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.