Methods: We obtained informed consent and then enrolled pediatric EGID patients, and also age-matched controls who underwent GI endoscopy due to clinical symptoms but had no eosinophilia (stomach, small intestine and colon; n=5 each). Eosinophilia in the GI mucosa was defined according to DeBrosse et al.’s report. The eosinophil-related gene expression profiles in the biopsies from each portion of the GI tract were determined.
Results: In agreement with the tissue eosinophilia of the patients, eosinophil-specific genes such as Charcot-Leyden crystals (CLC) and C-C chemokine receptor type 3 (CCR3) were significantly up-regulated (≥2 fold, p<0.05) in EG, EGE and EC patients compared with the controls. EG patients also showed markedly increased expression of mRNA for eotaxin-3/CCL26, MCP-3/CCL7 and IL-5RA compared with the controls. In EGE and EC patients, eotaxin-1/CCL11 was the most upregulated gene (≥5 fold, p<0.05).
Conclusions: Our results suggest that the main chemotactic factors inducing selective eosinophil recruitment differ with the portion of the GI tract: The main chemotactic factor for lower EGIDs was eotaxin-1/CCL11, whereas it was eotaxin-3/CCL26 for upper EGIDs.