Psychoneuroimmunology in oral biology and medicine: the model of oral lichen planus.

Rheumatoid arthritis involves psychoneuroendocrine-immunopathological comorbidities. In the stoma, patients with rheumatoid arthritis frequently show signs of periondontal disease consequent to elevated levels of crevicular proinflammatory cytokines. It is not clear whether rheumatoid arthritis may manifest in association with immunopathological manifestations of the oral soft mucosa. Oral lichen planus (OLP), first described by E. Wilson in 1859, is a T-cell-mediated inflammatory disease whose lesions characteristically lack B cells, plasma cells, immunoglobulin. or complement. It is increasingly well characterized and recognized as a model for psychoneuroimmunology research in oral biology and medicine. To date, we have shown an association between changes in hypothalamic-pituitary-adrenal (HPA) regulation, systemic markers of cellular immunity and mood states, with clinical stages of OLP (i.e., atrophic vs. erosive vs. bullous lesions). We report significant associations (p < 0.05) between the stage of OLP, HPA deregulation, and altered distribution and functional responses of naïve CD4(+) cells. We emphasize the need to study in greater details the psychoneuroendocrine-immune inter-relationships in OLP, and we propose a novel neuroimmune hypothesis for OLP.