IgG, IgE and IgG4 specific antibodies to molecular allergens of aspergillus fumigatus

Author:

Romain T 1; Carsin A 2; Gomez C 3; Cleach I 1; Dubus J 2 ;Reynaud Gaubert M 3; Mege J 4; Ranque S 5; Vitte J 4

Author address:

1 Assistance Publique Hopitaux de Marseille, Hopital de La Conception, Laboratoire d’Immunologie, Marseille, France; 2 Aix-Marseille Universite, Faculte de Medecine de Marseille-Assistance Publique Hopitaux de Marseille, Hopital Timone, Service de Pneumologie Pediatrique et Centrede Ressources et de Competence en Mucoviscidose (pediatrique), Marseille, France; 3 Aix-Marseille Universite, Faculte de Medecine de Marseille, Assistance Publique Hopitaux de Marseille, Hopital Nord, Centre de Ressources et de Competence et Mucoviscidose (adultes),Marseille, France; 4 Assistance Publique Hopitaux de Marseille, Hopitalde La Conception, Laboratoire d’Immunologie-Aix-Marseille Universite,Faculte de Medecine de Marseille, Marseille, France; 5 Aix-MarseilleUniversite, Faculte de Medecine de Marseille Laboratoire de Parasitologie & Mycologie, Hopital Timone, Marseille, France

Full conference title:

European Academy of Allergy and Clinical Immunology Congress 2017

Abstract:

Introduction: Detection of specific IgE responses is a cornerstone of allergy diagnosis, while specific IgG responses are usually considered as irrelevant. Aspergillus fumigatus (Af) is an ubiquitous airborne mold that causes allergic broncho-pulmonary aspergillosis (ABPA) in asthmatic and cystic fibrosis (CF) patients. Specific IgG and IgE are both presumed relevant for ABPA diagnosis. Specific IgE, but not IgG4, responses to Af molecular allergens were reported to display distinct profiles between ABPA patients and CF patients carrying « benign » fungal sensitization.

Objectives: 1. To describe specific IgG responses to Af extract and molecular allergens in CF and ABPA patients. 2. To compare specific IgG, IgE, and IgG4 responses in CF and ABPA patients. 3. To compare three commercial methods for the determination of specific IgG to Af.

Results: Specific IgG, IgE and IgG4 to Af extract and molecular allergens Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 were measured with a fluorescent immuno Assay (FEIA) method in 50 patients comprising 40 CF patients (16 children; 24 adults) and 10 ABPA patients (2 children; 3 CF). IgG to Af were measured with an ELISA kit and immunoelectrophoresis (IEP) in 44 of these patients. Mycological culture was performed in 38 patients. Concomitant IgG and IgE production against Af extract and Asp f 1 was most frequent (90%-100% of both groups). Dissociated IgG and IgE responses were found for other allergens; isolated IgE was more frequent than isolated IgG (29 vs 12) production, especially in the ABPA patients. IgG to Asp f 3 and Asp f 4 were more prevalent among ABPA patients (50% vs 21% and 70% vs 33%, P=.03 and 0.02). Except for Asp f 2, IgG levels to Af extract and allergens were significantly higher in ABPA patients (P ≤ 0.05). IgG and IgG4 levels to Af extract and allergens were correlated, except for Asp f 3 et 4 in the ABPA group and Asp f 6 in patients without ABPA. FEIA and ELISA or IEP IgG determinations were concordant in about 50%. Ten out of 14 positive Aspergillus spp cultures were associated with detection of IgG to Af extract with the three methods.

Conclusions: Specific IgG and IgE to Af extract and molecular allergens may help distinguish between ABPA and fungal sensitization. Af molecular allergens display distinct IgG and IgE responses, suggesting different immunogenic behavior and biomarker potential.

Abstract Number: 0511

Conference Year: 2017

Link Conference abstract: 

EAACI 2017

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