多发性骨髓瘤患者NK细胞杀伤功能异常的研究

Study of NK cells dysfunction in multiple myeloma patients

目的探讨多发性骨髓瘤（MM）患者NK细胞杀伤功能下降的机制。方法以13例MM患者为研究对象，以30名健康志愿者为正常对照，采用流式细胞术检测外周血单个核细胞中CD3-CD56^＋（NK细胞）表面抑制性受体（CD158a和CD158b）以及活化性受体NKG2D、NCRs（NKp30、NKp44、NKp46）的表达水平；ELISA法检测血清可溶性NKG2D配体水平；流式细胞术检测NK细胞对MM细胞株U266细胞杀伤作用的变化。结果MM患者外周血中NK细胞比例及绝对数、CD158a和CD158b表达水平与对照组比较差异无统计学意义（P值均〉0．05），两组NK细胞表面均不表达NKp44；与对照组比较，MM患者NK细胞表面活化性受体（NKG2D、NKp30和NKp46）水平均明显降低，血清中可溶性NKG2D配体水平明显升高，差异均有统计学意义（P值均〈0．05）；用MM患者血清培养后的正常对照者NK细胞对U266细胞的杀伤能力较共培养前明显下降[（25．4±5．9）％对（38．5±6．5）％]，差异有统计学意义（P=0．044）。结论MM患者血清可溶性NKG2D配体水平可能是导致NK细胞杀伤活性下降的原因。

Objective To explore the mechanism of NK cell dysfunction in patients with multiple myeloma （MM）. Methods The expression of inhibitory receptors （CD158a and CD158b） and activating receptors NKG2D and NCRs （NKp30, NKp44 and NKp46） on CD3-CD56^＋NK cell of 13 MM patients and 30 healthy controls were analyzed by flow cytometry. The concentration of soluble NKG2D ligands （MICA, MICB, ULBP1, ULBP2 and ULBP3） in serum was detected by enzyme-linked immunosorbent assay （ELISA）, and the cytotoxicity of NK cell against MM cell line by flow cytometry. Results There are no significant differences of percentage and absolute number of NK cells, and the expression level of CD158a and CD158b between MM patients and healthy individuals （P〉0.05）. No NKp44 expression was detected on fresh isolated NK cells from both groups. There is no difference in inhibitor receptors expression between MM patients and healthy individuals but the expression of NKG2D, NKp30 and NKp46 on NK cells were higher in MM patients as compared with that in healthy individuals. The concentration of soluble NKG2D ligands in serum was higher in MM patients as compared with that in healthy individuals （P〈0.05）. Cultured healthy individual＇ s NK cells with MM patient＇ s serum could significantly decrease its cytotoxicity against MM cell line U266 cells [ （38.5±6.5）% vs （25.4±5.9）%, P= 0.044 ]. Conclusion The higher level of soluble NKG2D ligands in serum may be the mechanism of NKcell dysfunction in MM patient.