Allergic response to medical products in patients with alpha-gal syndrome

J Thorac Cardiovasc Surg. 2021 Apr 9;S0022-5223(21)00586-9. doi: 10.1016/j.jtcvs.2021.03.100. Online ahead of print.

Abstract

Background: Galactose-α-1,3-galactose (alpha-gal) is a carbohydrate that is ubiquitously expressed in all mammals except for primates and humans. Patients can become sensitized to this antigen and develop alpha-gal syndrome (AGS), or a red meat allergy. Symptoms range from generalized gastroenteritis and malaise to anaphylaxis, and in endemic areas, the prevalence can be as high as 20%. Although AGS patients commonly avoid alpha-gal by avoiding meat, patients have also developed symptoms due to animal-derived medical products and devices. With the rise in transcatheter aortic valve replacement, we investigate the immunogenicity of common cardiac materials and valves.

Objective: To assess the in vitro immunoglobulin E response toward common medical products, including cardiac patch materials and bioprosthetic valves in patients with AGS.

Methods: Immunoblot and immunohistochemistry techniques were applied to assess immunoglobulin E reactivity to various mammalian derived tissues and medical products for patients with AGS.

Results: AGS serum showed strong reactivity to all of the commercially available, nonhuman products tested, including various decellularized cardiac patch materials and bioprosthetic aortic valves. AGS serum did not react to tissues prepared using alpha-gal knockout pigs.

Conclusions: Despite commercial decellularization processes, alpha-gal continues to be present in animal-derived medical products, including bioprosthetic valves. Serum from patients with AGS demonstrates a strong affinity for these products in vitro. This may have serious potential implications for sensitized patients undergoing cardiac surgery, including early valve failure and accelerated coronary artery disease.

Keywords: allergy; alpha-gal; alpha-gal syndrome; bioprosthetic valve; chronic inflammation; coronary artery disease; early valve degradation.