Immune mechanisms involved in the coexistence of oral lichen planus and autoimmune thyroid diseases.

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease with unclear etiology. Autoimmune thyroid diseases (AITD) is a type of autoimmune disease characterized by increased thyroid-specific antibodies. In recent years, more and more studies have found that the incidence of AITD is increased in OLP patients. The occurrence and development of OLP and AITD may be related to the expression of thyroid autoantigen in oral keratinocytes, the imbalance of thyroid hormone （Th）1/Th2 and Th17/Treg cell subsets, the abnormal quantity and function of follicular helper T cells and chemokines and the specific killing ability of CD8 T cells to target cells. In this article, the possible immune mechanisms involved in the coexistence of OLP and AITD are reviewed to provide insights for the diagnosis, treatment and prevention of these two diseases from the perspective of immunology.