C-type lectin domain family 5-member A (CLEC5A) associates with adaptor DAP12 (DNAX activation protein 12) to form receptor complexes involved in inflammatory responses. We postulated a potential role of CLEC5A in the pathogenesis of adult-onset Still’s disease (AOSD) and aimed to investigate CLEC5A expression and its association with activity parameters and disease course. In 34 AOSD patients and 12 healthy controls (HC), circulating levels of CLEC5A-expressing monocytes or granulocytes were determined by flow cytometry analysis, the mRNA expression of CLEC5A and DAP12 on PBMCs by quantitative PCR, and plasma levels of proinflammatory cytokines by ELISA. AOSD patients had significantly higher percentages and mean fluorescence intensity (MFI) of CLEC5A-expressing monocytes (median 62.1% and 3.20, respectively) or granulocytes (72.6% and 3.22, respectively) compared with HC (in monocytes: 17.0% and 0.65, both ; in granulocytes: 67.3%, and 0.90, ; respectively). Patients also had significantly higher levels of CLEC5A mRNA expression on PBMCs compared with HC (median 1.77 vs. 0.68, ). The levels of CLEC5A-expressing monocytes or granulocytes were positively associated with activity scores and levels of IL-1β and IL-18 in AOSD patients. The patients with a systemic pattern had significantly higher levels of CLEC5A-expressing granulocytes and IL-18 compared to those with a chronic articular pattern of disease course. After 6 months of therapy, levels of CLEC5A-expressing monocytes and granulocytes significantly declined, paralleling the decrease of AOSD activity. Elevated CLEC5A levels and their positive association with activity parameters suggest that CLEC5A is involved in the pathogenesis and may serve as an activity indicator of AOSD.

中文翻译：

---

C型凝集素域家族5成员A（CLEC5A）的表达升高及其与成人发作性静止疾病中炎症参数和疾病进程的关系。

C型凝集素结构域家族5成员A（CLEC5A）与衔接子DAP12（DNAX激活蛋白12）结合形成参与炎症反应的受体复合物。我们推测CLEC5A在成人发作性斯蒂尔氏病（AOSD）的发病机理中的潜在作用，旨在研究CLEC5A的表达及其与活性参数和疾病进程的关系。在34例AOSD患者和12例健康对照（HC）中，通过流式细胞仪分析确定了表达CLEC5A的单核细胞或粒细胞的循环水平，通过定量PCR测定了PBMC上CLEC5A和DAP12的mRNA表达，并通过ELISA测定了促炎细胞因子的血浆水平。AOSD患者的表达CLEC5A的单核细胞（分别为中值62.1％和3.20）或粒细胞（分别为72.6％和3.22）的百分比和平均荧光强度（MFI）明显更高。; 在粒细胞中：67.3％， 和0.90， ; 分别）。与HC相比，患者在PBMC上的CLEC5A mRNA表达水平也显着更高（中位数为1.77 vs. 0.68，）。AOSD患者中表达CLEC5A的单核细胞或粒细胞的水平与活性评分以及IL- 1β和IL-18的水平呈正相关。与具有慢性关节疾病模式的患者相比，具有全身模式的患者表达CLEC5A的粒细胞和IL-18的水平明显更高。治疗6个月后，表达CLEC5A的单核细胞和粒细胞水平显着下降，与AOSD活性下降平行。升高的CLEC5A水平及其与活性参数的正相关性表明CLEC5A参与了发病机理，并可能作为AOSD的活性指标。