Role of recombinant Aspergillus fumigatus antigens in diagnosing Aspergillus sensitisation among asthmatics

• Published in: Mycoses Vol. 63; no. 9; pp. 928 - 936
• Main Authors: Muthu, Valliappan, Singh, Pawan, Choudhary, Hansraj, Dhooria, Sahajal, Sehgal, Inderpaul Singh, Prasad, Kuruswamy Thurai, Aggarwal, Ashutosh Nath, Garg, Mandeep, Chakrabarti, Arunaloke, Agarwal, Ritesh
• Format: Journal Article
• Language: English
• Published: Berlin Wiley Subscription Services, Inc 01.09.2020
• Subjects: ABPA; ABPM; Allergic bronchopulmonary aspergillosis; allergic bronchopulmonary mycosis; allergy; alternaria; Antigens; Aspergillosis; Aspergillus; Asthma; candida; Fungi; Immunoglobulin E; Yard waste
• ISSN: 0933-7407; 1439-0507; 1439-0507
• DOI: 10.1111/myc.13124

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.