The liver-brain-gut neural arc maintains the Treg cell niche in the gut.

Recent clinical and experimental evidence has evoked the concept of the gut-brain axis to explain mutual interactions between the central nervous system and gut microbiota that are closely associated with the bidirectional effects of inflammatory bowel disease and central nervous system disorders1-4. Despite recent advances in our understanding of neuroimmune interactions, it remains unclear how the gut and brain communicate to maintain gut immune homeostasis, including in the induction and maintenance of peripheral regulatory T cells (pTreg cells), and what environmental cues prompt the host to protect itself from development of inflammatory bowel diseases. Here we report a liver-brain-gut neural arc that ensures the proper differentiation and maintenance of pTreg cells in the gut. The hepatic vagal sensory afferent nerves are responsible for indirectly sensing the gut microenvironment and relaying the sensory inputs to the nucleus tractus solitarius of the brainstem, and ultimately to the vagal parasympathetic nerves and enteric neurons. Surgical and chemical perturbation of the vagal sensory afferents at the hepatic afferent level reduced the abundance of colonic pTreg cells; this was attributed to decreased aldehyde dehydrogenase (ALDH) expression and retinoic acid synthesis by intestinal antigen-presenting cells. Activation of muscarinic acetylcholine receptors directly induced ALDH gene expression in both human and mouse colonic antigen-presenting cells, whereas genetic ablation of these receptors abolished the stimulation of antigen-presenting cells in vitro. Disruption of left vagal sensory afferents from the liver to the brainstem in mouse models of colitis reduced the colonic pTreg cell pool, resulting in increased susceptibility to colitis. These results demonstrate that the novel vago-vagal liver-brain-gut reflex arc controls the number of pTreg cells and maintains gut homeostasis. Intervention in this autonomic feedback feedforward system could help in the development of therapeutic strategies to treat or prevent immunological disorders of the gut.

Early Dynamics of MELD Scores Predict Corticosteroid Responsiveness to Severe Acute-Onset Autoimmune Hepatitis.

Timely diagnosis and management of severe acute-onset autoimmune hepatitis (SA-AIH), a potential cause of acute liver failure (ALF), are challenging. An initial trial of corticosteroids (CS) followed by an assessment of clinical responses over 1-2 weeks is advocated by the latest international practice guidelines1,2 and expert reviews.3,4 Consideration of a second-line drug while evaluating for liver transplantation (LT) is also recommended.2 Established predictors of "CS responsiveness" to guide decision-making are nonexistent. Herein, we determined the diagnostic abilities of early dynamics to define CS responsiveness in SA-AIH using the model for end-stage liver disease (MELD) scores.

C-C motif chemokine receptor 9 regulates obesity-induced insulin resistance via inflammation of the small intestine in mice.

AIMS/HYPOTHESIS: Accumulation of adipose tissue macrophages is considered pivotal in the development of obesity-associated inflammation and insulin resistance. In addition, recent studies suggest an involvement of the intestine as the primary organ in inducing hyperglycaemia and insulin resistance. We have reported that the C-C motif chemokine receptor (CCR) CCR9 is associated with intestinal immunity and has a pathogenic role in various liver diseases. However, its contribution to type 2 diabetes is unknown. In the current study, we aimed to clarify the involvement of CCR9 in the pathology of type 2 diabetes and the potential underlying mechanisms. METHODS: To elucidate how CCR9 affects the development of metabolic phenotypes, we examined the impact of CCR9 deficiency on the pathogenesis of type 2 diabetes using male C57BL/6J (wild-type [WT]) and CCR9-deficient (CCR9 knockout [KO]) mice fed a 60% high-fat diet (HFD) for 12 weeks. RESULTS: WT and Ccr9KO mice fed an HFD exhibited a comparable weight gain; however, glucose tolerance and insulin resistance were significantly improved in Ccr9KO mice. Moreover, visceral adipose tissue (VAT) and the liver of Ccr9KO mice presented with less inflammation and increased expression of glucose metabolism-related genes than WT mice. Ccr9 and Ccl25 expression were specifically higher in the small intestine but was not altered by HFD feeding and type 2 diabetes development. Accumulation of IFN-γ-producing CD4+ T lymphocytes and increased intestinal permeability in the small intestine was observed in WT mice following HFD feeding, but these changes were suppressed in HFD-fed Ccr9KO mice. Adoptive transfer of gut-tropic CCR9-expressing T lymphocytes partially reversed the favourable glucose tolerance found in Ccr9KO mice via exacerbated inflammation in the small intestine and VAT. CONCLUSIONS/INTERPRETATION: CCR9 plays a central role in the pathogenesis of type 2 diabetes by inducing an inflammatory shift in the small intestine. Our findings support CCR9 as a new therapeutic target for type 2 diabetes via the gut-VAT-liver axis.

Role of CC chemokine receptor 9 in the progression of murine and human non-alcoholic steatohepatitis.

BACKGROUND & AIMS: The number of patients with non-alcoholic steatohepatitis (NASH) is increasing globally. Recently, specific chemokine receptors have garnered interest as therapeutic targets in NASH. This is the first report to examine the role of the C-C chemokine receptor 9 (CCR9)/C-C chemokine receptor ligand 25 (CCL25) axis, and to reveal its therapeutic potential in NASH. METHODS: Patients with biopsy-proven non-alcoholic liver disease (NAFLD) were recruited and their serum and hepatic chemokine expression was examined. Furthermore, wild-type (WT) and Ccr9-/- mice were fed a high-fat high-cholesterol (HFHC) diet for 24 weeks to establish NASH. RESULTS: Serum CCL25, and hepatic CCR9 and CCL25 expression levels were increased in patients with NASH compared to healthy volunteers. Furthermore, Ccr9-/- mice were protected from HFHC diet-induced NASH progression both serologically and histologically. Flow cytometry and immunohistochemistry analysis showed that CCR9+CD11b+ inflammatory macrophages accumulated in the inflamed livers of HFHC diet-fed mice, while the number was reduced in Ccr9-/- mice. Consistent with human NASH livers, CCR9 was also expressed on hepatic stellate cells (HSCs) in mice with NASH, while CCR9-deficient HSCs showed less fibrogenic potential in vitro. Administration of a CCR9 antagonist hampered further fibrosis progression in mice with NASH, supporting its potential clinical application. Finally, we showed that CCR9 blockade attenuated the development of NAFLD-related hepatocellular carcinoma in HF diet-fed mice injected with diethylnitrosamine. CONCLUSIONS: These results highlight the role of the CCR9/CCL25 axis on macrophage recruitment and fibrosis formation in a murine NASH model, providing new insights into therapeutic strategies for NASH. LAY SUMMARY: Herein, we show that a specific chemokine axis involving a receptor (CCR9) and its ligand (CCL25) contributes to the progression of non-alcoholic steatohepatitis and carcinogenesis in humans and mice. Furthermore, treatment with a CCR9 antagonist ameliorates the development of steatohepatitis and holds promise for the treatment of patients with non-alcoholic steatohepatitis.

Clinical implications with tolvaptan on monitored bioimpedance-defined fluid status in patients with cirrhotic ascites: an observational study.

BACKGROUND: Prognostic value or clinical implications of fluid status monitoring in liver cirrhosis are not fully elucidated. Tolvaptan, an orally available, selective vasopressin V2-receptor antagonist approved for hyponatremia in the United States and European Union. It is also used for cirrhotic ascites at a relatively low dose (3.75 mg to 7.5 mg) in Japan, exerts its diuretic function by excreting electrolyte-free water. We hypothesized that bioimpedance-defined dynamic changes in fluid status allow prediction of response of V2 antagonism and survival in cirrhotic patients. METHODS: In this prospective observational study, 30 patients with decompensated liver cirrhosis who were unresponsive to conventional diuretics were enrolled. Detailed serial changes of body composition that were assessed by using non-invasive bioimpedance analysis (BIA) devices, along with biochemical studies, were monitored at 5 time points. RESULTS: Sixteen patients were classified as short-term responders (53%). Rapid and early decrease of BIA-defined intracellular water, as soon as 6 h after the first dose (ΔICWBIA%-6 h), significantly discriminated responders from non-responders (AUC = 0.97, P < 0.0001). ΔICWBIA%-6 h was highly correlated with the change of BIA-derived phase angle of trunk, e.g. reduced body reactance operated at 50 kHz after 24 h of the first dose of tolvaptan. Lower baseline blood urea nitrogen and lower serum aldosterone were predictive of a rapid and early decrease of ICWBIA. A rapid and early decrease of ICWBIA in response to tolvaptan was also predictive of a better transplant-free survival. CONCLUSIONS: BIA-defined water compartment monitoring may help predict short-term efficacy and survival in decompensated cirrhotic patients treated with tolvaptan.

Sustained virologic response to direct-acting antiviral therapy in patients with chronic hepatitis C and hepatocellular carcinoma: A systematic review and meta-analysis.

BACKGROUND & AIMS: The effect of hepatocellular carcinoma (HCC) on the response to interferon-free direct-acting antiviral (DAA) therapy in patients with chronic hepatitis C (CHC) infection remains unclear. Using a systematic review and meta-analysis approach, we aimed to investigate the effect of DAA therapy on sustained virologic response (SVR) among patients with CHC and either active, inactive or no HCC. METHODS: PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched from 1/1/2013 to 9/24/2018. The pooled SVR rates were computed using DerSimonian-Laird random-effects models. RESULTS: We included 49 studies from 15 countries, comprised of 3,341 patients with HCC and 35,701 without HCC. Overall, the pooled SVR was lower in patients with HCC than in those without HCC (89.6%, 95% CI 86.8-92.1%, I2 = 79.1% vs. 93.3%, 95% CI 91.9-94.7%, I2 = 95.0%, p = 0.0012), translating to a 4.8% (95% CI 0.2-7.4%) SVR reduction by meta-regression analysis. The largest SVR reduction (18.8%) occurred in patients with active/residual HCC vs. inactive/ablated HCC (SVR 73.1% vs. 92.6%, p = 0.002). Meanwhile, patients with HCC who received a prior liver transplant had higher SVR rates than those who did not (p <0.001). Regarding specific DAA regimens, patients with HCC treated with ledipasvir/sofosbuvir had lower SVR rates than patients without HCC (92.6%, n = 884 vs. 97.8%, n = 13,141, p = 0.026), but heterogeneity was high (I2 = 84.7%, p <0.001). The SVR rate was similar in patients with/without HCC who were treated with ombitasvir/paritaprevir/ritonavir ±â€¯dasabuvir (n = 101) (97.2% vs. 94.8%, p = 0.79), or daclatasvir/asunaprevir (91.7% vs. 89.8%, p = 0.66). CONCLUSION: Overall, SVR rates were lower in patients with HCC, especially with active HCC, compared to those without HCC, though heterogeneity was high. Continued efforts are needed to aggressively screen, diagnose, and treat HCC to ensure higher CHC cure rates. LAY SUMMARY: There are now medications (direct-acting antivirals or "DAAs") that can "cure" hepatitis C virus, but patients with hepatitis C and liver cancer may be less likely to achieve cure than those without liver cancer. However, patients with liver cancer are also more likely to have advanced liver disease and risk factors that can decrease cure rates, so better controlled studies are needed to confirm these findings.

Dual effects of the Nrf2 inhibitor for inhibition of hepatitis C virus and hepatic cancer cells.

BACKGROUND: We previously showed that knockdown of nuclear factor E2-related factor 2 (Nrf2) resulted in suppression of hepatitis C virus (HCV) infection. In this study, whether brusatol, an Nrf2 inhibitor, has dual anti-HCV and anticancer effects was explored. METHODS: The anti-HCV effect of brusatol was investigated by analyzing HCV RNA and proteins in a hepatic cell line persistently-infected with HCV, HPI cells, and by analyzing HCV replication in a replicon-replicating hepatic cell line, OR6 cells. Then, dual anti-HCV and anticancer effects of brusatol and enhancement of the effects by the combination of brusatol with anticancer drugs including sorafenib, which has been reported to have the dual effects, were then investigated. RESULTS: Brusatol suppressed the persistent HCV infection at both the RNA and protein levels in association with a reduction in Nrf2 protein in the HPI cells. Analysis of the OR6 cells treated with brusatol indicated that brusatol inhibited HCV persistence by inhibiting HCV replication. Combination of brusatol with an anticancer drug not only enhanced the anticancer effect but also, in the case of the combination with sorafenib, strongly suppressed HCV infection. CONCLUSIONS: Brusatol has dual anti-HCV and anticancer effects and can enhance the comparable effects of sorafenib. There is therefore the potential for combination therapy of brusatol and sorafenib for HCV-related hepatocellular carcinoma.

Detection of bacterial DNA by in situ hybridization in patients with decompensated liver cirrhosis.

BACKGROUND: Spontaneous bacterial peritonitis (SBP) is often difficult to diagnose because bacteria in ascites cannot be detected accurately by conventional culture. In situ hybridization (ISH) was previously developed for rapid detection of genes from bacteria phagocytized by neutrophils. SBP may develop after bacteria enter into the systemic circulation following bacterial translocation. Therefore, we performed ISH to identify bacteria in blood samples collected from patients with decompensated liver cirrhosis (LC). METHODS: In this retrospective study, peripheral blood samples were collected from 60 patients with decompensated LC, and bacteria were detected by both blood culture and ISH. Moreover, 35 patients underwent paracentesis for diagnosis of SBP. RESULTS: Eight of 35 patients were diagnosed with SBP by polymorphonuclear neutrophil counts, and one patient was diagnosed with bacterascites. Seven of the nine patients showed positive results for ISH, whereas bacteria were detected in only two cases by blood culture. Thirty-seven of 60 cases (62%) showed positive results for ISH, whereas only six samples (10%) were positive by blood culture analysis. Compared with the 23 cases of negative ISH, the 37 cases of positive ISH showed a higher frequency of fever, higher Child-Pugh scores, and lower albumin levels. CONCLUSIONS: Detection of bacteria by ISH suggested that bacterial translocation, which cannot be proven by conventional culture, occurred in these patients, and that ISH could be helpful for the early diagnosis of some types of infection and prevention of SBP in these patients.

Simeprevir/pegylated interferon/ribavirin triple therapy for recurrent hepatitis C after living donor liver transplantation.

AIM: Simeprevir (SMV) is a protease inhibitor which demonstrates good tolerability and high antiviral response in patients with hepatitis C. The clinical outcomes of triple therapy using simeprevir, pegylated interferon and ribavirin (SMV/PEG IFN/RBV) for recurrent hepatitis C after living donor liver transplantation (LDLT) have not been well reported. In this study, we assessed the outcomes of patients with recurrent hepatitis C (genotype 1) after LDLT who received triple therapy at our hospital. METHODS: SMV/PEG IFN/RBV was administrated for 12 weeks (triple therapy), followed by another 12 weeks or extended period of PEG IFN/RBV (dual therapy). Virological response, interaction with calcineurin inhibitors and adverse events were retrospectively analyzed. RESULTS: Ten patients with recurrent hepatitis C after LDLT completed 12 weeks of triple therapy. Nine patients achieved rapid or early virological response, and one patient was a non-responder. The nine responders received subsequent dual therapy, and the duration of dual therapy was extended (24 to 36 weeks) in five cases. Although one patient was in relapse 8 weeks after completing the standard duration (12 weeks) of dual therapy, eight patients achieved sustained virological response for 12 weeks (SVR12). The SVR12 rate was 80%. Trough levels of calcineurin inhibitor did not show marked changes after introduction of SMV in all cases. There were no major adverse events associated with SMV. CONCLUSION: SMV treatment may be a safe and effective option for recurrent hepatitis C after LDLT.

C-C motif chemokine receptor 9 positive macrophages activate hepatic stellate cells and promote liver fibrosis in mice.

UNLABELLED: Chemokine receptors mediate migration of immune cells into the liver, thereby promoting liver inflammation. C-C motif chemokine receptor (CCR) 9(+) macrophages are crucial in the pathogenesis of acute liver inflammation, but the role and underlying mechanisms of this macrophage subset in chronic liver injury and subsequent liver fibrosis are not fully understood. We confirmed that tumor necrosis factor alpha (TNF-α)-producing CCR9(+) macrophages accumulated during the initiation of carbon tetrachloride (CCl4 )-induced liver injury, and CCR9 deficiency attenuated the degree of liver damage. Accumulation of CCR9(+) macrophages persisted prominently during the process of liver fibrosis induced by repetitive CCl4 or thioacetamide (TAA)/leptin administration. Increased CCR9 expression was also found on activated hepatic stellate cells (HSCs). Importantly, experimental liver fibrosis was significantly ameliorated in CCR9(-/-) mice compared with wild-type (WT) mice, assessed by α-smooth muscle actin (α-SMA) immunostain, Sirius red staining, and messenger RNA (mRNA) expression levels of α-SMA, collagen 1α1, transforming growth factor (TGF)-ß1, and tissue inhibitor of metalloproteinase (TIMP)-1. Accumulated CD11b(+) macrophages in CCl4 -treated WT mice showed marked increases in TNF, NO synthase-2, and TGF-ß1 mRNA expression compared with CCR9(-/-) mice, implying proinflammatory and profibrogenic properties. Hepatic CD11b(+) macrophages from CCl4 -treated WT mice (i.e., CCR9(+) macrophages), but not CD8(+) T lymphocytes or non-CD11b(+) cells, significantly activated HSCs in vitro compared with those from CCR9(-/-) mice. TNF-α or TGF-ß1 antagonism attenuated CCR9(+) macrophage-induced HSC activation. Furthermore, C-C motif chemokine ligand (CCL) 25 mediated migration and, to a lesser extent, activation of HSCs in vitro. CONCLUSION: Accumulated CD11b(+) macrophages are critical for activating HSCs through the CCR9/CCL25 axis and therefore promote liver fibrosis. CCR9 antagonism might be a novel therapeutic target for liver fibrosis.

The gut-liver axis in hepatobiliary diseases.

Recent advances in the analysis of intestinal bacteria have led to reports of variations in intestinal bacterial levels among hepatobiliary diseases. The mechanisms behind the changes in intestinal bacteria in various hepatobiliary diseases include the abnormal composition of intestinal bacteria, weakening of the intestinal barrier, and bacterial translocation outside the intestinal tract, along with their metabolites, but many aspects remain unresolved. Further research employing clinical studies and animal models is expected to clarify the direct relationship between intestinal bacteria and hepatobiliary diseases and to validate the utility of intestinal bacteria as a diagnostic biomarker and potential therapeutic target. This review summarizes the involvement of the microbiota in the pathogenesis of hepatobiliary diseases via the gut-liver axis.

Granulocyte-monocyte/macrophage apheresis for steroid-nonresponsive or steroid-intolerant severe alcohol-associated hepatitis: A pilot study.

BACKGROUND: Patients with severe alcohol-associated hepatitis (SAH) have a high short-term mortality rate. Unmet needs exist in patients who are refractory to corticosteroids (CS) or are ineligible for early liver transplantation. METHODS: This was a prospective, open-label, nonrandomized pilot study conducted at a liver transplant center in Tokyo, Japan, starting in October 2015. Lille model and Model for End-stage Liver Disease (MELD) score-defined CS nonresponsive or CS-intolerant patients with SAH who fulfilled the inclusion criteria (leukocytosis over 10,000/µL, etc.) were considered for enrollment. The median duration from admission to enrollment was 23 days (IQR, 14-31 days), after standard of care. Granulocyte-monocyte/macrophage apheresis (GMA) performed with Adacolumn twice per week, up to 10 times per treatment course, was evaluated. RESULTS: 13 GMA treatments were conducted through December 2021. Maddrey Discriminant Function was 53.217.7 at admission. The overall survival rate was 90.9% at 90 and 180 days. MELD scores significantly improved, from median (IQRs) of 23 (20-25) to 15 (13-21) after GMA (p<0.0001). Estimated mortality risks using the Lille model and MELD scores significantly improved from 20.9%±16.5% to 7.4%±7.3% at 2 months and from 30.4%±21.3% to 11.6%±10.8% at 6 months, respectively (both p<0.01), and were internally validated. The cumulative rate of alcohol relapse was 35.9% per year. No severe adverse events were observed. In exploratory analysis, granulocyte colony-stimulating factor levels were significantly correlated with prognostic systems such as MELD-Sodium scores after GMA (correlation coefficient= -0.9943, p<0.0001) but not before GMA (p=0.62). CONCLUSIONS: Compared to published studies, GMA is associated with a lower-than-expected 90- and 180-day mortality in patients with CS-nonresponsive or CS-intolerant SAH. GMA may meet the needs as a salvage anti-inflammatory therapy for SAH. (Trial registration: UMIN000019351 and jRCTs No.032180221) (274 words).

Multiple asynchronous recurrence as a predictive factor for refractoriness against locoregional and surgical therapy in patients with intermediate-stage hepatocellular carcinoma.

Development of subclassification of intermediate-stage hepatocellular carcinoma (HCC) by treatment suitability is in demand. We aimed to identify predictors that define treatment refractoriness against locoregional(transarterial chemoembolization(TACE) or thermal ablation) and surgical therapy. This multicenter retrospective study enrolled 1167 HCC patients between 2015 and 2021. Of those, 209 patients were initially diagnosed with intermediate-stage HCC. Treatment refractoriness was defined as clinical settings that meets the following untreatable progressive conditions by TACE (1) 25% increase of intrahepatic tumor, (2) transient deterioration to Child-Pugh class C, (3) macrovascular invasion or extrahepatic spread, within one year. We then analyzed factors contributing to treatment refractoriness. The Child-Pugh score/class, number of tumors, infiltrative radiological type, and recurrence were significant factors. Focusing on recurrence as a predictor, median time to untreatable progression (TTUP) was 17.2 months in the recurrence subgroup whereas 35.5 months in the initial occurrence subgroup (HR, 2.06; 95% CI, 1.44-2.96; P = 0.001). Median TTUP decreased in cases with more later times of recurrence (3-5 recurrences, 17.3 months; ≥ 6 recurrences, 7.7 months). Recurrence, even more at later times, leads to increased treatment refractoriness. Early introduction of multidisciplinary treatment should be considered against HCC patients after multiple recurrent episodes.

CCR9+ macrophages are required for acute liver inflammation in mouse models of hepatitis.

BACKGROUND & AIMS: Antigen-presenting cells (APCs) are involved in the induction of liver inflammation. We investigated the roles of specific APCs in the pathogenesis of acute liver injury in mice. METHODS: We used concanavalin A (con A) or carbon tetrachloride to induce acute liver inflammation in mice and studied the roles of macrophages that express CCR9. RESULTS: After injection of con A, we detected CCR9(+)CD11b(+)CD11c(-) macrophages that express tumor necrosis factor (TNF)-α in livers of mice, whereas CCR9(+)Siglec-H(+)CD11b(-)CD11c(low) plasmacytoid DCs (pDCs), which are abundant in normal livers, disappeared. The CCR9(+) macrophages were also detected in the livers of RAG-2(-/-) mice, which lack lymphocytes and natural killer T cells, after injection of con A. Under inflammatory conditions, CCR9(+) macrophages induced naive CD4(+) T cells to become interferon gamma-producing Th1 cells in vivo and in vitro. CCR9(-/-) mice injected with con A did not develop hepatitis unless they also received CCR9(+) macrophages from mice that received con A; more CCR9(+) macrophages accumulated in their inflamed livers than CCR9(+) pDCs, CCR9(-) pDCs, or CCR9(-) macrophages isolated from mice that had received injections of con A. Levels of CCL25 messenger RNA increased in livers after injection of con A; neutralizing antibodies against CCL25 reduced the induction of hepatitis by con A by blocking the migration of CCR9(+) macrophages and their production of TNF-α. Peripheral blood samples from patients with acute hepatitis had greater numbers of TNF-α-producing CCR9(+)CD14(+)CD16(high) monocytes than controls. CONCLUSIONS: CCR9(+) macrophages contribute to the induction of acute liver inflammation in mouse models of hepatitis.

Successful treatment of refractory enteritis and arthritis with combination of tumour necrosis factor and interleukin-6 inhibition in patients with ulcerative colitis.

An 18 year-old man with autoimmune hepatitis-primary sclerosing cholangitis-overlap syndrome and ulcerative colitis was admitted due to relapsed enteritis and polyarthritis after cessation of infliximab. Colonoscopy and articular ultrasonography revealed large ulcers in the colon with crypt abscess in the specimens and active enthesitis and synovitis, respectively. His intestinitis was improved with golimumab but arthritis was persistent. Golimumab was switched to secukinumab, which was effective for arthritis. However, colitis was flared resulting in total colorectal resection. One month after colectomy, polyarthritis was relapsed. Tocilizumab ameliorated arthritis but enteritis emerged again, and switching tocilizumab to adalimumab improved enteritis but arthritis exacerbated. Finally, we restarted tocilizumab for arthritis with continued adalimumab for enteritis. The dual cytokine blocking strategy, tumour necrosis factor-α and interleukin-6 inhibition, subsided both of his refractory enteritis and arthritis and maintained remission for more than 3 years without any serious adverse event. Our case suggests that enteritis and arthritis in inflammatory bowel disease may be different in pathophysiology and raises the possible usefulness of simultaneous inhibition of two inflammatory cytokines in such cases.

Myeloid TLR4 signaling promotes post-injury withdrawal resolution of murine liver fibrosis.

The fate of resolution of liver fibrosis after withdrawal of liver injury is still incompletely elucidated. Toll-like receptor 4 (TLR4) in tissue fibroblasts is pro-fibrogenic. After withdrawal of liver injury, we unexpectedly observed a significant delay of fibrosis resolution as TLR4 signaling was pharmacologically inhibited in vivo in two murine models. Single-cell transcriptome analysis of hepatic CD11b+ cells, main producers of matrix metalloproteinases (MMPs), revealed a prominent cluster of restorative Tlr4-expressing Ly6c2-low myeloid cells. Delayed resolution after gut sterilization suggested its microbiome-dependent nature. Enrichment of a metabolic pathway linking to a significant increase of bile salt hydrolase-possessing family Erysipelotrichaceae during resolution. Farnesoid X receptor-stimulating secondary bile acids including 7-oxo-lithocholic acids upregulated MMP12 and TLR4 in myeloid cells in vitro. Fecal material transplant in germ-free mice confirmed phenotypical correlations in vivo. These findings highlight a pro-fibrolytic role of myeloid TLR4 signaling after injury withdrawal and may provide targets for anti-fibrotic therapy.

Concurrent de novo Thymoma-associated Paraneoplastic Type 1 Autoimmune Hepatitis and Pure Red Cell Aplasia after Thymectomy: A Case Report and Literature Review.

The precise manipulation of immune tolerance is the holy grail of immunotherapies for both autoimmunity and cancer immunity. Thymomas are well known to be associated with autoimmune diseases. The exact mechanism by which autoreactivity is induced after thymectomy remains to be elucidated. We herein present the case of a 50-year-old lady with concurrent de novo type 1 autoimmune hepatitis (AIH) and pure red cell aplasia (PRCA), 1 month after undergoing a successful total thymectomy for combined squamous cell carcinoma and thymoma (Masaoka stage II). Corticosteroids yielded short-term effects for both AIH and PRCA. Literature on thymoma-associated AIH, an extremely rare immune-related comorbidity, was also reviewed.

IL-15-producing splenic B cells play pathogenic roles in the development of autoimmune hepatitis.

Background & Aims: B-cell depletion therapy with an anti-CD20 is an effective treatment strategy for patients with refractory autoimmune hepatitis (AIH). However, the mechanisms underlying B-cell action are unclear. Methods: Herein, we used the adeno-associated virus IL-12 model, in which hepatic IL-12 expression triggers liver injuries characteristic of AIH. We also analysed the clinical samples of patients with AIH. Results: B-cell depletion using anti-CD20 or splenectomy was found to improve liver functions and decrease the cytotoxic CD8+ T-cell (cytotoxic T lymphocyte [CTL]) count in the liver. This improvement was reversed by the adoptive transfer of splenic B cells derived from AAV IL-12-treated mice to splenectomised mice as it caused the hepatic CTL count to increase. RNA-sequencing analysis identified IL-15 as a key factor in pathogenic B cells, which promotes CTL expansion and subsequent migration to the liver via the CXCL9/CXCR3 axis. Indeed, IL-15 neutralisation ameliorated hepatitis by suppressing splenic and hepatic CTLs in vivo. The close distribution of B220+ B cells and CD8+ T cells in the spleen of AIH mice suggested mutual interactions. Mechanistically, IFNγ and CD40L/CD40 signalling were indispensable for the expression of IL-15 in B cells, and in vitro co-culture experiments revealed that splenic CD40L+CD8+ T cells promoted IL-15 production in B cells, which led to CTL expansion. In patients with AIH, high serum IL-15 concentration and IL-15+ B-cell counts, positively correlating with serum alanine aminotransferase levels, support translation and potential therapeutic targeting in human AIH. Conclusions: This investigation elucidated the roles of IL-15-producing splenic B cells that occur in concert with pathogenic CD8+ T cells during the development of AIH. Impact and Implications: IL-15-producing B cells were shown to exacerbate experimental AIH via cytotoxic T lymphocyte expansion. CD40L+CD8+ T cells promoted IL-15 expression in B cells, indicating the mutual interaction of both cells. High serum IL-15 concentrations, IL-15+ B-cell counts, and CD40L+IL-15Rα+CD8+ T-cell counts were confirmed in the blood of patients with AIH.