokines were reduced by NF‐κB inhibitorsER stress was increased in lungs of AF‐exposed miceGRP78 was also upregulated in lungs of ABPA patients, and GRP78 and CHOP were upregulated in AF‐exposed miceER stress may be involved in pathogenesis of AF‐related allergic lung disorders, ER stress involved PI3K‐δ and mtROS generation. The gene discussed is AHR; the disease is atrial fibrillation.