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False-positive results of serological tests for allergy in alcoholics

Alvela-Suarez L1,4, Campos J1, Carballo I1, Gomez-Rial J2, Lombardero M5, Linneberg A6,7, Vidal C3, Gonzalez-Quintela A1

1Department of Internal Medicine, Complejo Hospitalario, University of Santiago de Compostela, Spain
2Department of Immunology, Complejo Hospitalario, University of Santiago de Compostela, Spain
3Department of Allergy Complejo Hospitalario, University of Santiago de Compostela, Spain
4HM-Hospital La Rosaleda, Santiago de Compostela, Spain
5CMC R&D Department, ALK-Abelló S. A., Madrid, Spain
6Research Centre for Prevention and Health, Rigshospitalet, Glostrup, Denmark
7Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark

J Investig Allergol Clin Immunol 2019; Vol. 29(3)
doi: 10.18176/jiaci.0309

Background: Alcohol consumption is associated with enhanced Th2 immune responses.
Aim: To investigate the frequency of false-positive serological tests of allergy in alcoholics.
Methods: A total of 138 alcoholic patients consecutively admitted to hospital underwent a panel of allergy tests that included serum total IgE, a multiallergen IgE test (UniCAP Phadiatop), and skin prick tests to relevant aeroallergens in the area, which were considered the standard reference for atopy. In selected cases with positive specific IgE (sIgE) to cross-reactive carbohydrate determinants (CCDs) on ImmunoCAP, we determined sIgE to Hymenoptera venom components (ADVIA Centaur) and a microarray of 103 allergen components (ISAC).
Results: Increased (>170 IU/mL) serum total IgE was observed in 59/110 (54%) of non-atopic (skin prick test-negative) alcoholics. Forty-six non-atopic alcoholics (42%) had a positive multiallergen IgE test. This finding was closely associated with high serum concentrations of total IgE and sIgE to CCDs. The vast majority of alcoholics with positive CCD-sIgE showed positivity to glycosylated plant and Hymenoptera allergen components on ISAC and ADVIA Centaur. Only one out of 26 patients with positive sIgE to CCD and Hymenoptera venoms developed honeybee venom allergy after a median follow-up of 166 months. Measurements of sIgE to CCD markers on ImmunoCAP, ADVIA Centaur, and ISAC showed imperfect correlation.
Conclusions: Serological tests for allergy should be interpreted with caution in alcoholics, who frequently show increased levels of total IgE, CCD-sIgE and subsequent positivity of sIgE to glycosylated allergen components, irrespective of the method used. 

Key words: Alcohol, Cross-reactive carbohydrate determinants, Allergy, Glycans, Specific IgE, Total IgE