Immune-mediated Hepatitis Research Articles

Histologic patterns of liver injury induced by anti-PD-1 therapy.

BackgroundNivolumab and pembrolizumab—two monoclonal antibodies that block human programmed cell death-1 (PD-1)—have been successfully used to treat patients with multiple advanced malignancies. The histologic patterns of hepatic toxicity induced by anti-PD-1 treatment have not been well studied and the aim of this study was to explore them.MethodsEight patients with advanced malignancies who were treated with either nivolumab or pembrolizumab were identified from five institutions. These patients had no history of underlying liver disease and a viral hepatitis panel was negative in all patients.ResultsSeven of eight patients exhibited mild to moderate gastrointestinal symptoms such as abdominal pain, fatigue, nausea, vomiting, and jaundice after anti-PD-1 treatment. Significant elevations in liver-chemistry tests were detected in all patients. Six cases (6/8) demonstrated an acute lobular hepatitis pattern of histologic injury. The remaining two cases showed different histologic patterns of injury: steatohepatitis with mild cholestasis (1/8) and pure acute cholestatic injury (1/8). No case showed typical features of autoimmune hepatitis. The liver function recovered in all eight cases after cessation of anti-PD-1 agents and with immunosuppressive therapy.ConclusionsOur study suggests that screening patients for abnormal liver-function tests prior to anti-PD-1 therapy as well as periodic monitoring of liver-function tests are necessary to prevent severe liver injury. Rather than causing classical autoimmune hepatitis, PD-1 inhibitors appear to produce an immune-mediated nonspecific acute hepatitis. Drug cessation, without steroid therapy, may therefore be sufficient in some patients.

Retinoic acid modulates IL-4, IL-10 and MCP-1 pathways in immune mediated hepatitis and interrupts CD4+ T cells infiltration

AimsImmune mediated liver injury includes activation of different immune pathways that requires various modalities to control their consequences. The current study involves evaluation of retinoic acid (RA) modulatory effects on immune responses induced in concanavalin A (ConA) model of acute hepatitis. Main methodsMice were divided as follows: Control group; RA group: received 35 mg/kg RA; ConA group: received 15 mg/kg ConA; ConA + RA group: received ConA and RA as described. Liver function biomarkers were measured in addition to malondialdehyde as lipid peroxidation biomarker. Liver tissue sections were scored for necro-inflammation, neutrophils infiltration, CD4+ T cells infiltration and NF-κb positive cells. Effect on hepatic levels of TNF-α, IL-4, IL-10 and MCP-1 was evaluated as well. Key findingsInjection of RA before ConA significantly (p < 0.001) decreased ALT, AST and LDH levels compared to their levels in ConA group. Hepatic infiltration of neutrophils and CD4+ T cells was markedly (p < 0.001) reduced by RA. Hepatic injury, necrosis and expression of NF-κb were significantly decreased by RA when injected before ConA challenge. A significant decrease in the measured cytokines TNF-α and IL-4 was observed in ConA + RA group in addition to a decrease in MCP-1 level. On the other hand, IL-10 was significantly increased in the latter group compared to ConA group. SignificanceRA can protect against ConA-induced hepatitis through: interrupting early inflammatory response as neutrophils, monocytes and CD4+ T cells infiltration, modulating IL-4 level and subsequent production of TNF-α and NF-κb activation, mitigating second inflammatory responses through increasing IL-10 liver production.

Safety and efficacy of nivolumab plus ipilimumab (NIVO+IPI) in patients with advanced renal cell carcinoma (aRCC) with brain metastases: Interim analysis of CheckMate 920.

4517 Background: Previous clinical trials of patients (pts) with aRCC, including CheckMate 214, have mostly excluded pts with brain metastases. However, antitumor activity in pts with brain metastases has been observed in pts with melanoma treated with NIVO 1 mg/kg + IPI 3mg/kg and pts with non-small cell lung cancer treated with NIVO 240 mg + IPI 1mg/kg. CheckMate 920 is an ongoing, phase 3b/4 clinical trial of NIVO + IPI treatment in pts with aRCC with a high unmet medical need. Here, we present the safety and efficacy interim results for the cohort of pts with brain metastases. Methods: Pts with previously untreated aRCC of any histology, with asymptomatic brain metastases (not on corticosteroids or receiving radiation), and Karnofsky performance status ≥70% were assigned to treatment with NIVO 3 mg/kg + IPI 1 mg/kg every 3 weeks for 4 doses, followed by NIVO 480 mg every 4 weeks. Pts were treated until disease progression, unacceptable toxicity, or for a maximum of 2 years. The primary endpoint was the incidence of high-grade immune-mediated adverse events (IMAEs). Key secondary endpoints included progression-free survival (PFS) and objective response rate (ORR) by RECIST v1.1 per investigator. Exploratory endpoints included additional safety analyses and overall survival (OS). Results: Overall, 28 patients were enrolled in the brain metastases cohort. With a minimum follow-up of 6.47 months, grade 3-4 IMAEs within 100 days of last dose were reported in 6 cases. The grade 3-4 IMAEs observed in ≥ 1 patient were diarrhea, colitis, diabetic ketoacidosis, immune-mediated hepatitis, hypophysitis, and rash of any type (n = 1 each). No treatment-related grade 5 IMAEs were reported. ORR by RECIST v1.1 per investigator in all treated subjects was 28.6% (95% CI 13.2–48.7). Median PFS in all treated subjects was 9.0 months (95% CI 2.9–not estimable [NE]). Median OS has not been reached (95% CI 13.1–NE). Conclusions: In pts with aRCC and brain metastases who are often excluded from clinical trials, NIVO + IPI treatment showed a safety profile consistent with previous reports of this dosing regimen, with encouraging antitumor activity. Clinical trial information: NCT02982954.

A phase II study of epacadostat and pembrolizumab in patients with advanced sarcoma.

11049 Background: Tumors express IDO1, an intracellular enzyme involved in the degradation of tryptophan to kynurenine, in order to evade immunosurveillance. Epacadostat inhibits IDO1 and shifts the tumor microenvironment from an immunosuppressive state to an immune-stimulated state. Pembrolizumab previously demonstrated activity in select sarcoma subtypes. We performed an open-label, single-center, phase II study of epacadostat and pembrolizumab in patients with advanced sarcoma. Methods: Patients received the recommended phase II dose of oral epacadostat (100mg) twice per day and intravenous pembrolizumab (200mg/dose) every 3 weeks. The primary endpoint was best objective response rate (ORR) (complete response and partial response [PR]) at 24 weeks by RECIST 1.1. Secondary endpoints included adverse events (AEs), ORR by irRECIST, progression free survival (PFS) and overall survival (OS). Correlative studies performed on pre/on-treatment biopsy specimens included PD-L1, IDO1, and kynurenine expression and characterization of tumor infiltrating lymphocytes by IHC, whole exome and RNA sequencing. Results: Twenty-nine patients were enrolled [median age 53 years (range, 24-78), 57% male, ECOG PS 0 83%]. Histological subtypes included leiomyosarcoma (17%), UPS (17%), myxofibrosarcoma (7%), liposarcoma (10.5%), EHE (10.5%), angiosarcoma (3%), “other” sarcoma subtype (35%). Patients were refractory to 0 (21%), 1 (38%), 2 (24%) and ≥ 3 (17%) prior lines of therapy. The most common ( &gt; 20% of pts) grade (G)1 or 2 treatment related AEs (TRAEs) observed included fatigue (31%), rash (31%) and ALT elevation (24%). G3 TRAEs included AST elevation (10%), ALT elevation, anemia, hypophosphatemia and increased lipase each occurred in 3% of pts. Three patients discontinued therapy due to G3 immune mediated hepatitis. Among the 29 evaluable patients 1 (3%) confirmed PR (leiomyosarcoma), 13 stable diseases (45%) and 15 progressions (52%) were observed by RECIST 1.1. The median PFS was 8.0 weeks (two-sided 95% CI: 6.9 ~ 26.7) and the PFS rate at 24 weeks was 27.9% (two-sided 95% CI: 15.0% ~ 52.2%). The median OS was not estimable (two-sided 95% CI: 40.9 weeks ~ NE). The OS at 24 weeks was 85.2% (95% CI: 72.8%, 99.7%). Conclusions: Epacadostat in combination with pembrolizumab was generally well tolerated. Limited anti-tumor activity was observed among advanced sarcoma patients. Correlative analyses including determination of adequacy of IDO1 inhibition will be reported. Clinical trial information: NCT03414229.

Su1089 – Disruption of the Intestinal Barrier Aggravates Immunemediated Hepatitis

Su1089 – Disruption of the Intestinal Barrier Aggravates Immunemediated Hepatitis

The Antidepressant Mirtazapine Inhibits Hepatic Innate Immune Networks to Attenuate Immune-Mediated Liver Injury in Mice.

Activation of the innate immune system, including tissue macrophages and associated neutrophil infiltration, is an important driver of subsequent adaptive immune responses in many autoimmune diseases, including autoimmune hepatitis (AIH). The antidepressant mirtazapine has a unique complex pharmacology, altering signaling through a number of serotonin and histamine receptors that can impact macrophage function; an effect potentially influencing AIH outcome. In the mouse model of concanavalin A (Con A) induced liver injury (mimics many aspects of human AIH), in which early innate immune activation (i.e., stimulated hepatic macrophages/monocytes recruit neutrophils and additional monocytes to the liver) critically drives immune-mediated hepatitis induction, mirtazapine strikingly and dose-dependently inhibited Con A-induced liver injury. This inflammation-suppressing effect of mirtazapine was linked to an attenuation of Con A-stimulated early innate immune responses within the liver, including inhibition of hepatic macrophage/monocyte activation, decreased hepatic macrophage/monocyte-derived pro-inflammatory cytokine (e.g., TNFα) and chemokine (e.g., CXCL1 and CXCL2) production, suppression of Con A-induced increases in the hepatic expression of the neutrophil relevant endothelial cell adhesion molecule ICAM-1, with the resultant significant reduction in neutrophil recruitment into the liver. Consistent with our findings in the Con A model, mirtazapine also significantly reduced activation-induced release of cytokine/chemokine mediators from human CD14+ monocytes in vitro.Conclusion: Our data suggest that mirtazapine can attenuate hepatic innate immune responses that critically regulate the subsequent development of autoimmune liver injury. Therefore, given that it is a safe and widely used medication, mirtazapine may represent a novel therapeutic approach to autoimmune liver disease.

Kctd9 Deficiency Impairs Natural Killer Cell Development and Effector Function.

We previously showed that potassium channel tetramerization domain containing 9 (KCTD9) is aberrantly expressed in natural killer (NK) cells in patients with hepatitis B virus-associated acute-on-chronic liver failure and mice with experimental fulminant hepatitis. However, the mechanism underlying the regulation of NK cell function and fulminant hepatitis progression by KCTD9 is unknown. Here, we investigated the role of Kctd9 in regulation of early development, maturation, and function of NK cells using Kctd9-knockout mice. Compared to wild-type mice, Kctd9-deficient mice exhibited impaired NK cell lineage commitment, as evidenced by selective reduction in the refined NK progenitors, and incomplete NK cell maturation, as manifested by a higher proportion of CD11b− NK cells and a lower percentage of CD11b+ NK cells with high proliferative potential. Moreover, Kctd9-depleted NK cells displayed insufficient IFN-γ production, degranulation, and granzyme B production in response to cytokine stimulation, and attenuated cytotoxicity to tumor cells in vitro. The defect in NK cells was further supported by ameliorated liver damage and improved survival in Kctd9-deficient mice following murine hepatitis virus strain-3 (MHV-3) infection, which otherwise leads to immune-mediated fulminant hepatitis, a phenotype homologous to that caused by NK cell depletion in wild-type mice. Further investigation to identify the underlying mechanism revealed that Kctd9 deficiency hindered the expression of transcription factors, including Ets1, Nfil3, Eomes, and Id2 in NK cells. Collectively, our data reveal that Kctd9 acts as a novel regulator for NK cell commitment, maturation, and effector function.

Hepatotoxicity induced by immune checkpoint inhibitors: a comprehensive review including current and alternative management strategies

ABSTRACTIntroduction: Immune checkpoint inhibitors (ICIs) block cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1)/PD ligand 1 (PD-L1) receptors that control antitumor activities of lymphocytes. While highly efficacious, these drugs have been associated with several immune-related adverse events (irAEs) due to the disruption of self-tolerance. Immune-mediated hepatitis (IMH) usually presents as mild elevations of liver enzymes though it can rarely be associated with life-threatening hepatic injury.Areas covered: A comprehensive review was performed to define the clinicopathologic forms of liver injury associated with ICIs, comparing the various ICI classes as well as comparing this form of IMH with idiopathic autoimmune hepatitis and drug-induced autoimmune hepatitis. Liver biopsy has proven very useful in selected patients. A specific form of fibrin ring granulomatous hepatitis appears to be associated with IMH. The current societal treatment algorithms and emerging data were reviewed to determine when to utilize corticosteroids.Expert opinion: Monitoring for severe ICI-IMH is recommended although acute liver failure remains rare. Most patients with grade 3–4 hepatotoxicity respond to corticosteroids, but a subset of patients with mild hepatitis on liver biopsy resolve without steroids and need to be carefully selected in concert with the consultation of a hepatologist.

Overexpression of KLF14 protects against immune-mediated hepatic injury in mice

The underlying immunopathogenic mechanisms of autoimmune hepatitis (AIH) have not yet been well elucidated. An impairment in regulatory T cells (Tregs) is key to the development of AIH. Krüppel-like factors (KLFs) regulate a broad of cellular processes including immunocyte maturation. KLF14 may regulate Treg differentiation, but the biological functions remain far from elucidated. In this study, we identified the hepatic expression of KLF14 in human and murine liver diseases. Immune-mediated hepatitis was induced by concanavalin A (Con A). A KLF14 recombinant adenoviruses plasmid (Ad-KLF14) was constructed and injected into mice. Tregs were assessed by flow cytometry analysis; inflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), were tested by enzyme-linked immunosorbent assay (ELISA). The expression of KLF14 was suppressed in a time-and dose-dependent manner. Changes in cytokine levels were consistent with the degree of hepatic injury. Overexpression of KLF14 protected the liver from immune-mediated damage in vivo. Ad-KLF14 transfection before Con A challenge increased the frequency of Tregs in liver mononuclear cells (MNCs), and suppressed the expression of cytokines. All of these improvements were completely abrogated after Treg deletion in vivo by intraperitoneal injection of a CD25 antibody. In conclusion, these data suggest that KLF14 plays an as-yet unrecognized role in immune-mediated hepatitis mainly via induced Treg differentiation. Our findings extend the knowledge of the biological function of KLF14 to the autoimmune disease field, and indicate the possibility of KLF14 as a therapeutic target in AIH patients.The underlying immunopathogenic mechanisms of autoimmune hepatitis (AIH) have not been well elucidated. Kruppel-like factors 14 (KLF14) may regulate Treg differentiation, but the biological functions remain unclear. In this study, the authors reveal that KLF14 plays an as yet unrecognized role in immune- mediated hepatitis via induced Treg differentiation and inflammatory cytokine suppression. These findings indicate the possibility of KLF14 as a therapeutic target in AIH patients.

肝臓マクロファージのRAMP1シグナルは免疫肝炎に重要な役割を果たす

肝臓マクロファージのRAMP1シグナルは免疫肝炎に重要な役割を果たす

Eugenol attenuates concanavalin A-induced hepatitis through modulation of cytokine levels and inhibition of mitochondrial oxidative stress

Therapeutic management of hepatitis with conventional drugs alone worsens hepatic functioning in the long term because of sustained oxidative stress. Active compounds from several plant sources have been investigated to counteract this. Eugenol, a phytochemical abundant in various plants, is known for its wide range of pharmacological effects. There is a lacuna in the deeper understanding of its hepatoprotective activity at the molecular level. Our present study aimed to determine the effects of eugenol on the changes in antioxidant components, inflammatory cytokines and modulation of mitochondrial oxidative stress in immune-mediated hepatitis. We employed a model that mimics viral hepatitis using concanavalin A (ConA) to induce T-cell-mediated acute hepatitis. Eugenol increased (P&lt;0.01) antioxidant enzyme activities, including reduced glutathione (GSH)-regenerating enzyme, glutathione reductase, and glucose-6-phosphate dehydrogenase. Its antiinflammatory and antifibrogenic effects were evident from the reduction (P&lt;0.01) in interleukin and tumor necrosis factor levels. Eugenol was found to decrease mitochondrial oxidative stress, which was elevated in hepatitis. The hepatoprotective effects of eugenol were confirmed by histological findings. The current investigation shows that eugenol exerts a hepatoprotective effect through the modulation of different pathways which include restoration of mitochondrial oxidative stress. Eugenol could be a promising candidate for human hepatitis management, warranting preclinical studies.

GPBAR1 Functions as Gatekeeper for Liver NKT Cells and provides Counterregulatory Signals in Mouse Models of Immune-Mediated Hepatitis.

Background & AimsGPBAR1, also known as TGR5, is a G protein–coupled receptor activated by bile acids. Hepatic innate immune cells are involved in the immunopathogenesis of human liver diseases and in several murine hepatitis models. Here, by using genetic and pharmacological approaches, we provide evidence that GPBAR1 ligation attenuates the inflammation in rodent models of hepatitis.Material and methodsHepatitis was induced by concanavalin A (Con A) or α-galactosyl-ceramide (α-GalCer). 6b-Ethyl-3a,7b-dihydroxy-5b-cholan-24-ol (BAR501), a selective agonist of GPBAR1, was administrated by o.s.ResultsIn the mouse models of hepatitis, the genetic ablation of Gpabar1 worsened the severity of liver injury and resulted in a type I NKT cells phenotype that was biased toward a NKT1, a proinflammatory, IFN-γ producing, NKT cells subtype. Further on, NKT cells from GPBAR1–/– mice were sufficient to cause a severe hepatitis when transferred to naïve mice. In contrast, GPBAR1 agonism rescued wild-type mice from acute liver damage and redirects the NKT cells polarization toward a NKT10, a regulatory, IL-10 secreting, type I NKT cell subset. In addition, GPBAR1 agonism significantly expanded the subset of IL-10 secreting type II NKT cells. RNAseq analysis of both NKT cells type confirmed that IL-10 is a major target for GPABR1. Accordingly, IL-10 gene ablation abrogated protection afforded by GPBAR1 agonism in the Con A model.ConclusionPresent results illustrate a role for GPBAR1 in regulating liver NKT ecology. Because NKT cells are an essential component of liver immune system, our data provide a compelling evidence for a GPBAR1-IL-10 axis in regulating of liver immunity.

Immunotherapy for hepatocellular carcinoma: recent advances and future perspectives.

The introduction of immunotherapies has been a major development in the treatment of many advanced cancers, including hepatocellular carcinoma (HCC). We are entering a new era of systemic therapy for advanced HCC associated with an explosion of clinical trial activity. Data from phase I/II studies of checkpoint inhibitors in advanced HCC have been promising, with durable objective response rates of approximately 20% seen (in both first- and second-line settings) and acceptable safety profiles (including immune-mediated hepatitis). Phase III studies evaluating anti-programmed cell death protein 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) antibodies compared with sorafenib are already underway. The potential synergistic effects of anti-PD-1/anti-PD-L1 when used in combination with agents against other checkpoint molecules, systemic therapies, as well as conventional surgical and locoregional therapies are also being explored in upcoming clinical trials. Aside from this, other strategies to harness the immune system, including chimeric antigen receptor-engineered T cells, natural killer cell therapies, and peptide vaccines directed against HCC antigens have entered phase I/II studies. Current limitations of immunotherapies and areas of future research include the accurate assessment and prediction of tumor response, overcoming the immunosuppressive effects of a hypoxic microenvironment, and the management of immune-related hepatitis in patients who already have limited liver reserve.

The Protective Effect of Sheep Placental Extract on Concanavalin A-induced Liver Injury in Mice.

Though the biological effects of human placental extract have been widely studied, it has limited availability and its use poses ethical problems. Thus, domestic animal placental extracts are suggested as alternatives. In this study, the protective effect of sheep placental extract (SPE) on concanavalin A (Con A)-induced liver injury was investigated. BALB/c mice were randomly divided into six groups, including one normal group and five experimental groups, which received different oral doses of SPE (0, 5, 10 and 50 mg/kg) or a mixture of amino acids for 3 days before Con A injection. Compared with Con A-induced model group, the SPE administration significantly decreased serum aminotransaminase activity, alleviated pathological changes, recovered liver antioxidant capacity and prevented the increase of nitric oxide. Secretion of pro-inflammatory cytokines in serum decreased and mRNA expression of hepatic intercellular adhesion molecule-1, interferon-inducible chemokine 10 and inducible nitric oxide synthase were downregulated, while B-cell lymphoma-2 expression increased. The administration of amino acids mixture had no significant effect in most measurements compared with the model group, which indicated proteins and peptides, rather than individual amino acid, were largely responsible for the bioactivity of SPE. The results indicate SPE has potential therapeutic effects against immune-mediated hepatitis.

Serum cytokine profiles and Mac-2 binding protein glycosylation isomer (M2BPGi) level in patients with autoimmune hepatitis.

Autoimmune hepatitis (AIH) is an autoimmune liver disease that is characterized by a progressive destruction of the liver parenchyma and the development of liver fibrosis. We aimed to examine the relationship between circulating cytokines/chemokines and the Mac-2 binding protein glycosylation isomer (M2BPGi) levels in Japanese patients with autoimmune hepatitis (AIH).We investigated the relationship between circulating cytokines/chemokines and M2BPGi levels in Japanese patients with AIH. Seventy-seven patients with well-documented AIH were enrolled in the National Hospital Organization (NHO)-AIH-liver-network database. We measured the serum levels of 20 cytokines in 31 selected AIH patients before and after steroid treatment using multisuspension cytokine array.Eleven cytokines and soluble adhesion molecules were increased in untreated AIH patients compared with treated AIH patients. Among these cytokines and soluble adhesion molecules, soluble intercellular adhesion molecule-1 (sICAM-1) and interferon-γ-inducible protein 10 (IP-10) were most downregulated by steroid therapy in AIH patients. We measured serum sICAM-1 and IP-10 by ELISA and found the levels were significantly higher in AIH patients (n = 77) compared with chronic viral hepatitis C patients (n = 32). Furthermore, there was a positive correlation between sICAM-1 or IP-10 and alanine aminotransferase, total bilirubin, and circulating M2BPGi levels. M2BPGi levels were increased in AIH patients with high stages of liver fibrosis. Additionally, M2BPGi levels were correlated with the histological grade of inflammation in AIH. Circulating M2BPGi levels were significantly reduced by steroid treatment in AIH patients.sICAM-1 and IP-10 are useful markers to assess immune-mediated hepatitis activity in AIH and they correlate with circulating M2BPGi. Serum M2BPGi levels increased in untreated AIH patients with active hepatitis and were decreased by steroid therapy. M2BPGi reflects autoimmune-mediated hepatic inflammation as well as liver fibrosis.

RAMP1 in Kupffer cells is a critical regulator in immune-mediated hepatitis.

The significance of the relationship between the nervous and immune systems with respect to disease course is increasingly apparent. Immune cells in the liver and spleen are responsible for the development of acute liver injury, yet the regulatory mechanisms of the interactions remain elusive. Calcitonin gene-related peptide (CGRP), which is released from the sensory nervous system, regulates innate immune activation via receptor activity-modifying protein 1 (RAMP1), a subunit of the CGRP receptor. Here, we show that RAMP1 in Kupffer cells (KCs) plays a critical role in the etiology of immune-mediated hepatitis. RAMP1-deficient mice with concanavalin A (ConA)-mediated hepatitis, characterized by severe liver injury accompanied by infiltration of immune cells and increased secretion of pro-inflammatory cytokines by KCs and splenic T cells, showed poor survival. Removing KCs ameliorated liver damage, while depleting T cells or splenectomy led to partial amelioration. Adoptive transfer of splenic T cells from RAMP1-deficient mice led to a modest increase in liver injury. Co-culture of KCs with splenic T cells led to increased cytokine expression by both cells in a RAMP1-dependent manner. Thus, immune-mediated hepatitis develops via crosstalk between immune cells. RAMP1 in KCs is a key regulator of immune responses.

Alpha-1 Anti-trypsin Exerts a Hepatoprotective Effect on Immune-mediated Hepatitis and Acetaminophen-induced Liver Injury.

Background and Aims: The serine proteinase inhibitor alpha-1 anti-trypsin (AAT) protects the body against protease activity. Several functions of AAT beyond those attributed to its anti-protease activity have been described, among them immunomodulatory and anti-inflammatory properties. The present study aimed to determine the efficacy of AAT for the treatment of immune-mediated liver injury using the models of concanavalin A-induced immune-mediated hepatitis and acetaminophen -induced liver damage.Methods: AAT was administered to mice subjected to concanavalin A-induced immune-mediated hepatitis or 2 h after acetaminophen-induced liver damage. Mice were followed for changes in serum levels of liver enzymes, liver histology, and for interferon gamma serum levels.Results: Treatment with AAT alleviated concanavalin A-induced immune-mediated liver damage, as demonstrated by a reduction in the serum levels of liver enzymes and interferon gamma, and an improved lymphocyte infiltration into the liver on liver biopsies. Moreover, treatment with AAT was associated with alleviation of the acetaminophen-induced liver injury.Conclusions: AAT exerts an hepatoprotective effect on immune-mediated and drug-induced liver damage. The data support its potential use in patients with immune-associated liver disorders.

Acute Liver Rejection After Exposure to Nivolumab in Treatment of Metastatic Hepatocellular Carcinoma

72 year old man with an orthotropic liver transplantation for hepatitis C with hepatocellular carcinoma (HCC) in 2012, complicated by metastatic HCC with a solitary lung lesion in 2015. Patient was initially treated with stereotactic body radiation with progression of disease in 2017 despite systemic therapy with sorafenib and regorafenib. Due to limited treatment options for progressive lung metastasis and excellent liver graft function, treatment with nivolumab was initiated. On routine monitoring, liver tests became elevated ten weeks after exposure to nivolumab with suspicion for either acute rejection or immune mediated hepatitis. Empiric treatment with oral steroids and an increased tacrolimus trough level to 5 ng/mL from 2-3 ng/ml failed to improve liver tests. A liver biopsy revealed lymphomonocytic infiltrate with endothelitis consistent with moderate acute rejection with Rejection Activity Index of 5. C4D staining was negative. Intravenous immunoglobulin 1 g/kg and methylprednisone 500 mg were employed without a durable response. Thymoglobulin 1.5 mg/kg/day with cumulative dose 6 mg/kg was started for steroid-resistant rejection with good response. Patient's liver enzymes trended down and normalized with addition of mycophenolate mofetil to tacrolimus to maintain remission. Recurrence rate of HCC is approximately 10% in five years in post-transplant population where transplant was performed due to HCC. Despite promising data in advanced HCC of immune checkpoint inhibitors (CPI) like nivolumab, an anti-PD-1 checkpoint inhibitor, these agents have not been studied in liver transplant recipients due to possibility of rejection and fatal liver failure. Current data regarding acute liver rejection caused by CPIs is scant and heterogenous. Most of the fatal rejections are found in the pediatrics population with aggressive fibrolamellar HCC and acute rejection happened within one week. There is a single case report of complete cancer remission with pembrolizumab, for metastatic HCC after live transplant. Here we report a case of acute liver rejection ten weeks after exposure to nivolumab that was resistant to steroids and IVIG. In this case, aggressive second line treatment with thymoglobulin was proven to be effective in the treatment of acute rejection. Factors that contribute to acute graft rejection with CPI use remain unknown and there is a need to develop regimens that optimize tumor response and minimize the risk of allograft rejection.2337_A Figure 1. Alanine aminotransferase/serum glutamic pyruvic transaminase trend2337_B Figure 2. Total bilirubin trend

In drug-induced, immune-mediated hepatitis, interleukin-33 reduces hepatitis and improves survival independently and as a consequence of FoxP3+ T-cell activity.

Immune-mediated, drug-induced hepatitis is a rare complication of halogenated volatile anesthetic administration. IL-4-regulated Th2-polarized reactions initiate this type and other types of hepatitis, while the mechanisms that regulate the severity remain elusive. IL-33 is an innate, IL-4-inducing, Th2-polarizing cytokine that has been detected in patients with liver failure and has been associated with upregulated ST2+Foxp3+CD4+CD25+ T cells; however, roles for IL-33 in drug-induced hepatitis are unclear. We investigated IL-33 in an anesthetic, immune-mediated hepatitis modeled in BALB/c, IL-33-/- and ST2-/- mice, as well as in patients with anesthetic hepatitis. The hepatic IL-33 and ST2 levels were elevated in BALB/c mice (p < 0.05) with hepatitis, and anti-IL-33 diminished hepatitis (p < 0.05) without reducing IL-33 levels. The complete absence of IL-33 reduced IL-10 (p < 0.05) and ST2+Foxp3+CD4+CD25+ T cells (p < 0.05), as well as reduced the overall survival (p < 0.05), suggesting suppressive roles for IL-33 in anesthetic, immune-mediated hepatitis. All of the mice demonstrated similar levels of CD4+ T-cell proliferation following direct T-cell receptor stimulation, but we detected splenic IL-33 and ST2-negative Foxp3+CD4+CD25+ T cells in ST2-/- mice that developed less hepatitis than BALB/c mice (p < 0.05), suggesting that ST2-negative Foxp3+CD4+CD25+ T cells reduced hepatitis. In patients, serum IL-33 and IPEX levels were correlated in controls (r2 = 0.5, p < 0.05), similar to the levels in mice, but not in anesthetic hepatitis patients (r2 = 0.01), who had elevated IL-33 (p < 0.001) and decreased IPEX (p < 0.01). Our results suggest that, in anesthetic, immune-mediated hepatitis, IL-33 does not regulate the CD4+ T-cell proliferation that initiates hepatitis, but IL-33, likely independent of ST2, reduces hepatitis via upregulation of Foxp3+CD4+CD25+ T cells. Further studies are needed to translate the role of IL-33 to human liver disease.

Comparison of lactate and β-hydroxybutyrate in the treatment of concanavalin-A induced hepatitis

Simple metabolites released during physical exercise and fasting like lactate (Lac) and β-hydroxybutyrate (BHB) have recently been shown to possess anti-inflammatory properties. However, the effects of these metabolites in immune mediated hepatitis are still unknown. Accordingly, we investigated the role of Lac, BHB and their combination on experimentally induced hepatic inflammation. Adult male mice were administered concanavalin A (Con A, 15 mg/kg, intravenous) for 12 h. In the treatment groups, mice were treated 1 h after Con A-intoxication with Lac (500 mg/kg, intraperitoneal), BHB (300 mg/kg, intraperitoneal) and their combination. The results demonstrated that Lac and BHB, especially when combined together, alleviated Con A-induced hepatocellular injury (ALT, AST and LDH) and necrosis (hematoxylin-eosin and electron microscopy). These beneficial effects correlated with attenuating Con A-induced elevation in hepatic oxidative stress parameters (MDA and NOx). Mechanistically, administration of Lac and BHB led to inhibition of Con A-induced phosphorylation of JNK and AMPK proteins in the liver to the same extent. These effects were concordant with curbing Con A-mediated overexpression of the pro-inflammatory cytokines TNF-α, IL-6 and IL-12 and activation of the transcription factor NF-κB. The marked anti-inflammatory properties of combining Lac and BHB were attributed to their cooperation in repressing immune cells (monocytes and neutrophils) infiltration to the liver. Unlike BHB, Lac administration markedly induced the reparative STAT3 and ERK phosphorylation in the livers of Con A-intoxicated mice at the early time point. In conclusion, the simultaneous use of Lac and BHB might be an auspicious strategy for limiting immune mediated hepatitis.