Activation of nucleotide-binding oligomerization domain 2 by muramyl dipeptide negatively regulates Toll-like receptor 9-mediated colonic inflammation through the induction of deubiquitinating enzyme A expression.

Mutations in nucleotide-binding oligomerization domain 2 (NOD2) are associated with Crohn's disease (CD). Although NOD2 activation contributes to the maintenance of intestinal homeostasis through the negative regulation of pro-inflammatory cytokine responses mediated by Toll-like receptors (TLRs), the effects of NOD2 activation on interferon (IFN)-α responses induced by TLR9 have been poorly defined. To explore the cross-talk between NOD2 and TLR9, human monocytes or dendritic cells (DCs) were stimulated with NOD2 and/or TLR9 ligands to measure IFN-α production. The severity of dextran sodium sulfate (DSS)-induced colitis was compared in mice treated with NOD2 and/or TLR9 ligands. Expression of IFN-α and IFN-stimulated genes (ISGs) was examined in the colonic mucosa of patients with inflammatory bowel disease (IBD). NOD2 activation reduced TLR9-induced IFN-α production by monocytes and DCs in a deubiquitinating enzyme A (DUBA)-dependent manner. Activation of DUBA induced by the co-stimulation of TLR9 and NOD2 inhibited Lys63-linked polyubiquitination of TRAF3 and suppressed TLR9-mediated IFN-α production. NOD2 activation in hematopoietic cells protected mice from TLR9-induced exacerbation of DSS-induced colitis by down-regulating IFN-α responses and up-regulating DUBA expression. Colonic mucosa of patients with active and remitted IBD phases was characterized by the enhanced and reduced expression of ISGs, respectively. Expression levels of IFN-α and IL-6 positively correlated in the active colonic mucosa of patients with ulcerative colitis and CD, whereas DUBA expression inversely correlated with that of IFN-α in patients with CD. Collectively, these data suggest that DUBA-dependent negative effect of NOD2 on TLR9-mediated IFN-α responses contributes to the maintenance of intestinal homeostasis.

Viral rebound occurrence immediately after drug discontinuation involving neither drug resistance nor latent reservoir.

Some viruses exhibit "rebound" when the administration of antiviral drugs is discontinued. Viral rebound caused by resistance mutations or latent reservoirs has been studied mathematically. In this study, we investigated the viral rebound due to other causes. Since immunity is weaker during antiviral treatment than without the treatment, drug discontinuation may lead to an increase in the viral load. We analyzed the dynamics of the number of virus-infected cells, cytotoxic T lymphocytes, and memory cells and identified the conditions under which the viral load increased upon drug discontinuation. If drug is administered for an extended period, a viral rebound occurs when the ratio of viral growth rate in the absence to that in the presence of the antiviral drug exceeds the "rebound threshold." We analyzed how the rebound threshold depended on the patient's conditions and the type of treatment. Mathematical and numerical analyses revealed that rebound after discontinuation was more likely to occur when the drug effectively reduced viral proliferation, drug discontinuation was delayed, and the processes activating immune responses directly were stronger than those occurring indirectly through immune memory formation. We discussed additional reasons for drugs to cause viral rebound more likely.

Modeling Developmental Changes in Caffeine Clearance Considering Differences between Pre- and Postnatal Period.

Taguchi et al. reported that postmenstrual age (PMA) is a promising factor in describing and understanding the developmental change of caffeine (CAF) clearance. The aim of the present study was to quantify how developmental changes occur and to determine the effect of the length of the gestational period on CAF clearance. We performed a nonlinear mixed effect model (NONMEM) analysis and evaluated the fit of six models. A total of 115 samples were obtained from 52 patients with a mean age of 34.3 ± 18.2 d. The median values of gestational age (GA) and postnatal age (PNA) were 196 and 31 d, respectively. Serum CAF levels corrected for dose per body surface area (BSA) (C/D ratioBSA) were dependent on PMA rather than PNA, which supports the findings of a previous study. NONMEM analysis provided the following final model of oral clearance: CL/F = 0.00603∙WT∙∙0.877GA ≤ 196 L/h. This model takes into account developmental changes during prenatal and postnatal periods separately. The model successfully described the variation in clearance of CAF. Our findings suggest that the dosage of CAF in preterm infants should be determined based not only on body weight (WT) but also on both PNA and GA.

Crosstalk between NOD2 and TLR2 suppresses the development of TLR2-mediated experimental colitis.

Nucleotide-binding oligomerization domain 2 (NOD2) is an intracellular sensor for muramyl dipeptide (MDP), a degradation product of bacterial cell wall peptidoglycan (PGN). PGN stimulates cell-surface Toll-like receptor 2 (TLR2) independently of NOD2, indicating the presence of crosstalk between extracellular TLR2 and intracellular NOD2 upon exposure to PGN. NOD2-deficient mice were sensitive, while TLR2-deficient mice were resistant to experimental colitis induced by intrarectal administration of PGN. Severe colitis in NOD2-deficient mice was accompanied by increased expression of nuclear factor-kappa B-dependent cytokines and decreased expression of autophagy-related 16-like 1 (ATG16L1). MDP activation of NOD2 enhanced autophagy mediated by TLR2 in human dendritic cells. mRNA expression of TLR2 tended to be higher in the colonic mucosa of patients with active ulcerative colitis compared to that of those in remission. Induction of remission was associated with increased mRNA expression of ATG16L1 in both ulcerative colitis and Crohn's disease patients. Conversely, mRNA expression of receptor-interacting serine/threonine-protein kinase 2 was higher in the inflammatory colonic mucosa of patients with active disease than in the non-inflamed mucosa of patients in remission, in both ulcerative colitis and Crohn's disease. These findings highlight the role of NOD2-TLR2 crosstalk in the immunopathogenesis of colitis.

Cytokine and chemokine profiles in ulcerative colitis relapse after coronavirus disease 2019 vaccination.

Coronavirus disease 2019 (COVID-19) vaccines are highly effective; however, vaccine-related adverse events, including autoimmunity, have been reported. Case reports describing relapse or new-onset of ulcerative colitis (UC) after COVID-19 mRNA vaccination are available. However, the molecular mechanisms underlying the development of colonic inflammation associated with COVID-19 mRNA vaccination are poorly understood. Furthermore, it is unclear whether the relapse of UC after COVID-19 vaccination is driven by unique cytokine responses that differ from those of UC not associated with vaccination. mRNAs derived from COVID-19 vaccines are potent inducers of type I IFN response. We encountered three cases of UC relapse after COVID-19 vaccination. mRNA expressions of IFN-α, IFN-ß, IL-1ß, and IL-12/23p40 showed higher tendency in the colonic mucosa of patients with UC associated with vaccination compared with those not associated with vaccination. In contrast, the expressions of C-X-C motif chemokine ligand 9 (CXCL9) and CXCL10 were comparable. Immunofluorescence analyses also showed higher expression of IFN-α in the colonic mucosa of patients with UC associated with COVID-19 vaccination than in those not associated with vaccination. Taken together, these data suggest that the colonic mucosa of patients with UC who relapsed after COVID-19 vaccination was characterized by enhanced type I IFN responses.

Leucine-rich repeat kinase 2 promotes the development of experimental severe acute pancreatitis.

Translocation of gut bacteria into the pancreas promotes the development of severe acute pancreatitis (SAP). Recent clinical studies have also highlighted the association between fungal infections and SAP. The sensing of gut bacteria by pattern recognition receptors promotes the development of SAP via the production of proinflammatory cytokines; however, the mechanism by which gut fungi mediate SAP remains largely unknown. Leucine-rich repeat kinase 2 (LRRK2) is a multifunctional protein that regulates innate immunity against fungi via Dectin-1 activation. Here, we investigated the role of LRRK2 in SAP development and observed that administration of LRRK2 inhibitors attenuated SAP development. The degree of SAP was greater in Lrrk2 transgenic (Tg) mice than in control mice and was accompanied by an increased production of nuclear factor-kappaB-dependent proinflammatory cytokines. Ablation of the fungal mycobiome by anti-fungal drugs inhibited SAP development in Lrrk2 Tg mice, whereas the degree of SAP was comparable in Lrrk2 Tg mice with or without gut sterilization by a broad range of antibiotics. Pancreatic mononuclear cells from Lrrk2 Tg mice produced large amounts of IL-6 and TNF-α upon stimulation with Dectin-1 ligands, and inhibition of the Dectin-1 pathway by a spleen tyrosine kinase inhibitor protected Lrrk2 Tg mice from SAP. These data indicate that LRRK2 activation is involved in the development of SAP through proinflammatory cytokine responses upon fungal exposure.

Activation of the aryl hydrocarbon receptor inhibits the development of experimental autoimmune pancreatitis through IL-22-mediated signaling pathways.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor expressed in hematopoietic and non-hematopoietic cells. Activation of the AhR by xenobiotics, microbial metabolites, and natural substances induces immunoregulatory responses. Autoimmune pancreatitis (AIP) is a chronic fibroinflammatory disorder of the pancreas driven by autoimmunity. Although AhR activation generally suppresses pathogenic autoimmune responses, the roles played by the AhR in AIP have been poorly defined. In this study, we examined how AhR activation affected the development of experimental AIP caused by the activation of plasmacytoid dendritic cells producing IFN-α and IL-33. Experimental AIP was induced in MRL/MpJ mice by repeated injections of polyinosinic-polycytidylic acid. Activation of the AhR by indole-3-pyruvic acid and indigo naturalis, which were supplemented in the diet, inhibited the development of experimental AIP, and these effects were independent of the activation of plasmacytoid dendritic cells producing IFN-α and IL-33. Interaction of indole-3-pyruvic acid and indigo naturalis with AhRs robustly augmented the production of IL-22 by pancreatic islet α cells. The blockade of IL-22 signaling pathways completely canceled the beneficial effects of AhR ligands on experimental AIP. Serum IL-22 concentrations were elevated in patients with type 1 AIP after the induction of remission with prednisolone. These data suggest that AhR activation suppresses chronic fibroinflammatory reactions that characterize AIP via IL-22 produced by pancreatic islet α cells.

Disruption of the intestinal barrier exacerbates experimental autoimmune pancreatitis by promoting the translocation of Staphylococcus sciuri into the pancreas.

Autoimmune pancreatitis (AIP) and IgG4-related disease (IgG4-RD) are new disease entities characterized by enhanced IgG4 antibody responses and involvement of multiple organs, including the pancreas and salivary glands. Although the immunopathogenesis of AIP and IgG4-RD is poorly understood, we previously reported that intestinal dysbiosis mediates experimental AIP through the activation of IFN-α- and IL-33-producing plasmacytoid dendritic cells (pDCs). Because intestinal dysbiosis is linked to intestinal barrier dysfunction, we explored whether the latter affects the development of AIP and autoimmune sialadenitis in MRL/MpJ mice treated with repeated injections of polyinosinic-polycytidylic acid [poly (I:C)]. Epithelial barrier disruption was induced by the administration of dextran sodium sulfate (DSS) in the drinking water. Mice co-treated with poly (I:C) and DSS, but not those treated with either agent alone, developed severe AIP, but not autoimmune sialadenitis, which was accompanied by the increased accumulation of IFN-α- and IL-33-producing pDCs. Sequencing of 16S ribosomal RNA revealed that Staphylococcus sciuri translocation from the gut to the pancreas was preferentially observed in mice with severe AIP co-treated with DSS and poly (I:C). The degree of experimental AIP, but not of autoimmune sialadenitis, was greater in germ-free mice mono-colonized with S. sciuri and treated with poly (I:C) than in germ-free mice treated with poly (I:C) alone, which was accompanied by the increased accumulation of IFN-α- and IL-33-producing pDCs. Taken together, these data suggest that intestinal barrier dysfunction exacerbates AIP through the activation of pDCs and translocation of S. sciuri into the pancreas.

Disentangling the growth curve of microbial culture.

Many researchers have studied the population dynamics of microbe of microbes as a typical example of population dynamics. The Monod equation, which mainly focuses on the growth and stationary phases, is used when plotting a growth curve. However, the growth potential in the late stage of culture has been overlooked. Previous studies considered the direct degradation of products to the limiting substrate. In this study, we considered microbial growth during the stationary phase, which enables us to describe the dynamics precisely. The microbes were divided into two populations: one grew by consuming the limiting substrate and the other degraded the products by metabolism. According to the numerical analysis of our model, microbes may choose one of two strategies: one consumes substrates and expands quickly, and the other grows slowly while cleaning up the environment in which they thrive. Furthermore, we found three types of microbial growth depending on their ability to detect metabolite accumulation. Using experimentally measured data, this model can estimate the dynamics of cell density, the substrates, and the metabolites used. The model's disentangling of growth curves offers novel interpretive possibilities for culture system dynamics.

Impact of Smad4 and p53 mutations on the prognosis of patients with pancreatic ductal adenocarcinoma undergoing chemotherapy.

BACKGROUND: This prospective cohort study evaluated the feasibility of using endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) samples for comprehensive mutational analysis of cancer-related genes using microtissues. METHODS: Fifty patients with suspected pancreatic cancer presenting consecutively at the Kindai University Hospital between January 2018 and January 2019 were enrolled. Cancerous tissues from EUS-FNB were obtained from each tumor and subjected to histological examination and mutational analysis. The primary endpoint was the collection rate of EUS-FNB specimens suitable for comprehensive cancer panels using deep sequencing. Clinical history and genetic variations between the disease control and progressive disease groups of patients on chemotherapy were evaluated as secondary endpoints. RESULTS: The collection rate of EUS-FNB specimens suitable for comprehensive cancer panels using deep sequencing was 93.6%. The cancer panel was sequenced for 25 patients with pancreatic cancer treated initially with systemic chemotherapy. Mutation in p53 and Smad4 were positively and negatively associated, respectively, with disease control at the initial evaluation. The median time to progression in 15 patients with p53 and without Smad4 mutations was 182.0 days; whereas, it was 92.5 days in other 10 patients; this difference was significant (p = 0.020). CONCLUSIONS: Tissue samples from EUS-FNB were suitable for mutational analysis. Pancreatic cancers with p53 and without Smad4 mutations responded better to chemotherapy and had a better prognosis than those others.

High-fat diet aggravates experimental autoimmune pancreatitis through the activation of type I interferon signaling pathways.

Autoimmune pancreatitis (AIP) is an autoimmune disorder of the pancreas characterized by enhanced IgG4 antibody responses and multiple organ involvement. AIP is a pancreatic manifestation of the systemic IgG4-related disease (IgG4-RD). Although AIP and IgG4-RD predominantly occur in middle-aged and elderly men, the roles of eating habits and lifestyle in the pathogenesis of these conditions are poorly understood. In this study, we examined whether a high-fat diet (HFD), preferred by middle-aged and elderly men, increases sensitivity to experimental AIP. We modeled AIP in MRL/MpJ mice by repeated injections of polyinosinic:polycytidylic acid. HFD exacerbated AIP development and promoted pancreatic accumulation of interferon (IFN)-α-producing plasmacytoid dendritic cells (pDCs). However, HFD did not increase the severity of autoimmune sialadenitis, another disorder associated with AIP and IgG4-RD. Neutralization of type I IFN signaling pathways prevented the development of severe AIP induced by HFD. In contrast, leaky gut was less likely to be associated with the HFD-induced exacerbation of AIP, as was evidenced by the lack of significant alterations in the jejunal or ileal expression of tight junction proteins. These data suggest that HFD exacerbates experimental AIP through the activation of pDCs producing IFN-α.

Expression levels of cellular inhibitor of apoptosis proteins and colitogenic cytokines are inversely correlated with the activation of interferon regulatory factor 4.

Cellular inhibitors of apoptosis proteins 1 (cIAP1) and 2 (cIAP2) are involved in signaling pathways mediated by Toll-like receptors (TLRs) and tumor necrosis factor (TNF)-α. Excessive activation of TLRs and TNF-α underlies the immunopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). However, the roles played by cIAP1 and cIAP2 in the development of CD and UC remain poorly understood. In this study, we attempted to clarify the molecular link between cIAP1/cIAP2 and colonic inflammation. Human monocyte-derived dendritic cells (DCs) treated with siRNAs specific for cIAP1 or cIAP2 exhibited reduced pro-inflammatory cytokine responses upon stimulation with TLR ligands. Expression of cIAP1 and cIAP2 in human DCs was suppressed in the presence of interferon regulatory factor 4 (IRF4). This effect was associated with inhibition of cIAP1 and cIAP2 polyubiquitination. To verify these in vitro findings, we created mice overexpressing IRF4 in DCs and showed that these mice were resistant to trinitrobenzene sulfonic acid-induced colitis as compared with wild-type mice; these effects were accompanied by reduced expression levels of cIAP1 and cIAP2. Pro-inflammatory cytokine production by mesenteric lymph node cells upon stimulation with TLR ligands was reduced in mice with DC-specific IRF4 overexpression as compared with that in wild-type mice. Finally, in clinical samples of the colonic mucosa from patients with CD, there was a negative relationship between the percentage of IRF4+ DCs and percentages of cIAP1+ or cIAP2+ lamina propria mononuclear cells. These data suggest that the colitogenic roles of cIAP1 and cIAP2 are negatively regulated by IRF4.

Utility of contrast-enhanced harmonic endoscopic ultrasonography for T-staging of patients with extrahepatic bile duct cancer.

BACKGROUND: The value of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for T-staging in patients with extrahepatic bile duct cancer was evaluated. METHODS: This single-center, retrospective study included consecutive patients with extrahepatic bile duct cancer who underwent surgical resection after preoperative EUS, CH-EUS, and contrast-enhanced CT (CE-CT) examinations between June 2014 and August 2017. The capacity of these modalities for T-staging of extrahepatic bile duct cancer was evaluated by assessing invasion beyond the biliary wall into the surrounding tissue, gallbladder, liver, pancreas, duodenum, portal vein system (portal vein and/or superior mesenteric vein), inferior vena cava, and hepatic arteries (proper hepatic artery, right. and/or left. hepatic artery). Blind reading of EUS, CH-EUS, and CE-CT images was performed by two expert reviewers each. RESULTS: 38 patients were eligible for analysis, of which eight had perihilar bile duct cancer and 30 had distal bile duct cancer. Postoperative T-staging was T1 in 6, T2 in 16, and T3 in 16 cases. CH-EUS was superior to CE-CT for diagnosing invasion beyond the biliary wall into surrounding tissue (92.1% vs. 45.9%, P = 0.0002); the ability to detect invasion to other organs did not differ significantly between the two modalities. The accuracy of CH-EUS for T-staging of tumors was better than that of CE-CT (73.7% vs. 39.5%, P = 0.0059). CH-EUS tended to have a better accuracy than EUS for the diagnosis of invasion beyond the biliary wall into the surrounding tissue (92.1% vs. 78.9%, P = 0.074) and T-staging (73.7% vs. 60.5%, P = 0.074). CONCLUSION: CH-EUS is useful for T-staging of extra hepatic bile duct cancer, especially in terms of invasion beyond the biliary wall into the surrounding tissue.

NOD2 deficiency protects mice from the development of adoptive transfer colitis through the induction of regulatory T cells expressing forkhead box P3.

Nucleotide-binding oligomerization domain 2 (NOD2) is an intracellular receptor for muramyl dipeptide derived from the intestinal microbiota. Loss-of-function mutations in Nod2 are associated with the development of Crohn's disease, suggesting that NOD2 signaling plays critical roles in the maintenance of intestinal immune homeostasis. Although NOD2 activation prevents the development of short-term experimental colitis, it remains unknown whether the sensitivity to long-term experimental colitis is influenced by NOD2. In this study, we explored the roles played by NOD2 in the development of long-term adoptive transfer colitis. Unexpectedly, we found that Rag1-/-Nod2-/- mice were more resistant to adoptive transfer colitis than Rag1-/- mice and had reduced proinflammatory cytokine responses and enhanced accumulation of regulatory T cells (Tregs) expressing forkhead box P3 in the colonic mucosa. Prevention of colitis in Rag1-/-Nod2-/- mice was mediated by TGF-ß1 because neutralization of TGF-ß1 resulted in the development of more severe colitis due to reduced accumulation of Tregs. Such paradoxical Treg responses in the absence of NOD2 could explain why Nod2 mutations in humans are not sufficient to cause Crohn's disease.

Virulence of a virus: How it depends on growth rate, effectors, memory cells, and immune escape.

A viral strain may infect a host, proliferate rapidly, become controlled by immune reactions, and eventually be eliminated from the body. The virulence, or the magnitude of harm to the host due to infection, depends on the abundance and duration of the viral strain in the body, and the importance of the damaged tissue of the host. In this study, we investigated how the cumulative viral load (time-integral of the number of infected cells) depends on various factors, such as the viral growth rate, the effectiveness of immune cells to kill infected cells, speed of immune activation, formation of memory cells, and longevity of immune cells. In addition, viruses may produce a mutant with different antigen types, escape the immune reaction targeting the original type, and inflate virulence. We succeeded in deriving simple and explicit formulas of the virulence in four different parameter regions. We found that, in some parameter region, enhancing memory cells is very effective in suppressing virulence, but direct activation of immune effector cells is not effective; while the opposite is the case in other regions. The result could be important in designing drug suppressing virus effectively. Additionally, we discussed the reported correlation between virulence and molecular evolution rate.

Why meals during resting time cause fat accumulation in mammals? Mathematical modeling of circadian regulation on glucose metabolism.

Synchronization of metabolic rhythms regulated by circadian clock and meal timing is essential for maintaining nutrient homeostasis in response to fluctuating food intake in animals. Despite numerous experimental findings on the involvement of circadian regulation of glucose and lipid metabolism, the optimal regulatory strategy for the maintenance of energy homeostasis remains poorly defined. A mathematical framework is useful to assess the circadian regulation of glycogen production/breakdown and de novo lipogenesis/lipolysis by evaluating the contribution of time of the day-dependent activation or the repression of each metabolic process in the maintenance of energy homeostasis. Here, we present a mathematical model that describes the dynamics of glycogen and triglyceride contents, two major forms of energy storage in the body that provide the fuel needed during different phases of food deprivation. By changing peak phases of glycogenesis and fat synthesis, we searched for the optimal phase set that minimizes the risks of two types of possible metabolic dysfunctions: (1) high blood glucose and (2) energy exhaustion. Based on the optimal phase set, we compared the level of fat accumulation between meal timing in the active and resting periods. Our results showed that an increased fat accumulation by food intake in the resting period can be the byproduct of minimizing energy homeostasis risks in the synchronized feeding schedule that animals adopt in nature. Our finding will be useful to schedule an optimal meal timing to prevent metabolic diseases caused by misalignment of biological and social time in modern society.

Utility of contrast-enhanced harmonic endoscopic ultrasonography for predicting the prognosis of pancreatic neuroendocrine neoplasms.

BACKGROUND AND AIMS: Pancreatic neuroendocrine neoplasms (PanNENs), including Grade 1 (G1) or G2 tumors, can have a poor prognosis. This study investigated the value of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for predicting the prognosis of PanNENs. METHODS: This single-center, retrospective study included 47 consecutive patients who underwent CH-EUS and were diagnosed with PanNEN by surgical resection or EUS-guided fine needle aspiration between December 2011 and February 2016. Patients were divided into aggressive and non-aggressive groups according to the degree of clinical malignancy. CH-EUS was assessed regarding its capacity for diagnosing aggressive PanNEN, the correspondence between contrast patterns and pathological features, and its ability to predict the prognosis of PanNEN. RESULTS: There were 19 cases of aggressive PanNEN and 28 cases of non-aggressive PanNEN. The aggressive group included three G1, four G2, three G3 tumors, three mixed neuroendocrine non-neuroendocrine neoplasms, and six neuroendocrine carcinomas. CH-EUS was superior to contrast-enhanced computed tomography for the diagnosis of aggressive PanNEN (P < 0.001): hypo-enhancement on CH-EUS was an indicator of aggressive PanNEN, with sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 94.7%, 100%, 100%, 96.6%, and 97.9%, respectively. Among G1/G2 PanNENs, cases with hypo-enhancement on CH-EUS had a poorer prognosis than those with hyper/iso-enhancement (P = 0.0009). Assessment of 36 resected specimens showed that hypo-enhancement on CH-EUS was associated with smaller and fewer vessels and greater degree of fibrosis. CONCLUSION: Contrast-enhanced harmonic endoscopic ultrasonography may be useful for predicting the prognosis of PanNENs.

A unique profile of serum cytokines in type 1 autoimmune pancreatitis and chronic rhinosinusitis.

BACKGROUND: Type 1 autoimmune pancreatitis (AIP) is a pancreatic manifestation of IgG4-related disease (IgG4-RD). Although AIP and IgG4-RD are characterized by multiple organ involvement including salivary glands, lung, and kidney, co-occurrence of chronic rhinosinusitis (CRS) and AIP/IgG4-RD has been poorly defined. OBJECTIVE: We explored molecular mechanism accounting for the co-occurrence of CRS and AIP/IgG4-RD. METHODS: Serum concentrations of IFN-α and IL-33 were measured by enzyme-linked immune-sorbent assay. RESULTS: We encountered a patient with concurrent type 1 AIP/IgG4-RD and CRS. Induction of remission by prednisolone (PSL) for type 1 AIP/IgG4-RD led to a marked improvement of CRS. Serum cytokine analysis after PSL treatment revealed a marked reduction in serum concentrations of IFN-α and IL-33, both of which are candidate pathogenic cytokines for AIP/IgG4-RD. CONCLUSIONS: Given that IL-33 is shared as one of pathogenic cytokines by type 1 AIP/IgG4-RD and CRS, enhanced IL33 responses may cause concurrent type 1 AIP/IgG4-RD and CRS.

Immunohistochemical characterization of granulomatosis with polyangiitis exhibiting spontaneous regression.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is characterized by granulomatous inflammation, vasculitis, and elevated levels of serum proteinase 3 (PR3)-anti-neutrophil cytoplasmic antibody (PR3-ANCA). OBJECTIVE: We tried to characterize immune cells accumulated into the lung lesions of a GPA patient exhibiting spontaneous regression. METHODS: Transbronchial lung biopsy (TBLB) samples were subjected to immunohistochemical analyses. RESULTS: Multiple lung nodules were detected by CT. TBLB showed granulomatous inflammation and small vessel vasculitis. This case was diagnosed as GPA based on pathological findings and elevation of PR-3 ANCA levels. Spontaneous disappearance of multiple lung nodules was observed in CT. CD3+ T cells and CD20+ B cells accumulated in the inflammatory lesions surrounding the vessels whereas granulomatous inflammation was mainly comprised of CD3+ T cells and CD68+ macrophages, but not B cells or myeloperoxidase+ neutrophils. CONCLUSIONS: We characterized immune cell compositions of the lung lesions of a patient with GPA exhibiting spontaneous regression.

Intestinal dysbiosis mediates experimental autoimmune pancreatitis via activation of plasmacytoid dendritic cells.

Autoimmune pancreatitis (AIP) is a pancreatic manifestation of a newly proposed disease entity, IgG4-related disease (IgG4-RD), characterized by enhanced IgG4 antibody responses and involvement of multiple organs. We have previously reported that innate immune activation contributes to the development of AIP and IgG4-RD, as these diseases are characterized by the production of IFN-α and IL-33 by plasmacytoid dendritic cells (pDCs) that mediate chronic fibroinflammatory responses. In this study, we investigated the roles played by innate immunity against intestinal microflora in experimental AIP induced in MRL/MpJ mice by repeated administrations of 100 µg of polyinosinic-polycytidylic acid [poly (I:C)]. Bowel sterilization with a broad spectrum of antibiotics inhibited pancreatic accumulation of pDCs producing IFN-α and IL-33, and thereby suppressed the development of AIP. Mice treated with 10 µg of poly (I:C) developed severe AIP equivalent to that induced by 100 µg of poly (I:C) upon co-housing with mice treated with 100 µg of poly (I:C). Fecal microbiota transplantation (FMT) from donor mice treated with 100 µg of poly (I:C) led to the development of severe AIP in the recipient mice upon injection with 10 µg of poly (I:C). Induction of severe AIP in mice with 10 µg of poly (I:C) was associated with pancreatic accumulation of pDCs producing IFN-α and IL-33 in the co-housing and FMT experiments. These data collectively suggest that innate immune responses against intestinal microflora are involved in the development of experimental AIP, and that intestinal dysbiosis increases sensitivity to experimental AIP via activation of pDCs.