Fungi may contribute to severe asthma in several ways: (a) through direct inhalation of fungal spores, (b) through fungal sensitization, which may or may not be associated with severe asthma, and manifests as immediate hypersensitivity reactions or elevated fungus-specific IgE levels, and (c) through the development of allergic bronchopulmonary mycosis (ABPM), a severe form of sensitization resulting in irreversible bronchopulmonary damage. The gene discussed is IGHE; the disease is allergic bronchopulmonary aspergillosis.