Differences in CD4IL-17+ in Children and Adults with Eosinophilic Esophagitis

Rationale: Eosinophilic esophagitis (EoE) is an atopic disease defined by eosinophilic infiltration greater than 15 eosinophils per high power field in the esophagus. The clinical manifestations of the disease are known to vary with age, however it is not known if local inflammation changes with age. CD4Th17 cells produce the pro-inflammatory cytokine, IL-17, which has been implicated in the pathogenesis of a variety of atopic and autoimmune diseases. Variations in Th17 in patients with EoE have not been previously reported.

Methods: Peripheral blood mononuclear cells (PBMCs) from 10 children with active EoE, 4 children with controlled EoE, 10 healthy pediatric controls, 7 adults with active EoE and 4 healthy adult controls were collected. CD4IL-17+ cells were quantified at baseline. The PBMCs were incubated with or without anti-CD3/CD28 beads and CD4IL-17+ levels were assessed after 7 days via flow cytometry.

Results: Children with EoE had lower levels of CD4IL-17+ compared to healthy controls (median ± standard error (SE): 0.061 ± 0.168 vs 1.49 ± 0.443 respectively p<0.02). Children with active EoE had lower levels of CD4IL-17+ compared to adults with active disease (0.052 ± 0.012 vs 0.4 ± 0.067, p<0.02). PBMCs that were cultured with anti-CD3/CD28 beads displayed an increase in CD4 IL-17+ compared to untreated cultures, but only in adult controls (14.10 ± 11.53 vs 0.0790 ± 0.1023, p<0.03).

Conclusions: This data suggests that Th17 cells are involved in the pathogenesis of EoE. Expression of IL-17 varies between children and adults with active disease, which may contribute to the age-related variation seen in EoE.