LncRNA XLOC_003810 promotes T cell activation and inhibits PD-1/PD-L1 expression in patients with myasthenia gravis-related thymoma.

This study aimed to investigate the effect of long non-coding RNA XLOC_003810 on the activation of CD4+ T cells and expression of PD-1/PD-L1 in patients with myasthenia gravis-related thymoma (MG-T). Thymus specimens and thymic mononuclear cells were obtained from MG and MG-T patients or cardiac surgery patients undergoing thoracotomy who were selected as negative controls (NC). XLOC_003810 expression was examined using quantitative real-time PCR (qRT-PCR). Frequency of CD4+ T cells and proportion of CD4+ PD-1+ T cells and CD14+ PD-L1+ monocytes were quantified by flow cytometry. The release of inflammatory cytokines was measured by qRT-PCR and enzyme-linked immunosorbent assay. Compared with the NC group, expression of XLOC_003810, frequency of CD4+ T cells and the production of inflammatory cytokines were increased in patients with MG and MG-T. XLOC_003810 overexpression significantly increased the frequency of CD4+ T cells, facilitated the production of inflammatory cytokines and decreased the proportion of CD4+ PD-1+ T cells and CD14+ PD-L1+ monocytes in the thymic mononuclear cells. In contrast, XLOC_003810 knockdown exerted the opposite effect. Together, XLOC_003810 promotes T cell activation and inhibits PD-1/PD-L1 pathway in patients with MG-T.