α-Gal Sensitization and Coronary Artery Disease: What’s the Link?

An increase in atheroma burden and plaques with less stable features demonstrated an association with immunoglobulin E (IgE) to the mammlian oligosaccharide galactose-α-1,3-galactose (α-Gal), with a more pronounced effect evident in individuals younger than 65 years, according to  a study published in Arteriosclerosis, Thrombosis, and Vascular Biology.

Inflammation plays a central role in the pathogenesis of coronary artery disease (CAD), and recent evidence has demonstrated elevated levels of total serum IgE in patients with cardiovascular disease. Evidence has also demonstrated a primary role for α-Gal in delayed anaphylaxis to red meat (α-Gal syndrome). Sensitization to α-Gal occurs in individuals bitten by the Amblyomma americanum tick, which is common to some areas of the southeastern United States, where the prevalence of α-Gal sensitization is as high as 20%. It is possible that a specific IgE on mast cells, including those in the coronary arteries, could intensify the inflammatory response to dietary glycolipids.

Jeffrey M. Wilson, MD, PhD, of the Division of Allergy and Immunology at the University of Virginia in Charlottesville, and colleagues, assayed total IgE and specific IgE to α-Gal on sera from 118 individuals who underwent cardiac catheterization and intravascular ultrasound. These individuals were from an area where sensitization to α-Gal is prevalent, and the researchers sought to determine the relationship between IgE sensitization to α-Gal and the burden of CAD.

IgE to α-Gal was found in 26% of participants, along with a higher burden of atheroma (P =.02). There was a stronger association with atheroma burden in younger individuals (≤65 years) than in older individuals (P <.001). Furthermore, plaques in the sensitized group were more unstable based on intravascular ultrasound findings.

To better determine whether IgE to α-Gal was specifically associated with CAD, the researchers assayed IgE to inhalants and peanuts. In contrast to the evidence for an association with IgE to α-Gal, the researchers found that sensitization to inhalants and peanuts were not associated with CAD. Moreover, the association between IgE to α-Gal and CAD was stronger than the association between total IgE and CAD.

The researchers noted a number of study limitations, including the lack of information on the allergic histories or dietary habits of the participants and the small cohort size. The investigators argued for larger cohorts from disparate geographic areas, as well as prospective studies of adults that include detailed histories on diet and allergies.

Disclosures: Dr Commins is part of the speaker’s bureau for Genetech; Dr Platts-Mills has a patent on the ImmunoCAP IgE assays to α-Gal and has received support from Thermo Fisher/Phadia, and Drs McNamara and Taylor have received research grants from AstraZeneca.

Reference

Wilson JM, Nguyen AT, Schuyler AJ, et al. IgE to the mammalian oligosaccharide galactose-α-1,3-galactose is associated with increased atheroma volume and plaques with unstable characteristics [published online June 14, 2018]. Arterioscler Thromb Vasc Biol. doi:10.1161/ATVBAHA,118.311222