[Role of corneal fibroblasts in the pathogenesis of ocular allergic diseases].

The accumulation of eosinophils and the subsequent release and deposition of cytotoxic proteins by these cells are thought to play an important role in the development of corneal lesions in individuals with vernal keratoconjunctivitis(VKC). Stimulation of corneal fibroblasts with the T helper 2 (Th2) type cytokines, interleukin (IL) -4 or IL-13, induces expression of both the chemokine eotaxin and vascular cell adhesion molecule-1, which together mediate eosinophil infiltration into the cornea. Corneal fibroblasts express a high-affinity receptor complex for IL-4 and IL-13, and their stimulation by these cytokines also induces expression of thymus- and activation-regulated chemokine(TARC), which is a potent chemoattractant for Th2 cells. Dermal fibroblasts, but not lung fibroblasts, also express TARC, suggesting that corneal, dermal, and lung fibroblasts play different roles in the initiation of corresponding Th2 cell-mediated allergic conditions. Corneal fibroblasts thus not only maintain tissue structure but also contribute to the induction and amplification of ocular allergic inflammation. These observations suggest that the development of drugs that specifically inhibit the functions of corneal fibroblasts may provide a basis for new treatments for the corneal disorders associated with VKC.