Th17/Treg失衡引发的免疫耐受在棘球蚴感染所致过敏性休克中的作用

Study on the role of Th17/Treg imbalance-induced immune tolerance in anaphylactic shock caused by echinococcosis infection

目的探讨辅助性T细胞17/调节性T细胞(Th17/Treg)失衡引发的免疫耐受在棘球蚴感染所致过敏性休克(AS)中的影响及作用机制。方法纳入棘球蚴感染患者、棘球蚴感染休克患者和健康受试者各20例。采用ELISA检测3组人群血清中白细胞介素17(IL-17)、转化生长因子-β(TGF-β)和IgE水平,流式细胞术检测3组人群外周血中Th17和Treg细胞比例。将45只C57/B6小鼠随机分为3组:对照组、模型组和治疗组,每组15只。模型组和治疗组腹腔注射棘球蚴囊液构建感染模型,治疗组尾静脉注射20 mg/kg CD25抗体,每周1次,持续1个月。通过流式细胞术检测各组小鼠脾脏中Th17和Treg细胞比例,ELISA检测各组小鼠血清中IL-17和TGF-β水平。将棘球蚴囊液再次注射至各组小鼠腹腔,监测各组小鼠休克和死亡情况,qRT-PCR检测各组小鼠脾脏中IgE和FcεRI表达,ELISA检测各组小鼠血清中IgE水平。结果与健康受试者比较,棘球蚴感染患者血清中IL-17和IgE水平降低,TGF-β水平升高,Th17/Treg细胞比例降低;与棘球蚴感染患者比较,棘球蚴感染休克患者血清中IL-17和IgE水平升高,Th17/Treg细胞比例升高,差异均有统计学意义(F=143.754、137.285、128.753、98.375,P均<0.05)。与对照组比较,模型组小鼠脾脏中Th17/Treg细胞比例降低,血清中IL-17水平降低,TGF-β水平升高;再次注射棘球蚴囊液后小鼠休克率和死亡率均升高,小鼠脾脏中IgE和FcεRI表达升高,血清中IgE水平升高,差异均有统计学意义(P均<0.05)。与模型组比较,治疗组小鼠脾脏中Th17/Treg细胞比例升高,血清中IL-17水平升高,TGF-β水平降低,差异均有统计学意义(F=104.653、112.645、109.753,P均<0.05);再次注射棘球蚴囊液后小鼠休克率和死亡率均降低,小鼠脾脏中IgE和FcεRI表达降低,血清中IgE水平降低,差异均有统计学意义(P均<0.05)。结论棘球蚴感染增加Treg细胞比例,导致Th17/Treg失衡引发机体免疫耐受和棘球蚴免疫逃逸,当棘球蚴感染超过机体阈值时会引起强烈的AS反应。使用CD25抗体特异性抑制Treg细胞数量可缓解棘球蚴所致AS。

Objective To explore the effect and mechanism of T helper cell 17/regulatory T cell(Th17/Treg)imbalance-induced immune tolerance in anaphylactic shock(AS)caused by echinococcosis infection.Methods Twenty cases of echinococcosis infected patients,echinococcosis shock patients,and healthy subjects were included.The levels of interleukin 17(IL-17),transforming growth factorβ(TGF-β),and IgE in the serum of the three groups were detected by ELISA,and the percentage of Th17 and Treg cells in peripheral blood was detected by flow cytometry.Forty-five C57/B6 mice were randomly divided into three groups:control,model,and treatment.The model and treatment groups were infected with echinococcal cyst fluid through intraperitoneal injection to construct infection models,and the treatment group was given an intravenous injection of 20 mg/kg CD25 antibody in addition of infection,once a week for a month.The percentage of Th17 and Treg cells in the spleen of mice in each group was detected by flow cytometry,and the levels of IL-17 and TGF-βin the serum were detected by ELISA.Echinococcal cyst fluid was reinjected into the abdominal cavity of mice in each group,the shock and death situations of mice in each group were monitored,the expression of IgE and FcεRI in the spleen of mice in each group was detected by qRT-PCR,and the level of IgE in the serum was detected by ELISA.Results Compared with healthy subjects,the levels of IL-17 and IgE in the serum of echinococcosis patients were decreased,the level of TGF-βwas increased,and the percentage of Th17/Treg cells was decreased.Compared with echinococcosis patients,the levels of IL-17 and IgE in the serum of echinococcosis shock patients were increased,and the percentage of Th17/Treg cells was increased(F=143.754,137.285,128.753,98.375;all P<0.05).Compared with the control group,the percentage of Th17/Treg cells in the spleen of mice in the model group was decreased,the level of IL-17 in the serum was decreased,and the level of TGF-βwas increased;the shock and mortality rates of mice were increased after reinjection of echinococcal cyst fluid,the expression of IgE and FcεRI in the spleen of mice was increased,and the level of IgE in the serum was increased.Compared with the model group,the percentage of Th17/Treg cells in the spleen of mice in the treatment group was increased,the level of IL-17 in the serum was increased,and the level of TGF-βwas decreased(F=104.653,112.645,109.753;all P<0.05);the shock and mortality rates of mice were decreased after reinjection of echinococcal cyst fluid,the expression of IgE and FcεRI in the spleen of mice was decreased,and the level of IgE in the serum was decreased(all P<0.05).Conclusions Echinococcosis infection increased the percentage of Treg cells,leading to an imbalance between Th17 and Treg,which triggered immune tolerance and immune evasion of echinococcosis.When the echinococcosis infection exceeded the body's threshold,it elicited a strong AS response.The use of CD25 antibodies to specifically reduce the number of Treg cells could alleviate AS caused by echinococcosis.