[Alpha/beta and gamma/delta T-cell receptors--analysis of conjunctival tissue of patients with ocular pemphigoid].

BACKGROUND

In the conjunctiva of asymptomatic persons and patients with ocular cicatricial pemphigoid the existence and distribution of alpha/beta- and gamma/delta-T cell receptor (TCR)-positive cells has not previously been investigated.

PATIENTS AND

METHODS

Biopsy specimens from 20 patients with clinically diagnosed ocular cicatricial pemphigoid (OCP) were compared with 20 specimens from asymptomatic persons. Additionally, 3 specimens from patients with OCP treated with cytotoxic drugs and 8 specimens from patients who had undergone mucosal transplantation were studied. Antigen retrieval was done in deparaffinized specimens for immunohistochemical identification of alpha/beta- and gamma/delta-TCR-positive cells by monoclonal antibodies and an appropriate detection system. All steps were performed in triplicate, and negative control sera were applied.

RESULTS

alpha/beta-TCR-positive cells were observed in the conjunctival epithelium and stroma of all the asymptomatic persons and in all patients with OCP. gamma/delta-TCR-positive cells were found in 4 out of 20 patients with OCP in epithelial sites, but not in asymptomatic persons. Patients with OCP who had received cytotoxic treatment exhibited neither alpha/beta- nor gamma/delta-TCR-positive cells. Staining sites of alpha/beta-TCR-positive cells changed from membrane-bound to nuclear in patients who had undergone mucosal transplantation, and were cytoplasmic rather than membrane-bound in gamma/delta-TCR positive cells.

CONCLUSIONS

This study presents preliminary evidence for the existence of distinct T-cell subsets in the conjunctiva of healthy persons and of patients with OCP. Further functional studies in fresh tissue material may provide better insights into the role of defined T-cell subsets in the immunopathogenesis of autoimmune diseases of the outer eye such as OCP.