甲状腺与外周血T淋巴细胞亚群比例差异

Differential proportions of T lymphocyte subsets in thyroid and peripheral blood of normal subjects

目的观察正常甲状腺与外周血T淋巴细胞亚群,包括调节性T细胞(regulatory T cells,Treg)、辅助性T细胞1(T helper 1 cells,Th1 cells)和辅助性T细胞2(T helper 2 cells,Th2 cells)的分布,Treg细胞中干扰素-γ(interferon-γ,IFN-γ)、白介素-4(interleukin-4,IL-4)及其mRNA的表达。方法20名良性甲状腺肿物患者、3名胸腺手术及3名脾脏切除术患者,术前当天留取外周空腹静脉血,术中分别留取甲状腺、胸腺及脾脏标本,分离单个核细胞,流式细胞术检测标本组织及外周血T淋巴细胞亚群差异。磁珠分离法分离甲状腺及外周血CD25+T细胞,RT-PCR检测Treg中IFN-γ和IL-4 mRNA的表达。NKT细胞受体激动剂α-Galcer刺激Treg 7 d后,RT-PCR检测Treg中IFN-γ、IL-4、CD1d、Vα24及Vβ11 mRNA的表达。结果1)甲状腺组织Th1、Th2细胞比例低于外周血(P<0.001),而Th0、Treg细胞比例高于外周血(P<0.001)。2)在甲状腺内,几乎所有的CD4+CD25+Foxp3+细胞可以同时分泌IL-4、IFN-γ,RT-PCR提示其IL-4、IFN-γmRNA表达明显高于外周血,而在外周血中,CD4+CD25+Foxp3+细胞并不表达IL-4或IFN-γ。3)在胸腺和脾脏中,未检测到同时表达IL-4、IFN-γ的CD4+CD25+Foxp3+细胞。4)甲状腺内Treg在α-GalCer刺激前后均不表达NKT细胞的表面标志CD1d、Vα24及Vβ11 m RNA,而IL-4和IFN-γmRNA的表达在刺激前后无明显差异。结论正常甲状腺与外周血T淋巴细胞亚群分布存在差异,甲状腺内Treg特异性的同时表达IL-4及IFN-γ。

To clarify the differences of T lymphocyte subsets in thyroid and peripheral blood,which may contribute to investigating the role of abnormal distributions of T lymphocytes in the development and progression of autoimmune thyroid diseases(AITD),we explored the difference of T lymphocyte subsets proportions in thyroid and peripheral blood of normal subjects,including regulatory T cells(Treg),T helper cells(Th cells)1 and Th2,and detected the mRNA expression of interferon-γ(IFN-γ)and interleukin-4(IL-4).Total of 20 eligible benign thyroid nodule patients,3 patients with thoracic operation,and 3 splenectomy patients were included.Peripheral blood was obtained the day of surgery,the normal thyroid specimens around the thyroid nodules and thymus,spleen specimens were gathered during the operations.Mononuclear cells from tissues and peripheral blood were isolated and measured for the proportions of T lymphocyte subsets by flow cytometry;CD25+T cells from thyroid and peripheral blood were isolated using magnetic bead separation column.Real-time RT-PCR was used to verify mRNA expression of IFN-γand IL-4 in Treg.The mRNA expression of IFN-γ,IL-4,CD1 d,Vα24 and Vβ11 in Treg stimulated withα-GalCer for 7 days was verified by Real-time RT-PCR.Data showed that the proportion of Th1 and Th2 cells were lower,while Th0 and Treg were higher in normal thyroid than those in peripheral blood.Almost all of the CD4+CD25+Foxp3+cells could co-secrete IL-4 and IFN-γin thyroid,and a considerable amount of mRNA expression of IL-4 and IFN-γwere found in these subsets of cells by RT-PCR.However,in peripheral blood,the CD4+CD25+Foxp3+cells could not express IL-4 or IFN-γin the same subjects.The CD4+CD25+Foxp3+cells from thymus and spleen could not express IL-4 or IFN-γ.Treg from thyroid did not express CD1 d,Vα24 or Vβ11 mRNA,while mRNA expression of IFN-γand IL-4 was not significantly different before and after stimulation withα-GalCer.In conclusion,there exist differences of T lymphocyte subsets in thyroid and peripheral blood of normal subjects;Treg in thyroid can express both IFN-γand IL-4 specifically.