Objectives: (i) to investigate the effects of BD serum and saliva on human buccal epithelial cell responses; (ii) to analyse the effects of T cell-derived molecules on cytokine production and epithelial cell differentiation.
Methods: Fifty-one saliva samples from 39 patients with BD (F/M: 26/13) and 32 samples from 32 healthy controls HC (F/M: 19:13) were used. Whole unstimulated saliva was collected, centrifuged and filtered (0.2 μm). Serum was extracted from blood taken by venepuncture. 34 samples from 34 of the same patients were obtained (F/M: 21/13), and 16 samples from 16 matched healthy controls. Ten BD patients and 8 healthy controls were included in the T cell study. T-cells were separated by density gradient separation, and magnetic cell sorting. Assays were carried out on the SVpgC2a buccal epithelial cell line, by incubation with saliva, serum or T-cell supernatants. Cellular proliferation (MTT assay) and cytokine responses (ELISA) were examined post-24-hour incubation with saliva or serum (100µl/ml in medium). Activation expression was analysed by immunohistochemical cell staining.
Results: Saliva, but not serum, dramatically stimulated epithelial cell proliferation. For all cytokines assayed (IL-1α, IL-6, IFNγ, IL-12, IL-15), release by epithelial cells was significantly higher in the presence of BD than HC saliva (p<0.0001, except for IL-12, p<0.001). IL-1α, IL-6 and IL-8 were expressed at the greatest levels. IL-6 was significantly up-regulated in the supernatants of non-stimulated or Con A-stimulated T cells from BD patients compared to healthy controls. Expression levels of MHC class II, CD40, CD54, CD58 and CD86 were stimulated by culture with Con A-stimulated supernatant from BD patients.
Conclusion: The saliva of BD patients plays a significant role in immune activation, and may provide greater understanding of the role of oral immunity in BD