318 DIAGNOSIS OF ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS (ABPA) IN CYSTIC FIBROSIS (CF)

Abstract

In patients with CF the importance of serological investigations are increased as the clinical diagnostic features of ABPA resemble those of pulmonary bacterial infections. However elevated specific IgE to Aspergillus fumigates (Af) while being sensitive, gives false positives as non ABPA patients may develop asymptomatic Type I sensitivity. We previously identified and isolated a 66KD allergenic protein of AF. An Enzyme Linked Immuno-sorbant Assay (ELISA) was used to detect specific IgE to this 66KD protein, and IgE to the un-fractioned AF extract was detected using a Radio Immunoassay. Serum was obtained from patients with ABPA (14), no ABPA but type I sensitive (27), and no ABPA & non allergic (38) who attended the paediatric cystic fibrosis clinic. Elevated IgE detection using the un-fractioned extract was 92.9% sensitive and 58.5% specific for diagnosis of ABPA while the new ELISA using the 66KD allergen maintained the 92.9% sensitivity but increased specificity to 78.5%. It is hoped that the use of this protein will aid in the diagnosis of ABPA particularly in patients with CF.