Abstract
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Lymphocytes bearing the T‐cell receptor (TCR) γ/δ are increased in the peripheral blood of patients with recurrent aphthous ulcers (RAU) and Behçet’s disease. In this study, we examined whether the density of TCR‐γ/δ bearing lymphocytes was also increased locally in RAU lesions. Ten RAU lesions from ten patients were compared with ulcer‐free mucosa from sites contralateral to the lesions, and with 10 samples of clinically healthy oral mucosa taken from 10 healthy volunteers. Samples were labeled with a panel of monoclonal antibodies specific to CD3, α/β TCR and γ/δ TCR in avidin‐biotin‐peroxidase complex (ABC) staining. Lymphocytes expressing γ/δ TCRs were very low in non‐lesional mucosa and clinically healthy mucosa. By contrast, γ/δ T‐cells were numerous and observed in all RAU lesions especially within the epithelium, inflammatory infiltrates and at perivascular locations. The count of γ/δ T‐cells was high in connective tissue of RAU (200±126 cells/mm2) compared with connective tissue of controls (4±4 cells/mm2; P<0.0001) or non‐lesional mucosa (5±7 cells/mm2). Interestingly, the density of γ/δ T‐cells was also high in the epithelium of RAU (70±34 cells/mm2) compared with the epithelium of non‐lesional mucosa (2.8±06 cells/mm2; P<0.0001) or epithelium of healthy controls (1.2±1.5 cells/mm2; P<0.0001). Moreover, the mean percentage of γ/δ+ T‐cells among total CD3+ lymphocytes was increased in the connective tissue area from 4% and 5% in controls and non‐lesional mucosa, respectively, to 19% in RAU. In epithelial areas, the average percentage was increased from 2% and 6% in controls and non‐lesional mucosa, respectively, to 36% in RAU. These data showed that γ/δ T‐cells are more numerous in RAU lesions and such an increase was purely restricted to RAU inflammatory areas.