Fu Rong, Liu Hui, Zhang Jiangbo, Liu Chunyan, Ding Shaoxue, Li Lijuan, Wang Huaquan, Wang Guojin, Song Jia, Shao Zonghong
Clin Lab. 2015;61(9):1221-9. doi: 10.7754/clin.lab.2015.150130.
Severe aplastic anemia (SAA) is a kind of bone marrow failure caused by complex pathogenesis, mainly characterized by severe pancytopenia which causes anemia, hemorrhage, and infection. Natural killer (NK) cells, derived from hematopoietic stem cells (HSCs) or common lymphoid progenitors (CLP), play an important role in the innate immunity and adaptive immune responses. Of the receptors on NK cells, the NKp46/NCR1 is considered to be an important activating receptor for NK cells. However, the quantity and function of NKp46/NCR1 remains unknown.
The quantity of NKp46/NCR1 on NK cells in patients with SAA before and after immunosuppressive therapy (IST) was investigated by flow cytometry, quantitative real-time PCR, and western blot. After knockdown of the NKp46/NCR1 gene, NK cells were cultured with K562 cells to detect the function of NK cells.
The results showed that the expression of NKp46/NCR1 in NK cells was significantly higher in untreated SAA patients than those in remission SAA and controls by FCM, qRT-PCR, and WB. After co-culturing with NK cells knockdown with siRNA-NKp46/NCR1, the apoptosis rate of K562 cells was significantly lower compared with the siRNA-scr group and control groups (7.08 ± 5.23% vs. 11.31 ± 7.20% and 10.30 ± 6.08%, p < 0.05).
We concluded that the decrease of total NK cells and the higher expressions of NKp46/NCR1 on them may be the reason for the hyperfunction of the immune system in SAA patients.
重型再生障碍性贫血（SAA）是一种发病机制复杂的骨髓衰竭疾病，主要特征为严重全血细胞减少，可导致贫血、出血和感染。自然杀伤（NK）细胞来源于造血干细胞（HSCs）或普通淋巴样祖细胞（CLP），在固有免疫和适应性免疫反应中发挥重要作用。在NK细胞的受体中，NKp46/NCR1被认为是NK细胞的重要激活受体。然而，NKp46/NCR1的数量和功能仍不清楚。
采用流式细胞术、定量实时PCR和蛋白质印迹法研究SAA患者免疫抑制治疗（IST）前后NK细胞上NKp46/NCR1的数量。敲低NKp46/NCR1基因后，将NK细胞与K562细胞共培养以检测NK细胞的功能。
流式细胞术、定量实时PCR和蛋白质印迹法结果显示，未经治疗的SAA患者NK细胞中NKp46/NCR1的表达明显高于缓解期SAA患者和对照组。用siRNA-NKp46/NCR1敲低NK细胞后与K562细胞共培养，K562细胞的凋亡率明显低于siRNA-scr组和对照组（7.08±5.23%对11.31±7.20%和10.30±6.08%，p<0.05）。
我们得出结论，SAA患者总NK细胞数量减少以及NK细胞上NKp46/NCR1表达升高可能是其免疫系统功能亢进的原因。
