髓源抑制性细胞与肾脏疾病

髓源抑制性细胞(MDSCs)是一类未成熟且具有免疫负调控作用的髓系细胞群体,在维持机体免疫平衡和慢性肾脏病的发生发展中起重要作用。MDSCs为一群异质性的细胞群体,对其细胞表型和作用机制目前并未完全阐明,本文就MDSCs的来源、表型鉴定及在肾脏疾病中的作用做一综述。     

髓系来源的抑制细胞在肝病发病中的作用研究进展*

髓系来源的抑制细胞来源于骨髓祖细胞和未成熟的髓系细胞。近年来的研究表明,该细胞参与调节多种肝脏疾病的病理变化。本文系统地归纳了髓系来源的抑制细胞的历史、分群、作用机制和当前该细胞在各种肝病发病中的免疫调控作用及其与疾病进展的关系。     

活动性肺结核病患者髓系抑制性细胞的检测分析

目的 研究活动性肺结核病患者、潜伏感染者和健康者髓系抑制性细胞(myeloid-derived suppressor cells,MDSCs)的产生及分布特性.方法 活动性肺结核病患者均为确诊的住院患者,潜伏感染者及健康者经ELISPOT检查确定.外周静脉血用CD14、HLA-DR、CD11b、CD33抗体共染色,采用流式细胞术分析.结果 通过对78例活动性肺结核病患者、30例潜伏感染者及66例健康者的对比分析发现,活动性肺结核病患者CD14-HLA-DR-CD33+ CD11bhighMDSCs细胞比例高于潜伏感染者(P=0.0238),也高于健康者( P＜0.001),而潜伏感染者与健康者CD14-HLA-DR- CD33+ CD11bhighMDSCs细胞比例差异无统计学意义;活动性肺结核病患者CD14+ HLA-DR-MDSCs比例与潜伏感染者及健康者比较差异无统计学意义.活动性肺结核病患者外周血转化生长因子β1水平高于健康对照组(P＜0.05).结论 活动性肺结核病患者CD14- HLA-DR- CD33+CD11bhigh MDSCs比例显著增高,提示活动性肺结核病可能诱导特定的MDSCs亚群,发挥免疫抑制作用,促进结核病的发生及发展.     

Myeloid-derived suppressor cells in lymphoma: The good,the bad and the ugly

Lymphomas cause significant morbidity and mortality worldwide. A substantial number of patients ultimately relapse after standard treatment. However, the efficacy of these therapies can be counteracted by the patients' immune system, more specifically by myeloid-derived suppressor cells (MDSC). MDSC are a heterogeneous group of immature myeloid cells that suppress the innate and adaptive immune system via different mechanisms and accumulate under pathological conditions, such as cancer. MDSC play a role in the induction and progression of cancer and immune evasion. Increased numbers of MDSC have been reported in different lymphoma subtypes and are associated with a poor clinical outcome. This review aims to clarify the role of MDSC and their working mechanism in different lymphoma subtypes. Furthermore, the effect of MDSC on immunotherapies will be discussed.     

Myeloid-derived suppressor cells express the death receptor Fas and apoptose in response to T cell-expressed FasL

Myeloid-derived suppressor cells (MDSCs) inhibit adaptive and innate immunity and accumulate in the blood of persons with cancer, chronic inflammation, trauma, infection, and stress. Some of the factors inducing their accumulation are known; however, mechanisms regulating their turnover have not been identified. Mass spectrometry showed prominent expression of apoptosis pathway proteins, suggesting that MDSC turnover may be regulated by Fas-FasL-mediated apoptosis. This hypothesis was confirmed by showing that blood MDSCs induced by 3 mouse tumors were Fas(+) and apoptosed in response to Fas agonist in vitro and to activated FasL(+) T cells in vivo. FasL-deficient mice contained significantly more blood MDSCs than FasL(+/+) mice, and after removal of primary tumors MDSCs regressed in STAT6(-/-) and CD1(-/-) mice but not in STAT6(-/-)FasL(-/-) or CD1(-/-)FasL(-/-) mice. Fas(+) macrophages and dendritic cells did not apoptose in response to activated T cells, indicating that Fas-FasL regulation of myeloid cells was restricted to MDSCs. These results identify a new mechanism regulating MDSC levels in vivo and show a retaliatory relationship between T cells and MDSCs in that MDSCs suppress T-cell activation; however, once activated, T cells mediate MDSC apoptosis.     

Covert suppressor T cells in Crohn's disease

To determine whether patients with Crohn's disease have a defect in immune regulation, suppressor T-cell activity was assessed in 16 patients with mild or inactive Crohn's disease and was compared with that of an equal number of randomly selected normal controls. Pokeweed mitogen-stimulated cultures of peripheral blood lymphocytes from patients synthesized as much IgM as those from normal controls. In addition, cocultures of patient and normal peripheral blood lymphocytes did not result in either suppression or enhancement of immunoglobulin M synthesis. In contrast to these results with cultures of peripheral blood lymphocytes, cultures containing optimal ratios of purified B cells and T cells from patients synthesized significantly less immunoglobulin M (p less than 0.005) than those from normals; in fact, the latter cultures from 6 patients synthesized no detectable immunoglobulin M. Detailed studies of cells from these patients indicated that a suppressor T cell was revealed in vitro during the cell-purification procedure. Finally, in those patients in whom it could be measured, radiation-sensitive suppressor T-cell activity was found to be normal. We conclude that there is no deficiency of suppressor T cells regulating antibody synthesis in patients with Crohn's disease; on the contrary, at least one-half of these patients have suppressor T cells that markedly inhibit the synthesis of immunoglobulin M, but which are revealed only after purification of the T cells.     

Inducer and suppressor T-cells in hepatitis B virus-induced liver disease

During acute type B hepatitis, the proportion of inducer to cytotoxic/suppressor T-cells is decreased due to an increase in the concentration of suppressor cells. Similar changes are seen in chronically infected subjects with evidence of active viral replication (HBeAg positive) and chronic hepatitis of varying severity. This imbalance of the regulatory cells returns to normal when viral replication decreases during the recovery phase of acute hepatitis and in patients who become chronic carriers with minimal liver disease (HBeAb positive patient). Patients in whom viral replication has subsided (HBeAb positive) but who continue to exhibit chronic active liver disease have increased inducer to cytotoxic/suppressor cell ratios due to a decrease in the concentration of the cytotoxic/suppressor cell population. Further studies are needed to determine whether these alterations of the regulatory cells of the immune system are a causal factor influencing the duration of active hepatitis B virus replication and the degree of inflammatory liver damage, or merely changes secondary to the presence of a replicating virus.     

Myeloid-derived suppressor cells--their role in haemato-oncological malignancies and other cancers and possible implications for therapy

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells at different stages of maturation that play a role in cancer tolerance and function as an immune-suppressive cell subpopulation. They utilize different mechanisms to block both innate and adaptive arms of anti-tumour immunity, mostly through inhibition of T cell activation and expansion. Further advances in our understanding of this cell population in both murine models and humans has enabled more accurate characterization of their phenotype and the recognition of two major classes of MDSCs: granulocytic and monocytic. Recently, the mechanism of action and clinical importance of MDSCs has been more clearly defined and their interactions with cancer cells have been shown to be among the factors influencing tumour development and induction of tolerance. Most of the earlier studies were performed using murine models, but recent clinical investigations have shown their potential role in human cancers. Here, we review the origin of MDSCs, their mechanisms of action, the factors influencing their production and related signalling pathways. We focus on their role in human solid tumours and haemato-oncological malignancies, and relate to possible novel therapeutic approaches targeting MDSCs which could be considered together with other anticancer strategies in the not too distant future.     

Ferritins in malignant and non-malignant lymphoid cells

Lymphoid cells from peripheral blood, thymus, malignant and non-malignant lymph nodes were analysed for ferritin content using radioimmunoassays specific for the 'acidic' H-subunit-rich and for 'basic' L-subunit-rich isoferritins, and the data were compared with the immunological characteristics of the cells. All tissues with high proportion of T or 'null' cells contained the lowest concentration of L-subunit-rich isoferritins, while the H-subunit-rich forms increased from low levels in the quiescent peripheral blood lymphocytes (PBL), to higher values in the immature and proliferating thymocytes and lymphoblasts, malignant or not. B-cell lymphomas contained concentrations of both ferritin types higher than those found in PBL. No significant difference was found in the isoferritin concentrations between non-malignant lymph nodes and tissues involved in Hodgkin's disease. These findings indicate that maturation stage, proliferative status and anatomical localization affect isoferritin expression in lymphoid cells.     

Diagnostic role of serum glypican-3 in differentiating hepatocellular carcinoma from non-malignant chronic liver disease and other liver cancers

Background and Aims:  The role of glypican-3 (GPC3), a novel serum marker, in differentiating hepatocellular carcinoma (HCC) from non-malignant chronic liver disease and other malignant space-occupying lesions in the liver is largely unknown. The aims of this study were to evaluate its diagnostic role and clinical correlations in patients with HCC.
Methods:  Six groups were studied which included 40 healthy subjects, 50 patients with chronic hepatitis (CH), 50 patients with liver cirrhosis (LC), 100 patients with HCC, 50 patients with intrahepatic cholangiocarcinoma (ICC) and 50 patients with metastatic carcinoma (MCA). Serum GPC3 levels were measured by using a sandwich enzyme-linked immunosorbent assay method.
Results:  Fifty-three percent of HCC patients had elevated serum GPC3 levels with values ranging 35.5–7826.6 ng/mL. The serum marker was undetectable in other groups except one patient (2%) with LC and another patient (2%) with MCA. In most cases of HCC, elevated GPC3 values did not correlate with α-fetoprotein (AFP) levels. Detectable GPC3 was significantly correlated with the presence of viral hepatitis markers but was not correlated with tumor size and stage of HCC. Serum GPC3 was superior to AFP in detecting small HCC (56.3% and 31.3%, respectively). A combination of serum GPC3 and AFP yielded an improved sensitivity for detecting small HCC to 75%.
Conclusion:  Serum GPC3 is highly specific for detecting HCC. The combined use of serum GPC3 and AFP provides a potentially promising tool to better differentiate HCC from benign liver disorders, as well as from other liver cancers.     

单核样髓系来源抑制细胞在酒精性肝病进展中的特点研究

目的调查单核样髓系来源抑制细胞(monocytic myeloid derived suppressor cells,m MDSCs)在酒精性肝病(alcoholic liver disease,ALD)患者外周血中的特点,探讨其与ALD进展的关系。方法采用流式检测技术对79例ALD患者和23例健康对照者外周血中m MDSCs的频率及其产生精氨酸酶的能力进行调查,并进一步分析m MDSCs频率与患者疾病进展及临床指标的相关性。结果与健康对照相比,ALD患者外周血m MDSCs频率显著升高(P0.001),且与中性粒细胞/淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)呈弱正相关(r=0.263,P=0.019)。进一步分析发现,ALD患者精氨酸酶阳性m MDSCs频率显著高于对照组(P0.001),且同样与NLR呈弱正相关(r=0.305,P=0.015)。结论ALD患者外周血m MDSCs显著增多,且与ALD进展密切相关。本研究为进一步阐明m MDSCs在ALD中的作用机制提供了研究基础。     

树突状细胞与肝脏疾病

免疫反应的产生首先是由抗原提呈细胞(antigenpresenting cells,APC)捕获抗原,经其加工处理后将抗原信息传递给T,B淋巴细胞,从而引发一系列的特异性免疫应答.APC包括树突状细胞(dendritic cells,DC)、巨噬细胞(MΦ)、B细胞等,其中DC是人体内最具潜能的抗原提呈细胞(APC),能在体内外直接激活纯真(naive)T细胞,提呈抗原给MHC-Ⅰ类限制性CD8+和MHC-Ⅱ类限制性CD4+T淋巴细胞,诱导特异性免疫应答[1-6].