原发免疫性血小板减少症患者Th17细胞和调节性T细胞检测的意义

目的探讨Th17细胞和调节性T细胞(Treg)在原发免疫性血小板减少症(ITP)患者中的意义。方法选取32例初诊ITP患者,其中位年龄49(18~70)岁;30例健康对照,中位年龄42岁(20~65岁)。用流式细胞术检测外周血Th17细胞及Treg细胞分别占淋巴细胞的比例;用ELISA法检测血浆中IL-6和IL-17的水平。并分析ITP患者Th17细胞、Treg细胞、IL-6和IL-17的水平与PLT的相关性。结果 (1)ITP患者Th17细胞比例明显高于健康对照(2.81%±1.33%vs.0.35%±0.75%,P<0.05);Treg细胞比例明显低于健康对照(0.70%±0.39%vs.1.26%±0.24%,P<0.05);Treg/Th17比值明显低于健康对照(0.27±0.17 vs.3.76±0.87,P<0.05);ITP患者血浆中IL-17和IL-6水平均明显高于健康对照,分别为(24.07±2.22 pg/ml vs.15.89±2.23 pg/ml,P<0.05)和(75.12±4.06 pg/ml vs.49.75±4.19 pg/ml,P<0.05)。(2)ITP患者外周血Treg细胞比例与IL-6、IL-17水平均呈显著负相关(r=-0.423,P<0.05;r=-0.456,P<0.05);IL-6与IL-17水平呈显著正相关(r=0.368,P<0.05);Th17细胞及Treg细胞呈显著负相关(r=-0.417、P<0.05)。Th17细胞比例与IL-6、IL-17水平不具相关性(r=-0.272,r=-0.104,P>0.05)。(3)ITP患者Th17细胞比例、IL-6水平和IL-17水平与血小板计数呈显著负相关(r=-0.365,P<0.05;r=-0.353,P<0.05;r=-0.464,P<0.01);Treg细胞比例与血小板计数不具相关性(r=-0.101,P>0.05)。ITP患者Th17细胞比例、IL-6水平与骨髓颗粒型巨核细胞比例呈显著正相关(r=0.371,P<0.05;r=0.359,P<0.05);Treg细胞比例、IL-17水平与骨髓颗粒型巨核细胞比例不具相关性(r=-0.230,P>0.05;r=-0.043,P>0.05)。结论 ITP患者Treg/Th17细胞平衡失调可能是影响其发生发展的一个重要因素,Th17细胞与疾病的严重程度相关。     

Pulmonary arterial remodeling induced by a Th2 immune response

Pulmonary arterial remodeling characterized by increased vascular smooth muscle density is a common lesion seen in pulmonary arterial hypertension (PAH), a deadly condition. Clinical correlation studies have suggested an immune pathogenesis of pulmonary arterial remodeling, but experimental proof has been lacking. We show that immunization and prolonged intermittent challenge via the airways with either of two different soluble antigens induced severe muscularization in small- to medium-sized pulmonary arteries. Depletion of CD4(+) T cells, antigen-specific T helper type 2 (Th2) response, or the pathogenic Th2 cytokine interleukin 13 significantly ameliorated pulmonary arterial muscularization. The severity of pulmonary arterial muscularization was associated with increased numbers of epithelial cells and macrophages that expressed a smooth muscle cell mitogen, resistin-like molecule alpha, but surprisingly, there was no correlation with pulmonary hypertension. Our data are the first to provide experimental proof that the adaptive immune response to a soluble antigen is sufficient to cause severe pulmonary arterial muscularization, and support the clinical observations in pediatric patients and in companion animals that muscularization represents one of several injurious events to the pulmonary artery that may collectively contribute to PAH.     

Isoprenoids determine Th1/Th2 fate in pathogenic T cells, providing a mechanism of modulation of autoimmunity by atorvastatin

3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is a critical enzyme in the mevalonate pathway that regulates the biosynthesis of cholesterol as well as isoprenoids that mediate the membrane association of certain GTPases. Blockade of this enzyme by atorvastatin (AT) inhibits the destructive proinflammatory T helper cell (Th)1 response during experimental autoimmune encephalomyelitis and may be beneficial in the treatment of multiple sclerosis and other Th1-mediated autoimmune diseases. Here we present evidence linking specific isoprenoid intermediates of the mevalonate pathway to signaling pathways that regulate T cell autoimmunity. We demonstrate that the isoprenoid geranylgeranyl-pyrophosphate (GGPP) mediates proliferation, whereas both GGPP and its precursor, farnesyl-PP, regulate the Th1 differentiation of myelin-reactive T cells. Depletion of these isoprenoid intermediates in vivo via oral AT administration hindered these T cell responses by decreasing geranylgeranylated RhoA and farnesylated Ras at the plasma membrane. This was associated with reduced extracellular signal-regulated kinase (ERK) and p38 phosphorylation and DNA binding of their cotarget c-fos in response to T cell receptor activation. Inhibition of ERK and p38 mimicked the effects of AT and induced a Th2 cytokine shift. Thus, by connecting isoprenoid availability to regulation of Th1/Th2 fate, we have elucidated a mechanism by which AT may suppress Th1-mediated central nervous system autoimmune disease.     

Suppression of T4 secretion in a metastatic follicular carcinoma

Despite total thyroidectomy, a patient with metastatic follicular carcinoma of the thyroid remained biologically euthyroid three months after stopping thyroxine (T4) therapy. Thyroid hormone production was investigated by means of a modified tri-iodothyronine (T3) suppression test, in which serum T4 was used as a suppression marker. After three weeks of oral T3 (Cytomel) therapy (50 micrograms/day), the serum T4 decreased from normal (108 nmol/L) to undetectable values. However, even though suppressive therapy was effective in preventing TSH dependent hormone secretion by the tumor, it did not prevent tumor growth and the eventual death of the patient.     

儿童过敏性紫癜TLR2、 TLR4表达及其与Tfh细胞的相关性

目的 研究过敏性紫癜(HSP)患儿外周血单个核细胞(PBMC)中Toll样受体(TLR)2、TLR4的表达及其与滤泡辅助性T细胞(Tfh)免疫应答的相关性.方法 选取2019年5月至10月于徐州医科大学附属医院住院的初发HSP患儿23例作为HSP组,另同时选取于门诊健康体检的儿童15例作为对照组.采用流式细胞术检测两组...     

Activation of CD4+ T cells in the presence of a nondepleting monoclonal antibody to CD4 induces a Th2-type response in vitro

In vitro experiments using purified rat CD4+ T cells in primary and secondary mixed leukocyte cultures (MLC) have been carried out to explore the mechanism of inhibition of cell-mediated autoimmune disease in the rat by a nondepleting monoclonal antibody (mAb) to CD4. Previous work has shown that W3/25, a mouse anti-rat CD4 mAb of immunoglobulin G1 isotype, completely prevents the development of the paralysis associated with experimental allergic encephalomyelitis (EAE) in Lewis rats, but does so without eliminating the encephalitogenic T cells. The in vitro experiments described in this study have shown that when CD4+ T cells were activated in the presence of the anti-CD4 mAb in a primary MLC, the synthesis of interferon (IFN) gamma, but not interleukin (IL) 2, was completely inhibited. After secondary stimulation, now in the absence of the mAb, the synthesis of IL-4 and IL-13 mRNA was greatly enhanced compared with that observed from CD4+ T cells derived from primary cultures in which the mAb was omitted. As IL-4 and IL-13 are known to antagonize cell-mediated immune reactions, and as EAE is cell- mediated disease, the data suggest that the W3/25 mAb controls EAE by modifying the cytokine repertoire of T cells that respond to the encephalitogen. The capacity for the mAb to suppress IFN-gamma synthesis provides, in part, an explanation for this change in cytokine production. These findings are discussed in terms of what is known of the factors that determine which cytokine genes are expressed on T cell activation. Possible implications for the evolution of T cell responses in human immunodeficiency virus infection are also discussed.     

Spontaneous loss and alteration of antigen receptor expression in mature CD4+ T cells

The TCR/CD3 complex plays a central role in antigen recognition and activation of mature T cells, and, therefore, abnormalities in the expression of the complex should induce unresponsiveness of T cells to antigen stimulus. Using flow cytometry, we detected and enumerated variant cells with loss or alteration of the surface TCR/CD3 expression among human mature CD4+ T cells. The presence of variant CD4+ T cells was demonstrated by isolating and cloning them from peripheral blood, and their abnormalities can be accounted for by alterations in TCR expression such as defects of protein expression and partial protein deletion. The variant frequency in peripheral blood increased with aging in normal donors and was highly elevated in patients with ataxia telangiectasia, an autosomal recessive inherited disease with defective DNA repair and variable T cell immunodeficiency. These findings suggest that such alterations in TCR expression are induced by somatic mutagenesis of TCR genes and can be important factors related to age-dependent and genetic disease-associated T cell dysfunction.     

Independent roles for IL-2 and GATA-3 in stimulating naive CD4+ T cells to generate a Th2-inducing cytokine environment

T cell receptor (TCR) signaling plays an important role in early interleukin (IL)-4 production by naive CD4+ T cells. This "antigen-stimulated" early IL-4 is sufficient for in vitro Th2 differentiation. Here, we provide evidence that early IL-4 production by naive CD4+ T cells stimulated with cognate peptide requires TCR-induced early GATA-3 expression and IL-2 receptor signaling, both of which are controlled by the degree of activation of extracellular signal-regulated kinase (ERK). Stimulation of naive CD4+ T cells from TCR transgenic mice with low concentrations of peptide-induced IL-2-dependent STAT5 phosphorylation, IL-4-independent early GATA-3 expression, and IL-4 production. Neutralization of IL-2 abolished early IL-4 production without affecting early GATA-3 expression. In addition, naive CD4+ T cells from GATA-3 conditional KO mice failed to produce early IL-4 in response to TCR/CD28 stimulation. Stimulation with high concentrations of peptide abrogated early GATA-3 expression and IL-2-dependent STAT5 phosphorylation, and resulted in the failure to produce early IL-4. This high concentration-mediated suppression of early IL-4 production was reversed by blockade of the ERK pathway. A MEK inhibition rescued early GATA-3 expression and responsiveness to IL-2; these cells were now capable of producing early IL-4 and undergoing subsequent Th2 differentiation.     

Suppression of allergic airway inflammation by helminth-induced regulatory T cells

Allergic diseases mediated by T helper type (Th) 2 cell immune responses are rising dramatically in most developed countries. Exaggerated Th2 cell reactivity could result, for example, from diminished exposure to Th1 cell-inducing microbial infections. Epidemiological studies, however, indicate that Th2 cell-stimulating helminth parasites may also counteract allergies, possibly by generating regulatory T cells which suppress both Th1 and Th2 arms of immunity. We therefore tested the ability of the Th2 cell-inducing gastrointestinal nematode Heligmosomoides polygyrus to influence experimentally induced airway allergy to ovalbumin and the house dust mite allergen Der p 1. Inflammatory cell infiltrates in the lung were suppressed in infected mice compared with uninfected controls. Suppression was reversed in mice treated with antibodies to CD25. Most notably, suppression was transferable with mesenteric lymph node cells (MLNC) from infected animals to uninfected sensitized mice, demonstrating that the effector phase was targeted. MLNC from infected animals contained elevated numbers of CD4(+)CD25(+)Foxp3(+) T cells, higher TGF-beta expression, and produced strong interleukin (IL)-10 responses to parasite antigen. However, MLNC from IL-10-deficient animals transferred suppression to sensitized hosts, indicating that IL-10 is not the primary modulator of the allergic response. Suppression was associated with CD4(+) T cells from MLNC, with the CD4(+)CD25(+) marker defining the most active population. These data support the contention that helminth infections elicit a regulatory T cell population able to down-regulate allergen induced lung pathology in vivo.