Objective. The aim of this study was to characterize the subsets of circulating CD56⁺ NK cells in pSS patients and their potential value in the diagnosis and/or prediction of prognosis in patients with pSS. Methods. We included 52 pSS patients fulfilling the 2002 AECG criteria or 2012 ACR criteria and 20 age- and gender-matched healthy volunteers. The frequency and absolute number of NK cells and CD56 NK cell subsets in peripheral blood samples were detected by flow cytometry. Other laboratory parameters such as the IgG level and complement protein levels were extracted from the clinical system. Results. Both the frequency and the absolute number of peripheral blood NK cells were reduced in pSS patients compared to healthy controls. The proportion of CD56^bright NK cell subset was increased, and the proportion of CD56^dim NK cell subset was decreased among NK cells, resulting in the ratio of CD56^bright NK to CD56^dim NK which was significantly elevated in pSS patients. ROC analysis indicated that the AUC of CD56^bright NK/CD56^dim NK ratio was 0.838, and the best diagnostic cut-off point was 0.0487 for pSS patients. Furthermore, this CD56^bright NK/CD56^dim NK ratio was positively correlated with the IgG level and negatively correlated with the complement protein C3 and C4 levels. More importantly, the CD56^bright/CD56^dim NK ratio was either slightly increased or not changed in other autoimmune diseases such as SLE and IgG4-related disease. Conclusion. Our findings suggest that the ratio of blood CD56^bright NK to CD56^dim NK might have a diagnostic value relatively specific for pSS.

中文翻译：

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血液 CD56bright NK 与 CD56dim NK 的比率增加是原发性干燥综合征的一个显着特征。

客观。本研究的目的是表征 pSS 患者中循环 CD56 ⁺ NK 细胞的亚群及其在诊断和/或预测 pSS 患者预后中的潜在价值。方法。我们纳入了 52 名符合 2002 年 AECG 标准或 2012 年 ACR 标准的 pSS 患者以及 20 名年龄和性别匹配的健康志愿者。通过流式细胞术检测外周血样本中NK细胞和CD56 NK细胞亚群的频率和绝对数量。从临床系统中提取其他实验室参数，例如 IgG 水平和补体蛋白水平。结果. 与健康对照组相比，pSS 患者外周血 NK 细胞的频率和绝对数量均减少。NK细胞中CD56 ^bright NK细胞亚群比例增加，CD56 ^dim NK细胞亚群比例降低，导致pSS患者CD56 ^bright NK与CD56 ^dim NK细胞比例显着升高。ROC 分析表明，CD56^亮NK/CD56^暗NK 比值的 AUC 为 0.838，pSS 患者的最佳诊断截止点为 0.0487。此外，这款 CD56^亮NK/CD56^暗NK比率与IgG水平呈正相关，与补体蛋白C3和C4水平呈负相关。更重要的是，在SLE 和 IgG4 相关疾病等其他自身免疫性疾病中，CD56^亮/CD56^{暗NK 比率要么略有增加，要么没有变化。}结论。我们的研究结果表明，血液 CD56^亮NK 与 CD56^暗NK 的比率可能对 pSS 具有相对特异性的诊断价值。