Regulatory T Cells in Autoimmune and Viral Chronic Hepatitis. J Immunol Res. 2015;2015:479703. [PMID: 26106627 PMCID: PMC4464004 DOI: 10.1155/2015/479703]

Qntrolling the LncRNA HULC-Tregs-PD-1 axis inhibits immune escape in the tumor microenvironment

Background

Immune escape remains a major challenge in the treatment of malignant tumors. Here, we studied the mechanisms underlying immune escape in the tumor microenvironment and identified a potential therapeutic target.

Methods

Pathological specimens from patients with liver cancer, soft tissue sarcoma, and liver metastasis of colon cancer were subjected to immunohistochemistry analysis to detect the expression of programmed death-1 (PD-1) in the tumor microenvironment (TME). Additionally, the expression of regulatory T cells (Tregs) and long non-coding RNAs (lncRNAs), such as highly upregulated in liver cancer (HULC) was evaluated by fluorescence in situ hybridization, and the relationship between HULC, Treg cells, and PD-1 was determined. The animals were divided into H22 hepatic carcinoma and S180 sarcoma groups. Each group was divided into Foxp3-/-C57BL/6J and C57BL/6J mice. Thereafter, mice were inoculated with 0.1 ml S180 sarcoma cells or 0.1 ml H22 hepatoma cells, at a concentration of 1 × 107/ml. The number of splenic CD4+CD25+Foxp3+ T cells was detected by flow cytometry, and serum interleukin-10 (IL-10) and transforming growth factor β1 (TGF-β1) levels were detected using a Luminex liquid suspension chip. Expression of PD-1, fork head box P3 (Foxp3), and HULC in the TME, were analyzed and the therapeutic effect of inhibiting the lncRNA HULC-Treg-PD-1 axis in malignant tumors was determined.

Results

High expression of lncRNA HULC promotes the proliferation of Treg cells and increases PD-1 expression in the tumor microenvironment. The HULC-Treg-PD-1 axis plays an immunosuppressive role and promotes the proliferation of malignant tumors. Knocking out the Foxp3 gene can affect the HULC-Treg-PD-1 axis and reduce PD-1, IL-10, and TGF-β1 expression to control the growth of malignant tumors.

Conclusion

The lncRNA HULC-Treg-PD-1 axis promotes the growth of malignant tumors. This axis could be modulated to reduce PD-1, IL-10, and TGF-β1 expression and the subsequent immune escape. The inhibition of immune escape in the tumor microenvironment can be achieved by controlling the LncRNA HULC-Treg-PD-1 axis.

Autoimmune hepatitis and primary sclerosing cholangitis after direct-acting antiviral treatment for hepatitis C virus: A case report

BACKGROUND

Chronic hepatitis C virus (HCV) infection is a major global health concern that leads to liver fibrosis, cirrhosis, and cancer. Regimens containing direct-acting antivirals (DAAs) have become the mainstay of HCV treatment, achieving a high sustained virological response (SVR) with minimal adverse events.

CASE SUMMARY

A 74-year-old woman with chronic HCV infection was treated with the DAAs ledipasvir, and sofosbuvir for 12 wk and achieved SVR. Twenty-four weeks after treatment completion, the liver enzyme and serum IgG levels increased, and antinuclear antibody became positive without HCV viremia, suggesting the development of autoimmune hepatitis (AIH). After liver biopsy indicated AIH, a definite AIH diagnosis was made and prednisolone was initiated. The treatment was effective, and the liver enzyme and serum IgG levels normalized. However, multiple strictures of the intrahepatic and extrahepatic bile ducts with dilatation of the peripheral bile ducts appeared on magnetic resonance cholangiopancreatography after 3 years of achieving SVR, which were consistent with primary sclerosing cholangitis.

CONCLUSION

The potential risk of developing autoimmune liver diseases after DAA treatment should be considered.

Circulating the HLA-DR+ T Cell Ratio Is a Prognostic Factor for Recurrence of Patients with Hepatocellular Carcinoma after Curative Surgery

Background

HLA-DR+ T cell, accounting for 1.2%-5.8% of peripheral lymphocyte, is a type of activated T lymphocyte. This retrospective study aimed to evaluate the prognostic value of HLA-DR+ T cell for progression-free survival (PFS) and overall survival (OS) in hepatocellular carcinoma (HCC) patients after curative surgery. Patients and Methods. Clinicopathological data of 192 patients who underwent curative resection for hepatocellular carcinoma in the affiliated hospital of Qingdao University between January 2013 and December 2021 were collected and analyzed. Statistical tests used in this study were the chi-square test and Fisher's exact test. The prognostic value of the HLA-DR+ T cell ratio was analyzed using univariate and multivariate Cox regression analyses. The Kaplan-Meier curves were drawn by the R programming language.

Results

HCC patients were divided into high (≥5.8%) and low (<5.8%) HLADR+ T cell ratio groups. Cox regression analysis indicated that a high HLA-DR+ T cell ratio was positively related to the PFS in HCC patients (P=0.003) and AFP-positive (≥20 ng/ml) HCC patients (P=0.020). HCC patients and AFP-positive HCC patients in the high HLA-DR+ T cell ratio group were prone to have a higher T cell ratio, a higher CD8+T cell ratio, and a lower B cell ratio than the low HLA-DR+ T cell ratio group. However, the HLA-DR+ T cell ratio was not a statistically significant predictor for OS in HCC patients (P=0.57) as well as PFS (P=0.088) and OS (P=0.63) in AFP-negative HCC patients.

Conclusions

This study confirmed that the HLA-DR+ T cell ratio was a significant predictor of PFS in HCC patients and AFP-positive HCC patients after curative surgery. This association may have guiding significance for the follow-up work of HCC patients after surgery.

AhR Activation Leads to Attenuation of Murine Autoimmune Hepatitis: Single-Cell RNA-Seq Analysis Reveals Unique Immune Cell Phenotypes and Gene Expression Changes in the Liver

The aryl hydrocarbon receptor (AhR) is a ubiquitously expressed ligand-activated transcription factor. While initially identified as an environmental sensor, this receptor has been shown more recently to regulate a variety of immune functions. AhR ligands vary in structure and source from environmental chemicals such as 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and indoles found in cruciferous vegetables to endogenous ligands derived from tryptophan metabolism. In the current study, we used TCDD, a high affinity AhR ligand to study the impact of AhR activation in the murine model of autoimmune hepatitis (AIH). Primarily, we used single-cell RNA-sequencing (scRNA-seq) technology to study the nature of changes occurring in the immune cells in the liver at the cellular and molecular level. We found that AhR activation attenuated concanavalin A (ConA)-induced AIH by limiting chemotaxis of pro-inflammatory immune cell subsets, promoting anti-inflammatory cytokine production, and suppressing pro-inflammatory cytokine production. scRNA-seq analysis showed some unusual events upon ConA injection such as increased presence of mature B cells, natural killer (NK) T cells, CD4+ or CD8+ T cells, Kupffer cells, memory CD8+ T cells, and activated T cells while TCDD treatment led to the reversal of most of these events. Additionally, the immune cells showed significant alterations in the gene expression profiles. Specifically, we observed downregulation of inflammation-associated genes including Ptma, Hspe1, and CD52 in TCDD-treated AIH mice as well as alterations in the expression of migratory markers such as CXCR2. Together, the current study characterizes the nature of inflammatory changes occurring in the liver during AIH, and sheds light on how AhR activation during AIH attenuates liver inflammation by inducing phenotypic and genotypic changes in immune cells found in the liver.

Activation of AMPKα1 is essential for regulatory T cell function and autoimmune liver disease prevention

Regulatory T cells (Treg cells) are crucial for maintaining immune tolerance. Compromising the regulatory function of Treg cells can lead to autoimmune liver disease. However, how Treg cell function is regulated has not been fully clarified. Here, we report that mice with AMP-activated protein kinase alpha 1 (AMPKα1) globally knocked out spontaneously develop immune-mediated liver injury, with massive lymphocyte infiltration in the liver, elevated serum alanine aminotransferase levels, and greater production of autoantibodies. Both transplantation of wild-type bone marrow and adoptive transfer of wild-type Treg cells can prevent liver injury in AMPKα1-KO mice. In addition, Treg cell-specific AMPKα1-KO mice display histological features similar to those associated with autoimmune liver disease, greater production of autoantibodies, and hyperactivation of CD4⁺ T cells. AMPKα1 deficiency significantly impairs Treg cell suppressive function but does not affect Treg cell differentiation or proliferation. Furthermore, AMPK is activated upon T cell receptor (TCR) stimulation, which triggers Foxp3 phosphorylation, suppressing Foxp3 ubiquitination and proteasomal degradation. Importantly, the frequency of Treg cells and the phosphorylation levels of AMPK at T172 in circulating blood are significantly lower in patients with autoimmune liver diseases. Conclusion: Our data suggest that AMPK maintains the immunosuppressive function of Treg cells and confers protection against autoimmune liver disease.

Hepatocellular carcinoma in viral and autoimmune liver diseases: Role of CD4+ CD25+ Foxp3+ regulatory T cells in the immune microenvironment

More than 90% of cases of hepatocellular carcinoma (HCC) occurs in patients with cirrhosis, of which hepatitis B virus and hepatitis C virus are the leading causes, while the tumor less frequently arises in autoimmune liver diseases. Advances in understanding tumor immunity have led to a major shift in the treatment of HCC, with the emergence of immunotherapy where therapeutic agents are used to target immune cells rather than cancer cells. Regulatory T cells (Tregs) are the most abundant suppressive cells in the tumor microenvironment and their presence has been correlated with tumor progression, invasiveness, as well as metastasis. Tregs are characterized by the expression of the transcription factor Foxp3 and various mechanisms ranging from cell-to-cell contact to secretion of inhibitory molecules have been implicated in their function. Notably, Tregs amply express checkpoint molecules such as cytotoxic T lymphocyte-associated antigen 4 and programmed cell-death 1 receptor and therefore represent a direct target of immune checkpoint inhibitor (ICI) immunotherapy. Taking into consideration the critical role of Tregs in maintenance of immune homeostasis as well as avoidance of autoimmunity, it is plausible that targeting of Tregs by ICI immunotherapy results in the development of immune-related adverse events (irAEs). Since the use of ICI becomes common in oncology, with an increasing number of new ICI currently under clinical trials for cancer treatment, the occurrence of irAEs is expected to dramatically rise. Herein, we review the current literature focusing on the role of Tregs in HCC evolution taking into account their opposite etiological function in viral and autoimmune chronic liver disease, and we discuss their involvement in irAEs due to the new immunotherapies.

Hepatocytes paradoxically affect intrahepatic IFN-γ production in autoimmune hepatitis due to Gal-9 expression and TLR2/4 ligand release

Hepatocytes are the targets in autoimmune hepatitis (AIH) that results in T cell-dependent liver injury. However, hepatocytes may also affect the hepatic T cells in AIH, but the underlying mechanisms are not fully understood. Here we report that hepatocytes could secrete galectin-9 (Gal-9) to suppress the intrahepatic production of Th1 cytokine IFN-γ and restrict AIH development, but hepatocyte damage resulted in opposite effects due to release of TLR2/4 ligands that promoted the intrahepatic production of IL-1β, IL-6, and IL-12. Through Tim-3, Gal-9 could efficiently suppress the intrahepatic T cell activation despite presence of TLR2/4 ligands, thus attenuating Th1 response in AIH. Intriguingly, intrahepatic IL-6/IL-12 suppressed the effect of TGF-β on Treg cells. Therefore, in AIH, Gal-9 promoted Foxp3 expression and function of hepatic Treg cells through TL1A signaling, although Treg function was still impaired, compared with that in naive state. Due to its promoting effect on Treg function, together with its effect on T effector cells in a Tim-3-independent way, Gal-9 could attenuate intrahepatic IFN-γ production by hindering the increase of hepatic CD4⁺CD43⁺ T cells resulting from extrahepatic T cell activation. TLR2/4 ligands attenuated the effects of Gal-9 on Treg cells and CD4⁺CD43⁺ T cells by increasing intrahepatic IL-6 and IL-12. Blocking TLR2/4 ligands could efficiently suppress intrahepatic IFN-γ production, liver injury, and hepatic fibrosis. These findings suggest that hepatocytes paradoxically affect Th1 response in AIH due to Gal-9 expression and TLR2/4 ligands release, and that targeting TLR2/4 signaling may provide an important approach in the therapeutic strategy for AIH.

Autoimmune phenomena in treated and naive pediatric patients with chronic viral hepatitis

Chronic viral hepatitis has been incriminated for inducing autoimmune events, but it is a known fact that interferon-based therapies also promote autoimmunity. We conducted an observational prospective study which included 114 pediatric patients with chronic viral hepatitis B and C. The patients were divided in 2 groups, the first group consisted of treatment-naive patients; the second group included patients who had received interferon-based therapy. We aimed to determine whether the ones who received treatment are more predisposed to developing autoimmune manifestations when compared to those naive. Fifty percent of the study group was found to have serological autoimmune phenomenon. Our research shows that the occurrence of the autoimmune phenomenon is delayed when the patient is treated with interferon-based regimens when compared to naive patients. Hence, even though interferon treatment has been reported to promote autoimmunity, the viruses themselves are more likely to induce the appearance of autoimmune markers over time in patients who do not receive treatment.

Chemical induced inflammation of the liver breaks tolerance and results in autoimmune hepatitis in Balb/c mice

Autoimmune hepatitis (AIH) is a chronic liver disease mediated by immunity, and could lead to liver fibrosis and hepatocellular carcinoma. However, the mechanisms for breaking hepatic tolerance and driving AIH still remain elusive. We herein reported that the non-specific liver inflammation triggered by carbon tetrachloride (CCl₄) recruited high numbers of CD4+T, CD8+T and B cells, and elevated the expression of proinflammaitory cytokines in Balb/c mice, further breaking liver tolerance and inducing autoimmune response, AIH inflammation and liver fibrosis in the presence of CYP2D6 antigen mimicry. In contrast, adenovirus infection could not break liver tolerance and induce AIH in Balb/c mice even in the presence of CYP2D6 antigen mimicry. These results suggested that genetic predisposition could determine liver tolerance in Balb/c mice. The chemical induced inflammation in the liver breaks tolerance and might be considered important for the initiation and development of AIH in Balb/c mice.

Genetic association between mannose-binding lectin polymorphisms and viral hepatitis: a meta-analysis

Some previous genetic association studies have tried to investigate potential associations between mannose-binding lectin (MBL) polymorphisms and viral hepatitis. However, the results of those studies were not consistent. Therefore, we performed the current meta-analysis to explore associations between MBL polymorphisms and viral hepatitis in a large pooled population. A systematic literature research of PubMed, Web of Science, Embase and CNKI was performed to identify eligible studies for pooled analyses. We used Review Manager version 5.3.3 to conduct statistical analyses. In total, 27 studies were included for analysis (4840 cases and 5729 controls). The pooled analyses showed that MBL promoter (-211C/G, dominant model: P = 0.0002, I2 = 40%; over-dominant model: P = 0.0001, I2 = 22%) and exon 1 (codon 52, 54 and 57, dominant model: P = 0.04, I2 = 49%; allele model: P = 0.01, I2 = 48%) polymorphisms were both significantly associated with viral hepatitis in the overall population. Further subgroup analyses revealed similarly significant findings for MBL promoter polymorphism in HBV and HCV, but no positive results were detected in subgroup analyses for MBL exon 1 polymorphism. These results suggested that MBL promoter and exon 1 polymorphisms could be used to identify individuals at higher susceptibility to HBV and HCV.

Development of Autoimmune Hepatitis during Direct-acting Antiviral Therapy for Chronic Hepatitis C Virus Infection

An 81-year-old woman developed liver dysfunction after two months' treatment with direct-acting antivirals (DAAs) for chronic hepatitis C virus (HCV) infection. She was positive for serum anti-nuclear antibody, with an elevated immunoglobulin G level. A liver biopsy revealed high-grade interface hepatitis and infiltrate of lymphocytes and plasma cells. DAA-associated drug-induced autoimmune hepatitis (DI-AIH) was considered. Her liver dysfunction improved after discontinuing DAA therapy and starting prednisolone treatment. The differential diagnosis for AIH should include liver injury during DAA therapy for chronic HCV infection.

TLR2/4 ligand-amplified liver inflammation promotes initiation of autoimmune hepatitis due to sustained IL-6/IL-12/IL-4/IL-25 expression

Autoimmune hepatitis (AIH), a serious autoimmune liver disease, can be a lifelong illness, leading to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). So far the mechanisms for disease initiation are largely unknown. Here we report that the amplified non-AIH liver inflammation could promote the initiation of AIH due to the sustained increase of IL-6, IL-12, IL-4, and IL-25 in the liver. The liver injury resulting from virus (adenovirus) or chemicals (CCl₄) could induce an amplified (stronger/long-lasting) hepatic inflammation by releasing the ligands for TLR2/TLR4. The amplified inflammation resulted in the increase of multiple cytokines and chemokines in the liver. Among them, the sustained increase of IL-6/IL-12 resulted in the activation of STAT3 and STAT4 in hepatic CD4⁺CD25⁺ Treg cells, thus suppressing Foxp3 gene expression to reduce the suppressive function of Treg cells in the liver, but not those in the spleen. The increase of IL-12 and the impairment of Treg function promoted Th1 response in presence of self-mimicking antigen (human CYP2D6). Intriguingly, the amplified inflammation resulted in the increase of IL-4 and IL-25 in the liver. The moderate increase of IL-4 was sufficient for cooperating with IL-25 to initiate Th2 response, but inefficient in suppressing Th1 response, favoring the initiation of autoimmune response. Consequently, either adenovirus/CYP2D6 or CCl₄/CYP2D6 could induce the autoimmune response and AIH in the mice, leading to hepatic fibrosis. The findings in this study suggest that the amplified non-AIH inflammation in the liver could be a driving force for the initiation of autoimmune response and AIH.

Polymorphisms in TIM-3 and breast cancer susceptibility in Chinese women: A case-control study

Previous studies have found associations between polymorphisms in T cell immunoglobulin and mucin domain 3 (TIM-3) and increased risks of various cancers. However, the association between TIM-3 polymorphisms and breast cancer (BC) remains uncertain. In this study, a total of 560 BC patients and 583 age, sex, and ethnicity-matched healthy controls from Northwest China were included. The polymorphisms were genotyped using Sequenom MassARRAY. The expression level of TIM-3 protein was detected by immunohistochemistry. We observed rs10053538 had a significantly increased risk of BC, comparing with the wild-type genotype even after Bonferroni correction. In addition, the rs4704853 G>A variants were more frequent among BC patients than the controls (GA + AA vs. GG: OR = 1.32, 95% CI = 1.03-1.69, P = 0.026); However, the significance was lost after Bonferroni correction (P = 0.078). Furthermore, rs10053538 was associated with lymph node metastasis. Age stratification revealed that among patients aged <49 years, those with the rs4704853 GA/AA genotype had a higher risk of BC; But there was no difference when Bonferroni correction was conducted. Immunohistochemical analysis showed that the expression of TIM-3 protein in the breast cancer tissues was higher in patients carrying the rs10053538 GT+TT genotype than those with GG genotype (P = 0.012). However, we failed to find any difference between BC patients and controls in any rs1036199 genetic model. These findings suggested that rs10053538 in TIM-3 might increase susceptibility to BC and promote the progression of BC in Chinese women.

[Autoimmune hepatitis: Immunological diagnosis]

Autoimmune hepatopathies (AIHT) including autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune cholangitis (AIC), represent an impressive entities in clinical practice. Their pathogenesis is not perfectly elucidated. Several factors are involved in the initiation of hepatic autoimmune and inflammatory phenomena such as genetic predisposition, molecular mimicry and/or abnormalities of T-regulatory lymphocytes. AIHT have a wide spectrum of presentation, ranging from asymptomatic forms to severe acute liver failure. The diagnosis of AIHT is based on the presence of hyperglobulinemia, cytolysis, cholestasis, typical even specific circulating auto-antibodies, distinctive of AIH or PBC, and histological abnormalities as well as necrosis and inflammation. Anti-F actin, anti-LKM1, anti-LC1 antibodies permit to distinguish between AIH type 1 and AIH type 2. Anti-SLA/LP antibodies are rather associated to more severe hepatitis, and particularly useful for the diagnosis of seronegative AIH for other the antibodies. Due to the relevant diagnostic value of anti-M2, anti-Sp100, and anti-gp210 antibodies, the diagnosis of PBC is more affordable than that of PSC and AIC. Based on clinical data, the immunological diagnosis of AIHT takes advantage of the various specialized laboratory techniques including immunofluorescence, immunodot or blot, and the Elisa systems, provided of a closer collaboration between the biologist and the physician.

Role of regulatory T cells in acute myeloid leukemia patients undergoing relapse-preventive immunotherapy

Regulatory T cells (T_regs) have been proposed to dampen functions of anti-neoplastic immune cells and thus promote cancer progression. In a phase IV trial (Re:Mission Trial, NCT01347996, http://www.clinicaltrials.gov) 84 patients (age 18–79) with acute myeloid leukemia (AML) in first complete remission (CR) received ten consecutive 3-week cycles of immunotherapy with histamine dihydrochloride (HDC) and low-dose interleukin-2 (IL-2) to prevent relapse of leukemia in the post-consolidation phase. This study aimed at defining the features, function and dynamics of Foxp3⁺CD25^highCD4⁺ T_regs during immunotherapy and to determine the potential impact of T_regs on relapse risk and survival. We observed a pronounced increase in T_reg counts in peripheral blood during initial cycles of HDC/IL-2. The accumulating T_regs resembled thymic-derived natural T_regs (nT_regs), showed augmented expression of CTLA-4 and suppressed the cell cycle proliferation of conventional T cells ex vivo. Relapse of AML was not prognosticated by T_reg counts at onset of treatment or after the first cycle of immunotherapy. However, the magnitude of T_reg induction was diminished in subsequent treatment cycles. Exploratory analyses implied that a reduced expansion of T_regs in later treatment cycles and a short T_reg telomere length were significantly associated with a favorable clinical outcome. Our results suggest that immunotherapy with HDC/IL-2 in AML entails induction of immunosuppressive T_regs that may be targeted for improved anti-leukemic efficiency.

Thymic NF-κB-inducing kinase regulates CD4+ T cell-elicited liver injury and fibrosis in mice

BACKGROUND & AIMS

The liver is an immunologically-privileged organ. Breakdown of liver immune privilege has been reported in chronic liver disease; however, the role of adaptive immunity in liver injury is poorly defined. Nuclear factor-κB-inducing kinase (NIK) is known to regulate immune tissue development, but its role in maintaining liver homeostasis remains unknown. This study aimed to assess the role of NIK, particularly thymic NIK, in regulating liver adaptive immunity.

METHODS

NIK was deleted systemically or conditionally using the Cre/loxp system. Cluster of differentiation [CD]4+ or CD8+ T cells were depleted using anti-CD4 or anti-CD8 antibody. Donor bone marrows or thymi were transferred into recipient mice. Immune cells were assessed by immunohistochemistry and flow cytometry.

RESULTS

Global, but not liver-specific or hematopoietic lineage cell-specific, deletion of NIK induced fatal liver injury, inflammation, and fibrosis. Likewise, adoptive transfer of NIK-null, but not wild-type, thymi into immune-deficient mice induced liver inflammation, injury, and fibrosis in recipients. Liver inflammation was characterized by a massive expansion of T cells, particularly the CD4+ T cell subpopulation. Depletion of CD4+, but not CD8+, T cells fully protected against liver injury, inflammation, and fibrosis in NIK-null mice. NIK deficiency also resulted in inflammation in the lung, kidney, and pancreas, but to a lesser degree relative to the liver.

CONCLUSIONS

Thymic NIK suppresses development of autoreactive T cells against liver antigens, and NIK deficiency in the thymus results in CD4+ T cell-orchestrated autoimmune hepatitis and liver fibrosis. Thus, thymic NIK is essential for the maintenance of liver immune privilege and liver homeostasis.

LAY SUMMARY

We found that global or thymus-specific ablation of the NIK gene results in fatal autoimmune liver disease in mice. NIK-deficient mice develop liver inflammation, injury, and fibrosis. Our findings indicate that thymic NIK is essential for the maintenance of liver integrity and homeostasis.

Immune Regulation of Intrahepatic Regulatory T Cells in Fibrotic Livers of Mice

Background

Liver fibrosis is the result of chronic inflammation and repair, and many immune cells contribute to the process. Regulatory T cells (Tregs) mediate immune tolerance and are highly expressed in liver fibrosis. However, few reports have studied the specific effects of Tregs on regulating immune cells in liver fibrosis. The present study aimed to investigate the regulation of Tregs on intrahepatic immune cells in liver fibrosis by depleting Tregs in mice.

Material/Methods

Liver fibrosis was induced by carbon tetrachloride, and an anti-CD25 mAb (PC61) was used to deplete Tregs. Liver fibrosis and injury were reflected by immunofluorescence staining and alanine aminotransferase level. The expressions of immune cell Tregs and cytokines were detected by flow cytometry and/or real-time PCR. Interferon-γ (IFN-γ) concentration was measured by ELISA.

Results

Tregs were rich in fibrotic livers; after Tregs depletion, the intrahepatic CD4⁺ T cell and Kupffer cells (KC) populations did not change compared with liver fibrosis, but CD8⁺ T cells were slightly elevated. However, natural killer (NK) cells and IFN-γ levels were significantly decreased in fibrosis and increased after Tregs depletion. Interesting, we found Tregs promoted KC M1/M2 balance to M2, because inducible nitric oxide synthase (M1) was increased but arginase-1 (M2) was reduced after depleting Tregs. Furthermore, in isolated KCs from livers, IL-12 (M1) was increased, but TGF-β (M2) was reduced after depleting Tregs, compared with fibrotic livers.

Conclusions

Tregs are involved in the immune regulation of liver fibrosis, primarily by suppressing NK cells and M1 KCs, and mildly suppressing CD8⁺ T cells.

Transplantation Tolerance Induction: Cell Therapies and Their Mechanisms

Cell-based therapies have been studied extensively in the context of transplantation tolerance induction. The most successful protocols have relied on transfusion of bone marrow prior to the transplantation of a renal allograft. However, it is not clear that stem cells found in bone marrow are required in order to render a transplant candidate immunologically tolerant. Accordingly, mesenchymal stem cells, regulatory myeloid cells, T regulatory cells, and other cell types are being tested as possible routes to tolerance induction, in the absence of donor-derived stem cells. Early data with each of these cell types have been encouraging. However, the induction regimen capable of achieving consistent tolerance, while avoiding unwanted sided effects, and which is scalable to the human patient, has yet to be identified. Here, we present the status of investigations of various tolerogenic cell types and the mechanistic rationale for their use in tolerance induction protocols.

Understanding autoimmunity: The ion channel perspective

Ion channels are integral membrane proteins that orchestrate the passage of ions across the cell membrane and thus regulate various key physiological processes of the living system. The stringently regulated expression and function of these channels hold a pivotal role in the development and execution of various cellular functions. Malfunction of these channels results in debilitating diseases collectively termed channelopathies. In this review, we highlight the role of these proteins in the immune system with special emphasis on the development of autoimmunity. The role of ion channels in various autoimmune diseases is also listed out. This comprehensive review summarizes the ion channels that could be used as molecular targets in the development of new therapeutics against autoimmune disorders.

Aggravation of Helicobacter pylori stomach infections in stressed military recruits

Objective

To investigate the effect of military stress on immune response and Helicobacter pylori stomach infections.

Methods

In this prospective, observational study, the Symptom Checklist-90 questionnaire was completed by military recruits before and following a 3-month basic training programme. H. pylori immunoglobulin (Ig)G levels, C¹⁴-urea breath-test values and levels of cortisol, catecholamine, and certain humoral and cellular immune responses were measured before and after the basic training.

Results

For 60 military recruits, somatization, depression and paranoid ideation scores were significantly increased after, compared with before, basic training. Post-training H. pylori IgG detection revealed three additional cases of H. pylori infection. Post-training C¹⁴-urea breath-test values were significantly higher compared with before training – thus suggesting higher levels of H. pylori colonization in the stomach. Post-training cortisol and catecholamine levels were increased, while serum IgG levels were decreased; complement component (C)3 and C4 levels remained unchanged. Post-training CD4⁺ and CD8⁺ T-cell percentages and the CD4⁺/CD8⁺ ratio were significantly reduced compared with before training. Serum interleukin (IL)-2 levels were lower and IL-10 levels were higher following training and there was a significant decrease in the IL-2/IL-10 ratio.

Conclusion

Military stress may reduce humoral and cellular immune responses and may aggravate the severity of H. pylori infection.