The study aimed to investigate the soluble programmed death-1 (sPD-1) and its ligand (sPD-L1) levels in systemic juvenile idiopathic arthritis (sJIA) patients and elucidate its underlying immunomodulatory mechanisms. Plasma levels of sPD-1, sPD-L1 and related cytokines and proteins were detected using an enzyme-linked immunosorbent assay (ELISA) and Luminex. The effects of PD-1/PD-L1 signal on mDC (myeloid dendritic cell) and IL-6 secretion were measured using flow cytometry. The results revealed decreased levels of sPD-1 in sJIA patients negatively correlated with JADAS-27, PGA, PtGA and CRP. sJIA patients had lower CD86 and MHC-II expression on mDC. When blocking PD-1/PD-L1 signal, IL-6 secretion of DC were increased. Our finding displayed downregulated sPD-1 was related with clinical indicators and could be a new biomarker for sJIA diagnosis. The reduced membrane and soluble forms of PD-1/PD-L1 might take part in sJIA pathogenesis by enhancing mDC proliferation and IL-6 secretion.

该研究旨在调查全身性幼年特发性关节炎 (sJIA) 患者的可溶性程序性死亡 1 (sPD-1) 及其配体 (sPD-L1) 水平，并阐明其潜在的免疫调节机制。使用酶联免疫吸附试验 (ELISA) 和 Luminex 检测 sPD-1、sPD-L1 和相关细胞因子和蛋白质的血浆水平。使用流式细胞术测量 PD-1/PD-L1 信号对 mDC（髓样树突细胞）和 IL-6 分泌的影响。结果显示sJIA患者sPD-1水平降低与JADAS-27、PGA、PtGA和CRP呈负相关。sJIA 患者在 mDC 上具有较低的 CD86 和 MHC-II 表达。当阻断PD-1/PD-L1信号时，DC的IL-6分泌增加。我们的发现显示下调的 sPD-1 与临床指标相关，可能成为 sJIA 诊断的新生物标志物。