Activated CD4+ and CD8+ T-cell subsets in Wegener's granulomatosis

Several lines of evidence argue in favour of an involvement of T cells in the pathogenesis of Wegener's granulomatosis (WG). These include the presence of highly specific IgG autoantibodies to proteinase 3, perivascular T-cell infiltrates and elevated amounts of soluble interleukin-2 (IL-2) receptors in patient's serum. In order to further address this question we evaluated by double immunoflourescence and flow cytometry the expression of several cell surface molecules associated with T-cell activation. As compared to healthy controls (n=15), the CD4⁺ subset was significantly diminished, while the percentage of CD8⁺ T cells was elevated in WG patients (n=24). Within the CD4⁺ T-cell subset we found a highly significant increase in activation/memory markers (CD25, CD29, HLA-DR). Within the CD8⁺ T-cell subset the expression of CD11b, CD29 and CD57 was significantly elevated, while the expression of VD28 was reduced. The use of 10 V-, 1 V-and 1 V-specific monoclonal reagents failed to reveal any significant bias in the peripheral T-cell receptor V-gene repertoire of WG patients. There was also no correlation between T-cell activation markers and laboratory parameters [C-reactive protein (CRP), ESR], disease duration or therapy. A significant correlation was found only for the degree of organ involvement and the increase in CD4⁺ T cells coexpressing HLA-DR, as well as the increase in CD57 expression on CD8⁺ T cells. In conclusion, both CD4⁺ and CD8⁺ T-cell subsets were activated in WG. Cytotoxic CD8⁺ CD57⁺ CD11b⁺ CD28^– T cells may directly contribute to damage of vascular endothelium.     

淋巴细胞趋化因子在慢性阻塞性肺疾病患者外周血中的表达及其对CD4+CD8+T细胞亚群的影响

目的 探讨淋巴细胞趋化因子(lymphotactin,XCL1)对COPD患者外周血CD4+ T、CD8+T细胞亚群及有关炎症因子的影响及机制.方法 随机选取1 3例COPD患者(急性加重期和稳定期)和13名健康人,分离外周血T淋巴细胞进行培养,经淋巴细胞趋化因子干预后,用流式细胞仪分别检测外周血中CD4+T、CD8+T细胞亚群变化及其表面Fas、FasL表达,并用酶联免疫吸附试验(enzymelinked immunosorbent assay,ELISA)分别检测血清及细胞培养上清液中的XCL1、IL-2表达水平.结果 AECOPD及稳定期患者外周血中的XCL1的表达均高于健康对照组(P＜0.05),AECOPD组又高于稳定期组患者(P＜0.05).COPD患者(包括急性发作期与稳定期)T细胞培养液中,XCL1干预组与未干预组相比,XCL1、CD4+-Fas、CD4+-FasL、CD8+-Fas、CD8+-FasL表达增高(P＜0.05),CD4+/CD8+降低(P＜0.05),而IL-2表达减少(P＜0.05).且XCL1的表达与CD4+-Fas、CD4+ FasL、CD8+-Fas、CD8+-FasL的表达呈正相关,与IL-2的表达及CD4+/CD8+呈负相关.结论 XCL1参与了COPD的炎症过程,其参与炎症反应的机制可能是通过促进Fas、FasL的表达,导致CD4+T、CD8+ T细胞的凋亡增加,CD4+ T/CD8+T比值下降,造成CD4+/℃D8 +比例失衡,XCL1还可引起IL-2水平降低,间接导致机体免疫功能紊乱或低下,可能是导致COPD炎症持续存在的重要机制.     

CD4+ and CD8+ subsets: Naive and memory cells in the peripheral blood of patients with systemic sclerosis

Summary Systemic Sclerosis (SSc; scleroderma) is associated with several immunological abnormalities, including altered proportion between lymphocyte subsets. Peripheral blood lymphocyte subsets from 25 patients with SSc were studied by two-colour flow cytometry using monoclonal antibodies against CD45RA and CD29 markers, which allow a dissection of CD4+ and CD8+ populations into naive and memory subsets. A decrease of the percentage of CD8+ (p<0.05) and of CD8+ CD29+ (p<0.001) cells was observed compared to that in 20 age and sex-matched controls. These abnormalities were not significantly associated with the extension of cutaneous disease or other clinical features of SSc nor with treatment, pattern of autoantibodies or HLA phenotype.     

Life after the thymus: CD31+ and CD31- human naive CD4+ T-cell subsets

Early in life, thymic export establishes the size and the diversity of the human naive T-cell pool. Yet, on puberty thymic activity drastically decreases. Because the overall size of the naive T-cell pool decreases only marginally during ageing, peripheral postthymic expansion of naive T cells has been postulated to account partly for the maintenance of T-cell immunity in adults. So far, the analysis of these processes had been hampered by the inability to distinguish recent thymic emigrants from proliferated, peripheral, naive T cells. However, recently, CD31 has been introduced as a marker to distinguish 2 subsets of naive CD4(+) T cells with distinct T-cell receptor excision circle (TREC) content in the peripheral blood of healthy humans. Here, we review studies that have characterized TREC(hi) CD31(+ thymic)naive CD4(+) T cells and have accordingly used the assessment of this distinct subset of naive CD4(+) T cells as a correlate of thymic activity. We will discuss further potential clinical applications and how more research on CD31(+ thymic)naive and CD31(- central)naive CD4(+) T cells may foster our knowledge of the impact of thymic involution on immune competence.     

Persistent expansions of CD4+ CD8+ peripheral blood T cells

CD4+ CD8+ cells are present during T cell differentiation in the thymus. Less than 2% of normal T cells that coexpress CD4 and CD8 also are released in the circulation and are present in the peripheral blood. In this study, nine individuals are described that manifested persistent expansions (11% to 43%) of circulating CD4+ CD8+ T cells that in three cases had large granular lymphocyte (LGL) morphology in the absence of either lymphocytosis or overt lymphoproliferative disorders. Southern blot hybridization of enriched CD4+ CD8+ cells with T-cell receptor beta (TCR beta) and TCR gamma probes showed that most cases had the 12-kb Eco RI germinal band deleted or of decreased intensity. In several individuals new TCR beta-specific bands of different intensity and distinct from case to case suggested either monoclonal or oligoclonal and polyclonal expansions. Immunophenotypic analysis showed that in 7 out of 9 cases the CD4+ CD8+ T cells presented with CD8 dim expression. Furthermore, all the CD4+ CD8+ cells did not express many of the known activation antigens (low or absent CD25, CD38, CD71, HLA-DR), whereas they expressed high levels of CD2, CD29, CD56, and CD57. In addition, the CD4+ CD8+ cells of 5 out of 9 subjects coexpressed CD45RA and CD45RO suggesting that these cells might be "frozen" in an intermediate state between naive and memory T cells. In conclusion, the present CD4+ CD8+ cases fall within a larger spectrum of disorders ranging from apparently normal to reactive or proliferative situations and encompassing cells with LGL morphology or LGL-associated antigens expression either in the presence or in the absence of absolute lymphocytosis that deserve careful follow-up investigations.     

慢性丙型肝炎患者外周血单个核细胞HCV RNA检测及其与机体免疫功能的相关性研究

目的观察慢性丙型肝炎患者外周血单个核细胞(PBMC)HCVRNA含量及其对T淋巴细胞亚群的影响,以探讨HCV感染者PBMC中HCVRNA水平及其与机体免疫功能的关系。方法采用荧光定量PCR(FQPCR)技术对128例丙型肝炎患者血清、外周血单个核细胞的HCVRNA含量进行了检测,同时检测CD3+、CD4+、CD8+、CD4+/CD8+。结果PBMC内HCVRNA阳性组与HCVRNA阴性组比较,前者CD3+、CD4+水平降低、CD8+水平增高,CD4+/CD8+比值下降大于后者,差异有显著性(P<0.05)。结论丙型肝炎病毒侵染PBMC后可加重患者的细胞免疫功能紊乱。     

FoxP3+ regulatory T cells essentially contribute to peripheral CD8+ T-cell tolerance induced by steady-state dendritic cells

Peripheral T-cell tolerance is thought to significantly contribute to the prevention of autoimmunity, and it has been shown that antigen-presenting steady-state dendritic cells efficiently induce peripheral tolerance. We previously showed that dendritic-cell–induced tolerance is a T-cell–intrinsic process that depends on coinhibitory molecules such as programmed death-1. Here we specifically analyze the involvement of FoxP3⁺ regulatory T cells, which are known to be important for maintenance of self-tolerance. We show that antigen presentation by steady-state dendritic cells failed to induce peripheral tolerance in the absence of FoxP3⁺ regulatory T cells but induced protective CD8⁺ T-cell–mediated immunity instead. Regulatory T-cell–depleted mice had massively increased numbers of dendritic cells in lymph nodes. Dendritic cells isolated from mice without regulatory T cells had up-regulated costimulatory molecules and showed stronger T-cell stimulatory capacity ex vivo, suggesting that regulatory T cells contribute to peripheral tolerance by keeping the dendritic cells in an immature state. Using blocking antibodies, we demonstrate that CTLA-4 but not IL-10 is necessary for control of dendritic cells by regulatory T cells.     

HLA-G expression defines a novel regulatory T-cell subset present in human peripheral blood and sites of inflammation

Regulatory T cells can inhibit harmful immunopathologic responses directed against self and foreign antigens and play a major role in controlling autoimmunity. Here we have identified and characterized a subpopulation of CD4 and CD8 T cells in human peripheral blood expressing the immune tolerizing molecule HLA-G. HLA-G-expressing T cells are hypoproliferative, are CD25- and FOXP3-negative, and exhibit potent suppressive properties that are partially mediated by HLA-G. HLA-G-positive (HLA-G(pos)) T cells are found at low percentages among CD4 and CD8 single-positive thymocytes, suggesting a thymic origin. The presence of HLA-G(pos) T cells at sites of inflammation such as inflamed skeletal muscle in myositis or the cerebrospinal fluid of patients with acute neuroinflammatory disorders suggests an important function in modulating parenchymal inflammatory responses in vivo.     

Selective stimulation of CD4+ versus CD8+ T-cell subsets in symptomatic and asymptomatic HIV-1-infected individuals.

To analyze the proliferative capacity of CD4+ or CD8+ T-cell subsets of individuals infected with human immunodeficiency virus type 1 (HIV-1) and to optimize the in vitro conditions for virus replication, CD4+ or CD8+ cells of HIV-1-infected patients were selectively activated inside the whole peripheral blood mononuclear cell (PMNC) population by dual antibody stimulation. To do so PMNC of HIV-1-infected individuals were stimulated with the per se nonmitogenic anti-CD3 antibody fragment BMA030 F(ab)2 crosslinked through goat antimouse antibodies with an anti-CD4 or an anti-CD8 antibody, which lead to selective proliferation of either the CD4+ or the CD8+ T-cell subset. In the presence of monocyte supernatant and recombinant interleukin-2 (rIL2) CD4+ cells of HIV-1 patients responded normally upon such stimulation as their proliferation correlated (r = 0.9) to the percentage CD4+ cells present in the PMNC population. Selective stimulation and proliferation of CD8+ cells could, however, only partially be elicited by dual antibody stimulation, even in the presence of rIL-2 and monocyte supernatant. Their proliferative response did not correspond (r = 0.1) to the percentage CD8+ cells present in the PMNC culture. A positive correlation (r = 0.7) was detected only between percentage CD8+ HLA-DR- cells and proliferation. This confirmed previous studies showing that the defective in vitro proliferative response of peripheral blood lymphocytes of HIV-infected individuals to mitogens, which is usually interpreted being due to a CD4 cell defect, is actually due to a failure of CD8+DR+ cells to proliferate.(ABSTRACT TRUNCATED AT 250 WORDS)     

小剂量氨茶碱对支气管哮喘患者外周血CD4+CD25+调节性T细胞凋亡的影响

目的 观察小剂量氨茶碱对分离培养的健康人和支气管哮喘(简称哮喘)患者外周血CD4+CD25+调节性T细胞(T regulatory cells,Treg)凋亡的影响.方法 经密度梯度离心法、尼龙棉柱法、磁珠分离法分离出健康人和哮喘患者外周血CD4+CD25+Treg,分小剂量氨茶碱(1.13 mg/L)、及空白组培养72 h后,用流式细胞仪检测凋亡率变化.结果 ①健康人外周血CD4+CD25+Treg的纯度为77.4%～92.3%,哮喘患者CD4+CD25+Treg的纯度为75.2%～93.8%.②CD4+CD25+Treg占外周血CD4+T细胞的比例在健康组为4.12%～7.98%,在哮喘组为4.51%～8.68%.两者差异无统计学意义.③小剂量氨茶碱均可以诱导健康组及哮喘组外周血CD4+CD25+Treg凋亡率增加(P<0.05).结论 小剂量氨茶碱(1.13 mg/L)可能通过促进CD4+CD25+Treg凋亡来发挥免疫调节作用.     

Reduced levels of T-cell subsets CD4+ and CD8+ in homozygous sickle cell anaemia patients with splenic defects

T-lymphocyte subsets were studied in two patient groups: (1) 50 patients with homozygous sickle cell anaemia (SCA) (mean age 12 (range 3-32) years old) in good health at the time of the study who showed no infectious complication. (2) 50 patients (mean age 13 (range 4-29) years old) with normal haemoglobin rate. The global response revealed a significant increase in levels of CD3+ (P=0.04) and CD8+ (P=0.04) cells when compared with the control group, there was no significant difference in levels of CD4+ cells (P=0.05) between the two groups. However, there was a relationship between T-cell subpopulation levels and spleen status. The average values of T-cell subsets (CD4+ and CD8+) in patients with SCA-induced splenic defects (asplenic, splenomegaly or splenectomized patients) were significantly reduced when compared to SCA patients with normal spleens and the control groups. These data show that T-cell activity was reduced in patients with splenic defects. A correlation between splenic status and a perturbed host defence system in patients with SCA suggests that monitoring T-cell subsets might have prognostic value in the course of sickle cell disease.     

T-cell receptor variable region gene usage by CD4+ and CD8+ T cells in bronchoalveolar lavage fluid and peripheral blood of sarcoidosis patients.

Sarcoidosis is a chronic noncaseating granulomatous disease of unknown etiology. An accumulation of CD4+ T cells in the alveolar space of the lungs is a characteristic feature of the disease. We have in this study analyzed T-cell receptor (TCR) variable region (V) gene usage by CD4+ and CD8+ lung and peripheral blood T cells of 29 sarcoidosis patients and 15 control subjects. In the patient group, we found a 100% positive correlation between TCR V alpha 2.3+ CD4+ lung T-cell expansions and the expression of the HLA-DR3(17),DQ2 haplotype. The remaining TCR V alpha/V beta gene products analyzed in this study--V alpha 12, V beta 2, V beta 3, V beta 5.1, V beta 5.2/5.3, V beta 5.3, V beta 6.7, V beta 8.1, and V beta 12--were in general normally expressed by CD4+ T cells, although some of them were used to a significantly higher or lower degree by lung T cells compared to peripheral blood T cells. We also performed repeated TCR V gene analyses on some HLA-DR3+ patients and found an association between the ratio bronchoalveolar lavage fluid/peripheral blood V alpha 2.3+ CD4+ T cells and clinical signs of disease activity. Finally, when analyzing TCR V gene usage by CD8+ bronchoalveolar lavage fluid and peripheral blood T cells, a normal V alpha 2.3 usage was found in all cases, but lung-restricted T-cell expansions using other TCR V gene segment products were identified.     

抗CD3单克隆抗体对支气管哮喘患者CD4＋CD25＋T细胞凋亡和自噬的影响

目的探讨抗CD3单克隆抗体对分离培养的支气管哮喘（简称哮喘）患者外周血CD4＋CD25＋T细胞凋亡和自噬及其分泌的代表性因子转化生长因子p（TGF—β）的影响。方法采用密度梯度离心法及尼龙棉柱法分离32例哮喘患者（哮喘组）及30名健康者（对照组）外周血T细胞,磁性细胞分离器分离得到CD4＋CD25＋T细胞,分别利用电镜及流式细胞仪观察、检测抗CD3单克隆抗体干预72h的细胞凋亡率、自噬率。用EI,ISA法检测细胞培养上清液中细胞因子TGF-β的水平。结果抗CD3单克隆抗体干预72h后两组外周血CD4＋CD25＋T细胞凋亡率、自噬率及TGF-β均增加（P值均〈0．01）,但哮喘组凋亡率、自噬率均低于健康对照组（P值均〈0．01）;两组间 TGF-β水平无显著差异（P〉0．01）。哮喘组外周虹CD4＋CD25＋T调节细胞在CD3单克隆抗体的干预下自噬与TGF-β的分泌呈显著负相关（r=-0．38,P〈0．01）。结论抗CD3单克隆抗体可促进CD4＋CD25＋T细胞凋亡和自噬及TGF-β分泌。     

氨茶碱对健康人外周血T细胞及CD4~+亚群凋亡的影响

目的观察氨茶碱对分离培养的健康人外周血T细胞及CD4+亚群凋亡的影响。方法密度梯度离心法及尼龙棉柱法分离健康成年人外周血T细胞,及CD8阴性选择磁性分离健康成年人外周血CD4+T细胞。分两部分进行:①外周血T细胞分对照组、氨茶碱组(0.14～18μg/ml),培养72h后用流式细胞术检测凋亡率变化;②CD4+T细胞分对照组、小剂量氨茶碱组(1.13μg/ml)培养48～72h后用流式细胞术检测凋亡率变化。结果①T细胞的分离纯度为81.3%～94.5%,CD4+T细胞的分离纯度为84%～90%;②(0.14～18μg/ml)氨茶碱共培养人外周血T细胞72h后,其中氨茶碱1.13～18μg/ml组凋亡率差异有统计学意义(P值均<0.05);氨茶碱0.14～0.56μg/ml组凋亡率与阴性对照组比较差异无统计学意义;③氨茶碱1.13μg/ml组干预后,培养CD4+T细胞48～72h,经流式细胞术检测凋亡率,与阴性对照组相比,P值均<0.05,48h的凋亡率与72h者相比,差异有统计学意义(P<0.05)。结论小剂量氨茶碱(1.13μg/ml)可诱导人外周血T细胞和CD4+T细胞凋亡率增加。     

Heterogeneity of the human CD4+ T-cell population: two distinct CD4+ T- cell subsets characterized by coexpression of CD45RA and CD45RO isoforms

Activation of unprimed CD4+CD45RA+/RO- T cells results in a gradual loss of CD45RA expression concomitant with the acquisition of CD45RO. It has been suggested that this conversion occurs in vivo through a CD45RAbright/RObright stage. Next to this small CD45RAbright/RObright subset (Dbright), a larger subpopulation that expresses both RA and RO isoforms at low levels (Ddull) can be found in the circulating CD4+ T- cell population of all donors. The properties of the latter population are largely undefined. Here, we show that Ddull cells have an intermediate phenotype for antigens such as CD31, CD621, CD58, and CD95 that are differentially expressed on unprimed versus primed T cells. In addition, they are able to provide help for B-cell differentiation and contain substantial numbers of tetanus toxoid (TT)-specific precursor cells. Remarkably, both intracellular cytokine staining and analysis of T-cell clones showed that Ddull cells and CD45RO+ T cells produce comparable high amounts of both interferon (IFN)-gamma and interleukin (IL)-4, which clearly distinguishes them from CD45RA+ and Dbright T cells. Finally, prolonged culture of sorted Ddull cells in a mixture of IL-2, IL-6, and tumor necrosis factor (TNF)-alpha showed that about half of the population retained the Ddull phenotype. Part of the cells upregulated the CD45RA isoform, whereas only a minority switched to single CD45RO expression. Our findings indicate that the Ddull population contains primed T cells, some of which may reacquire an "unprimed" phenotype in the absence of antigenic stimulation.