Use of antithymocyte globulin (rabbit) in a patient with known alpha-gal syndrome undergoing allogenic stem cell transplantation.

Abstract

Alpha-gal syndrome (AGS) is a hypersensitivity disorder in which tick bites-most commonly from the lone star tick (Ambylomma americanum)-trigger immunoglobulin E-mediated hypersensitivity reaction upon exposure to oligosaccharide galactosse-alpha-1,3-galactose (α-gal). α-gal is most notorious for being found in "red meat" products but is present in mammalian meats such as beef, pork, lamb, rabbit, and others. Manifestations of AGS hypersensitivity are variable. There is currently no in vivo data describing allergic reactions against rabbit products in patients with AGS. Here, we describe a case of a 44-year-old male with myelodysplastic syndrome and a known history of AGS undergoing allogeneic hematopoietic cell transplantation (allo-HSCT) with the use of rabbit antithymocyte globulin (rATG) for graft-versus-host disease (GVHD) prophylaxis. The risk of cross-reactivity against rATG in our patient with AGS could not be ruled out and, therefore, a test dose was administered. The patient tolerated the test dose with no signs of anaphylaxis. After demonstrating tolerance to the test dose, rATG was utilized for GVHD prophylaxis. Due to the heterogeneity of AGS manifestations in patients, the use of rATG in patients with known AGS should be considered on a case-by-case basis. The administration of a test dose may help predict the occurrence of severe hypersensitivity reactions. The limited data surrounding the risk of AGS with rabbit-containing products and the various indications for the use of rATG warrants more in-depth study of the reactivity of this medication in this population.