Role of recombinant Aspergillus fumigatus antigens in diagnosing Aspergillus sensitization among asthmatics.

Role of recombinant Aspergillus fumigatus antigens in diagnosing Aspergillus sensitization among asthmatics.

Mycoses. 2020 Jun 03;:

Authors: Muthu V, Singh P, Choudhary H, Dhooria S, Sehgal IS, Prasad KT, Aggarwal AN, Garg M, Chakrabarti A, Agarwal R

Abstract
BACKGROUND: The diagnosis of Aspergillus-sensitized asthma (ASA) and allergic bronchopulmonary aspergillosis (ABPA) is made using IgE against crude antigens of A.fumigatus (cAsp). However, the IgE against cAsp has limitations due to cross-reactivity with other fungi.
OBJECTIVE: To evaluate the utility of recombinant A.fumigatus (rAsp) antigens in detecting ASA, and their role in differentiating true from cross-sensitization.
METHODS: We performed IgE against rAsp (f 1, f 2, f 3, f 4, and f 6), cAsp, and other fungal (Alternaria, Candida, Cladosporium, Malassezia, and Trichophyton) antigens in subjects with A.fumigatus-unsensitized asthma (Af-UA [n=51]), ASA (n=71), and ABPA (n=123). The diagnoses were made using cAsp-IgE and compared using rAsp-IgE. Subjects with elevated cAsp-IgE, but negative rAsp f 1 and f 2, were presumed to lack true A.fumigatus sensitization.
RESULTS: The prevalence of any rAsp antigen positivity (cutoff, 0.35 kUA/L) varied from 2-22%, 32-73%, and 84-98% for Af-UA, ASA, and ABPA, respectively. The prevalence of sensitization to other fungi ranged from 29-65%, 59-85%, and 87-95%, respectively, among subjects with Af-UA, ASA, and ABPA. Nineteen subjects of ASA and one subject with ABPA, were positive with cAsp-IgE but negative for rAsp f 1 and f 2 and were also cross-sensitized to at least one of the other fungi. Five subjects of Af-UA (cAsp-IgE negative) were rAsp f 1 or f 2 positive.
CONCLUSIONS: Crude Aspergillus antigens may misclassify Aspergillus sensitization among asthmatics. IgE against rAsp antigens (f 1 and f 2) potentially detect true Aspergillus sensitization and could be used for this purpose.

PMID: 32490571 [PubMed – as supplied by publisher]

Source: Industry