T-helper 17 lymphocytes in ocular cicatricial pemphigoid

PURPOSE: T-helper 17 lymphocytes (Th17) were identified in the healthy conjunctiva and in patients with ocular cicatricial pemphigoid (OCP), a disease characterized by chronic ocular surface inflammation. METHODS: Conjunctival biopsies and blood samples were obtained from 10 patients with OCP (4 males, 6 females; 57–90 years of age) and 6 age/sex matched healthy subjects. Conjunctival samples were immunostained with anti-human IL17/CD4 antibodies and stained cells were then counted by confocal microscopy in three 60X field images per each sample. Mononuclear cells were isolated from both OCP and healthy blood samples and evaluated for IL17 and CD4 by FACS. IL17, TGF-β, IL4, and IFN-γ levels were determined in plasma of OCP and healthy patients by ELISA. RESULTS: The presence of Th17 lymphocytes in conjunctival biopsies was significantly (p<0.05) increased in patients with OCP (14.9±12.8 cells per microscopic field) compared to healthy subjects (0.5±0.8 cells per microscopic field). Th17 lymphocytes comprised 72% of CD4(+) cells in four stage-III OCP conjunctival samples. No significant difference was observed for IL17 in peripheral blood of OCP versus healthy subjects. CONCLUSIONS: In this study, we report an increased localization of Th17 lymphocytes in OCP conjunctiva, not accompanied by similar findings in peripheral blood. This finding suggests an increased recruitment of Th17 lymphocytes in conjunctiva and/or a dysfunctional local immune response in the chronically inflamed conjunctiva of OCP. Our findings are in line with previously reported evidence demonstrating that Th17 cells play a critical pathogenic role in mucosal autoimmunity.