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Role of recombinant Aspergillus fumigatus antigens in diagnosing Aspergillus sensitisation among asthmatics
Author(s) -
Muthu Valliappan,
Singh Pawan,
Choudhary Hansraj,
Dhooria Sahajal,
Sehgal Inderpaul Singh,
Prasad Kuruswamy Thurai,
Aggarwal Ashutosh Nath,
Garg Mandeep,
Chakrabarti Arunaloke,
Agarwal Ritesh
Publication year - 2020
Publication title -
mycoses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 69
eISSN - 1439-0507
pISSN - 0933-7407
DOI - 10.1111/myc.13124
Subject(s) - aspergillus fumigatus , allergic bronchopulmonary aspergillosis , immunoglobulin e , aspergillus , antigen , immunology , microbiology and biotechnology , asthma , allergy , medicine , allergen , malassezia , biology , antibody
Summary Background The diagnosis of Aspergillus ‐sensitised 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‐sensitisation. 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 ‐unsensitised 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 sensitisation. Results The prevalence of any rAsp antigen positivity (cut‐off, 0.35 kUA/L) varied from 2%‐22%, 32%‐73% and 84%‐98% for Af‐UA, ASA and ABPA, respectively. The prevalence of sensitisation 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‐sensitised 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 sensitisation among asthmatics. IgE against rAsp antigens (f 1 and f 2) potentially detect true Aspergillus sensitisation and could be used for this purpose.