Absence of Alpha-gal IgE Response in Humans Exposed to Larval Ixodes scapularis Tick Bites

Authors

• B Santra
• A Jha
• P Mukherjee
• M Patel
• K Pacak
• RM Summers

Abstract

Alpha-gal syndrome (AGS), also known as red meat allergy, is a delayed onset of an allergic reaction post ingestion of mammalian meat and other mammalian-derived food products. It is associated with IgE antibodies to galactose-alpha-1,3-galactose (alpha-gal). There is strong evidence that Amblyomma mericanum (Lone star) tick bites are a cause of AGS in humans, but it is unknown how tick bites initiate the anti–α-Gal IgE response. Although Ixodes scapularis (Deer) tick bites have not been associated with AGS, its genome was reported to contain three genes involved in alpha-gal synthesis. Our group developed the methodology for using laboratory reared I. scapularis larval ticks in research protocols investigating Lyme disease and tick immunity. The procedure is very well tolerated, and none of the participants have developed AGS. To further corroborate the clinical experience, we tested serum samples from participants for the presence of alpha-gal specific IgE. Of the 29 samples collected, 27 were found negative. Two samples had low positive results, and repeat testing showed a borderline result for one sample and a low positive result for the second. In samples collected over two years before the procedure, the second individual had similarly low levels of alpha-gal specific IgE. Therefore, procedures using I. scapularis larval ticks are not associated with development of significant anti-alpha-gal IgE antibodies and corroborates the clinical experience.

Scientific Focus Area: Microbiology and Infectious Diseases

This page was last updated on Monday, September 25, 2023