Cells In Autoimmune Hepatitis Research Articles

Clonal analysis of SepSecS-specific B and T cells in autoimmune hepatitis

Clonal analysis of SepSecS-specific B and T cells in autoimmune hepatitis

Elucidating the role of autoreactive T cells and B cells in autoimmune hepatitis

Elucidating the role of autoreactive T cells and B cells in autoimmune hepatitis

IRG1/Itaconate inhibits proliferation and promotes apoptosis of CD69+CD103+CD8+ tissue-resident memory T cells in autoimmune hepatitis by regulating the JAK3/STAT3/P53 signalling pathway.

To investigate the protective role of immune response gene 1 (IRG1) and exogenous itaconate in autoimmune hepatitis (AIH) and elucidate the underlying mechanisms. Wild-type and IRG1-/- AIH mouse models were established, and samples of liver tissue and ocular blood were collected from each group of mice to assess the effects of IRG1/itaconate on the expression of pro- and anti-inflammatory cytokines. The levels of liver enzymes and related inflammatory factors were determined using enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction (PCR). Liver histomorphology was detected through hematoxylin and eosin staining and then scored for liver injury, and the infiltration levels of tissue-resident memory T (TRM) cells and related molecules in the liver tissue were detected through immunofluorescence staining in vitro. RNA sequencing and gene enrichment analysis were conducted to identify the corresponding molecules and pathways, and lentiviral transfection was used to generate TRM cell lines with IRG1, Jak3, Stat3, and p53 knockdown. Real-time quantitative PCR and western blot were performed to detect the expression levels of relevant mRNAs and proteins in the liver tissue and cells. The percentage of apoptotic cells was determined using flow cytometry. IRG1/itaconate effectively reduced the release of pro-inflammatory cytokines and the pathological damage to liver tissue, thereby maintaining normal liver function. At the same time, IRG1/itaconate inhibited the JAK3/STAT3 signaling pathway, regulated the expression of related downstream proteins, and inhibited the proliferation and promoted the apoptosis of CD69+CD103+CD8+ TRM cells. For the first time, P53 was found to act as a downstream molecule of the JAK3/STAT3 pathway and was regulated by IRG1/itaconate to promote the apoptosis of CD8+ TRM cells. IRG1/itaconate can alleviate concanavalin A-induced autoimmune hepatitis in mice by inhibiting the proliferation and promoting the apoptosis of CD69+CD103+CD8+ TRM cells via the JAK3/STAT3/P53 pathway.

Natural Killer T (NKT) Cells in Autoimmune Hepatitis: Current Evidence from Basic and Clinical Research.

Natural killer T (NKT) cells are unconventional T cells that are activated by glycolipid antigens. They can produce a variety of inflammatory and regulatory cytokines and, therefore, modulate multiple aspects of the immune response in different pathological settings, including autoimmunity. NKT cells have also been implicated in the immunopathogenesis of autoimmune hepatitis, and in this review we summarize and analyze the main studies investigating the involvement and/or homeostasis of NKT cells in this disease. In detail, the evidence from both basic and clinical research has been specifically analyzed. Even though the experimental murine models supported a relevant role of NKT cells in immune-mediated hepatic injury, very few studies specifically investigated NKT cell homeostasis in patients with autoimmune hepatitis; however, these initial studies reported some alterations of NKT cells in these patients, which may also correlate with the disease activity to some extent. Further clinical studies are needed to investigate the potential role and use of NKT cell analysis as a disease marker of clinical relevance, and to better understand the precise cellular and molecular mechanisms by which NKT cells contribute to the pathogenesis of autoimmune hepatitis.

SAT-382 - TIGIT inhibits the cytotoxic effects of NK cells towards biliary epithelial cells in autoimmune hepatitis

SAT-382 - TIGIT inhibits the cytotoxic effects of NK cells towards biliary epithelial cells in autoimmune hepatitis

B-cell activating factor and IL-21 levels predict treatment response in autoimmune hepatitis

Background & AimsIncreased serum IgG and autoantibodies suggest involvement of B cells in autoimmune hepatitis (AIH). The aim of this study was to assess levels of B cell activating factor of the tumour necrosis family (BAFF), IL-21, and circulating B cell populations in AIH and correlate these to treatment response.MethodsBAFF and IL-21 levels were determined in 66 patients with AIH before treatment and 10 healthy controls. Flow cytometry was performed on circulating B cells of 10 patients with AIH and 12 healthy controls.ResultsBased on BAFF and IL-21 levels, untreated patients with AIH were divided into 3 groups: 27 (41%) patients with normal BAFF and IL-21 (normal BAFF), 27 (41%) patients with elevated BAFF but normal IL-21 (high BAFF), and 12 (18%) patients with elevated IL-21 (high IL-21). The high BAFF group presented with higher bilirubin compared with the normal BAFF and high IL-21 groups (159 vs. 26 vs. 89 μmol/L; p = 0.001; Mann–Whitney U test). After 12 months of treatment, 54% of the high BAFF group reached remission compared with 34% of the normal BAFF group and 0% of the high IL-21 group (p = 0.006, Chi-square test). During follow-up, 3 patients (25%) with high IL-21 developed primary sclerosing cholangitis (PSC) variant syndrome. Autoimmune-associated B cells were increased in patients with AIH compared with healthy controls (4.4 vs. 1.4%; p = 0.003, Mann–Whitney U test). BAFF levels were correlated positively with naïve B cells (p = 0.01) and negatively with class-switched B cells (p = 0.003) and nonclass-switched B cells (p = 0.005, Spearman correlation).DiscussionUsing BAFF and IL-21, we identified different immunological phenotypes of AIH with a different presentation, treatment response, and outcome. Patients with high IL-21 had the poorest treatment response and a risk of developing PSC variant syndrome. BAFF level was related to shifts in circulating B-cell populations.Lay summaryIn patients with untreated autoimmune hepatitis (AIH), circulating B-cell activating factor of the tumour necrosis family (BAFF), IL-21, and B-cell populations were determined. Three subgroups were identified: with (1) normal BAFF and IL-21, (2) elevated BAFF and normal IL-21, and (3) elevated IL-21. Remission after 1-year treatment occurred in 54, 34, and 0% in Groups 1, 2, and 3, respectively. Group 2 had higher bilirubin, indicating more liver dysfunction. In 25% of patients with high IL-21, AIH-PSC variant syndrome developed, but none in the other groups. Autoimmune-associated B cells were elevated and BAFF levels correlated with certain B cells.

Tim-3 suppresses autoimmune hepatitis via the p38/MKP-1 pathway in Th17 cells.

T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 (Tim‐3) mediates T‐cell suppression in various autoimmune diseases, such as chronic inflammatory liver disease. However, the regulatory effect of Tim‐3 on Th17 cells in autoimmune hepatitis (AIH) is incompletely understood. Here, we studied the expression and function of Tim‐3 in T cells in AIH patients and in a Con A (concanavalin A)‐induced mouse AIH model. We report that the frequency of CD4+Tim‐3+ T cells in peripheral blood samples of AIH patients was lower than that in the control group. The p38/MKP‐1 and p‐JNK pathways were activated, and the expression of interleukin‐17A protein was elevated in patients with AIH. Furthermore, the extent of pathological damage in the livers of mice with a blocked Tim‐3 signaling pathway (anti‐Tim‐3 group) was markedly increased and correlated with elevated alanine aminotransferase and aspartate aminotransferase levels. In addition, the frequency of CD4+ IL‐17+ T (Th17) cells in the anti‐Tim‐3 group was increased, while that in mice with blocked p38 activity was decreased. Finally, the expression of MKP‐1 (p‐p38) gradually increased in the control, Con A, and anti‐Tim‐3 groups, but the levels of interleukin‐17A were decreased in the p38‐blocked group. In summary, our results suggest that Tim‐3 suppresses AIH by regulating Th17 cells through the p38/MKP‐1 pathway.

From the Editor's Desk…

From the Editor's Desk…

THU110 - Single-cell analysis of self-antigen-specific CD4 T cells reveals the B helper signature and the peripheral reservoir of autoreactive T cells in autoimmune hepatitis

THU110 - Single-cell analysis of self-antigen-specific CD4 T cells reveals the B helper signature and the peripheral reservoir of autoreactive T cells in autoimmune hepatitis

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.

Total glucosides of paeony decreases apoptosis of hepatocytes and inhibits maturation of dendritic cells in autoimmune hepatitis

Total glucosides of paeony (TGP), an active mixture extracted from paeony root, has anti-inflammatory and immunoregulatory effects and is widely used for the treatment of autoimmune diseases such as rheumatoid arthritis. However, the role of TGP in autoimmune hepatitis (AIH) is still unknown. In this study, we aimed to investigate the effect of TGP in autoimmune liver disease (AILD) patients and in concanavalin A (Con A)-induced experimental autoimmune hepatitis (EAH). Changes in biochemical parameters of AILD patients showed that treatment with TGP exerts significant protective effects on liver function, as reflected by decreased levels of serum alanine transaminase, aspartate transaminase, γ-glutamyl transpeptidase and total bilirubin. In EAH mice, we found that pretreatment with TGP reduced the levels of serum liver enzyme levels, histopathological damage and hepatocyte apoptosis. Importantly, flow cytometry analysis showed that pretreatment with TGP reduced the infiltration of mature dendritic cells in the liver. In vitro, TGP pretreatment ameliorated the Con A-induced mitochondrial membrane potential decline, reactive oxygen species increase, and apoptosis increase in hepatocytes. In addition, the levels of Bax, Cleaved Caspase-3 and cytoplasmic Cytochrome C decreased during this process, whereas those of Bcl-2 and mitochondrial Cytochrome C increased. Therefore, TGP might decrease hepatocyte apoptosis through the mitochondrial apoptotic pathway. Moreover, the maturation of bone marrow dendritic cells was also inhibited by TGP treatment. In conclusion, TGP treatment ameliorates AIH by regulating hepatocyte apoptosis and DC maturation. TGP is a potential compound for AIH treatment.

TNF-Producing Th1 Cells Are Selectively Expanded in Liver Infiltrates of Patients with Autoimmune Hepatitis.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that is believed to be driven by a CD4+ T cell response to liver Ags. However, the pathogenic function of CD4+ effector T cells in AIH is not fully understood. To characterize liver-infiltrating lymphocytes in AIH, we determined the cytokine production of infiltrating cells obtained from biopsy material by quantitative RT-PCR and flow cytometry. A cytokine quantitiative RT-PCR array of AIH specimens revealed that TNF was the most strongly upregulated cytokine, as compared with control livers. To confirm this finding, we determined the frequencies of TNF-producing CD4+ T cells in peripheral blood and in liver biopsy specimens in comparison with those of CD4+ T cells producing IFN-γ or IL-17. In AIH, TNF-producing CD4+ T cells were significantly expanded, both in blood and liver, whereas IL-17-producing CD4+ T cells were not. However, the majority of the TNF-producing CD4+ T cells in AIH also produced IFN-γ, suggesting that TNF producers might represent a pathogenic activation state of Th1 cells. Ag-specific stimulation of PBMC from AIH patients with the AIH-associated autoantigen SEPSECS resulted in significant TNF production only in patients manifesting SLA/LP autoantibodies targeting SEPSEC but not in healthy individuals who do not manifest this reactivity. Taken together, our findings indicated that TNF-producing CD4+ T cells are expanded in AIH, both in blood and in liver. TNF-producing CD4+ T cells in AIH seem to be aberrantly activated Th1 cells. Our findings provide a rationale for therapeutic efforts using TNF blockade in AIH.

Assessment of intrahepatic regulatory T cells in children with autoimmune hepatitis

Background. T-cell populations regulate the balance of immune responses. The CD (Cluster of differentiation) 4+CD25+ regulatory T cells (Tregs) are crucial for maintaining negative control of various immune responses. There are different T-cell subpopulations with regulatory functions, as natural killer T cells, CD8+ and CD28. The forkhead box P3 (FOXP3) regulates Treg development and is required for its suppressive function.Aim. To evaluate the hepatic expression of the intrahepatic Tregs, Ig (immunoglobulin) G and IgM plasma cells in autoimmune hepatitis (AIH) and other chronic liver diseases (CLDs).Material and methods. This study included 100 pediatric patients; 50 AIH and 50 CLDs other than AIH. All patients were subjected to routine investigations of CLDs plus immune-staining of liver tissue for FOXp3, IgG and IgM plasma cells, CD4 and CD8 T-cells.Results. The FOXP3+ T cells in patients with AIH (6.3 ± 5) were significantly higher than that in the non-AIH (2.1 ± 2.6). FOXP3+ T cells were abundant in liver tissue with marked inflammatory cellular infiltrate. CD4+ and CD8+ infiltrating the liver tissue and IgG positive cells were significantly higher in AIH group, while the expression of IgM positive cells showed no significant difference. The IgG/IgM was significantly higher in the AIH treatment responders (3 ± 3) than non-responders (1.6 ± 0.5), while there was no significant difference regarding the intrahepatic expression of FOXP3+, CD4+, CD8+ cells, T-cells, IgG and IgM plasma cells.Conclusion. Intrahepatic Tregs were increased in number in patients with AIH in the initial presentation, and their presence is associated with increased activity and inflammation in liver biopsy.

THU-005-Activation regulators of peripheral blood and intrahepatic T effector cells in autoimmune hepatitis

THU-005-Activation regulators of peripheral blood and intrahepatic T effector cells in autoimmune hepatitis

Immunoglobulin IgG4 and autoimmune hepatitis.

IgG4 disease has been characterised by lymphoplasmacytic inflammation, rich in IgG4 plasma cells, elevated serum IgG4 and clinical improvement with steroid therapy. There is limited information about IgG4 plasma cells in autoimmune hepatitis (AIH). Aim of this study was to determine IgG4 plasma cells in autoimmune hepatitis and its impact on clinical course and treatment outcome. Liver biopsies from 40 patients with AIH before therapy were subjected to IgG4 immunostaining. Clinical history, liver function tests and response to immunosuppressive therapy were recorded. Patients were monitored for 4 weeks. Liver biopsy from 23 non AIH patients served as control. Depending on the presence of IgG4 plasma cells on immunohistochemistry, patients of autoimmune hepatitis were grouped into IgG4 positive (group A) and IgG4 negative (group B). Both groups were compared before and after immunosuppressive therapy for clinicopathological features. Tissue IgG4 plasma cells > 5 per high power field (hpf) were seen in 10/40 (25%) and > 10 per hpf in 4/40 (10%) cases of AIH. None of the cases from control group (non AIH) were positive for IgG4 plasma cells. Group A patients were significantly younger than group B. (p < 0.05). There were no differences in histological severity but liver enzymes, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly higher in group A than group B. Post treatment biochemical improvement was similar in both groups. IgG4 positive AIH patients were younger with more abnormal liver enzymes. There was no difference in histology and response to treatment in both groups.

P1203 : Effect of immunosuppressive drugs on the kinetics of co-inhibitory molecule expression and pro-inflammatory cytokine production by effector t cells in autoimmune hepatitis

P1203 : Effect of immunosuppressive drugs on the kinetics of co-inhibitory molecule expression and pro-inflammatory cytokine production by effector t cells in autoimmune hepatitis

Invariant natural killer T cell deficiency leads to the development of spontaneous liver inflammation dependent on γδT cells in mice.

Immune tolerance is maintained in the liver, and perturbation of tolerance can lead to immune-mediated liver diseases such as autoimmune hepatitis (AIH). Invariant natural killer T (iNKT) cells and γδT cells have been shown to maintain immune homeostasis as regulatory cells and to play pathogenic roles in immune-mediated diseases as effector cells. We hypothesized that iNKT cells and γδT cells are involved in the maintenance of hepatic immune tolerance and immune-mediated liver disease. We measured liver inflammation and the cytokine profiles of liver mononuclear cells in BALB/c wild-type (WT) mice and BALB/c Jα18-deficient (KO) mice lacking iNKT cells. We also examined the role of γδT cells in AIH using liver tissue from AIH patients and control subjects. Spontaneous liver inflammation, hepatocyte damage, and anti-nuclear-antibody production occurred in Jα18 KO mice but not in WT mice. Furthermore, liver mononuclear cells from Jα18 KO mice, but not those from WT mice, produced interleukin-17 (IL-17). γδT cells were the primary producers of the cytokine, and they were more abundant in the livers of Jα18 KO mice than in those of WT mice. In Jα18 KO mice, the administration of anti-γδT-cell-receptor antibody abolished liver inflammation, hepatocyte damage, and IL-17 production. γδT cells accumulated in the livers of AIH patients but not in those of the control subjects. Our results suggest a protective role for iNKT cells, a pathologic role for γδT cells, and an association between these cells in the pathogenesis of AIH.

Phenotypic alterations of regulatory T cells in autoimmune hepatitis: Causal or associated with treatment and remission?

Phenotypic alterations of regulatory T cells in autoimmune hepatitis: Causal or associated with treatment and remission?

Intrahepatic regulatory T cells in autoimmune hepatitis are associated with treatment response and depleted with current therapies

Autoimmune hepatitis (AIH) is a chronic autoimmune liver disease usually requiring life-long immunosuppression. The mechanisms for disease initiation and chronicity are largely unknown. A contribution of deficient regulatory T cells (Tregs) in the blood was controversially discussed recently. So far investigations in the target organ have been limited to single parameter analysis in untreated AIH. We retrospectively analysed the pattern of liver infiltrating T, B and regulatory T cells quantitatively with simultaneous multicolour immunofluorescence before (n=45) and under (n=31) therapy in adult AIH type 1 (AIH-1) patients. Intrahepatic CD4(+) cells dominate over CD8(+) at diagnosis, but with increasing disease activity the CD4(+)/CD8(+) ratio approached one. While there is no change of Tregs in the blood, they are enriched with effector T cells (Teffs) within the liver of patients with untreated AIH-1 with a constant Treg/Teff ratio. Even more importantly, immunosuppression mostly with steroids and azathioprine caused a disproportional loss of intrahepatic Tregs. Patients reaching biochemical remission had higher intrahepatic Treg/Teff and Treg/B cell ratios compared to patients failing to reach remission. In vitro proliferation of Tregs seemed to be more suppressed by prednisolone than expansion of Teffs. Furthermore, intraportal B cells correlated with serum IgG suggesting an autochthonous intrahepatic IgG production. Intrahepatic Tregs are rather enriched than numerically deficient in untreated AIH-1. The disproportional decrease of intrahepatic Tregs during therapy might explain high relapse rates after discontinuation of immunosuppression. Thus, future therapies increasing intrahepatic immunoregulation might be better suited for long-term control of AIH.

FOXP3+ regulatory T cells in autoimmune hepatitis are fully functional and not reduced in frequency

The pathogenesis of autoimmune hepatitis (AIH) is not understood, but it was suggested that AIH may be related to a numerical or functional impairment of CD4+CD25+FOXP3+ regulatory T cells (Treg), which are important mediators of immune tolerance to self-antigens. However, the role of Treg in AIH is not clear, since earlier studies reporting Treg impairment had used only CD25 as marker that cannot unambiguously distinguish Treg from activated effector T cells. We assessed the frequency and suppressor function of Treg using current staining protocols that can distinguish Treg from activated effector T cells. The frequency of CD4+CD25(high)CD127(low)FOXP3+ Treg cells in blood of AIH patients was not reduced compared to healthy subjects, as shown by flow cytometry and confirmed by quantifying Treg-specific demethylation of the FOXP3 gene. Moreover, the suppressor function of Treg isolated from AIH patients was similar to that of Treg isolated from healthy subjects, indicating that Treg function was not impaired in AIH patients. However, we observed that the Treg frequency was significantly higher in those AIH patients with active disease than in those who were in a state of remission, suggesting that the Treg frequency may increase with the degree of inflammation. Indeed, analysis of FOXP3+ Treg in liver histology revealed that the intrahepatic Treg frequency was higher in AIH patients than in NASH patients and correlated with the inflammatory activity of the liver. The frequency and function of circulating Treg cells is not impaired in AIH.