Immunoprofile of α-Gal- and B-antigen-specific responses differentiate red meat allergic patients from healthy individuals

Abstract

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/IgG_1-4 (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.

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