Recent findings suggest that extrinsic and intrinsic asthma, despite showing distinct clinical features, share many common immunopathological mechanisms. Inappropriate IgE-mediated mechanisms might occur in asthma, irrespective of its atopic status, as suggested by elevated serum IgE concentrations and bronchial mucosal expression of cells positive for FcεΡΙ, IL-4, IL-13, Iε and Cε. Future directions of research regarding intrinsic asthma include possible identification of novel allergens, detailed description of local bronchial mucosal IgE production and understanding of a possible macrophage dysfunction. In addition, a role for infectious or autoimmune processes has yet to be firmly identified. Pneumon 2002, 15(2):143-146.