Longitudinal changes in CD4+ T cell antigen receptor diversity and naive/memory cell phenotype during 9 to 26 months of antiretroviral therapy of HIV-infected patients

Although skewing of the CD4+ TCR repertoire in advanced HIV infection is well documented, increases in polyclonality during antiretroviral therapy have been less consistently observed. Ten patients, each with documented abnormalities within the CD4+ TCR repertoire, were studied by CDR3 spectratyping, semiquantitative PCR, and SSCP during 9-26 months of therapy. Naive and memory cell phenotypes were analyzed by flow cytometry. Six of 10 patients showed increased polyclonality of their TCR repertoires, 1 showed no change, and 3 showed increased TCR skewing, despite suppressed viral replication. Overall, there was no significant change in the percentage of abnormal BV subfamilies (from a mean of 25.5 to 17.1%) or the percentage of naive CD4+ T cells (from a mean of 18 to 25%). Further, progression of TCR repertoire disruptions was observed in some patients even with suppression of plasma viral RNA below 500 copies/ml. Although a spectrum of changes may be seen within the CD4+ TCR repertoire in the setting of antiretroviral therapy, increases in polyclonality are observed in some patients.     

T‐cell phenotypes in bronchoalveolar lavage fluid,blood and lymph nodes in pulmonary sarcoidosis – indication for an airborne antigen as the triggering factor in sarcoidosis

Abstract. Darlington P, Haugom‐Olsen H, von Sivers K, Wahlström J, Runold M, Svjatoha V, Porwit A, Eklund A, Grunewald J (Karolinska Institutet, Stockholm, Sweden). T‐cell phenotypes in bronchoalveolar lavage fluid, blood and lymph nodes in pulmonary sarcoidosis – indication for an airborne antigen as the triggering factor in sarcoidosis. J Intern Med 2012; 272: 465–471. Background. An increased percentage of CD4+ T cells is usually observed in bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis. In HLA‐DRB1*03‐positive patients, such T cells express the T‐cell receptor (TCR) AV2S3+ gene segment. It is not known whether cells found in BALF reflect those in enlarged regional lymph nodes (LNs). Therefore, the aim of this study was to compare T‐cell phenotypes in BALF, blood and mediastinal LNs. Methods. Fifteen patients underwent clinical investigation including bronchoscopy with bronchoalveolar lavage. Blood samples were drawn, and endoscopic ultrasound‐guided fine‐needle aspiration of enlarged mediastinal LNs was performed via the oesophagus. T cells from all three compartments were analysed by flow cytometry for markers of activity, differentiation and T regulatory function. Results. The CD4/CD8 ratio was significantly higher in BALF compared with regional LNs and was also significantly higher in LNs than in blood. The CD4+ T cells were recently activated and more differentiated in BALF than in blood and LNs. There was an accumulation of T regulatory cells (FOXP3+) in LNs and a correlation between high levels of FOXP3+ cells in BALF and in LNs. In HLA‐DRB1*03‐positive patients, TCR AV2S3+ CD4+ T cells were predominantly localized within BALF. Conclusions. The CD4+ T‐cell phenotype in BALF indicates an active ongoing specific immune response primarily localized to the alveolar space.     

Increased regulatory T cells and impaired functions of circulating CD8 T lymphocytes is associated with viral persistence in Hepatitis B virus‐positive newborns

Hepatitis B Virus (HBV) infection in infancy or early childhood leads to high rate of persistent infection (25–90%). The immunological basis of high rate of viral persistence in vertically acquired HBV infections is not completely understood. CD8 T cells play a pivotal role in clearing the Hepatitis B virus infection in adults. Herein, we sought to delineate the role of T cells in viral persistence in HBsAg+ve newborns . At birth peripheral and cord blood of HBsAg+ve (N = 12), HBsAg‐ve (N = 10) and healthy newborns (HC: N = 15) were evaluated for T‐cell frequency and functionality by flow cytometry. No significant differences were observed in the frequency of CD8 and CD4 T cells in all the three groups. However, significantly higher frequency of FoxP3 expressing regulatory T cells were observed in HBsAg+ve (63.79%) compared with HBsAg‐ve (28.12%) and HC (11.06%) (P < 0.05). Moreover, HBsAg+ve newborns showed functional defect in CD8 T cells by decreased IFN‐γ production and lower CD107A expression (cytotoxic capacity) compared with HBsAg‐ve and HC, which positively correlated with decreased TCRζ‐chain expression CD8 T cells (r² > 0.93, P < 0.05). Despite equal frequency of CD8 T cells in all the three groups, CD8 T cells in HBsAg+ve newborns are dysfunctional. An expansion of regulatory T cells and impaired TCR signalling may represent the immune tolerant state of the adaptive immune system in response to chronic HBV infection.     

Selective T‐cell depletion targeting CD45RA reduces viremia and enhances early T‐cell recovery compared with CD3‐targeted T‐cell depletion

1 Background

T‐cell depletion (TCD) effectively reduces severe graft‐versus‐host disease in recipients of HLA‐mismatched allografts. However, TCD is associated with delayed immune recovery and increased infections. We hypothesized that specific depletion of CD45RA+ naive T cells, rather than broad depletion of CD3+ T cells, can preserve memory‐immunity in the allografts and confer protection against important viral infections in the early post‐transplant period.

2 Methods

Sixty‐seven patients who received TCD haploidentical donor transplantation for hematologic malignancy on 3 consecutive trials were analyzed.

3 Results

Patients receiving CD45RA‐depleted donor grafts had 2000‐fold more donor T cells infused, significantly higher T‐cell counts at Day +30 post transplant (550/μL vs 10/μL; P < .001), and higher T‐cell diversity by Vbeta spectratyping at Day +100 (P < .001). Importantly, these recipients experienced a significant reduction in both the incidence (P = .002) and duration (P = .02) of any viremia (cytomegalovirus, Epstein‐Barr virus, or adenovirus) in the first 6 months post transplant. Specifically, recipients of CD3‐depleted grafts were more likely to experience adenovirus viremia (27% vs 4%, P = .02).

4 Conclusion

CD45RA‐depletion provided a large number of donor memory T cells to the recipients and was associated with enhanced early T‐cell recovery and protection against viremia.     

Early reconstitution of the T-cell repertoire after non-myeloablative peripheral blood stem cell transplantation is from post-thymic T-cell expansion and is unaffected by graft-versus-host disease or mixed chimaerism

To study immune recovery after non-myeloablative, reduced-intensity stem cell allografts (NST) and T-cell-depleted myeloablative transplants (TCD), we measured T-cell subset recovery by flow cytometry, T-cell repertoire by spectratyping and thymic T-cell output using a T-cell receptor excision circle (TREC) assay. We found a rapid and comparable increase in lymphocyte numbers in both NST and TCD, supporting the presence of a powerful drive for lymphocyte recovery after transplant. Spectratyping on d 45 and 100 revealed almost complete normalization of the T-cell repertoire in NST patients by d 45, whereas TCD patients demonstrated marked skewing of the repertoire, persisting to d 100. After NST, there was a significantly higher number of TREC-positive CD4+ and CD8+ cells (P = 0.02 and P = 0.01 respectively). However, in both NST and TCD, early T-cell recovery after transplant appeared to result entirely from post-thymic T cells, the expansion pattern of which is most influenced by the starting T-cell dose, but not markedly by graft-versus-host disease (GVHD) or mixed chimaerism. These results define important qualitative differences in the T-cell repertoire according to the type of transplant schedule used.     

Persistent gamma delta T‐cell dysfunction in chronic HCV infection despite direct‐acting antiviral therapy induced cure

Immune dysfunction is a hallmark of chronic HCV infection and viral clearance with direct antivirals recover some of these immune defects. TCRVγ9Vδ2 T‐cell dysfunction in treated HCV patients however is not well studied and was the subject of this investigation. Peripheral blood cells from patients who had achieved sustained virologic response (SVR) or those who had relapsed after interferon‐free therapy were phenotyped using flow cytometry. Functional potential of Vγ9Vδ2 T cells was tested by measuring proliferation in response to aminobisphosphonate zoledronic acid, and cytotoxicity against HepG2 hepatoma cell line. TCR sequencing was performed to analyse impact of HCV infection on Vδ2 T‐cell repertoire. Vγ9Vδ2 cells from patients were activated and therapy resulted in reduction of CD38 expression on these cells in SVR group. Relapsed patients had Vδ2 cells with persistently activated and terminally differentiated cytotoxic phenotype (CD38⁺CD45RA⁺CD27^?CD107a⁺). Irrespective of outcome with therapy, majority of patients had persistently poor Vδ2 T‐cell proliferative response to zoledronate along with lower expression of CD56, which identifies anti‐tumour cytotoxic subset, relative to healthy controls. There was no association between the number of antigen reactive Vγ2‐Jγ1.2 TCR rearrangements at baseline and levels of proliferation indicating nonresponse to zoledronate is not due to depletion of phosphoantigen responding chains. Thus, HCV infection results in circulating Vγ9Vδ2 T cells with a phenotype equipped for immediate effector function but poor cytokine response and expansion in response to antigen, a functional defect that may have implications for susceptibility for carcinogenesis despite HCV cure.     

肿瘤患者化疗前后外周血NK/T及Treg细胞比例分析

目的探讨肿瘤患者化疗前后,外周血免疫激活细胞及免疫抑制细胞比例变化。 方法本研究通过分析38例健康人外周血NK/T细胞及Treg细胞流式分析结果,并跟踪本中心140例常见肿瘤患者(结直肠癌31例、胃癌21例、乳腺癌27例、肺癌61例),发病前后、化疗疗程中外周血中的NK/T细胞及Treg细胞比例。 结果恶性肿瘤患者外周血中Treg细胞比例显著高于健康对照组分别为(6.95%±8.96%)、(4.25%±2.59%),P<0.05, NK细胞比例也显著高于健康人分别为(18.56%±9.19%)、(12.37%±6.24%),P<0.01。因统计病例数目有限,对69例肿瘤患者化疗的后续随访中发现,随着化疗进程,NK细胞以及Treg的比例变化无统计学意义,但在结直肠癌及胃癌中,Treg细胞比例可见先降低后升高的趋势。 结论肿瘤患者外周血Treg细胞比例高于健康人,在化疗过程中NK细胞比例以及Treg细胞比例均高于化疗前水平。随着本研究的继续深入,可能进一步证实Treg细胞在肿瘤中富集,形成免疫抑制微环境,是通过抑制CD4^＋、CD8^＋T淋巴细胞及NK细胞的肿瘤杀伤效应,介导肿瘤免疫逃逸的可能。     

Association of circulating regulatory T cell number with the incidence and prognosis of diffuse large B‐cell lymphoma

Regulatory T (Treg) cells are essential for maintaining immune tolerance. High Treg frequencies have been reported in peripheral blood and tissue samples of patients with solid tumors while their role in lymphomas, including diffuse large B‐cell lymphoma (DLBCL) has not been clearly established. In this study, we analyzed the circulating Treg numbers in 27 patients with newly diagnosed DLBCL and 17 healthy individuals. Tregs were detected by flow cytometry based on CD4⁺CD25^highFoxP3⁺ phenotype. In addition, the expression of CD45RA, HLA‐DR, CD62L, CD39, and CTLA4 was analyzed. The number of circulating Treg cells was lower in patients with DLBCL than in healthy controls: median 23 (range, 4–107)/μL vs. 41 (19–104)/μL (P = 0.04). In particular, the number of Tregs expressing CD45RA (naïve Tregs), HLA‐DR (marker of activation), and CD62L (L‐selectin) was decreased in the DLBCL group. Lower (below median) number of circulating Tregs was associated with reduced chance of achieving complete remission (29% vs. 69%, P = 0.05) and reduced probability of even‐free survival (24% vs. 84% at 1 yr, P = 0.0004), independently on the International Prognostic Index. We conclude that low number of circulating Tregs may be associated with poor prognosis in patients with DLBCL. However, our observations require confirmation in larger patient population.     

Hepatitis C‐specific effector and regulatory CD4 T‐cell responses are associated with the outcomes of primary infection

Clearance of primary hepatitis C virus (HCV) infection has been associated with strong and broadly targeted cellular immune responses. This study aimed to characterize HCV‐specific CD4+ effector and regulatory T‐cell numbers and cytokine production during primary infection. Antigen‐specific CD4+ T‐cell responses were investigated in a longitudinal cohort of subjects from pre‐infection to postoutcome, including subjects who cleared [n=12] or became chronically infected [n=17]. A cross‐sectional cohort with previously cleared, or chronic infection [n=15 for each], was also studied. Peripheral blood mononuclear cells were incubated with HCV antigens and surface stained for T‐effector (CD4+CD25^highCD134+CD39‐) and T‐regulatory (CD4+CD25^highCD134+CD39+) markers, and culture supernatants assayed for cytokine production. Contrary to expectations, the breadth and magnitude of the HCV‐specific CD4+ T‐cell responses were higher in subjects who became chronically infected. Subjects who cleared the virus had HCV‐specific CD4+ T‐cell responses dominated by effector T cells and produced higher levels of IFN‐γ, in contrast to HCV‐specific CD4+ T‐cell responses dominated by regulatory T cells and more IL‐10 production in those who became chronically infected. Better understanding of the role of antigen‐specific CD4+ T‐cell responses in primary HCV will further define pathogenesis and help guide development of a preventative vaccine.     

T cell expansions in lymph nodes and peripheral blood in HIV-1-infected individuals: effect of antiretroviral therapy.

OBJECTIVE: To evaluate dynamics in CD8 T cell expansions during highly active antiretroviral therapy (HAART). DESIGN: Various T cell subsets were isolated from blood and lymph nodes and analysed for T cell receptor (TCR) diversity. METHODS: TCR complementarity determining region 3 (CDR3) spectratyping and single-strand conformation polymorphism (SSCP) analyses were performed in combination with sequencing to assess clonality of the subsets. RESULTS: Strongly skewed CDR3 patterns in total CD8 cells and the CD8 subsets CD45RO+CD27+ and CD45RO-CD27+ showed substantial dynamics in dominant CDR3 sizes, resulting in relative improvement of CDR3 size diversity in the first months of therapy. During sustained treatment, TCR diversity changed only moderately. SSCP profiles confirmed oligoclonality of TCR CDR3 perturbations. Various dominant CDR3 sizes for CD4 and CD8 T cells present in lymph nodes, but not in peripheral blood mononuclear cells, before the start of therapy emerged in peripheral blood early during therapy. CONCLUSIONS: HAART induces substantial changes in CD8 TCR diversity, eventually resulting in improvement of the repertoire. Clonal expansions observed in lymph nodes before therapy were observed in peripheral blood after therapy, suggesting that recirculation of CD4 and CD8 T cells from lymph nodes contributes to the early T cell repopulation. Decreased immune activation and possibly naive T cell regeneration subsequently decreased clonal expansions and perturbations in the CD8 TCR repertoire.     

胰岛素抵抗的慢性丙型肝炎患者外周血CD4+CD25+调节性T细胞的数量及其功能

目的 了解胰岛素抵抗的慢性丙型肝炎患者外周血CD4 +CD25+调节性T细胞(Treg)数量和功能的变化.方法 筛选40例HLA-A2+慢性丙型肝炎患者(其中20例合并胰岛素抵抗),流式细胞仪检测患者CD4+CD25+Treg细胞占外周血中CD4+T细胞的频率,液闪计数仪检测对HCV特异性CD8+T细胞增殖的抑制作用,ELISA法检测IFN-y水平.统计学处理采用t检验.结果 胰岛素抵抗的慢性丙型肝炎患者外周血CD4 +CD25+ Treg细胞占CD4+T细胞的(9.5±1.9)％,明显低于慢性丙型肝炎患者的(11.2±2.2)％(t=2.615,P＜0.05).胰岛素抵抗指数(HOMA-IR)≥4患者的CD4+CD25+ Treg细胞比例为(9.0±1.8)％,明显低于HOMA-IR＜4患者的(10.8±2.3)％(t=2.413,P＜0.05).胰岛素抵抗的慢性丙型肝炎患者CD4+CD25+ Treg细胞和去除Treg的外周血单个核细胞(PBMC)共培养上清液中IFN-y为(4 050±580) pg/mL,明显高于慢性丙型肝炎患者的(2 005±330)pg/mL(t=13.705,P＜0.01).HOMA-IR≥4患者IFN-y为(5 682±986)pg/mL,明显高于HOMA-IR＜4患者的(2 819±660) pg/mL(t=7.630,P＜0.01).结论 随着胰岛素抵抗程度加重,慢性丙型肝炎患者外周血CD4+ CD25+ Treg细胞频率减低,对HCV特异性CD8+T细胞增殖的抑制作用减弱.     

CD4+ and CD8+ T cell receptor repertoire perturbations with normal levels of T cell receptor excision circles in HIV-infected,therapy-naive adolescents

Our objective was to determine whether treatment-naive HIV-infected adolescents manifest abnormalities in thymus function and peripheral T cell repertoire, and to assess relationships of these immunologic characteristics with each other, with plasma HIV virus load, and T cell surface markers. TCR Vbeta repertoire was determined by CDR3 length spectratyping in purified CD4(+) and CD8(+) T cells of high-risk, HIV-negative adolescents and of treatment-naive, HIV-infected adolescents. Thymus function was investigated by the simultaneous examination of T cell receptor excision circles (TRECs) in the CD4(+) and CD8(+) T cell subsets. HIV-infected adolescents exhibited significantly greater perturbations in their TCR Vbeta repertoire in comparison with HIV-negative subjects. Perturbations in the CD8(+) T cell compartment were more profound in comparison with CD4(+) T cells. The CD4(+) TCR Vbeta perturbations were negatively correlated with the total and phenotypically naive CD4(+) T cells, and with CD4(+) TRECs. CD8(+) TRECs, although not correlated with CD8(+) TCR Vbeta perturbations, showed negative correlation with memory and activated CD8(+) T cells. Interestingly, TRECs in CD4(+) and CD8(+) T cells were not significantly different between HIV-infected and uninfected adolescents. The TCR Vbeta repertoire in adolescents is profoundly perturbed even in early stages of HIV infection, when total CD4(+) cell counts in most subjects are within normal limits. The correlative analyses demonstrating negative association of CD4(+) cell TRECs with CD4(+) TCR Vbeta perturbations and of CD8(+) TRECs with CD8(+) cell activation markers provide evidence of the intense activation of the central and peripheral immune compartments in this study population.     

Significance of the frequency of CD4+CD25+CD127- T-cells in patients with pulmonary tuberculosis and diabetes mellitus

Background and objective: Pulmonary tuberculosis and diabetes mellitus (DM) are closely associated. The objective of this study was to determine whether the expression of CD4+CD25+CD127? T‐cells (regulatory T‐cells (Treg)) is associated with diabetic pulmonary tuberculosis. Methods: Flow cytometry was used to determine the frequencies of CD4+CD25+ and CD4+CD25+CD127? T‐cells in peripheral blood, bronchoalveolar lavage fluid (BALF) and pleural effusions from 120 patients (30 with pulmonary tuberculosis and DM (TBDM), 30 with pulmonary tuberculosis without DM (TB), 30 with tuberculous pleurisy without DM (TBP) and 30 healthy volunteers). The concentrations of interferon (IFN)‐γ and interleukin (IL)‐10 in BALF and pleural effusions were determined by enzyme‐linked immunosorbent assay. Results: Treg frequencies in peripheral blood were significantly higher in patients with TBDM, TB and TBP than in the control group, with the frequency in TBDM being the highest (P < 0.01 for all). In TBP patients, Treg frequencies were significantly lower in pleural effusions than in peripheral blood. In TB patients, Treg frequencies in BALF and peripheral blood were not significantly different. However, in TBDM patients, Treg frequencies were significantly higher in BALF than in peripheral blood. IL‐10 expression was significantly higher, and IFN‐γ expression was significantly lower in BALF of TBDM patients compared with BALF and pleural effusions of TB patients. Conclusions: In patients with pulmonary tuberculosis and DM, the imbalance between Treg and effector T‐cells at pathological sites may be associated with weakened immunity and clinical manifestations of TB.     

CD56‐expressing T cells that have features of senescence are expanded in rheumatoid arthritis

Objective

T cells deficient in CD28 expression have been implicated in the pathogenesis of rheumatoid arthritis (RA). Given that CD28‐null T cells are functionally heterogeneous, we undertook this study to screen for novel receptors on these cells.

Methods

Seventy‐two patients with RA (ages 35–84 years) and 53 healthy persons (32 young controls ages 19–34 years, 21 older controls ages 39–86 years) were recruited. Phenotypes and proliferative capacity of T cells from fresh leukocytes and of long‐term cultures were monitored by flow cytometry. Lung biopsy specimens from patients with RA‐associated interstitial pneumonitis (IP) were examined by immunohistochemistry. Receptor functionality was assessed by crosslinking bioassays.

Results

Chronic stimulation of CD28+ T cells in vitro yielded progenies that lacked CD28 but that gained CD56. Ex vivo analysis of leukocytes from patients with extraarticular RA showed a higher frequency of CD56+,CD28‐null T cells than in patients with disease confined to the joints or in healthy controls. CD56+,CD28‐null T cells had nil capacity for proliferation, consistent with cellular senescence. CD56+ T cells had skewed T cell receptor (TCR) α/β‐chain usage and restricted TCR third complementarity‐determining region spectra. Histologic studies showed that CD56+ T cells were components of cellular infiltrates in RA‐associated IP. CD56 crosslinking on T cells sufficiently induced cytokine production, although CD56/TCR coligation induced higher production levels.

Conclusion

Chronic activation of T cells induces counterregulation of CD28 and CD56 expression. The loss of CD28 is accompanied by the gain of CD56 that confers TCR‐independent and TCR‐dependent activation pathways. We propose that accumulation of CD56+ T cells in RA contributes to maladaptive immune responses and that CD56+ T cells are potential targets for therapy.

     

Selective T cell receptor decrease in peripheral blood T lymphocytes of patients with polymyalgia rheumatica and giant cell arteritis

OBJECTIVES: To investigate the phenotype and T cell receptor (TCR) use in peripheral blood T cells in patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). METHODS: Circulating T lymphocyte phenotype and TCR repertoire were studied by flow cytometry using specific monoclonal antibodies in 23 healthy controls and 37 patients with PMR/GCA. RESULTS: Patients with active PMR/GCA showed an inverse relation between naive and memory CD4+ T cells and unchanged expression of activation surface markers compared with controls. CD4+ TCR BV expansions were seen in 12 (52%) controls and in 8 (22%) patients with active disease (p = 0.03). Within the CD8+ subset, the frequency of expansions was similar between groups. Most T cell expansions remained stable over time. Seventeen of the 23 patients with active PMR/GCA disclosed a simultaneous CD4+ and CD8+ T cell depletion for at least one particular BV family with a clear predominance of BV5S2/S3. CONCLUSIONS: The phenotype of circulating T cells in patients with PMR/GCA is similar to that found in aged healthy subjects, except for the surface markers of naive and memory cells and a striking non-activated phenotype. Specific BV expansions in CD4+ and CD8+ T cells, which remain stable over time, are frequent in aged subjects, including patients with PMR/GCA. TCR BV changes in patients with active disease seem to be also age related, except for the significant decrease in certain BV families in both CD4+ and CD8+ T cell subsets, which may favour the participation of a superantigen stimulation in PMR/GCA.     

Expression of programmed cell death protein 1 and T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 on peripheral blood CD4+CD8+ double positive T cells in patients with chronic hepatitis C virus infection and in subjects who spontaneously cleared the virus

Chronic hepatitis C virus (HCV) infection is characterized by increased proportion of CD4+CD8+ double positive (DP) T cells, but their role in this infection is unclear. In chronic hepatitis C, immune responses to HCV become functionally exhausted, which manifests itself by increased expression of programmed cell death protein 1 (PD‐1) and T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 (Tim‐3) on T cells. The aim of our study was to determine PD‐1 and Tim‐3 phenotype of DP T cells in subjects with naturally resolved and chronic HCV infection. Peripheral blood mononuclear cells from 16 patients with chronic infection and 14 subjects who cleared HCV in the past were stained with anti‐CD3, anti‐CD4, anti‐CD8, anti‐PD‐1 and anti‐Tim‐3 antibodies and, in 12 HLA‐A*02‐positive subjects, MHC class I pentamer with HCV NS3₁₄₀₆ epitope. In chronic and past HCV infection, proportions of total DP T cells and PD‐1+ DP T cells were similar but significantly higher than in healthy controls. DP T cells were more likely to be PD‐1+ than either CD4+ or CD8+ single positive (SP) T cells. HCV‐specific cells were present in higher proportions among DP T cells than among CD8+ SP T cells in both patient groups. Furthermore, while the majority of HCV‐specific DP T cells were PD‐1+, the proportion of HCV‐specific CD8+ T cells which were PD‐1+ was 4.9 and 1.9 times lower (chronic and past infection, respectively). PD‐1 and Tim‐3 were predominantly expressed on CD4^highCD8^low and CD4^lowCD8^high cells, respectively, and co‐expression of both markers was uncommon.     

Inverse correlation between NKG2D expression on CD8+ T cells and the frequency of CD4+CD25+ regulatory T cells in patients with esophageal cancer

Although malignant diseases are known to be associated with immune suppression, detailed mechanisms of this phenomenon are still unknown. NKG2D is an activating cell surface receptor expressed by natural killer (NK) cells and CD8+ T cells, and it has been reported that NKG2D engagement is extremely important for T cell activation. In the current study, NKG2D expression on CD8+ T cells and the frequency of CD4+ CD25+ regulatory T (Treg) cells were determined by multicolor flow cytometry to investigate one of the mechanisms responsible for immune evasion in esophageal cancer patients. NKG2D expression on CD8+ T lymphocytes in esophageal cancer patients was significantly lower than in those of normal controls. NKG2D expression in T3/T4 esophageal cancer was significantly lower than that in T1/T2 esophageal cancer. CD8+ T cells from patients with lymph node metastasis expressed significantly lower NKG2D than those without lymph node metastasis. Moreover, significantly lower NKG2D expression was observed in stage III/IV cancer in comparison with stage I/II. The frequency of CD4+CD25+ Treg cells in esophageal cancer patients was significantly higher than those in normal controls. NKG2D expression on CD8+ T cells was significantly inversely correlated with the frequency of CD4+CD25+ Treg cells in esophageal cancer patients. Our data indicates that decreased NKG2D expression on CD8+ T cells is correlated with disease severity. Decreased NKG2D expression and an increase in Treg cells may be one of the key mechanisms responsible for immune evasion in esophageal cancer.     

Liver injury is associated with enhanced regulatory T-cell activity in patients with chronic hepatitis B

Chronic hepatitis B virus (HBV) infection is associated with impairment of HBV-specific immune responses. Recently, it has been shown that regulatory T (Treg) cells downregulate HBV-specific immune responses but their role in chronic hepatitis B is still controversial. We hypothesized that liver injury enhances the influence of Treg cells on HBV-specific immune responses. The frequency of Treg cell and the in vitro expansion of HBV-specific CD8+ T cell detected by the tetramer method were investigated in 79 patients with chronic hepatitis B. Thirty-three healthy volunteers were enrolled to measure the frequency of Treg cell as controls. The results showed that in chronic hepatitis B cases, the frequency of Treg cells in peripheral blood was significantly higher than that in normal volunteers. The higher level of serum transaminase was associated with higher frequency of Treg cells, which both had a linear correlation relationship. HBV-DNA level, HBe status, age and sex had no statistical association with Treg cell frequency. Furthermore, in patients with higher serum transaminase levels, the expansion of HBV-specific CD8+ T cells was higher after removal of Treg cells when compared with patients with lower serum transaminase levels. In conclusion, our data indicate a significant association between serum transaminase level and frequency/activity of Treg cells. Based on this observation, we propose that liver-injury enhances Treg cell frequency/activity in chronic hepatitis B patients.     

外周血Th17细胞及IL-17^＋FoxP3^＋T细胞在非小细胞肺癌患者的表达变化

目的：探讨辅助性T17（Th17）细胞及白细胞介素17（IL-17）＋叉头蛋白3（FoxP3）＋T细胞在非小细胞肺癌患者外周血中的表达及意义。方法：57例非小细胞肺癌患者作为研究对象．25名正常人作为对照。采用流式细胞术检测外周血Th17细胞、调节性T细胞（Treg细胞）的百分率以及IL-17＋FoxP3＋T细胞占Treg细胞的百分率。结果：Ⅳ期非小细胞肺癌患者外周血单核细胞（PBMC）中Th17细胞百分率高于Ⅰ-Ⅲ期患者及正常对照（均P〈0．01）。非小细胞肺癌患者PBMC中的Treg细胞百分率高于正常对照,并且IL-17＋FoxP3＋T细胞占Treg细胞的百分率高于正常对照（P〈0．05）。结论：Ⅳ期非小细胞肺癌患者中Th17细胞以及II-17＋FoxP3＋T细胞数量增加,Th17以及IL．17＋FoxP3＋T细胞可能参与了非小细胞肺癌的肿瘤远处转移过程．从而影响肿瘤进程。