Increased regulatory T cells in patients with liver cirrhosis correlated with hyperbilirubinemia and predict bacterial complications

Bacteremia (Sepsis), Hepatorenal Syndrome, and Serum Creatinine Levels Rather than Types or Microbial Patterns Predicted the Short-Term Survival of Cirrhotic Patients Complicated with Spontaneous Bacterial Peritonitis

(1) Background: Spontaneous bacterial peritonitis (SBP) is a major and severe complication in cirrhosis patients with ascites. Over the years, advance in antibiotic treatment has led to changes in microbial patterns in some regions, including the emergence of extended-spectrum beta-lactamases resistant (ESBL)-producing bacteria and an increase in Gram-positive bacteria (GPC). In addition, three SBP types (classic SBP, culture-negative neutrophilic ascites (CNNA), and monomicrobial non-neutrocytic bacterascites (MNB)), may also have different prognoses. Therefore, the study aimed to investigate the microbial pattern and the predictors of short-term outcomes in patients with SBP. (2) Methods: Patients discharged with a diagnosis of the first episode of SBP between January 2006 and July 2017 were enrolled. Patients' clinical, demographic, hematological, and biochemical data were obtained at diagnosis, and the model for end-stage liver disease (MELD)-based scores were calculated accordingly. Patients were followed up until February 2018 or until death. (3) Results: A total of 327 patients were analyzed. The prevalence of classic SBP was nearly equivalent to CNNA. As for the microbial pattern, Gram-negative bacillus (GNB) remained more prevalent than GPC (75 vs. 25%), with E. coli being the most common bacterial species, followed by K. Pneumoniae and then Staphylococcus. The percentage of ESBL strain in culture-positive patients was 10.9%. By univariable and multivariable logistic regression survival analysis, there was no significant difference in predicting short-term mortality among the three SBP types, neither between GNB vs. GPC nor between ESBL- and non-ESBL-producing bacteria. Only bacteremia (sepsis), hepatorenal syndrome (HRS), and serum creatinine (Cr) were independent predictors of in-hospital and 3-month mortality, whereas HRS and Cr were independent predictors of 6-month mortality. (4) Conclusions: SBP types, Gram stain result, and ESBL strain did not affect survival. Only bacteremia (sepsis), HRS, and serum Cr independently predicted the short-term mortality in patients with SBP.

Implications and Management of Cirrhosis-Associated Immune Dysfunction Before and After Liver Transplantation

Cirrhosis-associated immune dysfunction (CAID) describes a panacea of innate and adaptive deficits that result from the sequelae of cirrhotic portal hypertension that is similar in its manifestations regardless of etiology of chronic liver injury. CAID is associated with synchronous observations of dysregulated priming of innate immune effector cells that demonstrate a proinflammatory phenotype but are functionally impaired and unable to adequately prevent invading pathogens. CAID is mainly driven by gut-barrier dysfunction and is associated with deficits of microbial compartmentalization and homeostasis that lead to tonic activation, systemic inflammation, and exhaustion of innate-immune cells. CAID leads to a high frequency of bacterial and fungal infections in patients with cirrhosis that are often associated with acute decompensation of chronic liver disease and acute-on-chronic liver failure and carry a high mortality rate. Understanding the deficits of mucosal and systemic immunity in the context of chronic liver disease is essential to improving care for patients with cirrhosis, preventing precipitants of acute decompensation of cirrhosis, and improving morbidity and survival. In this review, we summarize the detailed dynamic immunological perturbations associated with advanced chronic liver disease and highlight the importance of recognizing immune dysregulation as a sequela of cirrhosis. Furthermore, we address the role of screening, prevention, and early treatment of infections in cirrhosis in improving patient outcomes in transplant and nontransplant settings.

Promising diagnostic biomarkers of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: From clinical proteomics to microbiome

Fatty liver has been present in the lives of patients and physicians for almost two centuries. Vast knowledge has been generated regarding its etiology and consequences, although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is still envisioned. On the one hand, proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis. In contrast, metabolomics has been able to distinguish between NAFLD and NASH, even detecting degrees of fibrosis. On the other hand, genetic and epigenetic markers have been useful in monitoring disease progression, eventually functioning as target therapies. Other markers involved in immune dysregulation, oxidative stress, and inflammation are involved in the instauration and evolution of the disease. Finally, the fascinating gut microbiome is significantly involved in NAFLD and NASH. This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease. As is evident, despite great advances in studying these biomarkers, there is still a long path before they translate into clinical benefits.

Treg cells in the course of chronic hepatitis C virus infection partially normalize in longitudinal observation after successful DAA treatment regardless of hepatic fibrosis stage

AIM OF THE STUDY

Elevated circulating CD4+ CD25+ Foxp3+ regulatory T cells in patients with chronic hepatitis C (CHC) play an unspecified role in liver fibrosis development. This study aimed to determine whether Treg cells diminish after successful treatment with directacting antivirals (DAA) in patients at different liver fibrosis stages.

MATERIAL AND METHODS

We examined 44 patients with CHC (including 29 with liver cirrhosis) seven days before DAA treatment (T0), six months later (T1) and then 22 of them were examined one year (T2) after the first dose. Subsequently, these were compared with 28 volunteers without hepatitis C virus (HCV) (15 with excessive alcohol intake). We assessed the degree of liver fibrosis with FibroScan, aspartate transaminase (AST) to platelet ratio index (APRI), FibroIndex, the Forns index and Fib-4. Circulating Treg cells were measured using flow cytometry.

RESULTS

All patients achieved a sustained virological response (SVR). After the treatment, all liver fibrosis indicators decreased significantly. The number of circulating Tregs was lower in healthy controls than in patients with CHC (0.0066 × 103 cells/µl and 0.0084 × 103 cells/µl, respectively, p = 0.048). After the treatment we observed an insignificant change to 0.0047 × 103 cells/µl for T1 (p > 0.05) and a significant fall to 0.0041 × 103 cells/µl for T2 (p = 0.03). There was no correlation between the degree of hepatic fibrosis and number of Tregs or post-treatment dynamics.

CONCLUSIONS

Our study shows that Treg cells normalize gradually over a prolonged period of time after a successful DAA treatment. Their number and dynamics remain independent of liver fibrosis degree. The correlation of this revelation with metabolic disorders, increased susceptibility to infections or persistent risk of HCC remains unclear.

Mucosal-Associated Invariant T Cell Dysregulation Correlates With Conjugated Bilirubin Level in Chronic HBV Infection

BACKGROUND AND AIMS

Mucosal-associated invariant T (MAIT) cells are nonconventional T cells restricted to major histocompatibility complex class I-related protein 1 (MR1). They are highly abundant in human liver and activated by T-cell receptor (TCR)-dependent and TCR-independent mechanisms to exhibit rapid, innate-like effector responses. However, the roles of MAIT cells in chronic HBV infection are still open for study. This study aims to test their antiviral potential and investigate their dynamic changes and regulating factors during chronic HBV infection.

APPROACH AND RESULTS

Blood samples from 257 chronic HBV-infected patients were enrolled, and nontumor liver specimens were collected from 58 HBV-infected HCC patients. Combining cell-culture experiments and human data, we showed that MAIT cells had strong cytotoxicity against HBV-transfected hepatocytes in an MR1-dependent way. However, circulating and hepatic MAIT cells in HBV-infected patients decreased significantly compared to controls. Correlation analysis suggested that MAIT cell frequency was associated with disease progression and inversely correlated with serum-conjugated bilirubin level. In particular, conjugated bilirubin not only directly promoted MAIT cell activation and apoptosis, but also impaired TCR-induced proliferation and expansion of MAIT cells, which could be partially rescued by IL-2 in the absence of conjugated bilirubin. Despite that MAIT cells from patients with high conjugated bilirubin levels showed decreased cytokine-producing capacity, the increased TCR-dependent antiviral cytokine production suggested MAIT cells as an important guardian of chronic HBV with high conjugated bilirubin.

CONCLUSIONS

We reveal the MR1-dependent, anti-HBV potential of MAIT cells and identify conjugated bilirubin as a major factor dysregulating its frequency and function in chronic HBV-infected patients, suggesting a therapeutic target for MAIT-cell-based immunity against chronic HBV infection.

IL-2 contributes to cirrhosis-associated immune dysfunction by impairing follicular T helper cells in advanced cirrhosis

BACKGROUND & AIMS

Patients with decompensated cirrhosis suffer from recurrent infections and inadequate responses to prophylactic vaccinations. However, many patients present with hypergammaglobulinemia (HGG), indicating a sustained ability to generate antibody responses. As follicular T helper (Tfh) cells are central facilitators of humoral immunity, we hypothesized that Tfh cell responses may be altered in advanced liver disease and we aimed to identify the mechanisms underlying any such alterations.

METHODS

Tfh, regulatory T (Treg) cells, B cells, circulating cytokines and immunoglobulins were analyzed in cohorts of patients with compensated (n = 37) and decompensated cirrhosis (n = 82) and in non-cirrhotic controls (n = 45). Intrahepatic T cells were analyzed in 8 decompensated patients. The influence of IL-2 on Tfh cell function was evaluated in vitro, including Tfh cell cloning and T cell-B cell co-cultures with clones and primary tonsil-derived Tfh cells.

RESULTS

Tfh cell frequencies were reduced in patients with decompensated cirrhosis, with phenotypic signatures indicative of increased IL-2 signaling. Soluble IL-2 receptor (sCD25) was elevated in these patients and CD4 T cells were more responsive to IL-2 signaling, as characterized by STAT5 phosphorylation. IL-2 exposure in vitro diminished the Tfh phenotype and resulted in impaired Tfh helper function in co-culture experiments with naïve B cells. Tfh cells were barely detectable in cirrhotic livers. IL-2 signatures on Tfh cells in decompensated patients correlated with immunoglobulin levels, which were found to be associated with improved survival.

CONCLUSIONS

Tfh cell impairment represents a previously underestimated feature of cirrhosis-associated immune dysfunction that is driven by IL-2. The presence of HGG in decompensated patients predicts an intact Tfh cell compartment and is associated with a favorable outcome.

LAY SUMMARY

Patients with advanced cirrhosis often fail to generate protective immunity after prophylactic vaccinations and suffer from recurring infections that are associated with high mortality. Follicular T helper (Tfh) cells are specialized CD4 T cells that enable the emergence of antibody responses against microbial pathogens. This report demonstrates that Tfh cells are impaired in patients with advanced cirrhosis due to interleukin-2 signaling, a cytokine that is known to impair the generation of Tfh cells.

Immunological consequences following splenectomy in patients with liver cirrhosis

The immune status in patients with liver cirrhosis is generally impaired due to concomitant hypersplenism. As the spleen is the largest lymphoid organ, deleterious events resulting from splenectomy are of concern in these patients. However, the immunological consequences after splenectomy have not yet been fully elucidated. In the present study, the immune status after splenectomy was comprehensively examined. Splenectomy was performed in 11 patients with liver cirrhosis and hypersplenism, and the immune status in peripheral blood was examined and compared before and at 1, 3 and 6 months after splenectomy. Splenectomy significantly lowered the neutrophil-to-lymphocyte ratio, due to a surge in lymphocytes in the peripheral circulation at 3 and 6 months after splenectomy. The frequency of cluster of differentiation (CD)4⁺ T cells decreased after splenectomy, whereas the frequency of CD8⁺ T cells increased. Notably, the frequencies of the naïve and central memory subsets of CD4⁺ and CD8⁺ T cells decreased, whereas those of the effector memory subset trended upward. In addition, the frequencies of other immune cells such as γδ T cells, natural killer T cells and natural killer cells transiently increased, while inhibitory cells such as regulatory T cells and myeloid-derived suppressor cells significantly decreased. T-cell responses to viral- and tumor-associated antigens increased after splenectomy in five of eight and two of five patients, respectively. To the best of our knowledge, this is the first study to precisely examine the drastic changes of immunological phenotypes in peripheral blood after splenectomy in patients with cirrhosis. Our findings suggested that splenectomy in patients with cirrhosis may ameliorate the impaired immune status, possibly by reducing suppressive cells and enhancing the effector cell population and function, which could, at least in part, explain the mechanisms responsible for the clinical benefits of splenectomy.

Protective Effect of Ganshuang Granules () on Liver Cirrhosis by Suppressing Regulatory T Cells in Mouse Model

OBJECTIVE

To investigate the potential antifibrotic mechanisms of Chinese medicine Ganshuang Granules (, GSG) and to provide clinical therapeutic evidence of its effects.

METHODS

A cirrhotic mouse model was established by intraperitoneally injecting a mixture of CCl4 (40%) and oil (60%) at 0.2 mL per 100 g of body weight twice a week for 12 weeks. After 12-week modeling, GSG was intragastric administrated to the mice for 2 weeks, and the mice were divided into low-, medium- and high-dose groups at doses of 1, 2 and 4 g/(kg·day), respectively. Liver morphology changes were observed using Masson's trichrome staining and B-ultrasound. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and hyaluronic acid (HA) in serum were detected using an automatic biochemistry analyzer. The expressions of desmin, smooth muscle actin (SMA) and Foxp3 in liver were detected by immunoflfluorescence. The regulatory T cell (Treg) frequency was determined through flflow cytometry analysis. Collagen-I, SMA, IL-6, tumor necrosis factor α (TNF-α), interleukin (IL)-1β and transforming growth factor β1 (TGF-β1) expression levels were measured using quantitative polymerase chain reaction (qPCR).

RESULTS

Masson's staining result showed fewer pseudolobule structures and fibrous connective tissue in the GSG-treatment groups than in the spontaneous recovery group. Ultrasonography showed that GSG treatment reduced the number of punctate hyperechoic lesions in mice cirrhotic livers. The serum ALT, AST, HA levels were significantly ameliorated by GSG treatment (ALT: F=8.104, P=0.000; AST: F=7.078, P=0.002; and HA: F=7.621, P=0.001). The expression levels of collagen-I and SMA in the cirrhotic livers were also attenuated by GSG treatment (collagen-I: F=3.938, P=0.011; SMA: F=4.115, P=0.009). Tregs, which were elevated in the fibrotic livers, were suppressed by GSG treatment (F=8.268, P=0.001). The expressions of IL-6, TNF-α and IL-1β increased, and TGF-β levels decreased in the cirrhotic livers after GSG treatment (IL-6: F=5.457, P=0.004; TNF-α: F=6.023, P=0.002; IL-1β: F=6.658, P=0.001; and TGF-β1: F=11.239, P=0.000).

CONCLUSIONS

GSG promoted the resolution/regression of cirrhosis and restored liver functions in part by suppressing Treg cell differentiation, which may be mediated by hepatic stellate cells.

Memory Regulatory T cells Increase Only In Inflammatory Phase of Chronic Hepatitis B Infection and Related to Galectin-9/Tim-3 interaction

CD4⁺Foxp3⁺ regulatory T cells (Tregs) are the main immune suppressors with subpopulation of inflamed-tissue related memory Tregs (mTregs) and non-related resting Treg (rTregs). Previously, Treg was proposed to be the cause of chronicity of hepatitis B virus (HBV) infection but with controversies. We then investigated the role of mTregs in distinct immune phases of chronic HBV infection, especially the non-inflammatory versus inflammatory phases. It was found mTregs but not rTregs increased only in the inflammatory phase and correlated with serum alanine aminotransferase (ALT) level. These mTregs accumulated in the inflamed liver, expressed significantly higher Tim-3, CCR4, CCR5 and fewer CCR7, and possessed potent suppressive function. These mTregs mainly originated from natural Tregs because of high Helios expression. Hierarchical clustering analysis showed higher frequency of mTreg was concordant with higher serum ALT and galectin-9 levels. Furthermore, galectin-9 could expand mTregs through galectin-9/Tim-3 interaction. In conclusion, increased mTregs are found only in inflammatory phase of chronic HBV infection. Galectin-9, associated with liver inflammation, contributes to the expansion of mTregs through galectin-9/Tim-3 interaction. Therefore, this expansion of mTregs only reflects as an immune regulatory mechanism to limit the on-going liver damages rather than the cause of chronicity of HBV infection.

Conjugated Bilirubin Upregulates TIM-3 Expression on CD4+CD25+ T Cells: Anti-Inflammatory Implications for Hepatitis A Virus Infection

Bilirubin (BR), a metabolite with increased concentrations in plasma during viral hepatitis, has been recognized as a potential immune-modulator. We recently reported that conjugated BR (CB) augments regulatory T cell (Treg) suppressor activity during acute hepatitis A virus (HAV) infection. However, the mechanisms related to the effects of CB on Treg function in the course of hepatotropic viral diseases have not been elucidated. T cell immunoglobulin domain and mucin domain 3 (TIM-3), via its interactions with galectin-9 (GAL-9), is a receptor associated with enhanced Treg function. Thus, TIM-3 expression may be related to the crosstalk between CB and Tregs during HAV infection. Herein, in vitro treatment with high concentrations of CB upregulated TIM-3 expression on Tregs from healthy donors. CB treatment in vitro did not induce de novo Treg generation, and in vitro stimulation with TGF-β, which shows increased secretion during HAV infection, resulted in a trend toward increased TIM-3 expression on Tregs and CD4⁺ T lymphocytes (TLs) from healthy donors. Interestingly, an upregulation of TIM-3 expression on CD4⁺CD25⁺ T cells and an increase in the proportion of CD4⁺ TLs expressing GAL-9 were found in HAV-infected patients with abnormal CB values relative to healthy controls. In addition, a statistically significantly reduction in IL-17F production was observed after treatment of CD4⁺ TLs from healthy donors with high doses of CB in vitro. In summary, our results suggest that CB might regulate Treg activity via a TIM-3-mediated mechanism, ultimately leading to an anti-inflammatory hepatoprotective effect.

Conjugated Bilirubin Differentially Regulates CD4+ T Effector Cells and T Regulatory Cell Function through Outside-In and Inside-Out Mechanisms: The Effects of HAV Cell Surface Receptor and Intracellular Signaling

We recently reported an immune-modulatory role of conjugated bilirubin (CB) in hepatitis A virus (HAV) infection. During this infection the immune response relies on CD4+ T lymphocytes (TLs) and it may be affected by the interaction of HAV with its cellular receptor (HAVCR1/TIM-1) on T cell surface. How CB might affect T cell function during HAV infection remains to be elucidated. Herein, in vitro stimulation of CD4+ TLs from healthy donors with CB resulted in a decrease in the degree of intracellular tyrosine phosphorylation and an increase in the activity of T regulatory cells (Tregs) expressing HAVCR1/TIM-1. A comparison between CD4+ TLs from healthy donors and HAV-infected patients revealed changes in the TCR signaling pathway relative to changes in CB levels. The proportion of CD4+CD25+ TLs increased in patients with low CB serum levels and an increase in the percentage of Tregs expressing HAVCR1/TIM-1 was found in HAV-infected patients relative to controls. A low frequency of 157insMTTTVP insertion in the viral receptor gene HAVCR1/TIM-1 was found in patients and controls. Our data revealed that, during HAV infection, CB differentially regulates CD4+ TLs and Tregs functions by modulating intracellular pathways and by inducing changes in the proportion of Tregs expressing HAVCR1/TIM-1.

Sepsis-induced immune alterations monitoring by flow cytometry as a promising tool for individualized therapy

Septic syndromes remain a major although largely under-recognized health care problem and represent the first cause of mortality in intensive care units. While sepsis has, for long, been solely described as inducing a tremendous systemic inflammatory response, novel findings indicate that sepsis indeed initiates a more complex immunologic response that varies over time, with the concomitant occurrence of both pro- and anti-inflammatory mechanisms. As a resultant, after a short proinflammatory phase, septic patients enter a stage of protracted immunosuppression. This is illustrated in those patients by reactivation of dormant viruses (CMV or HSV) or infections due to pathogens, including fungi, which are normally pathogenic solely in immunocompromised hosts. Although mechanisms are not totally understood, these alterations might be directly responsible for worsening outcome in patients who survived initial resuscitation as nearly all immune functions are deeply compromised. Indeed, the magnitude and persistence over time of these dysfunctions have been associated with increased mortality and health-care associated infection rate. Consequently, new promising therapeutic avenues are currently emerging from those recent findings such as adjunctive immunostimulation (IFN-γ, GM-CSF, IL-7, anti-PD1/L1 antibodies) for the most immunosuppressed patients. Nevertheless, as there is no clinical sign of immune dysfunctions, the prerequisite for such therapeutic intervention relies on our capacity in identifying the patients who could benefit from immunostimulation. To date, the most robust biomarkers of sepsis-induced immunosuppression are measured by flow cytometry. Of them, the decreased expression of monocyte HLA-DR appears as a "gold standard." This review reports on the mechanisms sustaining sepsis-induced immunosuppression and its related biomarkers measurable by flow cytometry. The objective is to integrate the most recent facts in an up-to-date account of clinical results, flow cytometry aspects as well as issues in results standardization for multicenter studies. © 2015 International Clinical Cytometry Society.