ABPA is characterized by a complex interplay of immune responses to A. fumigatus. Although the precise pathophysiology is yet unknown, a number of immunological responses are seen, such as abnormal T-lymphocyte responses and A. fumigatus-specific IgE-mediated type-1 and type-3 hypersensitivity. This evidence concerns the gene IGHE and allergic bronchopulmonary aspergillosis.