Genetic variations in the TLR3 locus are associated with eosinophilic esophagitis.

Background: Eosinophilic esophagitis (EoE) is an antigen-driven disease mediated by an abnormal immune Th2 response.

Objective: The objective of this article is to investigate genes associated with regulating immune responses leading to disease susceptibility.

Methods: Twenty-seven tag single nucleotide polymorphisms (tSNPs) selected in five candidate genes ( TLR3, TLR4, FOXP3, FLG and TSLP ) were genotyped in 218 EoE patients and 376 controls. Skin prick tests were carried out in EoE patients with a panel of 17 aeroallergens and 22 plant- and animal-derived foods.

Results: Five tSNPs located in the TSLP locus and one tSNP located in the TLR3 locus were significantly associated with EoE. The interactions between TLR3 and TSLP loci were analyzed. TLR3+/TSLP- and TLR3-/TSLP+ individuals showed a significantly reduced susceptibility to EoE compared to TLR3-/TSLP- individuals (OR = 0.66, p  = 0.036 and OR = 0.23, p  = 0.00014, respectively). Likewise, TLR3+/TSLP+ individuals showed the most decreased susceptibility of developing EoE (OR = 0.16, p  = 0.0001). However, the interaction gain attributed to the combination of both genes was negative (IG = -4.52%), which indicated redundancy or independent effect. Additionally, TLR3 locus was found to be associated with aeroallergen and food sensitization in EoE patients (OR = 9.67, p c  = 0.025 and OR = 0.53, p c  = 0.048, respectively).

Conclusion: TLR3 constitutes a novel genetic susceptibility locus for developing EoE, and the effects would be independent of TSLP .