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

BackgroundThe galactose--1,3-galactose (-Gal) epitope is involved in red meat allergy. As -Gal is structurally similar to the blood group B-antigen, we explored the relationship between the immune responses to -Gal- and the B-antigen in red meat-allergic patients compared to healthy A/O or B blood donors. MethodsSera from 51 red meat-allergic patients IgE-positive to -Gal and 102 healthy blood donors (51 blood group A/O; 51 blood group B) were included. -Gal- and B-antigen-specific IgE (ImmunoCAP) and IgG/IgG(1-4) (ELISA) responses were determined. Basophil activation tests were performed. ResultsFifteen healthy donors were IgE positive to -Gal, of which 3 had blood group B. The allergic patients had significantly higher -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 -Gal and the B-antigen. The biological activity of the B-antigen was confirmed by basophil activation tests. Anti--Gal IgG(1) and IgG(4) 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. ConclusionRed meat-allergic patients showed significantly higher -Gal IgE, IgG(1), and IgG(4) levels, reflecting a Th2 response, compared to healthy blood donors. Blood group B donors had significantly reduced antibody responses to -Gal, due to similarities with the B-antigen, resulting in a lower risk of sensitization to -Gal and development of red meat allergy.