A case of a solitary Mycobacterium avium complex lesion of the liver.

A 70-year-old woman was admitted to our hospital on suspicion of liver tumor on regular abdominal ultrasonography. The abdominal ultrasonography identified a solitary, low-echoic lesion measuring 17mm in diameter in S7. This lesion was not enhanced in any phase of contrast-enhanced computed tomography (CT), and thus we performed a liver biopsy. Histopathological examination revealed a caseating granuloma. The chest CT showed pulmonary nodules, and Mycobacterium intracellulare was cultured from the bronchoalveolar lavage fluid. We diagnosed the individual with a Mycobacterium avium complex infection, and suspected that this was the cause of the solitary liver lesion.

TIE2-expressing monocytes as a diagnostic marker for hepatocellular carcinoma correlates with angiogenesis.

UNLABELLED: Angiogenesis is a critical step in the development and progression of hepatocellular carcinoma (HCC). Myeloid lineage cells, such as macrophages and monocytes, have been reported to regulate angiogenesis in mouse tumor models. TIE2, a receptor of angiopoietins, conveys pro-angiogenic signals and identifies a monocyte/macrophage subset with pro-angiogenic activity. Here, we analyzed the occurrence and kinetics of TIE2-expressing monocytes/macrophages (TEMs) in HCC patients. This study enrolled 168 HCV-infected patients including 89 with HCC. We examined the frequency of TEMs, as defined as CD14+CD16+TIE2+ cells, in the peripheral blood and liver. The localization of TEMs in the liver was determined by immunofluorescence staining. Micro-vessel density in the liver was measured by counting CD34+ vascular structures. We found that the frequency of circulating TEMs was significantly higher in HCC than non-HCC patients, while being higher in the liver than in the blood. In patients who underwent local radio-ablation or resection of HCC, the frequency of TEMs dynamically changed in the blood in parallel with HCC recurrence. Most TEMs were identified in the perivascular areas of tumor tissue. A significant positive correlation was observed between micro-vessel density in HCC and frequency of TEMs in the blood or tumors, suggesting that TEMs are involved in HCC angiogenesis. Receiver operating characteristic analyses revealed the superiority of TEM frequency to AFP, PIVKA-II and ANG-2 serum levels as diagnostic marker for HCC. CONCLUSION: TEMs increase in patients with HCC and their frequency changes with the therapeutic response or recurrence. We thus suggest that TEM frequency can be used as a diagnostic marker for HCC, potentially reflecting angiogenesis in the liver.

Association of enhanced activity of indoleamine 2,3-dioxygenase in dendritic cells with the induction of regulatory T cells in chronic hepatitis C infection.

BACKGROUND: Altered functions of dendritic cells (DCs) and/or increases of regulatory T cells (Tregs) are involved in the pathogenesis of chronic hepatitis C virus (HCV) infection. A tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase (IDO), is reported to be an inducer of immune tolerance. Our aim was to clarify whether or not IDO is activated in chronic hepatitis C patients and its role in immune responses. METHODS: This study enrolled 176 patients with chronic HCV infection and 37 healthy volunteers. Serum kynurenine concentration was evaluated by high-performance liquid chromatography, and its correlation with clinical parameters was examined. Monocyte-derived DCs were prepared from the subjects and subsequently stimulated with a combination of lipopolysaccharide and interferon-gamma to induce functional IDO (defined as IDO-DCs). The phenotypes, kynurenine or cytokine production, and T-cell responses with IDO-DCs were compared between the patients and healthy volunteers. RESULTS: The serum kynurenine level in the patients was significantly higher than that in the healthy volunteers, and the level of serum kynurenine was positively correlated with the histological activity or fibrosis score. IDO activity in IDO-DCs from the patients was significantly higher than that in IDO-DCs from the volunteers. Furthermore, IDO-DCs from the patients induced more Tregs in vitro compared with those from the volunteers, and the frequency of induced Tregs by IDO-DCs was decreased with an IDO-specific inhibitor. CONCLUSIONS: Systemic IDO activity is enhanced in chronic hepatitis C patients in correlation with the degree of liver inflammation and fibrosis. In response to inflammatory stimuli, DCs from the patients tend to induce Tregs, with some of this action being dependent on IDO.

Human blood dendritic cell antigen 3 (BDCA3)(+) dendritic cells are a potent producer of interferon-λ in response to hepatitis C virus.

UNLABELLED: The polymorphisms in the interleukin (IL)-28B (interferon-lambda [IFN]-λ3) gene are strongly associated with the efficacy of hepatitis C virus (HCV) clearance. Dendritic cells (DCs) sense HCV and produce IFNs, thereby playing some cooperative roles with HCV-infected hepatocytes in the induction of interferon-stimulated genes (ISGs). Blood dendritic cell antigen 3 (BDCA3)(+) DCs were discovered as a producer of IFN-λ upon Toll-like receptor 3 (TLR3) stimulation. We thus aimed to clarify the roles of BDCA3(+) DCs in anti-HCV innate immunity. Seventy healthy subjects and 20 patients with liver tumors were enrolled. BDCA3(+) DCs, in comparison with plasmacytoid DCs and myeloid DCs, were stimulated with TLR agonists, cell-cultured HCV (HCVcc), or Huh7.5.1 cells transfected with HCV/JFH-1. BDCA3(+) DCs were treated with anti-CD81 antibody, inhibitors of endosome acidification, TIR-domain-containing adapter-inducing interferon-ß (TRIF)-specific inhibitor, or ultraviolet-irradiated HCVcc. The amounts of IL-29/IFN-λ1, IL-28A/IFN-λ2, and IL-28B were quantified by subtype-specific enzyme-linked immunosorbent assay (ELISA). The frequency of BDCA3(+) DCs in peripheral blood mononuclear cell (PBMC) was extremely low but higher in the liver. BDCA3(+) DCs recovered from PBMC or the liver released large amounts of IFN-λs, when stimulated with HCVcc or HCV-transfected Huh7.5.1. BDCA3(+) DCs were able to induce ISGs in the coexisting JFH-1-positive Huh7.5.1 cells. The treatments of BDCA3(+) DCs with anti-CD81 antibody, cloroquine, or bafilomycin A1 reduced HCVcc-induced IL-28B release, whereas BDCA3(+) DCs comparably produced IL-28B upon replication-defective HCVcc. The TRIF-specific inhibitor reduced IL-28B release from HCVcc-stimulated BDCA3(+) DCs. In response to HCVcc or JFH-1-Huh7.5.1, BDCA3(+) DCs in healthy subjects with IL-28B major (rs8099917, TT) released more IL-28B than those with IL-28B minor genotype (TG). CONCLUSION: Human BDCA3(+) DCs, having a tendency to accumulate in the liver, recognize HCV in a CD81-, endosome-, and TRIF-dependent manner and produce substantial amounts of IL-28B/IFN-λ3, the ability of which is superior in subjects with IL-28B major genotype.

Comparative analyses of regulatory T cell subsets in patients with hepatocellular carcinoma: a crucial role of CD25(-) FOXP3(-) T cells.

Regulatory T cells (Tregs) play pivotal role in cancer-induced immunoediting. Increment of CD25(high+) FOXP3+ natural Tregs has been reported in patients with hepatocellular carcinoma (HCC); however, the involvement of other type of Tregs remain elusive. We aimed to clarify whether FOXP3- Tregs are increased and functionally suppressive or not in patients with HCC. We enrolled 184 hepatitis C-infected patients with chronic liver diseases or HCC, 57 healthy subjects and 27 HCC patients with other etiology. Distinct Treg subsets were phenotypically identified by the expression of CD4, CD25, CD127 and forkhead/winged helix transcription factor (FOXP3). Their gene profiles, frequency and suppressor functions against T cell proliferation were compared among the subjects. To examine the molecules involving in Treg differentiation, we cultured naive CD4+ T cells in the presence of HCC cells and dendritic cells. We determined two types of CD4+ CD127- T cells with comparable regulatory ability; one is CD25(high+) cells expressing FOXP3 (CD25(high+) FOXP3+ Tregs) and the other is CD25- cells without FOXP3- expression (CD25- FOXP3- cells). The peripheral or intrahepatic frequency of CD25- FOXP3- Tregs in HCC patients is higher than those in other groups, of which significance is more than CD25(high+) FOXP3+ cells. Of importance, CD25- FOXP3- Tregs, but not CD25(high+) FOXP3+ cells, dynamically change in patients accompanied by the ablation or the recurrence of HCC. CD25- FOXP3- T cells with CD127- IL-10+ phenoype are inducible in vitro from naive CD4(+) T cells, in which programmed cell death 1 ligand 1, immunoglobulin-like transcript 4 and human leukocyte antigen G are involved.. In conclusion, CD25- FOXP3- Tregs with suppressive capacity are increased in patients with HCC, suggesting their distinct roles from CD25+ FOXP3+ Tregs.

Dynamics of regulatory T cells and plasmacytoid dendritic cells as immune markers for virological response in pegylated interferon-α and ribavirin therapy for chronic hepatitis C patients.

BACKGROUND: For the treatment of chronic hepatitis C, a combination of pegylated interferon-α (PEG-IFNα) and ribavirin has been widely used as a standard of care. Enhancement of immune response against hepatitis C virus (HCV) is known to be involved in the efficacy of the combination therapy. Our aim was to elucidate whether or not the frequency or function of blood cells is related to the outcome of the therapy. METHODS: Sixty-seven chronic hepatitis C patients with high viral load of HCV genotype 1 infection who underwent 48 weeks of PEG-IFNα2b and ribavirin therapy were examined. During the treatment, frequencies of myeloid or plasmacytoid dendritic cells, Th1, Th2 cells, NK cells, and regulatory T cells were phenotypically determined. RESULTS: Among the patients enrolled, 29 showed a sustained virological response (SVR), 18 a transient response (TR) and 17 no response (NR). The clinical and immunological markers were compared between the SVR and non-SVR patients, including TR and NR. Based on clinical, histological, immunological parameters, and cumulative dosage of PEG-IFNα2b and ribavirin, multivariate analyses revealed that higher platelet counts and higher regulatory T cell frequency at week 12 are indicative of SVR. Even in patients who attained complete early virological response at week 12, multivariate analyses disclosed that higher platelet counts and higher plasmacytoid dendritic cell frequency are indicative of SVR. CONCLUSIONS: In PEG-IFNα and ribavirin combination therapy for chronic hepatitis C patients, the increments of regulatory T cells and plasmacytoid dendritic cell frequency are independently related to favorable virological response to the therapy.

Comprehensive immunological analyses of colorectal cancer patients in the phase I/II study of quickly matured dendritic cell vaccine pulsed with carcinoembryonic antigen peptide.

Dendritic cell (DC) vaccine has been used to treat patients with advanced colorectal cancer (CRC). The results of vaccine-induced clinical responses have not always been satisfactory partially because of DC incompetence. In order to evaluate the feasibility of novel mature DCs for therapeutic adjuvants against CRC, we conducted clinical trials with carcinoembryonic antigen (CEA) peptide-loaded DC quickly generated with a combination of OK432 (Streptococcuspyogenes preparation), prostanoid, and interferon-α (OPA-DC). In the ten patients enrolled in this study, the OPA-DC vaccine was well tolerated and administered four times every 2 weeks except for two patients, who were switched to other treatments due to disease progression. Among the eight evaluable patients, one displayed stable disease (SD), while the remaining seven showed progressive disease (PD). In the SD patient, natural killer (NK) cell frequency and cytolytic activity were increased. In the same patient, the frequency of CEA-specific cytotoxic T cells (CTLs) increased stepwise with repetitive vaccinations; however, most of the CTLs exhibited central memory phenotype. In those with PD, NK cells proliferated well regardless of failure of response, whereas CTLs failed to do so. We concluded that the OPA-DC vaccine is well tolerated and has immune-stimulatory capacity in patients with CRC. Additional modulation is needed to attain significant clinical impact.