Background: The galactose-α-1,3-galactose (α-Gal) epitope is involved in red meat allergy. As α-Gal is structurally similar to the blood group B-antigen, we explored the relationship between the immune responses to α-Gal- and the B-antigen in red meat-allergic patients compared to healthy A/O or B blood donors.
Methods: Sera from 51 red meat-allergic patients IgE-positive to α-Gal and 102 healthy blood donors (51 blood group A/O; 51 blood group B) were included. α-Gal- and B-antigen-specific IgE (ImmunoCAP) and IgG/IgG1-4 (ELISA) responses were determined. Basophil activation tests were performed.
Results: Fifteen healthy donors were IgE positive to α-Gal, of which 3 had blood group B. The allergic patients had significantly higher α-Gal IgE levels compared to the healthy donors. The majority of the allergic patients, but none of the healthy donors, had IgE against the B-antigen. Inhibition studies revealed cross-reactivity between α-Gal and the B-antigen. The biological activity of the B-antigen was confirmed by basophil activation tests. Anti-α-Gal IgG1 and IgG4 levels were significantly higher in the patients compared to the healthy donors. Moreover, the IgG response to the B-antigen was comparable between the allergic patients and healthy A/O donors.
Conclusion: Red meat-allergic patients showed significantly higher α-Gal IgE, IgG1 , and IgG4 levels, reflecting a Th2 response, compared to healthy blood donors. Blood group B donors had significantly reduced antibody responses to α-Gal, due to similarities with the B-antigen, resulting in a lower risk of sensitization to α-Gal and development of red meat allergy.
Keywords: B-antigen; IgE; allergenicity; red meat allergy; α-Gal.
© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.