Phenotypic characterization of T cells infiltrating the conjunctiva in chronic allergic eye disease.

Abstract

Chronic allergic conjunctivitis comprises a spectrum of diseases including atopic keratoconjunctivitis, atopic blepharoconjunctivitis, vernal keratoconjunctivitis, and contact lens-associated giant pupillary conjunctivitis. Each condition is characterized by a complex immunopathology with a mixed cellular infiltrate. Treatment with conventional mast cell stabilizers is often unsatisfactory, and therapy depends heavily on topical corticosteroids. Recent evidence suggests that T lymphocytes play an important role in mediating the immunopathology seen in the chronic allergic response in the skin and the lungs. We have therefore investigated the prevalence of T cells and their subsets in the different chronic allergic eye conditions by means of immunohistochemistry. We found significantly increased numbers of CD4+, CD45RO+, and HLA-DR+ T cells in the conjunctiva of patients with atopic and vernal keratoconjunctivitis and giant papillary conjunctivitis, with a corresponding upregulation of markers present on antigen presenting cells. These findings suggest that like allergic conditions in the skin and lungs, CD4+ memory T cells are involved in the regulation of the immunopathology of chronic allergic eye responses. Further characterization of these T cells will provide the information necessary for future immunotherapeutic interventions.