实时定量PCR检测正常人外周血T细胞和胸腺细胞中sjTRECs水平

目的了解正常人外周血T细胞和胸腺细胞中信号结合T细胞受体删除 DNA环(sjTRECs)的含量,从而推测正常人中幼稚T细胞的含量和胸腺的输出功能. 方法利用实时定量PCR和TaqMan方法检测11例正常人外周血单个核细胞、7例儿童和3例成人胸腺细胞DNA中sjTRECs的水平. 结果正常人中sjTRECs含量分别为:8.83±4.81/1000个外周血单个核细胞;27.31±3.23/1000个成人胸腺细胞和170 .29 ±59.52/1000个儿童胸腺细胞. 结论 sjTRECs水平与年龄有关,正常人外周血中每1000个单个核细胞中约含4.5个幼稚T细胞.     

定量检测T细胞受体重排删除DNA环含量评价急性非淋巴细胞白血病患者胸腺近期输出功能

目的检测急性非淋巴细胞白血病(ANLL)患者T细胞受体重排删除DNA环(signaljoint T-cell receptor exc ision DNA c irc les sjTRECs,TRECs)的含量,从而探讨患者的初始型naive T细胞水平和胸腺近期输出功能特点。方法利用实时定量PCR(TaqM an)方法,检测77例ANLL患者外周血单个核细胞(PBMC)TRECs的水平,并根据外周血中CD3阳性率计算CD3细胞中TRECs水平。14例ANLL缓解期患者和14例正常人外周血作为对照。结果ANLL患者外周血中TRECs含量为(0.43±0.92)拷贝/1 000 PBMCs,(2.02±3.25)拷贝/1 000 CD3+细胞,明显低于正常人TRECs水平[(4.10±3.65)拷贝/1 000 PBMCs和(6.84±4.71)拷贝/1 000 CD3+细胞,P=0.0000和P=0.0001]和缓解期患者[(2.19±2.49)拷贝/1 000 PBMCs和(6.30±7.13)拷贝/1 000 CD3+细胞,P=0.0000和P=0.0005]。各亚型ANLL患者的TREC水平差异无统计学意义(P>0.05)。结论绝大多数ANLL型患者胸腺近期输出naive T细胞功能明显降低,缓解期患者的胸腺近期输出功能有一定程度恢复。     

多发性骨髓瘤患者外周血中TCR Vβ亚家族nave T细胞水平变化

目的： 检测多发性骨髓瘤（MM）患者外周血中23个TCR Vβ亚家族的T细胞受体删除DNA环（sjTRECs）的存在特点，从而了解MM患者相应Vβ亚家族nave T细胞的近期胸腺输出情况。方法: 利用半巢式PCR分别扩增12例MM患者每5×104个外周血单个核细胞（PBMCs）中的23个Vβ亚家族sjTRECs，10例正常人外周血作为对照。结果: 在5×104个PBMCs中，检测到MM患者sjTRECs的Vβ亚家族数量约为（5.00±2.45）个，与正常人的（9.60±5.48）个相比，检出的亚家族数量明显减少（P<0.05）；23个Vβ亚家族sjTRECs在正常人中均可以检测到，而在MM患者仅检测到部分；并且Vβ2、Vβ10、Vβ16、Vβ17和Vβ21等5个亚家族sjTRECs的检出率明显低于正常水平。12例MM患者检出的亚家族数量（2-9个）不等，患者的年龄与检出的亚家族数量存在负相关（r=-0.892；P<0.01）。结论: MM患者胸腺近期输出的23个Vβ亚家族nave T细胞存在不同程度的缺失或水平降低，表明患者存在不同程度的细胞免疫功能缺陷以及T细胞谱系重建的能力和潜能受损。     

TCR Vβ2、Vβ5和Vβ17-Dβ1 sjTRECs在正常人胸腺、脐血和外周血中的检测情况

目的建立检测TCR Vβ2、Vβ5和Vβ17-Dβ1 sjTRECs的方法,分析其在胸腺细胞、脐血和正常人外周血T细胞中的存在情况,从而了解近期胸腺输出相应的TCR Vβ亚家族naive T细胞的情况。方法利用半巢式PCR分别扩增3例正常胸腺细胞、10例脐血和10例正常人外周血单个核细胞DNA中的Vβ2、Vβ5和Vβ17与Dβ1基因片段重排时产生的sjTRECs。结果在正常胸腺细胞、脐血和正常人外周血单个核细胞中均可检测到Vβ2、Vβ5和Vβ17与Dβ1片段形成的sjTRECs,其中胸腺细胞和脐血单个核细胞DNA中3种删除环的检出率均为100％,正常人外周血3种删除环的检出率分别为50％、70％和40％。结论成功地建立检测3种Vβ-Dβ1 sjTRECs的方法,并提供了Vβ2、Vβ5和Vβ17亚家族sjTRECs在胸腺、脐血和外周血中的检测情况。     

MDS患者外周血中TCR Vβ1-24-Dβ1 sjTRECs的分析

目的检测骨髓增生异常综合征（MDS）患者外周血中TCRVβ1-24-Dβ1 sjTRECs的存在情况。方法利用半巢式PCR扩增9例MDS患者外周血单个核细胞DNA中TCRβ链基因重排时形成的T细胞受体DNA删除环（Vβ1-24-Dβ1 sjTRECs）,10例正常人外周血作为对照。结果所有TCRVβ1-24-Dβ1sjTRECs在正常人组外周血T细胞DNA中均有检出,除TCR Vβ12-Dβ1sjTRECs和TCRβ19-Dβ1sjTRECs外,其余TCRVβ-Dβ1 sjTRECs在MDS患者外周血T细胞DNA中均可检。大多数TCRVβ1-24-Dβ1sjTRECs在正常人组中的检出率较MDS患者高,但其中只有6种TCRVβ-Dβ1sjTRECs（分别是TCRVβ3、12、13、15、21、22-Dβ1sjTRECs）的检出率差异有统计学意义。结论本研究率先提供了MDS患者外周血T细胞中TCRVβ-Dβ1sjTRECs的存在情况。MDS患者TCRVβ-Dβ1sjTRECs出现频率低于正常人提示其胸腺近期输出功能存在部分缺陷情况。     

多发性骨髓瘤患者外周血中TCR Vβ亚家族na(i)ve T细胞水平变化

目的:检测多发性骨髓瘤(MM)患者外周血中23个TCR Vβ亚家族的T细胞受体删除DNA环(sjTRECs)的存在特点,从而了解MM患者相应Vβ亚家族na(i)ve T细胞的近期胸腺输出情况.方法:利用半巢式PCR分别扩增12例MM患者每5×104个外周血单个核细胞(PBMCs)中的23个Vβ亚家族sjTRECs,10例正常人外周血作为对照.结果:在5×104个PBMCs中,检测到MM患者sjTRECs的Vβ亚家族数量约为(5.00±2.45)个,与正常人的(9.60±5.48)个相比,检出的亚家族数量明显减少(P＜0.05);23个Vβ亚家族sjTRECs在正常人中均可以检测到,而在MM患者仅检测到部分;并且Vβ2、Vβ10、Vβ16、Vβ17和Vβ21等5个亚家族sjTRECs的检出率明显低于正常水平.12例MM患者检出的亚家族数量(2-9个)不等,患者的年龄与检出的亚家族数量存在负相关(r=-0.892;P＜0.01).结论:MM患者胸腺近期输出的23个Vβ亚家族na(i)ve T细胞存在不同程度的缺失或水平降低,表明患者存在不同程度的细胞免疫功能缺陷以及T细胞谱系重建的能力和潜能受损.     

定量检测T细胞受体重排删除DNA环含量评价急性非淋巴细胞白血病患者胸腺近期输出功能

目的 检测急性非淋巴细胞白血病(ANLL)患者 T细胞受体重排删除DNA环(signal joint T-cell receptor excision DNA circles sjTRECs,TRECs)的含量,从而探讨患者的初始型naive T细胞水平和胸腺近期输出功能特点.方法利用实时定量PCR(TaqMan)方法,检测77例ANLL患者外周血单个核细胞(PBMC)TRECs的水平,并根据外周血中CD3阳性率计算CD3细胞中TRECs水平.14例ANLL缓解期患者和14例正常人外周血作为对照.结果 ANLL患者外周血中TRECs含量为(0.43±0.92)拷贝/1 000 PBMCs, (2.02±3.25)拷贝/1 000 CD3+细胞,明显低于正常人TRECs水平[(4.10±3.65)拷贝/1 000 PBMCs和(6.84±4.71)拷贝/1 000 CD3+细胞,P=0.0000和P=0.0001]和缓解期患者[(2.19±2.49)拷贝/1 000 PBMCs和(6.30±7.13)拷贝/1 000 CD3+细胞,P=0.0000和P=0.0005].各亚型ANLL患者的TREC水平差异无统计学意义(P＞0.05).结论 绝大多数ANLL型患者胸腺近期输出naive T细胞功能明显降低,缓解期患者的胸腺近期输出功能有一定程度恢复.     

正常人外周血和脐血中TCR Vβ亚家族sjTRECs的检测情况

目的:检测TCR23个Vβ亚家族sjTRECs在正常人外周血中的存在特点,从而进一步了解正常人胸腺近期各Vβ亚家族初始T细胞的输出情况。方法:采用半巢式PCR对4例胸腺、10例脐血和10例正常人外周血分别在2×105、5×104、1×104和1×103个单个核细胞中的23个Vβ亚家族sjTRECs进行扩增。结果:在细胞数相同的情况下,各Vβ-Dβ1sjTRECs的检出率胸腺细胞最高,其次是脐血,正常人最低。当细胞数为2×105、5×104和1×104时,正常人Vβ2、Vβ4、Vβ7、Vβ11和Vβ19亚家族sjTRECs的检出率以及检出sjTRECs的亚家族数量均显著低于脐血。当细胞数为2×105和5×104时,正常人可检测到绝大多数Vβ亚家族的sjTRECs,随着细胞数的降低,部分Vβ亚家族的sjTRECs则检测不到,而少部分Vβ亚家族的sjTRECs则在1000个细胞时仍能检测到。结论:成功建立了半定量检测23个Vβ亚家族sjTRECs的检测方法;在2×105细胞中约可以检测到80%左右的Vβ亚家族初始T细胞,而在5×104细胞中约有半数的Vβ亚家族初始T细胞可检测到,提示不同Vβ亚家族初始T细胞的出现频率有所差异。     

TCR Dβ-Jβ sjTRECs检测方法的建立和应用

目的：建立检测TCR Dβ-Jβ sjTRECs的方法，并了解不同T细胞受体Dβ-Jβ之间T细胞受体删除DNA环(sjTRECs)在胸腺细胞和外周血T细胞中的形成情况。方法：利用巢式PCR分别扩增10例正常人外周血单个核细胞和3例正常胸腺细胞DNA中不同的Dβ片段和Jβ重排时形成的sjTRECs的情况，PCR产物进一步进行克隆和序列分析以确定结合区的位置。结果：可检测到Dβ1与5个Jβ1基因片段、Dβ2与4个Jβ2基因片段分别形成的sjTRECs，其中以Dβ1-Jβ1S1、Dβ1-Jβ1S2和Dβ2-Jβ2S2sjTRECs最常见，PCR产物经克隆和序列分析证实其形成Dβ-jβsjTRECs的情况。结论：成功地建立了检测Dβ-Jβ-sjTRECs的方法，为分析各TCRβ亚家族的sjTRECs含量和确定TCRβ naive细胞提供了新方法。     

CML中TCRVβ2、Vβ5和Vβ17亚家族sjTRECs的检测情况

目的检测慢性粒细胞白血病(CML)患者外周血TCR Vβ2-、Vβ5-和Vβ17-Dβ1 sjTRECs的存在情况,从而了解相应3种Vβ亚家族naive T细胞的近期胸腺输出情况.方法利用半巢式PCR扩增9例CML患者外周血单个核细胞(PBMC)、CD4+细胞和CD8+细胞DNA的Vβ2-、Vβ5-和Vβ17-Dβ1 sjTRECs,13例正常人外周血作为对照.结果 TCR Vβ2-、Vβ5-和Vβ17-Dβ1 sjTRECs在部分正常人和1例CML患者CD4+或CD8+细胞可以检测到,而在CML患者PBMC中则未能检测到.结论在CML患者Vβ2-、Vβ5-和Vβ17-Dβ1 sjTRECs检出率低,与其胸腺输出相应的TCR Vβ亚家族naive T细胞水平低下有关.     

Altered naive CD4 and CD8 T cell homeostasis in patients with relapsing-remitting multiple sclerosis: thymic versus peripheral (non-thymic) mechanisms

We have reported previously that naive T cells from relapsing-remitting multiple sclerosis (RRMS) patients have T cell receptor (TCR) repertoire shifts, but the basis of these TCR repertoire shifts was uncertain. Here, we questioned whether RRMS patients have altered naive CD4 and CD8 T cell homeostasis by studying homeostatic proliferation and thymic production in RRMS patients and healthy controls. We measured thymic production by quantifying signal joint T cell receptor excision circles (sjTRECs). Both naive T subsets from controls showed an age-associated decrease in sjTRECs, i.e. evidence of progressive thymic involution, but we detected no age-associated decrease in sjTRECs in RRMS patients. Instead, naive CD8 T cells from patients had lower sjTRECs (P = 0.012) and higher Ki-67 proliferation levels (P = 0.04) than controls. Naive CD4 T cell sjTRECs did not differ between patients and controls. However, in RRMS these sjTRECs correlated strongly with CD31, a marker expressed by newly generated CD4 T cells but not by naive CD4 T cells that have undergone homeostatic proliferation. HLA-DR2 positivity correlated negatively with naive CD4 T cell CD31 expression in RRMS (P = 0.002). We conclude in RRMS that naive T subsets have homeostatic abnormalities due probably to peripheral (non-thymic) mechanisms. These abnormalities could have relevance for MS pathogenesis, as naive T cell changes may precede MS onset.     

T-Cell recovery in adults and children following umbilical cord blood transplantation.

T-cell reconstitution following allogeneic stem cell transplantation may involve thymic education of donor-derived precursors or peripheral expansion of mature T cells transferred in the graft. T cell-receptor excision circles (sjTRECs) are generated within the thymus and identify new thymic emigrants and those that have not divided. We measured quantitative and qualitative immunologic reconstitution and sjTREC levels in adult and pediatric recipients of umbilical cord blood transplants (UCBTs). sjTRECs were detected at normal levels in all children, starting 12 months after transplantation. sjTRECs were not detected until 18 months after transplantation in adults, and then only at a 3-fold lower level than expected for age. We used complementarity-determining region 3 (CDR3) spectratyping to measure changes in T cell-receptor diversity occurring with restoration of thymic function. T-cell repertoires were skewed in adults and children at 12 to 18 months after transplantation but recovered to near-normal diversity at 2 to 3 years post-UCBT. T-cell repertoires appeared more diverse earlier in children (at 1 to 2 years post-UCBT) than in adults (at 3 to 4 years post-UCBT). We conclude that early T-cell recovery after UCBT occurs primarily through peripheral expansion of adoptively transferred donor T cells and results in skewing of the T-cell repertoire. The reappearance of sjTREC-containing cells after UCBT is associated with increasing numbers of phenotypicaly naive T cells, improved mitogen and recall antigen responses, and diversification of the T-cell repertoire. The delay in central T-cell recovery in adults relative to children may be due to differences in thymic function resulting from age-related atrophy, graft-versus-host disease, or the pharmacologic effects of prophylaxis and treatment of graft-versus-host disease.     

Recent thymic emigrants in lymphoma patients with and without human immunodeficiency virus infection candidates for autologous peripheral stem cell transplantation

Signal joint T cell receptor excision circles (sjTRECs) have been reported as a clinical marker to measure the potential for recovery of the immune system after immunosuppressive treatments. The aim of this study was to investigate the thymic regenerative potential in 55 human immunodeficiency virus (HIV)-1 infected (HIV(+)) and non-infected (HIV(-)) lymphoma patients, candidates for autologous stem cell transplantation (ASCT). Moreover, the possible associations between sjTRECs and other immunological and clinical parameters were examined. SjTRECs levels in peripheral blood mononuclear cells (PBMCs) were quantified by real-time polymerase chain reaction and T lymphocyte subsets were analysed by flow cytometry. Our data showed that sjTRECs were reduced in lymphoma patients compared to healthy controls, although a weak significant association between low sjTRECs levels and increasing age was maintained [odds ratio (OR) = 4.00; 95% confidence interval (CI) 1.09-17.17]. We found that different chemotherapeutic treatments seem to induce similar effects on the thymic reservoir, independently from their intensity (type and number of cycles of previous chemotherapy). Results from multivariate models including adjustment for patients' sex, type of lymphoma and type of chemotherapy showed that thymic output was independent from HIV infection (OR, 0.95; 95% CI 0.20-4.48). SjTRECs levels correlated with naive T cell subsets in overall lymphoma patients and after stratification by HIV infection (r > 0.37). HIV replication should be maximally suppressed to properly evaluate thymic output by sjTREC markers. Our results suggested that de novo T cell generation is maintained partially in pretreated recurrent lymphoma patients, candidates for ASCT, and could contribute to restore the immune function after transplantation.     

Secretion of Interleukin-2 from Unstimulated Peripheral Blood Mononuclear Cells Is a Possible Pathogenic Mechanism in Recurrent Abortion

PROBLEM: The objective of this study was to evaluate the activated status of helper T cells in women with recurrent abortion. METHOD OF STUDY: The spontaneous secretion of interleukin (IL)-2 from peripheral blood mononuclear cells (PBMCs) obtained from 12 women with primary partner-specific recurrent abortion and 7 normal females and 10 normal males was measured. RESULTS: IL-2 concentrations in medium conditioned with PBMCs from the recurrent abortion group were 1.44 ± 0.32 (mean ± standard deviation) U/ml, whereas those from the normal female and male groups were below the minimum detectable concentration. CONCLUSION: The fact that PBMCs from recurrent aborters spontaneously secrete IL-2 suggests that helper T cells are activated in recurrent aborters.     

Hypomethylation of Notch1 DNA is associated with the occurrence of uveitis

Uveitis is a serious intra-ocular inflammatory disease that can lead to visual impairment even blindness worldwide. Notch signaling can regulate the differentiation of naive CD4⁺ T cells, influencing the development of uveitis. DNA methylation is closely related to the autoimmune diseases. In this study, we measured the Notch1 DNA methylation level, determined the Notch1 and related DNA methylases mRNA expression and evaluated the ratio of T helper type 17 regulatory T cell (Th17/T_reg) in peripheral blood mononuclear cells (PBMCs) from uveitis patients and normal control subjects; we also tested the levels of relevant inflammatory cytokines in serum from the participants. Results indicated that compared with those in normal control individuals, the expression of ten–eleven translocation 2 (TET2) and Notch1 mRNA is elevated in uveitis patients, whereas the methylation level in Notch1 DNA promotor region [−842 ~ −646 base pairs (bp)] is down-regulated, and is unrelated to anatomical location. Moreover, the Th17/T_reg ratio is up-regulated in PBMCs from uveitis patients, accompanied by the elevated levels of proinflammatory cytokines [e.g. interleukin (IL)-2, IL-6, IL-17 and interferon (IFN)-γ] in serum from uveitis patients. These findings suggest that the over-expression of TET2 DNA demethylase may lead to hypomethylation of Notch1, activate the Notch1 signaling, induce naive CD4⁺ T cells to differentiate theTh17 subset and thus disturb the balance of the Th17/T_reg ratio in uveitis patients. Overall, hypomethylation of Notch1 DNA is closely associated with the occurrence of uveitis. Our study preliminarily reveals the underlying mechanism for the occurrence of uveitis related to the hypomethylation of Notch1 DNA, providing a novel therapeutic strategy against uveitis in clinical practice.     

HIV infection rapidly induces and maintains a substantial suppression of thymocyte proliferation

The supply of naive T cells by the thymus normally requires precursor T cell proliferation within the thymus and would be particularly important in the setting of HIV infection when both naive and memory T cells are progressively depleted. As a robust, quantitative index of intrathymic proliferation, the ratio of different T cell receptor excision circles (TRECs), molecular markers of distinct T cell receptor rearrangements occurring at different stages of thymocyte development, was measured in peripheral blood-mononuclear cells (PBMCs). This ratio has the virtue that it is a "signature" of thymic emigrants throughout their entire life and, thus, can be measured in peripheral cell populations that are easy to obtain. Using the new assay, we evaluated the effect of HIV infection on intrathymic precursor T cell proliferation by longitudinal analysis of PBMCs from recently infected individuals. Our findings reveal a substantial reduction in intrathymic proliferation. The analysis also indicates the existence of a compensatory mechanism acting to sustain the numbers of recent thymic emigrants (RTEs) in the periphery.     

人外周血sjTREC水平与年龄的相关性调查

目的探讨人外周血中sjTREC水平及其与年龄的相关性。方法收集225例不同年龄健康人外周血样品,抽提基因组DNA,利用实时定量PCR技术,定量测定不同年龄组外周血中sjTREC含量的分布情况。sjTREC含量与年龄的关系作相关分析;各年龄组性别差异作t检验。结果 225例外周血sjTREC含量随年龄增长逐渐减少;对0～14岁、15～54岁及55岁以上3组进行方差分析(LSD检验),差异显示有统计学意义(P0.001);性别差异不显著;供体年龄与外周血sjTREC水平呈显著负相关,r=-0.823(P0.001)。结论人外周血中sjTREC含量与年龄存在明显相关性,对于法医物证实践中血痕的年龄推测具有一定指导意义。