Yanling Sun

Imbalanced intrahepatic cytokine expression of interferon-gamma, tumor necrosis factor-alpha, and interleukin-10 in patients with acute-on-chronic liver failure associated with hepatitis B virus infection.

Goals This study attempts to determine expressions of intrahepatic proinflammatory and anti-inflammatory cytokines and their secreting immunocytes to evaluate their roles in the pathogenesis of acute-on-chronic liver failure (ACLF) in chronically hepatitis B virus (HBV)-infected patients. Background ACLF generally affects patients with established, compensated chronic liver diseases who develop an acute deterioration in liver function. In China, HBV-associated ACLF patients account for more than 80% of ACLF patients owing to a high prevalence of chronic HBV infection. Clinical observation showed that the deterioration of this disease may correlate with host immune responses, but related underlying mechanism remains largely unknown. Study In situ expressions of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and their secreting CD4, CD8 T cells, and Kupffer cells (KCs) were analyzed in the livers of patients with ACLF, chronic hepatitis B (CHB), and normal controls (NC) using immunohistochemistry. Results Intrahepatic proinflammatory IFN-γ and TNF-α expressions were markedly up-regulated in ACLF compared with CHB and NC. However, similar anti-inflammatory IL-10 expressions were observed in ACLF and CHB. IFN-γ overexpression correlated significantly with increased CD4 and CD8 T-cell accumulation. TNF-α up-regulation also correlated significantly with increased KCs. Conclusions The imbalanced expression of proinflammatory and anti-inflammatory cytokines and increased accumulation of CD4, CD8 T cells, and KCs may contribute to immunopathogenesis in HBV-infected ACLF.

Pathological functions of interleukin‐22 in chronic liver inflammation and fibrosis with hepatitis B virus infection by promoting T helper 17 cell recruitment

It is well established that interleukin (IL)‐22 has hepatoprotective and antifibrotic functions in acute liver injury models; however, its function in patients with liver fibrosis and liver cirrhosis (LC) remains obscure. In the current study, we demonstrated that expression of numerous IL‐22 pathway‐associated genes was significantly up‐regulated in hepatitis B virus (HBV)‐infected liver tissues, compared to normal controls, through microarray analysis. In agreement with these findings, liver‐infiltrating IL‐22+ cells were largely increased in HBV‐infected patients with LC, compared to those without LC or healthy subjects, and were positively associated with liver fibrosis staging scores. Immunohistochemistry and flow cytometric analyses revealed that IL‐22 was produced by multiple intrahepatic immune cells and, preferentially, by T‐helper (Th) 17 cells in LC patients. In an HBV transgenic (Tg) mouse model of T‐cell‐mediated chronic liver inflammation and fibrosis, blockade of IL‐22 attenuated hepatic expression of chemokine (C‐X‐C motif) ligand 10 and chemokine (C‐C motif) ligand 20 (CCL20) and subsequently reduced Th17 recruitment and liver inflammation and fibrosis progression. In vitro treatment with IL‐22 stimulated hepatic stellate cells (HSCs) to secrete several chemokines and subsequently promoted Th17 cell chemotaxis. Blocking C‐X‐C chemokine receptor type 3 or CCL20 reduced Th17 cell chemotaxis by IL‐22‐treated HSCs. Conclusions: IL‐22 plays a pathological role in exacerbating chronic liver inflammation and fibrosis by recruiting hepatic Th17 cells in HBV‐infected patients and HBV Tg mice. (Hepatology 2014;59:1331‐1342)

CXCR5+ CD4+ T Follicular Helper Cells Participate in the Pathogenesis of Primary Biliary Cirrhosis

There is increasing interest in the role of T follicular helper (Tfh) cells in autoimmunity from the perspective of both their role in breach of tolerance and their effects on the natural history of disease progression. Indeed, the critical role of Tfh cells in autoimmunity is further highlighted based on their location in the germinal center (GC), a pathogenic hot spot for development of autoreactivity. To address the role of Tfh cells in primary biliary cirrhosis (PBC), we comprehensively evaluated the immunobiology of CXCR5+CD4+ Tfh cells in 69 patients with PBC, including a nested subgroup of 16 autoimmune hepatitis (AIH) and 20 healthy controls (HC), followed for 1 year. We report herein several key observations. First, there was an increased frequency of circulating Tfh cells in patients with PBC compared to AIH (P < 0.05) and HC (P < 0.01). Second, the function of circulating Tfh cells from PBC patients, including interleukin (IL)‐21 production (P < 0.05), the ability to promote B‐cell maturation, and autoantibody production, were greater than HC. Third, the frequency of these cells was significantly decreased in ursodeoxycholic acid (UDCA) responders compared to UDCA‐treated nonresponders, in both cross‐sectional (P = 0.023) and longitudinal studies (P = 0.036), respectively. Indeed, similar increases of Tfh cells were noted in liver and spleen. Conclusion: These results significantly extend our understanding of lymphoid subpopulations in PBC and their relative role in disease expression. Our data also provide a novel biomarker for evaluation of the effectiveness of new therapeutic approaches. (Hepatology 2015;61:627‐638)

Compartmentalization and its implication for peripheral immunologically-competent cells to the liver in patients with HBV-related acute-on-chronic liver failure.

Aims:  This study attempts to characterize the feature of immunologically competent cells (ICCs) and evaluate its clinical implication in patients with acute‐on‐chronic liver failure (ACLF) in relation to chronic hepatitis B virus (HBV) infection.

Natural Killer Cells Are Characterized by the Concomitantly Increased Interferon-γ and Cytotoxicity in Acute Resolved Hepatitis B Patients

Natural killer (NK) cells are abundant in the liver and have been implicated in inducing hepatocellular damage in patients with chronic hepatitis B virus (HBV) infection. However, the role of NK cells in acute HBV infection remains to be elucidated. We comprehensively characterized NK cells and investigated their roles in HBV clearance and liver pathology in 19 chronic hepatitis B (CHB) patients and 21 acute hepatitis B (AHB) patients as well as 16 healthy subjects. It was found that NKp46+ NK cells were enriched in the livers of AHB and CHB patients. We further found that peripheral NK cells from AHB patients expressed higher levels of activation receptors and lower levels of inhibitory receptors than those from CHB patients and HC subjects, thus displaying the increased cytolytic activity and interferon-γ production. NK cell activation levels were also correlated positively with serum alanine aminotransferase levels and negatively with plasma HBV DNA levels in AHB patients, which is further confirmed by the longitudinal follow-up of AHB patients. Serum pro-inflammatory cytokine and chemokine levels were also increased in AHB patients as compared with CHB and HC subjects. Thus, the concomitantly increased interferon-γ and cytotoxicity of NK cells were associated with liver injury and viral clearance in AHB patients.

The ratio of circulating regulatory T cells (Tregs)/Th17 cells is associated with acute allograft rejection in liver transplantation.

CD4+CD25+FoxP3+ regulatory T cells (Tregs) and Th17 cells are known to be involved in the alloreactive responses in organ transplantation, but little is known about the relationship between Tregs and Th17 cells in the context of liver alloresponse. Here, we investigated whether the circulating Tregs/Th17 ratio is associated with acute allograft rejection in liver transplantation. In present study, thirty-eight patients who received liver transplant were enrolled. The patients were divided into two groups: acute allograft rejection group (Gr-AR) (n = 16) and stable allograft liver function group (Gr-SF) (n = 22). The frequencies of circulating Tregs and circulating Th17 cells, as well as Tregs/Th17 ratio were determined using flow cytometry. The association between Tregs/Th17 ratio and acute allograft rejection was then analyzed. Our results showed that the frequency of circulating Tregs was significantly decreased, whereas the frequency of circulating Th17 cells was significantly increased in liver allograft recipients who developed acute rejection. Tregs/Th17 ratio had a negative correlation with liver damage indices and the score of rejection activity index (RAI) after liver transplantation. In addition, the percentages of CTLA-4+, HLA-DR+, Ki67+, and IL-10+ Tregs were higher in Gr-SF group than in Gr-AR group. Our results suggested that the ratio of circulating Tregs/Th17 cells is associated with acute allograft rejection, thus the ratio may serve as an alternative marker for the diagnosis of acute rejection.

A Pilot Study of Mesenchymal Stem Cell Therapy for Acute Liver Allograft Rejection

Acute allograft rejection remains common after liver transplantation despite modern immunosuppressive agents. In addition, the long‐term side effects of these regimens, including opportunistic infections, are challenging. This study evaluated the safety and clinical feasibility of umbilical cord‐derived mesenchymal stem cell (UC‐MSC) therapy in liver transplant patients with acute graft rejection. Twenty‐seven liver allograft recipients with acute rejection were randomly assigned into the UC‐MSC infusion group or the control group. Thirteen patients received one infusion of UC‐MSCs (1 × 106/kg body weight); one patient received multiple UC‐MSC infusions; 13 patients were used as controls. All enrolled patients received conventional immunosuppressive agents with follow‐up for 12 weeks after UC‐MSC infusions. No side effects occurred in treated patients. Four weeks after UC‐MSC infusions, alanine aminotransferase levels had decreased markedly and remained lower throughout the 12‐week follow‐up period. Importantly, allograft histology was improved after administration of UC‐MSCs. The percentage of regulatory T cells (Tregs) and the Treg/T helper 17 (Th17) cell ratio were significantly increased 4 weeks after infusions; in contrast, the percentage of Th17 cells showed a decreasing trend. In controls, the percentages of Tregs and Th17 cells and the Treg/Th17 ratio were statistically unchanged from the baseline measurements. Transforming growth factor beta 1 and prostaglandin E2 were increased significantly after UC‐MSC infusions; by contrast, there were no significant changes in controls. Our data suggest that UC‐MSC infusion for acute graft rejection following liver transplantation is feasible and may mediate a therapeutic immunosuppressive effect. Stem Cells Translational Medicine 2017;6:2053–2061

Activated hepatic stellate cells impair NK cell anti-fibrosis capacity through a TGF-β-dependent emperipolesis in HBV cirrhotic patients

Natural killer (NK) cells can induce liver fibrosis remission by killing hepatic stellate cells (HSCs) and producing interferon (IFN)-γ in a mouse model; however, their anti-fibrotic immune-characteristics and regulatory mechanisms by HSCs remain to be determined, especially in livers from HBV-infected liver cirrhosis (LC) patients. We analyzed frequency, phenotype and anti-fibrotic function of hepatic and peripheral NK subsets in 43 HBV-LC patients. We found that hepatic NK subsets from LC patients displayed a decreased frequency, activation status and anti-fibrotic activity compared with those from chronic hepatitis B patients, which were mainly mediated by increased intrahepatic tumour-growth factor (TGF)-β because blockade of TGF-β significantly reversed NK anti-fibrotic function in vitro. In vivo, hepatic NK cells were enriched in proximity to the α-smooth muscle actin (α-SMA+) area within mild fibrosis regions; while in severe fibrotic areas, they were either directly attached to or separated from the α-SMA+ region. NK cells from LC patients could enter HSCs to form emperipolesis (a cell-in-cell structure) and become apoptotic; anti-TGF-β treatment ameliorated this emperipolesis. This finding suggested a novel mechanism by which activated HSCs impair NK cells’ anti-fibrosis capacity through a TGF-β-dependent emperipolesis in LC patients, providing an anti-fibrotic rational by enhancing NK cell activity.

Characteristics of Vδ1+ and Vδ2+ γδ T cell subsets in acute liver allograft rejection

BACKGROUND To investigate the characteristics of γδ T cells as well as the Vδ1(+) and Vδ2(+) subsets in the peripheral blood in liver allograft recipients. METHODS Sixty-three liver transplant recipients were enrolled in this study: 26 cases with acute allograft rejection (Gr-AR), and 37 cases with stable allograft liver function (Gr-SF). The frequencies of γδ T cells, the Vδ1(+) and Vδ2(+) subsets, and interleukin (IL)-10-producing Vδ1(+) γδ T cells in the peripheral blood were analyzed by flow cytometry. The relationship between liver function parameters and the Vδ1(+)/Vδ2(+) ratio was analyzed. RESULTS The frequency of the Vδ1(+) subset and the Vδ1(+)/Vδ2(+) ratio in Gr-SF was significantly higher than that in Gr-AR; in contrast, the frequency of the Vδ2(+) subset in Gr-SF was markedly lower than that in Gr-AR. In addition, there was no significant difference in the frequency of γδ T cells between the Gr-AR and Gr-SF groups. Moreover, there was a significant negative correlation between the Vδ1(+)/Vδ2(+) ratio with the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in Gr-AR. CONCLUSIONS Vδ1(+) γδ T cells may have a potential role in maintaining stable graft liver function, and Vδ2(+) γδ T cells may be associated with liver allograft rejection. The Vδ1(+)/Vδ2(+) ratio could serve as a prognostic marker for acute rejection after liver transplantation.

A pilot study on the characteristics of circulating T follicular helper cells in liver transplant recipients

Circulating CD4+CXCR5+ T follicular helper cells (cTfh) have been demonstrated to be involved in B cell-mediated systemic autoimmune diseases and alloreactive responses following kidney transplantation; however, whether cTfh cells are involved in alloreactive responses after liver transplantation (LT) remains unclear. Our present study aimed to investigate the characteristics of cTfh, as well as CXCR3+CCR6-Tfh1, CXCR3-CCR6-Tfh2, and CXCR3-CCR6+Tfh17 subsets in liver allograft recipients. A total of 30 liver transplant recipients were enrolled in this study. The frequencies of cTfh, Tfh1, Tfh2, and Tfh17 subsets, and interleukin (IL)-21-producing Tfh cells in the circulating blood were analyzed by flow cytometry. The capacity of cTfh cells to help B cells differentiate into plasmablasts was determined one day before and one month after LT. The results revealed that the frequency of cTfh cells remained unaltered before and after LT. However, the frequency of the cTfh subsets (e.g., Tfh1 and Tfh2 cells) and B cells were reduced one month after LT. Functionally, the capacity of Tfh cells to produce IL-21 was reduced one month after LT. In addition, cTfh cells exhibited the capacity to help B cells differentiate into plasmablasts in an IL-21-dependent manner in vitro, which was reduced after LT, despite the unaltered production of IgM and IgG by plasmablasts. Thus, our data suggest that cTfh cells may be involved in alloreactive responses following LT via helping B cells differentiate into plasmablasts and plasma cells.