An overview of allergic bronchopulmonary aspergillosis with some new insights.

Allergic bronchopulmonary aspergillosis (ABPA) occurs as a complication of bronchial asthma or cystic fibrosis (CF). The diagnostic criteria speak to an exaggerated type I hypersensitivity response to the ubiquitous organism Aspergillus fumigatus. Immunologic parameters indicative of Aspergillus sensitization in CF may be lost spontaneously. Therefore, it is important that the diagnosis of ABPA in CF include clinical parameters. CF transmembrane regulator gene mutations may occur in asthmatic ABPA patients indicating a subset of ABPA patients that warrant further study to exclude the diagnosis of CF. The extensive tissue damage seen in ABPA may, in part, be caused by proteases released from aspergillus. Host characteristics may predispose to the development of ABPA. It appears that human leukocyte antigen DR2 and particularly DRB1*1503 and *1501 alleles represent significant ABPA susceptibility genes with the possibility that human leukocyte antigen DQ2 allele confers protection in the non-ABPA population. These findings may offer an additional clinical aid in early diagnosis and provide insight into T-cell reactivity in ABPA that may lead to the development of specific immunotherapy.