B Antigen Protects Against the Development of α-Gal-mediated Red Meat Allergy
Monday, March 5, 2018
South Hall A2 (Convention Center)
Jonathan R. Brestoff, Merih T Tesfazghi, PhD, Ronald Jackups, Jr, MD, PhD, Mitchell G Scott, PhD, Ann M Gronowski, PhD, Brenda J Grossman, MD, MPH
RATIONALE: Red meat allergy (RMA) is a recently recognized disease characterized by delayed-onset anaphylaxis, angioedema, and/or urticaria occurring approximately 3-6 hours after ingesting mammalian meats containing the antigen galactose-α-1,3-galactose (α-Gal). The molecular structure of α-Gal is similar to that of the B antigen, a self-antigen in patients with blood types B or AB. This provokes the hypothesis that patients who harbor the B antigen are less likely to undergo allergic sensitization to α-Gal and develop RMA.

METHODS: To test this, we employed a cohort of n=92 RMA patients and n=188 controls, all with known ABO types. We compared expected and observed frequencies of blood types O, A, B and AB in the two groups, and we performed logistic regression to determine the odds ratios (OR) and 95% confidence intervals (95%CI) of having RMA according to blood type.

RESULTS: Among those with RMA, the observed frequency of the B antigen (types B or AB) was markedly lower than expected (expected 20.3%, observed 4.35%, P=0.005). Patients expressing the B antigen were less likely than those without the B antigen (blood types O or A) to produce α-Gal-specific IgE (OR 0.19, 95%CI 0.04-0.80, P=0.023) or beef-specific IgE (OR 0.29, 95%CI 0.11-0.80, P=0.016) and were 5-times less likely to have been diagnosed with red meat allergy (OR 0.20, 95%CI 0.07-0.62, P=0.004).

CONCLUSIONS: Patients whose red blood cells express the B antigen are protected from developing red meat allergy and are less likely to produce anti-α-Gal IgE. These findings suggest that ABO blood type affects one’s susceptibility to RMA.