A genome-wide association study identified PTPN2 as a population-specific susceptibility gene locus for primary biliary cholangitis.

BACKGROUND AIMS: Previous genome-wide association studies (GWAS) have indicated the involvement of shared (population-non-specific) and non-shared (population-specific) susceptibility genes in the pathogenesis of primary biliary cholangitis (PBC) among European and East-Asian populations. Although a meta-analysis of these distinct populations has recently identified more than 20 novel PBC susceptibility loci, analyses of population-specific genetic architecture are still needed for a more comprehensive search for genetic factors in PBC. APPROACH RESULTS: Protein tyrosine phosphatase non-receptor type 2 (PTPN2) was identified as a novel PBC susceptibility gene locus through a GWAS and subsequent genome-wide meta-analysis involving 2,181 cases and 2,699 controls from the Japanese population (GWAS-lead variant: rs8098858, p=2.6×10-8). In-silico and in-vitro functional analyses indicated that the risk allele of rs2292758, which is a primary functional variant, decreases PTPN2 expression by disrupting Sp1 binding to the PTPN2 promoter in T follicular helper cells (Tfh) and plasmacytoid dendritic cells (pDCs). Infiltration of PTPN2-positive T-cells and pDCs were confirmed in the portal area of the PBC-liver by immunohistochemistry. Furthermore, transcriptomic analysis of PBC-liver samples indicated the presence of a compromised negative feedback loop in-vivo between PTPN2 and IFNG in patients carrying the risk allele of rs2292758. CONCLUSIONS: PTPN2, a novel susceptibility gene for PBC in the Japanese population, may be involved in the pathogenesis of PBC via an insufficient negative feedback loop caused by the PTPN2 risk allele of rs2292758 in IFN signaling. This suggests that PTPN2 could be a potential molecular target for PBC treatment.

Analysis of prognostic factors in patients with self-expandable metallic stents for treatment of malignant gastric outlet obstruction.

BACKGROUND AND AIM: Self-expandable metallic stents (SEMSs) are widely accepted as a less-invasive treatment for malignant gastric outlet obstruction (GOO). However, the factors related to prognosis and stent dysfunction after SEMS placement are not well known, and we aimed to investigate them. METHODS: This was a single-center retrospective cohort study of 212 malignant strictures in 207 patients. Factors related to prolonged overall survival (OS) and time to recurrent GOO (TRGOO) after SEMS placement were evaluated. RESULTS: Improvement of oral intake was confirmed in 179 patients (86%). The median OS was 65 days. A Cox proportional hazards model revealed that lower cancer stage, lower performance status score at the time of SEMS placement, and administration of chemotherapy after SEMS placement were significant predictive factors for prolonged OS. The median OS was 182 days in the group of SEMS followed by chemotherapy (group A) and 43 days in the group of SEMS alone (group B) (p< .0001). Chemotherapy after SEMS implantation contributed to the prolongation of survival in gastric cancer (hazard ratio (HR), 0.12) and pancreatic cancer (HR, 0.41). Furthermore, the cumulative incidence rates of stent dysfunction on day 120 after SEMS placement were 30% in group A and 61% in group B (p=.03). Notably, the preventive effect of chemotherapy on stent dysfunction was significant in pancreatic cancer. CONCLUSIONS: SEMS is a treatment with high technical and clinical success rate for malignant GOO. Furthermore, subsequent chemotherapy prolongs OS especially in gastric cancer, and TRGOO in pancreatic cancer.

Selection of regimens for patients with hepatitis C virus genotype/serotype discrepancy.

In the present study, the usefulness of the resistance-associated variant (RAV) analysis to select direct acting antiviral (DAA) drugs for patients with hepatitis C virus (HCV) genotype/serotype discrepancy was evaluated. The core-genotype and serotype were determined in the 559 patients recruited in the study. The RAV analysis and NS5B-genotype determination were performed in the eight patients who exhibited a genotype/serotype discrepancy. One of these patients exhibited a core-genotype 1b/serotype 2, and detection by RAV analysis was possible in this patient. The other seven patients demonstrated a core-genotype 2/serotype 1, and detection using the RAV analysis was possible in four of them. The NS5B-genotype was 1b in all patients in whom detection using the RAV analysis was possible and was other than 1b in patients in whom detection using the RAV analysis was impossible. The RAV analysis could detect RNA sequences specific to genotype 1b in the NS5A region. Therefore, in patients with genotype/serotype discrepancy in whom detection using the RAV analysis is possible, the treatment regimens should be selected based on the assumption that HCV with genome that is highly homologous to genotype 1b is present in the NS5A region.

Diagnostic performance of a new endoscopic scraper for malignant biliary strictures: a multicenter prospective study.

BACKGROUND AND AIMS: The efficacy of ERCP for histologic diagnosis of malignant biliary strictures is disappointingly low. The aim of this study was to investigate the diagnostic performance of a newly developed endoscopic device with scraping loops in combination with conventional biopsy forceps. METHODS: We performed a multicenter single-arm prospective study. Between February 2013 and December 2014, 123 patients with suspected malignant biliary strictures were enrolled in the study. The new device and conventional biopsy forceps were applied for histologic diagnosis by ERCP. The primary outcome was to evaluate cancer detectability by biopsy forceps, the new device, and their combined use. RESULTS: Of the 123 patients, 119 were diagnosed with a malignant stricture. Sufficient samples were collected in 83.7% (103/123), 93.5% (115/123), and 95.9% (118/123) of patients using biopsy forceps, the new device, and their combination, respectively. Cancer detectability of forceps biopsy, the new device, and their combination were 51.3% (61/119), 64.7% (77/119), and 74.8% (89/119), respectively. The new device had a significantly higher sample yield and cancer detectability than biopsy forceps (P < .01 and P = .018, respectively, McNemar test). Complementary use of the new device with biopsy forceps demonstrated a significantly additive effect in both sample yield and cancer detection (P < .01 each, McNemar test). The new device detected 48.3% (28/58) of cancers that were not diagnosed as malignant by biopsy forceps. CONCLUSIONS: The new endoscopic scraper demonstrated a large sample yield and high cancer detectability. It could be a first-line tissue-sampling device for biliary strictures. (University Hospital Medical Information Network Clinical Trial Registry [UMIN-CTR] (http://www.umin.ac.jp/ctr/index.htm) registration number: UMIN000009895.).

Progression of autoimmune hepatitis is mediated by IL-18-producing dendritic cells and hepatic CXCL9 expression in mice.

UNLABELLED: Clinical manifestations of autoimmune hepatitis (AIH) range from mild chronic to acute, sometimes fulminant hepatitis. However, it is unknown how the progression to fatal hepatitis occurs. We developed a mouse model of fatal AIH by inducing a concurrent loss of forkhead box P3(+) regulatory T cells and programmed cell death-1 (PD-1)-mediated signaling. In this model, dysregulated follicular helper T cells in the spleen are responsible for the induction, and the C-C chemokine receptor 6/C-C chemokine ligand 20 axis is crucial for the migration of these T cells into the liver. Using this fatal AIH model, we aimed to clarify key molecules triggering fatal AIH progression. During progression, T-bet together with interferon (IFN)-γ and C-X-C chemokine receptor (CXCR)3 were highly expressed in the inflamed liver, suggesting helper T (Th)1-type inflammation. T cells that dominantly expanded in the spleen and the inflamed liver were CXCR3-expressing CD8(+) T cells; depletion of these CD8(+) T cells suppressed AIH progression. Expression of one CXCR3 ligand, chemokine (C-X-C motif) ligand (CXCL)9, was elevated in the liver. CXCL9-expressing macrophages/Kupffer cells were colocalized with infiltrating T cells, and in vivo administration of anti-CXCL9 suppressed AIH progression. In addition, serum levels of interleukin (IL)-18, but not IL-1ß, were elevated during progression, and dendritic cells in the spleen and liver highly produced IL-18. In vivo administration of anti-IL-18R suppressed the increase of splenic CXCR3(+) T cells and the progression to fatal AIH. Moreover, tumor necrosis factor alpha, but not IFN-γ, was involved in up-regulating CXCL9 in the liver and for increased serum levels of IL-18. CONCLUSION: These data suggest that, in our mouse model, fatal progression of AIH is mediated by IL-18-dependent differentiation of T cells into Th1 cells and effector T cells, respectively, and that CXCR3-CXCL9 axis-dependent migration of those T cells is crucial for fatal progression.

Splenectomy prolongs the effects of corticosteroids in mouse models of autoimmune hepatitis.

BACKGROUND & AIMS: Most patients with autoimmune hepatitis (AIH) initially respond to treatment with corticosteroids but often experience a relapse after treatment is withdrawn. BALB/c mice with disruption of programmed cell death 1 (PD-1(-/-) mice) that undergo thymectomy 3 days after birth develop a deregulated immune system, have reduced numbers of Foxp3(+) regulatory T cells, and develop fulminant hepatic failure that resembles acute-onset AIH in humans. We examined whether splenectomy overcomes corticosteroid insufficiency and reduces the severity of AIH in these mice. We also developed a mouse model of chronic AIH to investigate the effects of splenectomy. METHODS: After thymectomy, BALB/c PD-1(-/-) mice were treated with dexamethasone before or after induction of AIH; splenectomy was performed in mice that had and had not been treated with dexamethasone. Neonatal C57BL/6 PD-1(-/-) mice underwent thymectomy to create a model of chronic AIH. RESULTS: Injection of dexamethasone before or after induction of AIH prevented development of fatal AIH in BALB/c PD-1(-/-) mice. However, injection of dexamethasone after induction of AIH did not suppress splenic production of follicular helper T cells, and discontinuation of dexamethasone led to a relapse of AIH. Splenectomy (even without administration of dexamethasone) prevented AIH. Neonatal C57BL/6 PD-1(-/-) mice that underwent thymectomy developed chronic hepatitis with fibrosis and hypergammaglobulinemia and produced antinuclear antibodies; AIH was found to be induced in the spleen. Splenectomy reduced liver inflammation in these mice and in BALB/c PD-1(-/-) mice with AIH. CONCLUSIONS: AIH can be induced in mice via disruption of PD-1 and thymectomy; these cause the same disruptions in immune regulation in BALB/c and C57BL/6 mice but produce different phenotypes. Splenectomy overcomes corticosteroid insufficiency in mice and prolongs the effects of dexamethasone.

Interleukin-21 and tumor necrosis factor-α are critical for the development of autoimmune gastritis in mice.

BACKGROUND AND AIM: Autoimmune gastritis (AIG), an organ-specific autoimmune disease, is accompanied by achlorhydria, pernicious anemia, gastric carcinoid tumors, and gastric cancer. Patients with AIG initially respond to corticosteroids but have a great potential to relapse after treatment is withdrawn. This study examines the roles of cytokines in order to identify potential therapeutic options for AIG patients. METHODS: Using a mouse model of AIG, we monitored disease progression and administered antibodies in vivo to block cytokines. RESULTS: We developed a mouse model of AIG with early onset and rapid progression in which neonatal thymectomy (NTx) was performed on programmed cell death 1-deficient (PD-1(-/-) ) mice on the BALB/c background. Using NTx-PD-1(-/-) mice, we found that in AIG lesions, interferon-γ, and tumor necrosis factor (TNF)-α together with interleukin-21 (IL-21) were highly expressed in the inflamed gastric mucosa. In addition, as with the injection of dexamethasone, in vivo administration of either anti-TNF-α or anti-IL-21 suppressed the development of AIG in NTx-PD-1(-/-) mice. CONCLUSIONS: These data reveal the essential role of IL-21 in the development of AIG and suggest that in addition to corticosteroids, anti-TNF-α as well as anti-IL-21 have the potential to induce the remission of AIG, offering additional therapeutic options for AIG patients.

TNF-α is essential in the induction of fatal autoimmune hepatitis in mice through upregulation of hepatic CCL20 expression.

It is unclear what roles TNF-α has in the development of autoimmune hepatitis (AIH) and whether AIH is responsive to anti-TNF-α. We recently developed a mouse model of fatal AIH that develops in PD-1-deficient mice thymectomized three days after birth, finding that CCR6-CCL20 axis-dependent migration of dysregulated splenic T cells is crucial to induce AIH. In this study, we show the indispensable role of TNF-α in the development of AIH. Administering anti-TNF-α prevented the induction, but treatment by anti-TNF-α after the induction did not suppress progression. Administering anti-TNF-α did not prevent splenic T-cell activation, but did suppress hepatic CCL20 expression. In contrast, administering anti-CCL20 suppressed AIH but not elevated serum TNF-α levels. TNF-α stimulation enhanced CCL20 expression in hepatocytes. These findings suggest that TNF-α is essential in the induction of AIH through upregulation of hepatic CCL20 expression, which allows migration of dysregulated splenic T cells.

IFN-γ is reciprocally involved in the concurrent development of organ-specific autoimmunity in the liver and stomach.

Interferon (IFN)-γ acts as a critical proinflammatory mediator in autoimmune processes, whereas it exerts regulatory functions to limit tissue damage associated with inflammation. However, a detailed understanding of the complex roles of IFN-γ in the development of organ-specific autoimmunity is still lacking. Recently, we found that programmed cell death 1-deficient mice thymectomized 3 days after birth (NTx-PD-1(-/-) mice) concurrently developed autoimmune hepatitis (AIH) and autoimmune gastritis (AIG). In this study, we investigated the roles of IFN-γ in the development of AIH and AIG in this mouse model. In NTx-PD-1(-/-) mice, serum levels of IFN-γ were markedly elevated. Neutralization of IFN-γ prevented the development of AIG. However, the same treatment exacerbated hepatic T-cell infiltration in AIH. Because of the loss of anti-proliferative effects by IFN-γ, neutralization of IFN-γ increased T-cell proliferation in the spleen and liver, resulting in exacerbated T-cell infiltration in the liver. On the other hand, in the development of AIG, CD4+ T-cell migration into the gastric mucosa is essential for induction. CCL20 expression was up-regulated in the gastric mucosa, and anti-CCL20 suppressed CD4+ T-cell infiltration into the gastric mucosa. Importantly, anti-IFN-γ suppressed CCL20 expression and infiltration of CD4+ T cells in the gastric mucosa, whereas in vivo injection of recombinant IFN-γ up-regulated CCL20 expression in the stomach, suggesting that IFN-γ is critically involved in CD4+ T-cell accumulation in AIG by up-regulating local CCL20 expression. In conclusion, IFN-γ is involved differently in the development of AIH and of AIG. IFN-γ negatively regulates T-cell proliferation in fatal AIH, whereas it initiates development of AIG. These findings imply that increased production of IFN-γ induced by an organ-specific autoimmunity may trigger the concurrent development of another organ-specific autoimmune disease.

Increased susceptibility to autoimmune gastritis in thymic stromal lymphopoietin receptor-deficient mice.

Thymic stromal lymphopoietin (TSLP), mainly produced by epithelial cells, activates a variety of cell types, including dendritic cells, mast cells, T cells, and B cells. It is involved in the pathogenesis of allergic inflammation in the lung, skin, and gastrointestinal tract. In addition, TSLP promotes Th2-type intestinal immunity against helminth infection and regulates Th1-type inflammation in a mouse model of colitis, suggesting that it plays crucial roles in intestinal immune homeostasis. Although autoimmune gastritis (AIG), mediated by inflammatory Th1 responses, develops in the gastric mucosa, it is not clear whether TSLP is involved in regulating these responses in AIG. The aim of this study was to examine the roles of TSLP in the development of AIG. Because BALB/c mice thymectomized 3 d after birth (NTx mice) develop AIG, we used this model to test the role of TSLP in the development of AIG. We found that in AIG-bearing mice, TSLP was expressed in the inflamed stomach and that the serum anti-parietal cell Ab levels in neonatal thymectomized TSLPR-deficient mice (NTx-TSLPR(-/-) mice) were significantly elevated over those in NTx-TSLPR(+/+) mice. In addition, NTx-TSLPR(-/-) mice exhibited an earlier onset of AIG than that observed in NTx-TSLPR(+/+) mice. The rapid development of AIG in NTx-TSLPR(-/-) mice resulted in more aggressive CD4(+) T cell infiltration and more severe loss of parietal and chief cells in the progression phase of AIG, accompanied by enhanced production of IL-12/23p40 and IFN-γ. Taken together, these data suggested that TSLP negatively regulates the development of AIG.

Dual roles of CagA protein in Helicobacterpylori-induced chronic gastritis in mice.

Cytotoxin-associated gene A (CagA) acts directly on gastric epithelial cells. However, the roles of CagA in host adaptive immunity against Helicobacter pylori (H. pylori) infection are not fully understood. In this study, to investigate the roles of CagA in the development of H. pylori-induced chronic gastritis, we used an adoptive-transfer model in which spleen cells from C57BL/6 mice with or without H. pylori infection were transferred into RAG2(-/-) mice, with gastric colonization of either CagA(+) H. pylori or CagA(-) H. pylori. Colonization of CagA(+) H. pylori but not CagA(-) H. pylori in the host gastric mucosa induced severe chronic gastritis in RAG2(-/-) mice transferred with spleen cells from H. pylori-uninfected mice. In addition, when CagA(+) H. pylori-primed spleen cells were transferred into RAG2(-/-) mice, CD4(+) T cell infiltration in the host gastric mucosa were observed only in RAG2(-/-) mice infected with CagA(+) H. pylori but not CagA(-) H. pylori, suggesting that colonization of CagA(+) H. pylori in the host gastric mucosa is essential for the migration of H. pylori-primed CD4(+) T cells. On the other hand, transfer of CagA(-) H. pylori-primed spleen cells into CagA(+) H. pylori-infected RAG2(-/-) mice induced more severe chronic gastritis with less Foxp3(+) regulatory T-cell infiltration as compared to transfer of CagA(+) H. pylori-primed spleen cells. In conclusion, CagA in the stomach plays an important role in the migration of H. pylori-primed CD4(+) T cells in the gastric mucosa, whereas CagA-dependent T-cell priming induces regulatory T-cell differentiation, suggesting dual roles for CagA in the pathophysiology of H. pylori-induced chronic gastritis.

Dysregulated generation of follicular helper T cells in the spleen triggers fatal autoimmune hepatitis in mice.

BACKGROUND & AIMS: To clarify mechanisms involved in the development of autoimmune hepatitis (AIH), we recently developed a mouse model of spontaneous AIH by inducing a concurrent loss of Foxp3(+) regulatory T cells and programmed cell death 1 (PD-1)-mediated signaling. Fatal AIH in these mice was characterized by severe T-cell infiltration and huge production of antinuclear antibodies (Abs). This study aims to identify induction sites, responsible T-cell subsets, and key molecules for induction of AIH. METHODS: To develop the mouse model of AIH, neonatal thymectomy (NTx) was performed on PD-1-deficient (PD-1(-/-)) mice. We then conducted neonatal splenectomy or in vivo administration of Abs to cytokines, chemokines, or cell-surface molecules. RESULTS: In NTx-PD-1(-/-) mice, either neonatal splenectomy or in vivo CD4(+) T-cell depletion suppressed CD4(+) and CD8(+) T-cell infiltration in the liver. In the induction phase of AIH, splenic CD4(+) T cells were localized in B-cell follicles with huge germinal centers and showed the Bcl6(+) inducible costimulator (ICOS)(+) interleukin (IL)-21(+) IL-21 receptor (IL-21R)(+) follicular helper T (T(FH)) cell phenotype. Blocking Abs to ICOS or IL-21 suppressed T(FH)-cell generation and induction of AIH. In addition, IL-21 produced by T(FH) cells drove CD8(+) T-cell activation. Splenic T(FH) cells and CD8(+) T cells expressed CCR6, and CCL20 expression was elevated in the liver. Administration of anti-CCL20 suppressed migration of these T cells to the liver and induction of AIH. CONCLUSIONS: Dysregulated T(FH) cells in the spleen are responsible for the induction of fatal AIH, and CCR6-CCL20 axis-dependent migration of splenic T cells is crucial to induce AIH in NTx-PD-1(-/-) mice.

[A case of jejunal adenocarcinoma with serum DUPAN-2 elevation].

A 50-year-old woman was admitted to our hospital because of abdominal pain and vomiting. Ileus with ulcerated jejunal tumor was diagnosed and biopsy revealed adenocarcinoma. Because her serum level of DUPAN-2 was high, she was examined by PET scan, which revealed that she had a left ovarian mass in addition to the jejunal tumor. Surgical resection was performed: both tumors were adenocarcinoma, but the ovarian tumor was considered to be metastatic clinically and histologically. Immunostaining for DUPAN-2 was positive in the both tumors. The serum level of DUPAN-2 returned to normal after the surgery, and has been within normal limits for about 3 years without any additional therapy. This case shows a possible relation between small bowel adenocarcinoma and DUPAN-2.

Helicobacter pylori promotes the production of thymic stromal lymphopoietin by gastric epithelial cells and induces dendritic cell-mediated inflammatory Th2 responses.

Helicobacter pylori colonizes the stomach and induces strong, specific local and systemic humoral and cell-mediated immunity, resulting in the development of chronic gastritis in humans. Although H. pylori-induced chronic atrophic gastritis is characterized by marked infiltration of T helper type 1 (Th1) cytokine-producing CD4(+) T cells, almost all of the inflamed gastric mucosae also contain focal lymphoid aggregates with germinal centers. In addition, typical H. pylori-induced chronic gastritis in children, called follicular gastritis, is characterized by B-cell follicle formation in the gastric mucosa. The aim of this study was to examine whether thymic stromal lymphopoietin (TSLP), an epithelial-cell-derived cytokine inducing a dendritic cell (DC)-mediated inflammatory Th2 response, is involved in Th2 responses triggering B-cell activation in H. pylori-induced gastritis. Here, we show that H. pylori triggered human gastric epithelial cells to produce TSLP, together with the DC-attracting chemokine MIP-3alpha and the B-cell-activating factor BAFF. After DCs were incubated with supernatants from H. pylori-infected epithelial cells, the conditioned cells expressed high levels of costimulatory molecules, such as CD80, and triggered naïve CD4(+) T cells to produce high levels of the Th2 cytokines interleukin-4 and interleukin-13 and of the inflammatory cytokines tumor necrosis factor alpha and gamma interferon. In contrast, after incubation of the supernatants with the neutralizing antibodies to TSLP, the conditioned DCs did not prime T cells to produce high levels of Th2 cytokines. These results, together with the finding that TSLP was expressed by the epithelial cells of human follicular gastritis, suggest that H. pylori can directly trigger epithelial cells to produce TSLP. It also suggests that TSLP-mediated DC activation may be involved in Th2 responses triggering B-cell activation in H. pylori-induced gastritis.