Natural killer T cells exacerbate liver injury in a transforming growth factor beta receptor II dominant-negative mouse model of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an organ-specific autoimmune liver disease characterized by the presence of antimitochondrial antibodies and the destruction of small intrahepatic bile ducts with portal inflammation. In previous studies, we reported that both CD1d expression and the frequency of CD1d-restricted natural killer T (NKT) cells were increased in the livers of patients with PBC. To define a specific role of CD1d-restricted NKT cells in the pathogenesis of PBC, particularly early events, we investigated the function of hepatic CD1d-restricted NKT cells in our transforming growth factor beta (TGF-beta) receptor II dominant-negative (dnTGFbetaRII) mouse model of PBC. We generated CD1d(-/-) and CD1d(+/-) dnTGFbetaRII mice and performed a comparative study of liver immunopathology. We report herein that these dnTGFbetaRII mice demonstrate a massive increase of hyperactive CD1d-restricted NKT cells within the hepatic tissues. CD1d(-/-)dnTGFbetaRII mice, which lack CD1d-restricted CD1d-restricted NKT cells, exhibit significantly decreased hepatic lymphoid cell infiltrates and milder cholangitis compared with CD1d(+/-)dnTGFbetaRII mice. Interestingly, there was a significant increase in the production of interferon-gamma in hepatic CD1d-restricted NKT cells activated by alpha-galactosylceramide in young but not older dnTGFbetaRII mice, suggesting an age-dependent role of CD1d-restricted NKT cells. CONCLUSION: These data demonstrate that CD1d-restricted NKT cells in dnTGFbetaRII mice are a critical factor in liver injury.     

自身免疫性肝病患者外周血淋巴细胞亚群的频率变化及临床意义

目的调查原发性胆汁性肝硬化(PBC)、自身免疫性肝炎(AIH)及AIH-PBC重叠综合征患者外周血淋巴细胞亚群频率变化及其临床意义。方法本中心2001年6月-2010年12月期间,对41例AIH-PBC、37例AIH和36例PBC患者,以及50例健康人群外周血进行淋巴细胞亚群频率检测。分析患者年龄、性别、肝功能、是否肝硬化及淋巴细胞亚群频率的变化。结果与健康组相比,AIH-PBC重叠综合征组、PBC组和AIH组的CD3+CD4+T细胞频率显著升高,而CD3-CD16+CD56+NK细胞频率显著降低;PBC组和AIH-PBC重叠综合征中CD4+/CD8+比值、CD3-CD19+B细胞频率偏高,CD3+CD8+%T细胞频率降低。在疾病发展的不同阶段,AIH-PBC重叠综合征组和PBC组中,肝硬化组CD3+%T细胞频率、CD3+CD8+%T细胞频率较非肝硬化组偏低。结论通过回顾性分析健康人群和AIH、PBC及AIH-PBC重叠综合征患者淋巴细胞亚群的分布特点及其与疾病进展的关系,为临床科学评价上述自身免疫性肝病人群的免疫状态提供重要的免疫指标。     

原发性胆汁性肝硬化的细胞免疫学发病机制

原发性胆汁性肝硬化（PBC）是一种器官特异性的进行性自身免疫疾病,常见于女性,以肝脏门脉周围的淋巴细胞浸润,胆管上皮细胞特异性损伤以及血清中高滴度抗线粒体抗体（AMA）为主要特征。最新的PBC研究采用了CD4启动子控制下的TGFβ受体2显性失活（dnTGFβRⅡ）小鼠模型,这种小鼠模型很好地模拟了PBC患者的典型特征。在这种小鼠的基因背景下,通过分别敲除Rag1,μ以及CD1d基因建立了多种双基因缺陷鼠,通过研究发现T细胞,B细胞以及CD1d限制的NKT细胞等对肝脏淋巴细胞浸润,胆管上皮细胞损伤以及AMA的产生发挥着重要的作用。一系列的细胞免疫学实验结果显示,是CD8＋T细胞而非CD4＋T细胞在肝脏损伤过程中起着决定性的作用,而B细胞除分泌抗自身抗体之外,还具有抑制PBC发生的免疫调节作用。这些机制的研究为揭示人类PBC疾病的细胞免疫学致病机理提供了有力的证据和依托     

Autoreactive CD8-specific T-cell response in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology. Autoimmune attack in PBC is predominantly organ-specific, despite the presence of mitochondrial autoantigens, the major targets of autoimmunity in PBC, in all nucleated cells. Cytotoxic T lymphocytes are thought to be directly involved in the tissue injury in PBC. The major histocompatibility complex (MHC) class I-restricted epitope for E2 components of pyruvate dehydrogenase complexes, namely amino acid 159–167, a region very close to the epitoperecognized by MHC class II-restricted CD4 cells and by antibody, has been characterized. In addition, there was a 10-fold increase in the frequency of autoreactive cytotoxic T lymphocytes in the liver as compared to the blood in PBC patients using tetramer technology.     

Human CD1d knock-in mouse model demonstrates potent antitumor potential of human CD1d-restricted invariant natural killer T cells

Despite a high degree of conservation, subtle but important differences exist between the CD1d antigen presentation pathways of humans and mice. These differences may account for the minimal success of natural killer T (NKT) cell-based antitumor therapies in human clinical trials, which contrast strongly with the powerful antitumor effects in conventional mouse models. To develop an accurate model for in vivo human CD1d (hCD1d) antigen presentation, we have generated a hCD1d knock-in (hCD1d-KI) mouse. In these mice, hCD1d is expressed in a native tissue distribution pattern and supports NKT cell development. Reduced numbers of invariant NKT (iNKT) cells were observed, but at an abundance comparable to that in most normal humans. These iNKT cells predominantly expressed mouse Vβ8, the homolog of human Vβ11, and phenotypically resembled human iNKT cells in their reduced expression of CD4. Importantly, iNKT cells in hCD1d knock-in mice exert a potent antitumor function in a melanoma challenge model. Our results show that replacement of mCD1d by hCD1d can select a population of functional iNKT cells closely resembling human iNKT cells. These hCD1d knock-in mice will allow more accurate in vivo modeling of human iNKT cell responses and will facilitate the preclinical assessment of iNKT cell-targeted antitumor therapies.     

Intrahepatic status of regulatory T cells in autoimmune liver diseases and chronic viral hepatitis.

Aim: Regulatory T cells (Tregs) maintain immunological tolerance and suppress autoreactive immune responses. We evaluated the intrahepatic status of Tregs in patients with autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), chronic hepatitis C (CH-C), or chronic hepatitis B (CH-B). Methods: We analyzed 85 patients (20 AIH, 22 PBC, 27 CH-C, and 16 CH-B) and 14 controls. Using liver tissue samples obtained by needle biopsy or from marginal parts of resected metastatic liver tumors in the controls, immunohistochemical analyses of forkhead box P3(+), which is a specific marker for Tregs, CD4(+), and CD8(+) cells were performed. Results: Intrahepatic Tregs were significantly more infiltrated in patients with liver diseases than in the controls. There were significantly fewer intrahepatic Tregs in the AIH patients than in the PBC patients (P = 0.037). Patients with alow frequency of intrahepatic Tregs were detected significantly more in the AIH and CH-B groups than in the PBC and CH-C groups (P < 0.05). In addition, the frequency of Tregs decreased in the liver of PBC patients as the pathological stage of the disease advanced. We found significantly less infiltration of CD4(+) T cells in AIH than in other diseases (P < 0.05). Liver-infiltrating CD8(+) T cells were detected more frequently in the CH-B group than in other groups (P < 0.003). Conclusion: Intrahepatic Tregs were increased in both patients with autoimmune liver diseases and those with viral hepatitis. In autoimmune liver diseases, intrahepatic Tregs were fewer in the AIH patients than in the PBC patients.     

Dysfunction of T cell receptor AV24AJ18+, BV11+ double-negative regulatory natural killer T cells in autoimmune diseases

OBJECTIVE: We examined the reduction of T cell receptor (TCR) AV24+,BV11+ CD4-,CD8- (double-negative [DN]) natural killer T (NKT) cells in peripheral blood lymphocytes (PBLs) from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and Sjogren's syndrome (SS) to analyze why NKT cells are selectively reduced in autoimmune diseases, and to examine whether nonresponse to alpha-galactosylceramide (alpha-GalCer) is due to an abnormality in the antigen-presenting cells (APCs) or NKT cells. METHODS: Peripheral blood from patients with RA (n = 20), SLE (n = 18), SSc (n = 13), and SS (n = 17), as well as from healthy donors (n = 13) and patients with Beh?et's disease (BD; n = 20), was examined by flow cytometry to determine the number of TCR AV24+,BV11+ DN T cells. PBLs from 10 RA, 10 SLE, 8 SSc, and 9 SS patients, as well as from 7 healthy subjects, were cultured in vitro with alpha-GalCer, and the number of TCR AV24+,BV11+ DN NKT cells was estimated. APCs from responder and nonresponder patients were cocultured with NKT cells from responder and nonresponder patients. RESULTS: The mean +/- SEM number of TCR AV24+,BV11+ DN NKT cells per ml of whole blood was found to be 48.8+/-10.0 in RA patients, 50.6+/-12.9 in SLE patients, 80.8+/-30.6 in SSc patients, and 40.0+/-11.7 in SS patients, while 290.0+/-69.6 and 321.2+/-103.4 NKT cells were present in healthy subjects and BD patients, respectively (P < 0.01). Three of 10 RA patients, 5 of 10 SLE patients, 4 of 8 SSc patients, and 6 of 9 SS patients (a total of 18 of 37 patients, or 48.6%) responded to alpha-GalCer, indicating that patients could be divided into two groups: alpha-GalCer responders and nonresponders. In contrast, NKT cells from all healthy subjects proliferated against alpha-GalCer. APCs from all nonresponder patients were found to function as alpha-GalCer-presenting cells, while NKT cells from nonresponders did not expand even in the presence of APCs from normal responders. CONCLUSION: These findings strongly suggest that patients with autoimmune diseases can be divided into two groups (alpha-GalCer responders and nonresponders). They also suggest that the reduced numbers of NKT cells in patients with autoimmune diseases may be due to an inadequate amount of alpha-GalCer-like natural ligands (i.e., adequate in only 48.6% of patients) for the induction of NKT cells in vivo, or to a dysfunction in the NKT cells themselves (in 51.4% of patients).     

Low expression levels of soluble CD1d gene in patients with rheumatoid arthritis

OBJECTIVE: To examine whether the expression of intact CD1d, a critical molecule for the presentation of glycolipid antigens to natural killer T (NKT) cells, and its variants differs between patients with autoimmune diseases including rheumatoid arthritis (RA) and healthy subjects. Recently, we identified 8 different CD1d variants, generated by alternative splicing. V1 lacking exon 4 (CD1d without beta2 microglobulin, beta2m) and V2 lacking exons 4 and 5 (soluble CD1d) may be functional molecules, because the antigen binding sites (exons 2 and 3) are intact. METHODS: Peripheral blood mononuclear cells (PBMC) from 44 patients with autoimmune disease (RA 19, systemic lupus erythematosus, SLE 10, Sj?gren's syndrome, SS 15) and 15 healthy controls were separated and complementary (c)DNA was prepared. The expression of intact CD1d on PBMC was detected by flow cytometry. Alternatively spliced CD1d variants were quantified by TaqMan PCR using polymerase chain reaction with confronting 2-pair primers (PCR-CTPP) based amplification. RESULTS: The mean (+/- SEM) transmembrane and beta2m binding site deleted CD1d mRNA level in 19 patients with RA (2.0 +/- 0.33) was significantly lower than in 15 controls (6.9 +/- 2.08; p < 0.05), whereas there were no differences in beta2m deleted variants and intact CD1d mRNA. CONCLUSION: Our findings suggest that low expression of soluble CD1d variants might play a role in the formation of symptoms or pathogenesis of RA.     

Liver-targeted and peripheral blood alterations of regulatory T cells in primary biliary cirrhosis

CD4+CD25high regulatory T cells (Tregs) play a critical role in self-tolerance, as seen in murine autoimmunity. Studies on Tregs in human autoimmunity have focused primarily on peripheral blood samples. A study targeting diseased tissue should identify direct relationships between Tregs and autoimmunity. Peripheral blood samples were collected from 91 patients with primary biliary cirrhosis (PBC), 28 immediate relatives, and 41 healthy controls, and Treg frequencies were determined as a percentage of CD4+CD25high T cells in CD4+TCR-alphabeta+ T cells. A tissue-targeted determination of frequency and distribution of FoxP3+ Tregs was also performed on 90 different liver tissue specimens exhibiting PBC (n = 52), chronic hepatitis C (CHC) (n = 30), and autoimmune hepatitis (AIH) (n = 8). Treg suppression studies were performed on 50 PBC patients and 27 controls. Patients with PBC demonstrated a relative reduction of Tregs compared with controls (P < .0002). Interestingly, a deficiency in CD4+CD25+ Tregs was also found in the daughters and sisters of PBC patients compared with controls (P < .0007). However, functional studies did not reveal a global PBC Treg defect. The level of FoxP3-expressing Tregs was markedly lower in affected PBC portal tracts compared with CHC and AIH (P < .001). In addition, the CD8+T cell/FoxP3+ Treg ratio was significantly higher in livers of late-stage PBC compared with those of CHC (P < .001) and early-stage AIH (P < .001). In conclusion, these data provide support for a genetic modulation of Treg frequency and illustrate the role Tregs play in the loss of tolerance in PBC.     

Changes in natural killer T cells subsets during therapy in type C hepatitis and hepatocellular carcinoma.

Natural killer T (NKT) cells share features of both classical T cells and NK cells. NKT are heterogenous populations, and recognize glycolipids associated with CD1d molecule. We investigated Th1/Th2 cytokine production as well as frequency and phenotype of circulating NKT cells in 14 healthy subjects and in patients during therapy with type C chronic hepatitis (CH; 14 cases) and hepatocellular carcinoma (HCC; 13 cases). Peripheral blood mononuclear cells (PBMC) were obtained before and 2 weeks later interferon (IFN)/ribavirin and radiofrequency ablation therapy for CH and HCC, respectively. PBMC were cultured for 10 days with alpha-galactosylceramide (alpha-GalCer) and interleukin-2 (IL-2). Frequencies and IFN-gamma/IL-4 production of NKT cells were analyzed using flow cytometry. Intrahepatic lymphocytes were analyzed in seven CH patients with liver biopsy specimen. Prevalence of circulating Valpha24+CD3+ T cells was 0.9+/-0.9% of PBMC for controls and increased to 8.5+/-8.9% (p<0.001) in response to alpha-GalCel. Similar frequency and expansion were noted in CH. The frequency increased during therapy. The prevalence in HCC tended to be high compared to controls and response to alpha-GalCel was well. Although frequency of Valpha24+Vbeta11+CD3+ T cells was low in all groups, the distribution pattern was similar to Valpha24+Vbeta11-CD3+ T cells. Prevalence of CD56+CD3+ T cells was low independent of therapy in CH (2-3%) compared to 5.0+/-4.0% of controls, although response to alpha-GalCel was not impaired. IFN-gamma production of Valpha24+CD3+ T cells did not differ among groups, but became greater after treatment in contrast to lowered IL-4 production. Frequencies of NKT populations were higher in liver than in peripheral blood. Our study suggests that CD1d-reactive T cells have distinct distribution in different populations and therapy for patients alters cytokine response of NKT cells.     

Sustained response to interferon-alpha plus ribavirin therapy for chronic hepatitis C is closely associated with increased dynamism of intrahepatic natural killer and natural killer T cells.

Aim: Previous studies have revealed that functional impairment of innate immune cells, including natural killer (NK) and natural killer T (NKT) cells, might be associated with the persistence of hepatitis C virus (HCV) infection. However, the involvement of innate immune cells, which predominate in the liver, in therapeutic HCV clearance is still unclear. Methods: To clarify the role of intrahepatic innate immune cells in the clinical outcome of patients with chronic hepatitis C (CHC) treated with interferon-alpha plus ribavirin (IFN/RBV), we prospectively investigated the status of NK and NKT cells in paired liver biopsy and peripheral blood (PB) samples obtained from 21 CHC patients before and immediately after IFN/RBV treatment by flow cytometry. Normal liver and PB samples were obtained from 10 healthy donors for living donor liver transplantation. Results: Before treatment, intrahepatic NK and NKT cells constituted a significantly lower proportion in CHC patients than in healthy individuals (P < 0.05). After IFN/RBV treatment, the proportions and absolute numbers of CD3(-)CD161(+) NK and CD3(+)CD56(+) NKT cells in the liver, but not in PB, were significantly increased in sustained responders (SR) as compared with poor responders (P < 0.05). The proportion of CD3(+)CD161(+) NKT cells was also increased in the liver of SR after the treatment. Moreover, there was a striking increase of activated CD152(+) cells among CD3(+)CD56(+) NKT cells in the liver of SR (P = 0.041). Conclusion: These findings demonstrate that sustained response to IFN/RBV treatment for patients with CHC is closely associated with increased dynamism of NK and NKT cells in the liver.     

Respiratory syncytial virus-specific CD8+ memory T cell responses in elderly persons

BACKGROUND: We investigated respiratory syncytial virus (RSV)-specific CD8(+) memory T cell responses in healthy control participants (n=31) and in patients with chronic obstructive pulmonary disease (COPD) (n=9), with respect to frequency, memory phenotype, and proliferative requirements. METHODS: The properties of RSV-specific CD8(+) T cells were analyzed by use of RSV tetramers. The proliferative requirements of RSV-specific CD8(+) T cells were analyzed by culture of peripheral-blood mononuclear cells with RSV peptide in combination with distinct cytokines. RESULTS: RSV-specific CD8(+) memory T cells showed a high level of expression of CD27 and interleukin-7R alpha and a low level of expression of CCR7. In the healthy participants, the frequency of RSV tetramer(+) CD8(+) T cells was significantly lower than the frequency of influenza virus A (FLU) tetramer(+) CD8(+) T cells (P=.0001). In contrast to FLU tetramer(+) CD8(+) T cells, we could detect RSV tetramer(+) CD8(+) T cells in the subgroup of elderly healthy participants (age, > or =55 years) and in the patients with COPD only after in vitro expansion. Expanded RSV-specific T cells produced interferon- gamma and granzyme B. CONCLUSION: We provide evidence that a pool of functional RSV-specific CD8(+) memory T cells persists in the peripheral blood of healthy individuals and patients with COPD. Low numbers of RSV-specific memory T cells in the elderly and in patients with COPD may explain the increased susceptibility to RSV infection in these populations.     

Phenotypic and genetic analyses of T-cell-mediated immunoregulation in patients with Type 1 diabetes.

AIMS: To investigate the contribution of regulatory T cells and co-stimulatory molecules in CD4(+) T cells to the development of Type 1 diabetes (T1D). METHODS: Twelve patients with T1D, nine patients with systemic lupus erythematosus (SLE), and 12 age-matched healthy control subjects participated. We analysed the proportions of CD25(+)CD4(+) T cells and natural killer T cells (NKT cells), and the expression levels of Foxp3, CTLA-4, CD28, ICOS, PD-1 and BTLA in peripheral blood mononuclear cells and purified CD4(+) T cells. RESULTS: There were no significant differences in the proportions of CD25(+) CD4(+) T cells or NKT cells among the three groups. PD-1 expression levels of peripheral CD4(+) T cells from T1D patients were significantly lower than those from healthy control subjects (P = 0.00066). In contrast, PD-1 expression levels were similar in SLE patients and healthy control subjects. The expression levels of Foxp3, CTLA-4, CD28, ICOS and BTLA were similar in the three groups. CONCLUSIONS: Decreased expression of the PD-1 gene in CD4(+) T cells may contribute to the development and/or maintenance of autoimmune T1D. As the population studied was small and heterogeneous, further studies are required to confirm the findings.     

原发性胆汁性肝硬化患者外周血NK细胞、CD4+T淋巴细胞和B细胞HLA-G受体表达分析及其临床意义

目的 研究3种人类白细胞抗G(human leukocyte antigen G,HLA-G)受体CD158d(KIR2DL4)、CD85j(ILT-2)和CD85d(ILT-4)在原发性胆汁性肝硬化(primary biliary cirrhosis,PBC)患者外周血自然杀伤细胞(natural killer ce...     

中国乙型肝炎患者外周血淋巴细胞亚群频率参考值范围

目的 调查中国乙型肝炎患者外周血淋巴细胞亚群频率参考值范围.方法 利用流式细胞术检测2846例乙型肝炎患者和117例健康人群外周血淋巴细胞亚群数值,调查我国健康人群和乙型肝炎人群的参考值范围.结果 调查了16～60岁健康人群和HBV感染相关的急性肝炎、慢性肝炎、重型肝炎和肝硬化人群外周血CD3+T淋巴细胞、CD3+CD...     

Association of the frequency of peripheral natural killer T cells with nonalcoholic fatty liver disease

AIM To investigate whether changes in the frequency of peripheral natural killer T (NKT) cells were correlated with liver disease in patients who had metabolic predispositions to nonalcoholic fatty liver disease (NAFLD).METHODS Peripheral blood samples were obtained from 60 Chinese NAFLD patients and 60 age and gender matched healthy controls. The frequency of peripheral NKT cells was detected by flow cytometry. Clinical and laboratory data were collected for further analysis.RESULTS NAFLD patients had a lower frequency of peripheral NKT cells than healthy controls (1.21% ± 0.06% vs 1.62% ± 0.07%, P ＜ 0.001). Further analysis revealed that the frequency of peripheral NKT cells was negatively correlated with body mass index, waist circumference and serum levels of alanine aminotransferase. Logistic regression analysis revealed that elevated body mass index [hazard ratio (HR)2.991], aspartate aminotransferase levels (HR 1.148)and fasting blood sugar (HR 3.133) increased the risk of NAFLD, whereas an elevated frequency of peripheral NKT cells (HR 0.107) decreased the risk.CONCLUSION Changes in the frequency of peripheral NKT cells were correlated with NAFLD and a decreased frequency of peripheral NKT cells was a risk factor for NAFLD.     

丙型肝炎病毒感染者外周血淋巴细胞亚群的变化及意义

目的调查丙型肝炎患者外周血淋巴细胞亚群变化及影响因素。方法利用流式细胞术检测241例丙型肝炎患者和117例健康人群外周血淋巴细胞亚群数值,通过回顾性分析,调查我国丙型肝炎人群淋巴细胞亚群变化及其相关的影响因素。结果在健康人群中,CD3＋CD4＋T细胞、CD3＋CD16＋CD56＋NKT细胞频率以及CD4/CD8比值与年龄呈显著正相关;而在慢性丙型肝炎人群中,CD3＋CD4＋T细胞与年龄呈显著正相关,CD3-CD19＋B细胞则与年龄呈显著负相关;在肝硬化人群中,只有CD3-CD16＋CD56＋NK细胞频率与年龄呈显著正相关;在15～49岁的健康人及慢性肝炎人群中,女性CD3＋CD4＋T细胞亚群频率高于男性,而在肝硬化患者中女性CD3-CD19＋B细胞频率低于男性;同时,在HCV感染的不同阶段,CD3-CD16＋CD56＋NK细胞亚群频率均较正常人显著降低,而CD3＋CD8＋T细胞频率则显著升高,在15岁以上人群,CD3-CD19＋B细胞在健康人、慢性肝炎、肝硬化人群中呈持续升高的现象。结论通过回顾性分析健康人群和HCV感染不同阶段人群淋巴细胞亚群的分布特点及其与HCV疾病进展、年龄、性别的关系,为临床科学评价丙型肝炎人群免疫状态提供重要的免疫指标。     

Decreased CD161+CD8+ T cells in the peripheral blood of patients suffering from rheumatic diseases

OBJECTIVES: Although it has been reported that the numbers of both CD4(-)CD8(-) and CD4(+) natural killer T (NKT) cells are selectively decreased in the peripheral blood of patients with rheumatic diseases, there have been no reports concerning a novel subpopulation of CD8(+) NKT cells. To examine whether CD161(+)CD8(+) T cells, which are closely related to CD8(+) NKT cells, are also decreased in patients with rheumatic diseases, we have investigated the expression of CD161, together with that of CD28, CD25 and CD62L, on T cells in the peripheral blood of these patients. METHODS: The rheumatic diseases evaluated in this study were systemic lupus erythematosus (SLE) (n= 54), mixed connective-tissue disease (MCTD) (n= 15), systemic sclerosis (SSc) (n= 14), polymyositis/dermatomyositis (PM/DM) (n= 13) and rheumatoid arthritis (RA) (n= 24). Healthy donors were examined as controls (n= 18). The expression of CD161, CD28, CD25 and CD62L on T cells was analysed by flow cytometry. RESULTS: Both the frequency of CD161 expression on CD8(+) cells and the absolute number of CD161(+)CD8(+) cells were significantly decreased in patients with SLE, MCTD, SSc and PM/DM. Only the absolute number of CD161(+)CD8(+) T cells was significantly decreased in RA. CD161 expression on CD28(-)CD8(+) T cells was significantly decreased in SLE, MCTD and SSc. The absolute number of CD161(+)CD8(+)CD62L(-) T cells was significantly decreased in SLE, MCTD and SSc. CONCLUSIONS: Both the frequency and the absolute number of CD161(+)CD8(+) T cells were decreased in the peripheral blood of patients suffering from SLE, MCTD, SSc and PM/DM. This result suggests that there is also an abnormality of NKT cells in the CD8(+) population.     

Activated virus-specific T cells are early indicators of anti-CMV immune reactions in liver transplant patients

BACKGROUND & AIMS: Cytomegalovirus (CMV) infection represents the most common infectious complication after liver transplantation. Because CMV-associated complications in liver transplantation patients are often liver-restricted and clinically unrecognized, diagnosis of early infection or reactivation is still very difficult. Because cytotoxic T cells (CTLs) are crucial for the immune control of CMV, analysis of virus-specific CTLs could contribute to diagnosis and management of CMV infection. METHODS: Major histocompatibility complex class I tetramers and intracellular cytokine staining were used to determine frequencies and phenotypes of peripheral blood CMV/pp65-specific CD8(+) T cells in HLA-A2, -B7, and -B35 positive liver transplantation patients and in healthy individuals. RESULTS: After liver transplantation (6-33 months after liver transplantation), frequencies of CMV-specific T cells were significantly elevated compared with healthy individuals. In contrast to immunoglobulin (Ig) M-negative patients and healthy blood donors, patients with increasing CMV IgM titers or IgG seroconversion had high percentages of activated (CD38(high)) CMV-specific T cells. In recently transplanted patients, activation of CMV-specific T cells was associated with increased transaminases and histopathological abnormalities in the absence of positive CMV-polymerase chain reaction results from peripheral blood. CONCLUSIONS: These data indicate that T-cell analysis based on MHC tetramer staining may be a valuable parameter in the early diagnosis of CMV-induced, liver-restricted complications after liver transplantation.