The Role of Regulatory CD4 T Cells in Maintaining Tolerance in a Mouse Model of Autoimmune Hepatitis

Cysteinyl leukotriene receptor-1 as a potential target for host-directed therapy during chronic schistosomiasis in murine model

Schistosomiasis remains the most devastating neglected tropical disease, affecting over 240 million people world-wide. The disease is caused by the eggs laid by mature female worms that are trapped in host's tissues, resulting in chronic Th2 driven fibrogranulmatous pathology. Although the disease can be treated with a relatively inexpensive drug, praziquantel (PZQ), re-infections remain a major problem in endemic areas. There is a need for new therapeutic drugs and alternative drug treatments for schistosomiasis. The current study hypothesized that cysteinyl leukotrienes (cysLTs) could mediate fibroproliferative pathology during schistosomiasis. Cysteinyl leukotrienes (cysLTs) are potent lipid mediators that are known to be key players in inflammatory diseases, such as asthma and allergic rhinitis. The present study aimed to investigate the role of cysLTR1 during experimental acute and chronic schistosomiasis using cysLTR1-/- mice, as well as the use of cysLTR1 inhibitor (Montelukast) to assess immune responses during chronic Schistosoma mansoni infection. Mice deficient of cysLTR1 and littermate control mice were infected with either high or low dose of Schistosoma mansoni to achieve chronic or acute schistosomiasis, respectively. Hepatic granulomatous inflammation, hepatic fibrosis and IL-4 production in the liver was significantly reduced in mice lacking cysLTR1 during chronic schistosomiasis, while reduced liver pathology was observed during acute schistosomiasis. Pharmacological blockade of cysLTR1 using montelukast in combination with PZQ reduced hepatic inflammation and parasite egg burden in chronically infected mice. Combination therapy led to the expansion of Tregs in chronically infected mice. We show that the disruption of cysLTR1 is dispensable for host survival during schistosomiasis, suggesting an important role cysLTR1 may play during early immunity against schistosomiasis. Our findings revealed that the combination of montelukast and PZQ could be a potential prophylactic treatment for chronic schistosomiasis by reducing fibrogranulomatous pathology in mice. In conclusion, the present study demonstrated that cysLTR1 is a potential target for host-directed therapy to ameliorate fibrogranulomatous pathology in the liver during chronic and acute schistosomiasis in mice.

CQMUH-011 mitigates autoimmune hepatitis via inhibiting the function of T lymphocytes

CQMUH-011 is a modified adamantane sulfonamide compound, that inhibits macrophage proliferation and possesses anti-inflammatory properties. Here, fresh mouse splenocytes were obtained and stimulated with concanavalin A (ConA, 5 μg/ml) in vitro; and experimental autoimmune hepatitis (AIH) was induced by ConA (20 mg/kg, iv) in vivo, to clarify the protective effects of CQMUH-011 against AIH and its possible mechanisms. Our results demonstrated that CQMUH-011 pretreatment can dose-dependently inhibit the proliferation of splenocytes in vitro. In vivo, CQMUH-011 administration reduced the hepatic histopathological score and the infiltration of lymphocytes in the liver parenchyma; additionally, it downregulated the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and pro-inflammatory cytokines interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in serum, as well as those of methane dicarboxylic aldehyde and myeloperoxidase in the liver tissues. It also down-regulated the expression of p-NF-κB and related proteins in the liver tissues. Furthermore, CQMUH-011 could maintain the balance of CD3+ CD4+ /CD3+ CD8+ and decrease the percentages of CD8+ CD69+ and CD4+ CD25+/- CD69+ T-cells in the splenocytes of ConA-challenged mice. Moreover, we found thatCD4+ CD25+/- CD69+ T-cells were significantly correlated with ALT levels, especially CD4+ CD25- CD69+ T-cells. In conclusion, CQMUH-011 exerts potential protective effects against ConA-induced hepatitis, which may be partially attributed to its inhibition of T cells, especially the suppression of the proliferation of CD4+ CD25- CD69+ and CD8+ CD69+ subsets in the spleen. CQMUH-011 also reduced the early apoptosis of lymphocytes in the thymus.

Stem cell therapies for autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory hepatic disorder which may cause liver fibrosis. Appropriate treatment of autoimmune hepatitis is therefore important. Adult stem cells have been investigated as therapies for a variety of disorders in latest years. Hematopoietic stem cells (HSCs) were the first known adult stem cells (ASCs) and can give rise to all of the cell types in the blood and immune system. Originally, HSC transplantation was served as a therapy for hematological malignancies, but more recently researchers have found the treatment to have positive effects in autoimmune diseases such as multiple sclerosis. Mesenchymal stem cells (MSCs) are ASCs which can be extracted from different tissues, such as bone marrow, adipose tissue, umbilical cord, and dental pulp. MSCs interact with several immune response pathways either by direct cell-to-cell interactions or by the secretion of soluble factors. These characteristics make MSCs potentially valuable as a therapy for autoimmune diseases. Both ASC and ASC-derived exosomes have been investigated as a therapy for autoimmune hepatitis. This review aims to summarize studies focused on the effects of ASCs and their products on autoimmune hepatitis.

Regulatory T cells in autoimmune hepatitis: an updated overview

Regulatory T-cells (Tregs) are key players in the maintenance of immune homeostasis by preventing immune responses to self-antigens. Defects in Treg frequency and/or function result in overwhelming CD4 and CD8 T cell immune responses participating in the autoimmune attack. Perpetuation of autoimmune damage is also favored by Treg predisposition to acquire effector cell features upon exposure to a proinflammatory challenge. Treg impairment plays a permissive role in the initiation and perpetuation of autoimmune liver diseases, namely autoimmune hepatitis, primary biliary cholangitis and primary sclerosing cholangitis. In this Review, we outline studies reporting the role of Treg impairment in the pathogenesis of these conditions and discuss methods to restore Treg number and function either by generation/expansion in the test tube or through in vivo expansion upon administration of low dose IL-2. Challenges and caveats of these potential therapeutic strategies are also reviewed and discussed.

Regulatory T Cells in Autoimmune Hepatitis: Unveiling Their Roles in Mouse Models and Patients

Autoimmune hepatitis (AIH) is a severe and chronic liver disease, and its incidence has increased worldwide in recent years. Research into the pathogenesis of AIH remains limited largely owing to the lack of suitable mouse models. The concanavalin A (ConA) mouse model is a typical and well-established model used to investigate T cell-dependent liver injury. However, ConA-induced hepatitis is acute and usually disappears after 48 h; thus, it does not mimic the pathogenesis of AIH in the human body. Several studies have explored various AIH mouse models, but as yet there is no widely accepted and valid mouse model for AIH. Immunosuppression is the standard clinical therapy for AIH, but patient side effects and recurrence limit its use. Regulatory T cells (Tregs) play critical roles in the maintenance of immune homeostasis and in the prevention of autoimmune diseases, which may provide a potential therapeutic target for AIH therapy. However, the role of Tregs in AIH has not yet been clarified, partly because of difficulties in diagnosing AIH and in collecting patient samples. In this review, we discuss the studies related to Treg in various AIH mouse models and patients with AIH and provide some novel insights for this research area.

Attenuation of Experimental Autoimmune Hepatitis in Mice with Bone Mesenchymal Stem Cell-Derived Exosomes Carrying MicroRNA-223-3p

MicroRNA-223-3p (miR-223-3p) is one of the potential microRNAs that have been shown to alleviate inflammatory responses in pre-clinical investigations and is highly encased in exosomes derived from bone mesenchymal stem cells (MSC-exosomes). MSC-exosomes are able to function as carriers to deliver microRNAs into cells. Autoimmune hepatitis is one of the challenging liver diseases with no effective treatment other than steroid hormones. Here, we examined whether MSC-exosomes can transfer miR-223-3p to treat autoimmune hepatitis in an experimental model. We found that MSC-exosomes were successfully incorporated with miR-223-3p and delivered miR-223-3p into macrophages. Moreover, there was no toxic effect of exosomes on the macrophages. Furthermore, treatments of either exosomes or exosomes with miR-223-3p successfully attenuated inflammatory responses in the liver of autoimmune hepatitis and inflammatory cytokine release in both the liver and macrophages. The mechanism may be related to the regulation of miR-223-3p level and STAT3 expression in the liver and macrophages. These results suggest that MSC-exosomes can be used to deliver miR-223-3p for the treatment of autoimmune hepatitis.

Foxp3⁺ Treg Cells Are Associated with Pathological Process of Autoimmune Hepatitis by Activating Methylation Modification in Autoimmune Hepatitis Patients

Background

Autoimmune hepatitis (AIH) is a chronic hepatic disorder. This study investigated role of Foxp3⁺ regulatory T cells (Treg) and methylation-regulated Tregs in AIH pathological processes.

Material/Methods

Forty consecutive patients diagnosed with hepatitis were enrolled and divided into a virus hepatitis (n=20) group and an AIH group (n=20). Twenty healthy individuals were assigned to the healthy control group (HC, n=20), Liver function biomarkers were detected on an automatic biochemical analyzer. Serum auto-antibodies were evaluated using immunofluorescence method. Histopathological evaluation was conducted with liver tissues. Treg cells were counted using FACS flow cytometry. Peripheral lymphocytes surface/intracellular biomarkers, CD4⁺CD25⁺, CD127, and Foxp3, were examined. Serum cytokines were evaluated using cytometric bead array. Methylation-specific PCR (MS-PCR) was conducted to identify the status of Foxp3 gene methylation.

Results

Levels of liver function biomarkers were significantly increased in the AIH group compared to the HC group (p<0.05). Levels of ANA and ASMA were significantly enhanced in the AIH group compared to the HC group (p<0.05). Other auto-antibodies, including anti-AHA, anti-ribosome P protein, and anti-RO-52, were also discovered in the AIH group. Severe lymphocytic infiltration and inflammatory cells clustering were discovered in AIH patients. There were significantly fewer CD4⁺CD25⁺ T cells in the AIH group, and interleukin 6 (IL-6) and IL-10 levels were significantly decreased compared to the HC group (p<0.05). CD127⁺ Treg and Foxp3⁺ Treg expressions were decreased in the AIH group compared to the HC group (p<0.05). Foxp3 in Treg cells of AIH patients exhibited higher methylation frequency compared to that of HC patients (p<0.05).

Conclusions

Foxp3⁺ regulatory T cells were involved in pathological processes by activating methylation modification in autoimmune hepatitis patients.

Dual effect of T helper cell 17 (Th17) and regulatory T cell (Treg) in liver pathological process: From occurrence to end stage of disease

Liver disease is a complicated pathological status with acute or chronic progressions, causing a series of damages to liver and massive burden to public health and society. Th17 and Treg, two subsets of CD4⁺ T helper cells, seem to keep a subtle balance in the maintenance of organic immune homeostasis including liver. The dysfunction of Th17/Treg balance in liver has been proved associated with hepatic injury and disease. Herein, we summarized the research advance of Th17 and Treg cells in different phenotypes of liver diseases in the past decade. It is known to all that hepatic diseases start from stimulations or infections like virus, autoimmune, alcohol and so on in the early stage, which would cause inflammation. With the disease consistently existed, severe outcomes like cirrhosis and hepatocellular carcinoma appear finally. In conclusion, it is found that Th17 and Treg cells serve as an important role in the immune response imbalance of liver diseases from the beginning to the end stage. However, the effect of these two subsets of CD4⁺ T helper cells is not a stereotype. Pathological role which exacerbates the disease and protective character which inhibits damage to liver are co-existed in the effect of Th17 and Treg cells. Still, more studies should be carried out to enrich the understandings of liver disease and Th17/Treg immune balance in the future.

Inhibition of microRNA-155 attenuates concanavalin-A-induced autoimmune hepatitis by regulating Treg/Th17 cell differentiation

Autoimmune hepatitis (AIH) is a chronic progressive autoimmune disease characterized by hepatic inflammation. This study aimed to investigate the effect of antagomir-155 on concanavalin A (ConA)-induced AIH, and its possible mechanisms. According to the results, the expression of miR-155 was raised in liver tissues after 48 h exposure to ConA. Treatment with antagomir-155 attenuated ConA-induced liver injury in mice by reducing serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels. In addition, antagomir-155 significantly alleviated the differentiation of Treg/Th17 cells in the livers of AIH mice, and suppressed Th17-cells-mediated production of pro-inflammatory cytokines IL-17A, IL-23, but not Treg-cells-mediated production of anti-inflammatory cytokine IL-10. Finally, the beneficial effect of antagomir-155 on ConA-induced AIH was abolished by administration of recombinant IL-17A. Our data demonstrated that antagomir-155 treatment could prevent AIH via regulating the differentiation of Treg and Th17 cells, suggesting that microRNA-155 may be an intriguing therapeutic target of AIH.

Adoptive immunotherapy for autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease caused by an autoimmune disorder, which has attracted more and more attention due to its unique clinical and pathological features. European epidemiological data show that the incidence of AIH is increasing year by year, but its pathogenesis is not yet clear, and the targeted treatments are limited. Immunotherapy of autoimmune hepatitis has been extensively studied in recent years, especially in the area of adoptive immunotherapy. In this paper, we summarize the functional mechanism and clinical applications of adoptive immunotherapy with different kinds of immunocompetent cells in the treatment of AIH.

Liver tissue metabolically transformed by alcohol induces immune recognition of liver self-proteins but not in vivo inflammation

Precision-cut liver slices (PCLSs) provide a novel model for studies of alcoholic liver disease (ALD). This is relevant, as in vivo ethanol exposure does not appear to generate significant liver damage in ethanol-fed mice, except in the National Institute on Alcohol Abuse and Alcoholism binge model of ALD. Previous studies have shown that the two metabolites of ethanol consumption, malondialdhyde (MDA) and acetaldehyde (AA), combine to form MDA-AA (MAA) adducts, which have been correlated with the development and progression of ALD. In this study, murine PCLSs were incubated with ethanol and examined for the production of MAA adducts. PCLSs were homogenized, and homogenates were injected into C57BL/6 mice. PCLSs from control-, pair-, and ethanol-fed animals served as targets in in situ cytotoxic assays using primed T cells from mice hyperimmunized with control or ethanol-exposed PCLS homogenates. A CD45.1/CD45.2 passive-transfer model was used to determine whether T cells from the spleens of mice hyperimmunized with PCLS ethanol-exposed homogenates trafficked to the liver. PCLSs incubated with ethanol generated MAA-modified proteins in situ. Cytotoxic (CD8⁺) T cells from immunized mice killed naïve PCLSs from control- and pair-fed mice in vitro, a response that was blunted in PCLSs from ethanol-fed mice. Furthermore, CD45.1 CD8⁺ T cells from hyperimmunized mice trafficked to the liver but did not initiate liver damage. This study demonstrates that exposure to liver tissue damaged by ethanol mediates robust immune responses to well-characterized alcohol metabolites and native liver proteins in vitro. Moreover, although these proinflammatory T cells traffic to the liver, these responses appear to be dampened in vivo by locally acting pathways. NEW & NOTEWORTHY This study shows that the metabolites of ethanol and lipid breakdown produce malondialdehyde-acetaldehyde adducts in the precision-cut liver slice model system. Additionally, precision-cut liver slices exposed to ethanol and harboring malondialdehyde-acetaldehyde adducts generate liver-specific antibody and T cell responses in the spleens of naïve mice that could traffic to the liver.

The Imbalance between Foxp3+Tregs and Th1/Th17/Th22 Cells in Patients with Newly Diagnosed Autoimmune Hepatitis

This study is aimed at examining the potential role of regulatory T- (Treg-) Th1-Th17-Th22 cells in the pathogenic process of autoimmune hepatitis (AIH). The numbers of Foxp3⁺Tregs and Th1, Th17, and Th22 cells were measured in 32 AIH patients using flow cytometry. Moreover, a murine model of experimental autoimmune hepatitis (EAH) was also established and used to investigate the function of Treg-Th1-Th17-Th22 cells in disease progression. AIH patients undergoing an active state had significantly decreased numbers of CD3⁺CD4⁺CD25⁺Foxp3⁺Tregs and increased numbers of CD3⁺CD4⁺CD25^-Foxp3⁺T, CD3⁺CD4⁺IFN-γ⁺Th1, CD3⁺CD4⁺IL-17⁺Th17, and CD3⁺CD4⁺IL-2⁺Th22 cells as well as higher levels of Th1/Th17/Th22-type cytokines compared to AIH patients in remission and HC. Additionally, the numbers of CD3⁺CD4⁺CD25⁺Foxp3⁺Tregs were negatively correlated with the numbers of Th1-Th17-Th22 cells. Also, the serum levels of IL-17A and IL-22 were correlated positively with liver injury (ALT/AST), whereas the serum levels of IL-10 were correlated negatively with hypergammaglobulinaemia (IgG, IgM) in AIH patients. Interestingly, the percentages of spleen Tregs, expression of Foxp3 mRNA, and liver IL-10 levels decreased, whereas the percentages of spleen Th1-Th17-Th22 cells, expression of T-bet/AHR/RORγt mRNA, and liver IFN-γ, IL-17, and IL-22 levels increased in the murine model of EAH. Our findings demonstrated that an imbalance between Tregs and Th1-Th17-Th22 cells might contribute to the pathogenic process of AIH.

Environmental peer pressure: CD4+ T cell help in tolerance and transplantation

The liver participates in a multitude of metabolic functions that are critical for sustaining human life. Despite constant encounters with antigenic-rich intestinal blood, oxidative stress, and metabolic intermediates, there is no appreciable immune response. Interestingly, patients undergoing orthotopic liver transplantation benefit from a high rate of graft acceptance in comparison to other solid organ transplant recipients. In fact, cotransplantation of a donor liver in tandem with a rejection-prone graft increases the likelihood of graft acceptance. A variety of players may account for this phenomenon including the interaction of intrahepatic antigen-presenting cells with CD4⁺ T cells and the preferential induction of forkhead box P3 (Foxp3) expression on CD4⁺ T cells following injurious stimuli. Ineffective insult management can cause chronic liver disease, which manifests systemically as the following: antibody-mediated disorders, ineffective antiviral and antibacterial immunity, and gastrointestinal disorders. These sequelae sharing the requirement of CD4⁺ T cell help to coordinate aberrant immune responses. In this review, we will focus on CD4⁺ T cell help due to the shared requirements in hepatic tolerance and coordination of extrahepatic immune responses. Overall, intrahepatic deviations from steady state can have deleterious systemic immune outcomes and highlight the liver's remarkable capacity to maintain a balance between tolerance and inflammatory response while simultaneously being inundated with a panoply of antigenic stimuli. Liver Transplantation 24 89-97 2018 AASLD.

Evaluation of the toxicity of iron-ion irradiation in murine bone marrow dendritic cells via increasing the expression of indoleamine 2,3-dioxygenase 1

High linear energy transfer radiation is known to deposit higher energy in tissues and cause greater toxicity compared to low-LET irradiation. Local immunosuppression is frequently observed after irradiation (IR). Dendritic cells (DCs) play important roles in the initiation and maintenance of the immune response. The dysfunction of DCs contributes to tumor evasion and growth. However, molecular mechanisms underlying the establishment of immune tolerance induced by heavy ion IR through this DC population are poorly understood. Therefore, here we report our findings on the dysfunction of bone marrow-derived dendritic cells (BMDCs) induced by 1 Gy iron ion radiation and promotions of expressions of JNK1/2/3, indoleamine 2,3-dioxygenase 1 (IDO1), p-ERK1/2 and p38/MAPK; and decrease of IDO2, MHC class II, CD40, CD80 expressions and IFN-γ and TNF-α secretion after total-body IR in mice. JNK+IDO1+ BMDCs showed up-expression of p-ERK1/2 and p-p38/MAPK, reduced expression of MHC class II and CD80, and were not able to effectively stimulate allogeneic spleen T cells. The inhibition of IDO1 expressions could partly restore the function of BMDCs. In all, our study shows that elevated JNK and IDO1 expression induced by Fe ion IR could result in dysfunction of BMDCs via p-p38/MAPK and p-ERK1/2 signal pathway, and it may represent a new mechanism in radiation-induced immune tolerance.

Crosstalk between type II NKT cells and T cells leads to spontaneous chronic inflammatory liver disease

BACKGROUND & AIM

Natural killer T (NKT) cells are CD1d-restricted innate-like T cells that modulate innate and adaptive immune responses. Unlike the well-characterized invariant/type I NKT cells, type II NKT cells with a diverse T cell receptor repertoire are poorly understood. This study defines the pathogenic role of type II NKT cells in the etiology of chronic liver inflammation.

METHODS

Transgenic mice with the Lck promoter directing CD1d overexpression on T cells in Jα18 wild-type (Lck-CD1dTgJα18⁺; type I NKT cell sufficient) and Jα18-deficient (Lck-CD1dTgJα18^o, type I NKT cell deficient) mice were analyzed for liver pathology and crosstalk between type II NKT cells and conventional T cells. CD1d expression on T cells in peripheral blood samples and liver sections from autoimmune hepatitis patients and healthy individuals were also examined.

RESULTS

Lck-CD1dTgJα18^o and Lck-CD1dTgJα18⁺ mice developed similar degrees of liver pathology resembling chronic autoimmune hepatitis in humans. Increased CD1d expression on T cells promoted the activation of type II NKT cells and other T cells. This resulted in T_h1-skewing and impaired T_h2 cytokine production in type II NKT cells. Dysfunction of type II NKT cells was accompanied by conventional T cell activation and pro-inflammatory cytokine production, leading to a hepatic T/B lymphocyte infiltration, elevated autoantibodies and hepatic injury in Lck-CD1dTg mice. A similar mechanism could be extended to humans as CD1d expression is upregulated on activated human T cells and increased presence of CD1d-expressing T cells was observed in autoimmune hepatitis patients.

CONCLUSIONS

Our data reveals enhanced crosstalk between type II NKT cells and conventional T cells, leading to a T_h1-skewed inflammatory milieu, and consequently, to the development of chronic autoimmune liver disease. Lay summary: CD1d overexpression on T cells enhances crosstalk between type II NKT cells and T cells, resulting in their aberrant activation and leading to the development of chronic autoimmune liver disease.

Anti‑inflammatory effects of oxymatrine on rheumatoid arthritis in rats via regulating the imbalance between Treg and Th17 cells

Oxymatrine (OMT), a monosomic alkaloid extracted from the Chinese herb, Sophora flavescens Ait, has long been used as a traditional Chinese medicine for the treatment of inflammatory diseases. The aim of the present study was to investigate the potential anti‑inflammatory effect of OMT, and its modulation on imbalance between regulatory T (Treg) cells and T helper (Th) 17 cells in rats with collagen‑induced arthritis (CIA). Sprague‑Dawley rats were immunized with type II collagen and following a second collagen immunization, the rats were treated with OMT or dexamethasone (DXM) intraperitoneally once a day for 43 days. Paw swelling, arthritic score and joint histopathology were evaluated. The Treg/Th17‑mediated autoreactive response was assessed by determining serum levels of inflammatory response cytokines, including tumor necrosis factor (TNF)‑α and interleukin (IL)‑17, using an enzyme‑linked immunosorbent assay. The mRNA levels of forkhead box P3 (FOXP3) and retinoic acid‑related orphan receptor (ROR)γt in spleen cells stimulated with type II collagen were determined using reverse transcription‑quantitative polymerase chain reaction analysis. In addition, the protein expression levels of FOXP3 and RORγt were measured using western blot analysis. The results showed that OMT treatment significantly reduced the severity of CIA, markedly abrogating paw swelling, arthritic scores and synovial hyperplasia, and the increased loss in body weight. OMT significantly reduced the production of TNF‑α and IL‑17A, upregulated FOXP3 and downregulated RORγt in rats with CIA. In conclusion, the present study demonstrated that OMT exhibited a protective effect on rheumatoid arthritis (RA) through the inhibition of inflammation and regulation of Treg/Th17 in the CIA rats, suggesting that OMT may be used as an immune suppressive and cartilage protective medicine in human RA.

De novo autoimmune hepatitis after liver transplantation: A focus on glutathione S-transferase theta 1

De novo autoimmune hepatitis (DAIH) is a rare clinical condition with features that resemble those of autoimmune hepatitis (AIH) in patients undergoing liver transplantation (LT) for nonautoimmune liver disease. The diagnosis of this entity has been based on the presence of biochemical and histological patterns similar to those observed in the primary AIH, although several considerations must be taken into account. The impact of DAIH on graft survival is relevant, and early diagnosis and treatment is associated with a good longterm outcome. Although glutathione S-transferase theta 1 (GSTT1) alloimmune recognition has been shown to be involved in the pathogenesis of DAIH, further studies are necessary to fully determine its pathogenic mechanisms and risk factors. We review the pathophysiology, the most common histological patterns, the treatment strategies, and the longterm outcomes of DAIH after LT with a special focus on GSTT1. Liver Transplantation 23:75-85 2017 AASLD.