The Mechanism of Immune Intervention by Iguratimod in Oral Lichen Planus Patients: An In Vitro Experimental Study

ABSTRACT Background Oral lichen planus (OLP) is a T cell‐mediated immune disease. Iguratimod (IGU) is a novel immunomodulatory agent for rheumatoid arthritis. No studies have been reported on the mechanism of IGU in the treatment of OLP, which deserves investigation. Methods Samples were collected from two batches of non‐erosive OLP, erosive OLP (EOLP) patients and healthy control subjects. In the first batch, the effects of IGU or the same volume of dimethyl sulfoxide (DMSO) on proliferation, apoptosis and migration of peripheral blood T lymphocytes (PBL T) were examined by CCK‐8, flow cytometry and transwell assay respectively. The levels of IL‐6, IL‐17, TNF‐α, TGF‐β and IL‐10 were measured by enzyme‐linked immunosorbent assay. In the second batch, the percentages of Th17 and Treg cells were determined by flow cytometry in peripheral blood mononuclear cells after IGU or DMSO stimulation. Results Compared with the control, IGU promoted apoptosis and inhibited migration, but had no significant effect on the proliferation of PBL T in OLP. IL‐6, IL‐17 and TNF‐α were decreased in OLP. TGF‐β and IL‐10 showed an upward trend in the IGU‐treated EOLP. IGU decreased Th17 in OLP and reduced Th17/Treg ratio in EOLP. The percentage of Treg cells showed an upregulated trend but the difference was not statistically significant. Conclusion IGU may intervene in the immune response of OLP by affecting functions of PBL T, improving the balance of Th17/Treg and regulating related cytokines.