Galactose α-1,3-galactose phenotypes: Lessons from various patient populations

Objective: To review published studies on galactose α-1,3-galactose (α-gal), a carbohydrate epitope found on proteins and lipids in nonprimate mammals and present in foods (particularly organ or fat-rich red meat)and medications, where it causes delayed-onset and immediate-onset anaphylaxis. Data Sources: A literature search for the terms galactose α-1,3-galactose and α-gal using PubMed and Embase was performed. Study Selections: Studies on α-gal were included in this review. Results: Several species of ticks contain α-gal epitopes and possibly salivary adjuvants that promote high titer sensitization and clinical reactivity. Risk factors for α-gal syndrome include exposure to ticks of particular species. Age and sex differences seen in various cohorts possibly reflect the prevalence of these exposures that vary according to setting. Conclusion: The reason and mechanisms for delayed onset of food-related anaphylaxis and the preponderance of abdominal reactions are not clear but may involve the kinetics of allergen digestion and processing or immunologic presentation via a different mechanism from usual immediate-type food allergy.