脓毒症早期恒定自然杀伤T细胞活化对预后的影响

Effects of invariant natural killer T cell activation on prognosis in early sepsis

目的探讨脓毒症早期外周血恒定自然杀伤T(iNKT)细胞活化对炎症及病情的影响。方法取健康雄性C57BL/6小鼠随机分为3组,分别为假手术组、盲肠结扎穿孔(CLP)脓毒症模型组和CLP模型+CD1d阻断性抗体预处理组(抗-CD1d组)。CLP术后24h应用流式细胞术检测小鼠外周血、脾脏、胸腺iNKT细胞水平,ELISA法后检测血清肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-6、干扰素γ(IFN-γ)和IL-4等细胞因子水平,分析iNKT细胞与细胞因子的相关性,检测外周血和腹腔灌洗液中的细菌菌落数。观察各组小鼠CLP后10d生存率。选取脓毒症确诊患者及健康志愿者各20例,年龄18~70岁,检测脓毒症患者及健康志愿者外周血iNKT细胞比例及细胞因子水平,分析iNKT细胞与细胞因子及急性生理和慢性健康(APACHEⅡ)评分的相关性。结果脓毒症模型组小鼠的iNKT细胞和TNF-α、IL-6、IFN-γ、IL-4水平均高于假手术组(P<0.05,P<0.01),外周血及腹腔中细菌菌落数高于假手术组(P<0.01),术后7d内小鼠全部死亡;与脓毒症模型组小鼠相比,给予抗-CD1d抗体预处理后,抗-CD1d组小鼠外周血、脾脏、胸腺的iNKT细胞比例下降(P<0.05,P<0.01),外周血TNF-α、IL-6、IFN-γ和IL-4水平及外周血和腹腔液中细菌菌落数减少(P<0.05,P<0.01),术后第10天时小鼠仍存活4只。脓毒症患者的iNKT细胞及细胞因子TNF-α、IL-6、IFN-γ和IL-4水平相比健康对照组增加(P<0.05,P<0.01),且iNKT细胞与IFN-γ、IL-4水平及APACHEⅡ评分呈正相关(P<0.05)。结论脓毒症早期外周血iNKT细胞水平明显增加并与脓毒症病情严重程度及预后有一定关系,提示iNKT细胞可能在脓毒症炎症反应中起重要调节作用。

Objective To explore the effects of invariant natural killer T（iNKT）cell activation on inflammation and severity of early sepsis.Methods Healthy C57BL/6male mice were randomly divided into 3groups：sham group,cecal ligation and puncture（CLP）-induced sepsis model group（CLP group）and CLP-induced sepsis model plus treatment with anti-CD1 dblocking antibody group（anti-CD1dgroup）.Flow cytometry was used to determine the frequencies of the iNKT cells in the peripheral blood,spleen and thymus of mice after 24 h of CLP operation.Meanwhile,the ELISA assay was used to detect the serum levels of tumor necrosis factor-α（TNF-α）,interleukin（IL）-6,interferon-γ（IFN-γ）and IL-4.The correlation of iNKT cells and cytokine was analyzed.The bacterial colonies in peripheral blood and peritoneal lavage fluid were determined.The 10-day survival rates of mice after CLP operation were observed.Twenty patients with confirmed sepsis and 20 healthy volunteers aging 18-70 years were selected.The frequency of peripheral blood iNKT cells and serum cytokine levels of all patients and healthy volunteers were detected.Correlations of iNKT cells and cytokines,Acute Physiology and Chronic Health EvaluationⅡ（APACHE Ⅱ）scores in septic patients were analyzed.Results Compared with the sham group,the mice in the CLP group showed significantly more iNKT cells,significantly higher levels of TNF-α,IL-6,IFN-γand IL-4（P〈0.05,P〈0.01）,and significantly higher levels of bacterial colonies in peripheral blood and peritoneal lavage fluid（P〈0.01）.The mice in the CLP group all died within 7days after operation.In the mice of the anti-CD1 dgroup,iNKT cell proportions in peripheral blood,spleen and thymus,the serum levels of TNF-α,IL-6,IFN-γand IL-4in peripheral blood,and the bacterial burden in the abdominal cavity were decreased compared with the CLP group（P〈0.05,P〈0.01）.Four mice in anti-CD1 dgroup survived at 10 days of post-operation.Compared with healthy volunteers,septic patients displayed significantly higher frequency of iNKT cells and significantly higher levels of TNF-α,IL-6,IFN-γand IL-4（P〈0.05,P〈0.01）.Moreover,there was a positive correlation between frequency of iNKT cells with serum IFN-γand IL-4 and the score of APACHE Ⅱ（P〈0.05）.Conclusion Increase of peripheral blood iNKT cells in early sepsis is associated with the severity and prognoses of sepsis,which suggests iNKT cells may play an important role in the inflammation of sepsis.