Skin Test Reactivity to Recombinant <i>Aspergillus fumigatus</i> Allergen l/a in Patients with Cystic Fibrosis

Abstract

We evaluated the diagnostic value of recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) for skin testing in cystic fibrosis (CF) patients with allergic bronchopulmonary aspergillosis (ABPA), allergy to A.fumigatus and in CF controls not allergic to A. fumigatus. Skin prick test reactions to rAsp f I/a were 8.5-fold stronger in A.-fumigatus-allergic and 3.3-fold stronger in ABPA patients compared to the CF controls. Three out of 6 well-characterized ABPA patients had positive skin prick test reactions to rAsp f I/a; the same number reacted to crude A. fumigatus extracts. The skin prick test results to rAsp f I/a were significantly correlated with those to crude and commercial preparations. According to these results, rAsp f l/a represents a defined allergen that provides the possibility to perform skin prick tests in CF patients in a highly standardized way. In future, a larger panel of recombinant allergens might also pick up those CF patients with ABPA and allergy to A. fumigatus who did not react to this single allergen.

Risk factors for allergic bronchopulmonary aspergillosis and sensitisation to Aspergillus fumigatus in patients with cystic fibrosis

“…Using either positive skin test or elevated specific IgE titre (RAST >2), Wojnarowski et al [34] found 26% AFS patients in their clinic in Vienna and Nikolaizik et al [25,26] described 105 CF patients in the UK of whom 30% had positive skin tests to A. fumigatus and 23% had positive IgE antibody to A. fumigatus. The reliability of skin tests is limited as they depend on the composition of antigen preparation [12,26] and therefore skin tests are not routinely done, as was the case in our patients. Instead of skin testing we used a combination of specific IgE (RAST) against A. fumigatus and specific IgE against recombinant allergens (rAsp f) to define AFS [12].…”

“…There have been many proposals for a set of diagnostic criteria for ABPA with marked nonconformity between different authors [1,10,14,16,18,19,21,26]. Therefore a consensus conference held in 2001, proposed the following diagnostic criteria for ABPA [33]: (1) clinical deterioration (cough, wheeze, exercise intolerance, exercise-induced asthma, decline in pulmonary function, increased sputum), (2) serum total IgE concentration of >1000 IU/ml, (3) immediate cutaneous reactivity to A. fumigatus in prick skin test or in vitro presence of serum IgE antibody to A. fumigatus, (4) precipitating antibodies to A. fumigatus or serum IgG antibody to A. fumigatus by an in vitro test, and (5) new or recent abnormalities on chest radiography or chest CT that have not cleared with antibiotics and standard physiotherapy.…”

Specific IgE Testing (RAST)

“…Obviously serologic and skin test investigations with different extracts showing such a high variability even for the content of major allergens will automatically generate discordant results. This was impressively shown by a skin prick test study with four different commercial A. fumigatus extracts [25]. None of the four commercial skin prick test extracts was able to detect all of the 31 A. fumigatus-sensitised patients enrolled in the study.…”

Análogos de Asp f 1 (alfa-sarcina, mitogilina e restrictocina) no diagnóstico e estadiamento da aspergilose broncopulmonar alérgica

“…Embora a ABPA seja uma doença alérgica de caráter agressivo, o processo destrutivo é autolimitado e os relatos de evolução de ABPA para aspergilose invasiva são raros (Riley et al, 1975;Nikolaizik et al, 1996). Outras formas de doença pulmonar como os aspergilomas não se associam à ABPA (Safirstein, 1973b;Shah et al, 1989).…”

“…A aplicabilidade desses recombinantes foi confirmada em pacientes com fibrose cística (Nikolaizik et al, 1996) e outro estudo mostrou que a mitogilina recombinante tem as mesmas propriedades que as proteínas naturais no que se refere aos testes sorológicos (Weig et al, 2001;Crameri, 2002).…”