Alpha/beta- and gamma/delta-T-cell-receptor-positive lymphocytes in healthy and inflamed human conjunctiva.

Abstract

The possible existence and distribution patterns of alpha/beta- and gamma/delta-TCR+ cells, which are important constituents of immune surveillance and act via the CD3+ cell complex have not yet been elucidated in the healthy and inflamed conjunctiva. Paraffin-embedded conjunctival specimens included 18 from 18 patients with ocular cicatricial pemphigoid (OCP), 20 from 20 healthy controls, 6 from 6 patients with lye burns, and 6 from 2 patients with Stevens-Johnson syndrome; all were worked up by histology and immunohistochemistry. alpha/beta-TCR+ cells were visualized in the conjunctival epithelium and stroma of healthy persons, OCP, lye burns and Stevens-Johnson syndrome. alpha/ beta-TCR+ cells and a small number of gamma/delta-TCR+ cells were observed in the corneal epithelium and stroma of patients who have failing corneal grafts. After ileal mucosa transplantation to the epibulbar conjunctiva, membrane staining changes to nuclear and cytoplasmic staining. Treatment with systemic cytotoxic drugs abolishes all alpha/beta-TCR+ and gamma/delta-TCR+ cells. alpha/beta-TCR+ cells can be found in the non-infected epithelium and stroma of the healthy and inflamed (OCP, lye burns, and Stevens-Johnson syndrome) conjunctiva, as well as in the corneal epithelium and stroma of failing corneal grafts, whereas gamma/delta-TCR+ cells are absent. A small number of gamma/delta-TCR+ cells are present in the corneal stroma and adjacent conjunctival epithelium of patients with chronic corneal graft rejection or after transplantation of gut tissue. Further investigations may establish the role, if any, of these T-cell subsets in immune surveillance of the non-infected outer eye and in corneal graft rejection.