目的：探讨外周血自然杀伤T淋巴细胞（NKT细胞）和CD4＋NKT细胞对哮喘患儿发病的影响。方法选取2008年1月至2012年12月住院治疗的哮喘病患儿150例（哮喘组），另选160例体检健康的儿童作为健康对照组。收集研究对象外周静脉血标本，采用密度梯度离心法分离获得外周血单个核细胞，应用免疫荧光标记和流式细胞术检测哮喘组和健康对照组儿童外周血NKT细胞和CD4＋NKT细胞的比例，并观察两类细胞与过敏指标总免疫球蛋白E（IgE）、嗜酸性细胞阳离子蛋白（ECP）的相关性。酶联免疫吸附试验检测外周血细胞因子白细胞介素（IL）‐4、IL‐10、干扰素‐γ（IFN‐γ）水平。比较两组间的差异。结果哮喘组患儿的NKT细胞和CD4＋NKT细胞比例均较健康对照组明显下降（P＜0．05）。NKT细胞、CD4＋NKT细胞的比例与总IgE、ECP均无明显相关性（P＞0．05）。外周血IL‐4水平较健康对照组明显升高（P＜0．05），IL‐10水平明显下降（P＜0．05），而IFN‐γ水平与健康对照组比较差异无统计学意义（P＞0．05）。结论NKT细胞和CD4＋NKT细胞数量降低下及所分泌细胞因子功能变化是导致哮喘发病的重要原因。%Objective To study the effect of natural killer T(NKT)lymphocytes and CD4+ NKT lymphocytes levels in peripheral blood onset of children asthma .Methods 150 asthmatic children inpatients from January 2008 to December 2012 were selected as the asthmatic group .160 healthy children were selected as the healthy control group . The peripheral venous blood specimens were collected .The peripheral blood mononuclear cells were obtained by using the density gradient centrifugation method .The ratio of peripheral blood NKT cells and CD4+ NKT cells were as‐sessed by immunofluorescence and flow cytometry assays .The relationships between the two kinds of NKT cells with allergic indexes of the total IgE and eosinophil cationic protein(ECP)was observed .The 1evels of IL‐4 ,IL‐10 and IFN‐γin peripheral blood were measured by the enzyme‐linked immunosorbent assay(ELISA) .Results Compared with the healthy control group ,the ratio of peripheral blood NKT and CD4+ NKT cells in the asthmatic patients was significantly decreased(P< 0 .05) .There was no significant correlation between the NKT cells and proportion of CD4+ NKT cells with the allergic indexes of the total IgE and ECP(P>0 .05) .The level of IL‐4 in peripheral blood in the asthmatic group was significantly higher than that of the healthy control group(P<0 .05) ,but the level of IL‐10 was decreased significantly(P<0 .05);There was no statistically significant difference in the IFN‐γlevel between the asthmatic group and the healthy control group(P>0 .05) .Conclusion The low count of NKT cells and CD4+ NKT cells and the functional change of cytokines secreted by NKT cells are the important causes leading to asthma onset .
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