在慢性关节病中，有几种关节破坏机制。最近的研究报告了核因子 kappa-B 激活因子受体配体 (RANKL) 和骨保护素 (OPG) 在骨溶解细胞的活化和分化过程中的含义，这是骨侵蚀发展中的关键细胞。血清中 RANKL/OPG 比值在恶性疾病、溶骨性骨病和类风湿性关节炎 (RA) 患者中增加。本研究的目的是测量和比较类风湿性关节炎、强直性脊柱炎 (SpA) 和骨关节炎 (OA) 患者滑液中 OPG 和 RANKL 的浓度。本研究是一个观察性交叉研究，涉及 83 名患者，其中 33 名患有 RA，32 名患有 SpA，18 名患有 OA，他们均在里贝朗普雷图医学院临床医院风湿科门诊进行定期随访。所有患者在滑液采集时，由主治医生评估关节穿刺表征，并对人口统计学变量和用药情况进行评估。对 RA 和 SpA 患者进行了疾病活动性评估。采用酶联免疫吸附法定量滑液 OPG 和 RANKL 水平，并评估结果与临床、实验室和放射学指标之间的相关性。 我们发现各组之间的 RANKL 和 OPG 水平没有统计学上显著的差异。RA 患者滑液细胞计数与 RANKL 水平 (r = 0.59；p＜0.05) 和 RANKL/OPG 比值 (r = 0.55；p＜0.05) 呈正相关。OA 患者 C-反应蛋白 (CRP) 与 RANKL/OPG 比值 (r = 0.82；p＜0.05) 呈强相关。RA 或 SpA 患者中 OPG 和 RANKL 水平与炎性活动标志物或疾病活动指数之间没有相关性。在此患者群中，RA 患者的 RANKL/OPG 比值与滑液细胞计数相关，OA 患者的 RANKL/OPG 比值与血清 CRP 相关，这可能表明与活动性炎症和更具破坏性的关节疾病有关。 ©2023年作者。

In chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA).This was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed.We found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA.Within this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.© 2023. The Author(s).