Predominance of infiltrating IL-4-producing T cells in conjunctiva of patients with allergic conjunctival disease.

Purpose: Previous reports have suggested that type 2 cytokine responses at the site of inflammation are important in the pathogenesis of allergic disease. In this study, we investigated the frequency of IFN-gamma- or IL-4-producing T cells from conjunctiva or peripheral blood mononuclear cells (PBMC) from patients with allergic conjunctival diseases.

Methods: We obtained conjunctival samples using Cytobrush and peripheral blood samples from the patients with allergic conjunctival disease. Conjunctival samples and PBMC were stimulated with phorbol myristate acetate and calcium ionophore. Frequencies of cytokine-producing T cells were analyzed by flow cytometry based on the intracellular cytokine staining.

Results: The frequency of IL-4-producing conjunctival T cells in patients with vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) were significantly higher than that in patients with allergic conjunctivitis (AC). The frequencies of IL-4-producing conjunctival CD4+ T cells of the patients with AC, AKC, or VKC were significantly higher than those of peripheral blood CD4+ T cells of the same disease. Further, increased frequency of P-selectin ligand expressing IL-4-producing T cells was observed in conjunctiva compared to that in PBMC of the patients with allergic conjunctival diseases. The frequencies of IL-4-producing peripheral blood T cells in the patients with ACD were significantly higher than that in normal controls.

Conclusion: These results suggest that IL-4-producing T cells that have infiltrated into the conjunctiva play an important role in the immunopathogenesis of allergic conjunctival diseases, and P-selectin ligand is involved in the entry of T cells into allergic inflammatory site.