Clinical and Serological Characterization of the α-Gal Syndrome-Importance of Atopy for Symptom Severity in a European Cohort

BACKGROUND: The galactose -a1,3-galactose (a-Gal) syndrome (AGS) is a novel form of food allergy. Patients experience delayed severe allergic reactions after mammalian meat consumption due to IgE antibodies directed against the carbohydrate a-Gal present in mammalian meat. The onset of the disease is associated with tick bites. OBJECTIVE: To characterize a cohort of patients with AGS from Sweden on a clinical and serological level, and identify risk factors for disease severity. METHODS: A total of 128 patients with symptoms after mammalian meat intake and IgE to a-Gal were included. Medical examination and diagnosis were made by an allergologist and questionnaires were filled in regarding onset of symptoms, tick exposure, and airborne allergies. Serum IgE reactivity against multiple food and airborne allergens, as well as protein extract from the tick Ixodes ricinus, was measured using ImmunoCAP. RESULTS: The majority of patients were middle aged, with equal gender distribution. Nearly all reported symptoms more than 2 hours after meat consumption. Urticaria (90%) and gastrointestinal symptoms (74%) were most common. Almost half of the patients suffered from anaphylaxis, and a-Gal IgE levels were significantly higher among these patients compared with those without anaphylaxis. Nearly all patients had been tick bitten and 75% had IgE against I. ricinus. More than half of the patients with AGS were atopic, and atopy increased the risk of anaphylaxis with pulmonary manifestations. Only 2 patients belonged to blood group B/AB. CONCLUSION: AGS is an upcoming food allergy where patients report severe symptoms and tick bites. Atopy was found to affect the manifestation of the disease in Swedish patients. (c) 2020 The Authors. Published by Elsevier Inc. on behalf of the American Academy of Allergy, Asthma & Immunology. This is an open access article under the CC BY NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).