Allergic bronchopulmonary aspergillosis' diagnosis remains a challenge

Allergic bronchopulmonary aspergillosis (ABPA) is a complex disease, triggered by a hypersensitivity reaction to the allergens of Aspergillus fumigatus, a fungus that opportunistically colonizes the lungs of patients with asthma. The diagnosis of ABPA is difficult. A major problem is the lack of standardized allergens used in the determination of specific IgE, but the use of recombinant allergens has been proposed to overcome this. The aim of the present study is to evaluate whether serological tests for IgE specific to recombinant allergens of A. fumigatus (rAsp) can aid in the detection of sensitization to this fungus and in the diagnosis of ABPA.

This was an observational, cross-sectional study. The diagnosis of ABPA, using classical criteria, was searched in 65 asthmatics patients with immediate cutaneous reactivity to A. fumigatus. After that, serum titers of IgE against rAsp f 1, rAsp f 2, rAsp f 3, rAsp f 4 and rAsp f 6 were determined. In order to compare the differences between patients with confirmed and excluded diagnosis of ABPA, the two-tailed Fisher's exact test was used.

Although 19 of 65 patients had IgE against at least one recombinant, the disease was diagnosed in only six patients by classical criteria. One of them had IgE against all recombinant allergens tested and another one had antibody against Asp f 3.

The determination of serum IgE against recombinant A. fumigatus allergens in this group was not helpful to make the diagnosis of ABPA, neither to detect sensitization to fungus.