慢性HBV感染者血清IL-15和外周血iNKT细胞水平变化及相关性研究

Changes and correlation analysis of the levels of IL-15 and iNKT in patients with chronic hepatitis B virus infection

目的探讨慢性乙肝病毒(hepatitis B virus,HBV)感染者血清IL-15和外周血恒定自然杀伤T(invariant nature killer T,i NKT)细胞水平的变化。方法收集54例慢性HBV感染者和15名健康者外周血,分离血清和外周血单个核细胞(PBMC);ELISA法检测血清中IL-15水平;流式细胞术检测i NKT细胞占T细胞的比例,PMA、BFA和ionomycin处理PBMC后,流式细胞术检测i NKT分泌的IFN-γ和TNF-α水平,并利用Pearson法进行相关性分析。结果与正常对照者相比,免疫清除期患者血清中IL-15水平明显升高(P<0.05),免疫耐受期患者高于正常对照者,低于免疫清除组,差异无统计学意义(P>0.05);免疫清除期和免疫耐受期患者血清ALT水平和HBV DNA载量与IL-15水平无明显相关性(P>0.05)。免疫清除期患者外周血i NKT细胞比例显著降低,免疫耐受期患者略升高,但差异无统计学意义(P>0.05)。免疫耐受期和清除期患者外周血i NKT细胞分泌IFN-γ和TNF-α的细胞比例略有升高,但差异无统计学意义(P>0.05)。免疫耐受期和免疫清除期患者i NKT细胞分泌IFN-γ水平与IL-15水平呈正相关;免疫耐受期和免疫清除期患者i NKT细胞分泌TNF-α水平与IL-15水平无相关性(P>0.05)。结论慢性HBV感染者血清中IL-15水平升高,且外周血i NKT细胞数量减少,且不同感染状态患者血清IL-15水平和外周血i NKT细胞数量呈动态变化。

Objective To investigate the changes and correlation analysis of serum levels of interleukin-15 （IL-15） and invariant nature killer T （iNKT） in patients with chronic hepatitis B virus （HBV） infection. Methods Serum and peripheral blood mononuclear cells （PBMC） were isolated from 54 patients with chronic HBV infection and 15 healthy subjects. The serum IL-15 level was determined by ELISA. The ratio of iNKT cells in T cell was detected by flow cytometry. The expressions of intracellular IFN-γ and TNF-α in iNKT cells were analyzed by flow cytometry after the treatment with PMA, BFA and ionomycin in vitro. The relationship between the IL-15 level and the iNKT rate was analyzed by Pearson correlation analysis. Results Compared with the normol control group （P 〈 0.05） , the expression of IL-15 was elevated in serum of immune clearance phase （P 〈 0.05）. Compared with immune clearance phase, the expression of IL-15 was reduced in serum of immune tolerance phase （P 〉 0.05）. There was no significant correlation between the ALT, HBV DNA level and IL-15 level in immune clearance phase and immune tolerance phase （P 〉 0.05 ）. Compared with the normol control group, the expression of iNKT was elevated in PBMC of immune tolerance phase and reduced in PBMC of immune clearance phase. Compared with immune tolerance phase, the expression of iNKT was reduced in PB- MC of immune clearance phase. Compared with normol control group, the expressions of IFN-γ and TNF-α iNKT were slight elevated in PBMC of immune tolerance phase and immune clearance phase, but no significant differences. Compared with immune tolerance phase, the expressions of IFN-γ and TNF-α iNKT were slight elevated in PBMC of immune clearance phase, but no significant differences （P 〉 0.05）. There was positive correlation between IFN-α＋iNKT and IL-15 level and there was no significant correlation between TNF-α＋ iNKT and IL-15 level in immune clearance phase and immune tolerance phase. Conclusion The level of IL-15 in serum there is elevated and the number of iNKT cells of peripheral blood reduce in chronic HBV infection patients, and a dynamic changes trend between them in different immune phase.