IMMUNE-RESPONSES TO ASPERGILLUS-FUMIGATUS AND PSEUDOMONAS-AERUGINOSA ANTIGENS IN CYSTIC-FIBROSIS AND ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS

Allergic bronchopulmonary aspergillosis (ABPA) in Cystic Fibrosis (CF) is well documented. Aspergillus fumigatus is the causative agent of A BPA, and Pseudomonas aeruginosa particularly the mucoid variety has be en frequently isolated from the sputum of patients with CF. This study investigates the cellular and humoral immune response to both A fumig atus and P aeruginosa antigens in patients with CF and ABPA (CF/ABPA), CF only, and healthy controls. The A fumigatus and P aeruginosa antig en specific IgE and IgG in sera and peripheral blood mononuclear cell culture supernatants (PBMC sups), lymphoproliferation to antigens, and leukotriene B-4 (LTB(4)) were measured. Results indicate significant elevated levels of A fumigatus specific IgG (Afumigatus-IgG) and Paeru ginosa-IgE in serum. Significant Paeruginosa-IgG was measured in PBMC sups. The concanavalin A nonbinding A fumigatus antigen, previously sh own to induce specific T-cell responses in vitro in patients with ABPA , elicited significant lymphoproliferative response in a greater propo rtion of patients with CF/ABPA and not in CF or controls, underlining the importance of this antigen in the diagnosis of ABPA. In contrast, a greater proportion of the CF group responded to P aeruginosa antigen s compared with the controls and CF/ABPA. Hence, the CF and CF/ABPA gr oups respond to both P aeruginosa and A fumigatus antigens with the fo rmer group responding strongly to P aeruginosa and the latter to A fum igatus antigens.