363 Increased Frequency of γδ T Cells in Patients with Allergic Conjunctivitis

BACKGROUND: It is well known involvement of CD4+ T cells in the maintenance of allergic immune response at conjunctiva; recently, it was suggested in the mouse model that γδ T cells are needed for the ocular allergic response maintenance; however contribution of γδ T cells in human allergic conjunctivitis is still unknown. The aim of this study was to evaluate the frequency of γδ T cells in AC patients. METHODS: Patients with AC diagnosis were included. All participants gave their informed consent for blood sampling after written information was provided. Peripheral blood mononuclear cells (PBMC) were separated on a Ficoll density gradient, after that PBMC were stained with mAb against human CD3-PeCy5 and γδ-PE. The cells were analysed for marker expression by collecting 10,000 events using a FACScan flow cytometer (Becton Dickinson, CA, USA) and CellQuest Pro software. To analyse cell surface marker staining, a gate was drawn around the lymphocyte population based on their physical properties (forward and side scatter). Data were analyzed with t test and differences were considered statistically significant with P < 0.05. RESULTS: We observed a higher frequency of gd T cells in patients with AC, gd T cells were increased 11.9 times in AC-patients (22.63 ± 2.9%) than healthy donors (1.9 ± 1.9%) (P = 0.002). CONCLUSIONS: γδ T cells are increased in allergic conjunctivitis patients. These data suggest that lipids antigens could be involved in pathogenesis of allergic conjunctivitis in humans and possibly implicated in chronic responses at ocular level, as has been suggested in the mouse model of allergic conjunctivitis.