Objectives

To investigate the changes and mechanism of Siglec-9 on NK cells in peripheral blood of patients with severe fever with thrombocytopenia syndrome (SFTS).

Methods

First, we used single-cell RNA sequencing to analyze the frequency of NK cells in Peripheral Blood Mononuclear Cells (PBMCs) of SFTS patients and healthy controls (HCs), as well as the differences in the genes on NK cells. Secondly, we analyzed the expression of Siglec-9 and other receptors on NK cells by flow cytometry. Thirdly, we analyzed the correlation between Siglec-9 on NK cells and DBV viral load in plasma.

Results

Compared with HCs, the frequency of NK cells in peripheral blood of SFTS patients was significantly decreased, and the activating receptors on NK cells were reduced. The expression of Siglec-9 on NK cells and the frequency of Siglec-9⁺NK cells decreased significantly in SFTS patients. The expression of Siglec-9 on CD16⁺CD56^dim NK cells was negatively correlated with DBV viral load. In addition, Siglec-9⁺NK cells expressed higher levels of activating receptors and exhibited stronger effector functions than Siglec-9⁻NK cells.

Conclusions

The decreased expression of Siglec-9 on NK cells predicts NK cell dysfunction in SFTS patients, suggesting that Siglec-9 may be a potential marker for functional NK cell subsets in SFTS patients.

中文翻译：

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SFTS患者外周血NK细胞中Siglec-9表达的变化可影响NK细胞的功能

目标

探讨Siglec-9对发热伴血小板减少综合征（SFTS）患者外周血NK细胞的变化及机制。

方法

首先，我们利用单细胞RNA测序分析了SFTS患者和健康对照（HC）的外周血单核细胞（PBMC）中NK细胞的频率，以及NK细胞上基因的差异。其次，我们通过流式细胞术分析了NK细胞上Siglec-9和其他受体的表达。第三，我们分析了 NK 细胞上的 Siglec-9 与血浆中 DBV 病毒载量之间的相关性。

结果

与HC相比，SFTS患者外周血中NK细胞的频率明显降低，NK细胞上的激活受体减少。SFTS患者中NK细胞上Siglec-9的表达以及Siglec-9 ⁺ NK细胞的频率显着下降。^{CD16 +} CD56dim NK细胞上Siglec-9的表达与DBV病毒载量呈^负相关。此外，Siglec-9 ^{+ NK 细胞比 Siglec-9 -} NK 细胞表达更高水平的激活受体，并表现出更强的效应功能。

结论

NK 细胞上 Siglec-9 表达的降低预示着 SFTS 患者的 NK 细胞功能障碍，这表明 Siglec-9 可能是 SFTS 患者功能性 NK 细胞亚群的潜在标志物。