title: Food allergy to the carbohydrate galactose-alpha-1,3-galactose (alpha-gal): four case reports and a review.
abstract: Until recently, food allergies to mammalian meats have been considered to be very rare. The observation that patients not previously exposed to the monoclonal chimeric antibody cetuximab suffered from severe anaphylaxis upon first exposure, led to the identification of galactose-alpha-1,3-galactose as a new relevant carbohydrate allergen. These patients later often suffered from anaphylactic reactions to red meat. Epidemiological data indicated that bites by the tick Amblyomma americanum in the USA, later also by Ixodes species in other continents, resulted in sensitisation to alpha-gal. On the other hand, in African patients with parasitic disorders, a high prevalence of anti-alpha-gal IgE, without clinical relevance, has been reported. In our four cases, one patient with a late onset of meat allergy had a history of a tick bite. The other three patients had symptoms from childhood or at a juvenile age. This indicates that in some patients, other ways of sensitisation may also take place. However, in patients without atopy, tick bite-induced IgE to alpha-gal may be more relevant. Diagnosis is based on a history of delayed onset of anaphylaxis. Skin tests with commercially available meat test solutions are often equivocal or negative; skin tests with raw meat and particularly pork kidney are more sensitive. Determination of specific IgE to alpha-gal is commercially available. The highest sensitivity is observed with skin and basophil activation tests with cetuximab which is, however, limited by its high costs.
authors.affiliation: Allergy Unit, Dermatology Clinic.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Bircher
authors.affiliation: Allergy Unit, Dermatology Clinic.
authors.forename: Kathrin Scherer
authors.initials: KS
authors.lastname: Hofmeier
authors.affiliation: Medical Immunology, Laboratory Medicine, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Susanne
authors.initials: S
authors.lastname: Link
authors.affiliation: Medical Immunology, Laboratory Medicine, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Heijnen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects; D002417:Cattle; D000068818:Cetuximab / Q000009:adverse effects; D004187:Disaccharides / Q000009:adverse effects* / Q000276:immunology; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008460:Meat / Q000009:adverse effects*; D064927:Tick Bites / Q000150:complications* / Q000453:epidemiology
chemical_list: D000970:Antineoplastic Agents; D004187:Disaccharides; C055075:galactosyl-(1-3)galactose; D007073:Immunoglobulin E; D000068818:Cetuximab
keywords: alpha-gal; delayed anaphylaxis; food allergy; red meat