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Background Vedolizumab is a widely used and safe therapy in inflammatory bowel disease, particularly in ulcerative colitis (UC), making it a promising candidate for enhanced efficacy by combining it with additional immunomodulatory medications. In this study, we studied the impact of vedolizumab monotreatment vs vedolizumab coadministration with other immunomodulatory drugs on intestinal inflammation and intestinal immune cells in vivo. Methods Colon tissue from human patients with UC with active disease or in remission with or without vedolizumab treatment was stained by immunohistochemistry. We reconstituted NOD-SCID-SGM3 mice with human CD34+ cells and treated them with dextran sodium sulfate to induce acute colitis. Mice were treated with vedolizumab alone, or in combination with tacrolimus, ozanimid, or tofacitinib. Results Vedolizumab reduced the number of CD3+ T cells and CD68+ monocytes/macrophages in the colon of patients with UC with active disease. Vedolizumab moderately decreased immune cell numbers in acute dextran sodium sulfate–induced colitis. The combination of vedolizumab with tacrolimus further reduced the number of infiltrating CD3+ T cells and CD68+ monocytes/macrophages and was superior in ameliorating intestinal inflammation when compared to vedolizumab monotreatment. In contrast, cotreatment using vedolizumab with ozanimod or tofacitinib had no additive effect. Conclusions Our data show that vedolizumab reduces the number of innate and adaptive immune cells in the mucosa of patients with UC. Further, the combination of vedolizumab with tacrolimus was more efficient to reduce immune cell numbers and to increase therapeutic efficacy than vedolizumab monotreatment. This finding indicates that combination treatment using these two drugs may be beneficial for patients who do not respond to vedolizumab monotherapy.

Intestinal stem cells (ISC) are characterized by their ability to continuously self-renew and differentiate into various functionally distinct intestinal epithelial cell types. Impaired stem cell proliferation and differentiation can cause severe dysfunction of the gastrointestinal tract and lead to the development of several clinical disorders. Animal mouse models provide a valuable platform to study ISC function, disease mechanisms, and the intestinal epithelium's regenerative capacity upon tissue damage. However, advanced in vitro systems that are more relevant to human physiology are needed to understand better the diverse disease-triggering factors and the heterogeneity in clinical manifestations. Intestinal biopsies from patients might serve as potent starting material for such "gut-in-a-dish" approaches. While many promising tools for intestinal tissue processing, in vitro expansion, and downstream analysis have been developed in recent years, a comprehensive guide with recommendations to successfully launch or improve intestinal stem cell culture is missing. In this review, we present a selection of currently established methods, highlight recent publications and discuss the potential and limitations of those methodological approaches to facilitate and support the future design of novel and more personalized therapeutic options.

Plastic pollution is a major global challenge of our times, baring a potential threat for the environment and the human health. The increasing abundance of nanoplastic (NP) and microplastic (MP) particles in the human diet might negatively affect human health since they - particularly in patients suffering from inflammatory bowel disease (IBD) - might surpass the intestinal barrier. To investigate whether ingested plastic particles cross the intestinal epithelium and promote bowel inflammation, mice were supplemented with NP or MP polystyrene (PS) particles for 24 or 12 weeks before inducing acute or chronic dextran sodium sulfate (DSS) colitis with continuous plastic administration. Although ingested PS particles accumulated in the small intestine and organs distant from the gastrointestinal tract, PS ingestion did not affect intestinal health nor did it promote colitis severity. Although the lack of colitis-promoting effects of small PS particles might be a relief for IBD patients, potential accumulative effects of ingested plastic particles on the gastrointestinal health cannot be excluded.

Crohn’s disease (CD) is a major form of inflammatory bowel disease characterized by transmural inflammation along the alimentary tract. Changes in the microbial composition and reduction in species diversity are recognized as pivotal hallmarks in disease dynamics, challenging the gut barrier function and shaping a pathological immune response in genetically influenced subjects. The purpose of this review is to delve into the modification of the gut microbiota cluster network during CD progression and to discuss how this shift compromises the gut barrier integrity, granting the translocation of microbes and their products. We then complete the scope of the review by retracing gut microbiota dysbiosis interactions with the main pathophysiologic factors of CD, starting from the host’s genetic background to the immune inflammatory and fibrotic processes, providing a standpoint on the lifestyle/exogenous factors and the potential benefits of targeting a specific gut microbiota.

Background: The single nucleotide polymorphism (SNP) rs1042058 within the gene locus encoding tumor progression locus 2 (TPL2) has been recently identified as a risk gene for inflammatory bowel disease (IBD). TPL2 has been shown to regulate pro-inflammatory signaling and cytokine secretion, while inhibition of TPL2 decreases intestinal inflammation in vivo. However, the clinical and molecular implications of this disease-associated TPL2 variation in IBD patients have not yet been studied. Methods: We analyzed the impact of the IBD-associated TPL2 variation using clinical data of 2145 genotyped patients from the Swiss IBD Cohort Study (SIBDCS). Furthermore, we assessed the molecular consequences of the TPL2 variation in ulcerative colitis (UC) and Crohn’s disease (CD) patients by real-time PCR and multiplex ELISA of colon biopsies or serum, respectively. Results: We found that presence of the SNP rs1042058 within the TPL2 gene locus results in significantly higher numbers of CD patients suffering from peripheral arthritis. In contrast, UC patients carrying this variant feature a lower risk for intestinal surgery. On a molecular level, the presence of the rs1042058 (GG) IBD-risk polymorphism in TPL2 was associated with decreased mRNA levels of IL-10 in CD patients and decreased levels of IL-18 in the intestine of UC patients. Conclusions: Our data suggest that the presence of the IBD-associated TPL2 variation might indicate a more severe disease course in CD patients. These results reveal a potential therapeutic target and demonstrate the relevance of the IBD-associated TPL2 SNP as a predictive biomarker in IBD.

Asthma is a heterologous disease that is influenced by complex interactions between multiple environmental exposures, metabolism, and host immunoregulatory processes. Specific metabolites are increasingly recognized to influence respiratory inflammation. However, the role of protein‐derived metabolites in regulating inflammatory responses in the lung are poorly described. The aims of the present study were to quantify polyamine levels in bronchoalveolar lavages (BALs) from healthy volunteers and asthma patients, and to evaluate the impact of each polyamine on inflammatory responses using in vitro models and in a house dust mite (HDM)‐induced respiratory allergy model. Spermidine levels were decreased, while cadaverine levels were increased in BALs from asthma patients compared to healthy controls, using Ultra Performance Liquid Chromatography (UPLC). Both spermine and spermidine inhibit lipopolysaccharide (LPS)‐induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) in vitro. In addition, oral gavage with spermine or spermidine modulate HDM‐induced cell infiltration, cytokine secretion, and epithelial cell tight junction expression in murine models. Spermidine also reduces airway hyper‐responsiveness. These results suggest that modulation of polyamine metabolism, in particular spermidine, is associated with respiratory inflammation and these molecules and pathways should be further explored as biomarkers of disease and potential targets for novel therapies., Spermine and spermidine display anti‐inflammatory effects using in vitro models and protect against house dust mite (HDM) extract‐induced airway inflammation in murine models.

BACKGROUND: Allergen-specific immunotherapy (AIT) is the only available treatment for allergic diseases that can induce specific immune tolerance to allergens. The key mechanisms involved in this process include changes in allergen-specific regulatory T (Treg) cells. METHODS: We studied 25 allergic rhinitis patients undergoing subcutaneous house dust mite-specific immunotherapy. Peripheral blood mononuclear cells were studied before and after 10, 30 weeks, and 3 years of AIT. Der p 1-specific T regulatory cell responses were investigated by characterization of Der p 1-MHC class II tetramer-positive cells and correlated with nasal symptom score. RESULTS: Twelve of 25 AIT patients matched with their MHC class II expression to the Der p 1 peptide-MHC class II tetramers. A significant increase in the numbers of Der p 1-specific FOXP3+ Helios+ CD25+ CD127- Treg cells after 30 weeks was observed, which slightly decreased after 3 years of AIT. In contrast, Der p 1-specific immunoglobulin-like transcript 3 (ILT3)+ CD25+ Treg cells decreased substantially from baseline after 3 years of AIT. ILT3+ Treg cells displayed compromised suppressive function and low FOXP3 expression. In addition, Der p 1-specific IL-10 and IL-22 responses have increased after 30 weeks, but only IL-10+ Der p 1-specific Treg cells remained present at high frequency after 3 years of AIT. Increased number of FOXP3+ Helios+ and IL-10+ and decreased ILT3+ Treg cell responses correlated with improved allergic symptoms. CONCLUSION: The results indicate that AIT involves upregulation of the activated allergen-specific Treg cells and downregulation of dysfunctional allergen-specific Treg cell subset. Correction of dysregulated Treg cells responses during AIT is associated with improved clinical response.

Background and Aims: Antibodies targeting tumor necrosis factor-alpha [TNF-alpha] are a mainstay in the treatment of inflammatory bowel disease. However, they fail to demonstrate efficacy in a considerable proportion of patients. On the other hand, glycosylation of antibodies might influence not only their immunogenicity but also their structure and function. We investigated whether specific glycosylation patterns of the Fc-fragment would affect the immunogenicity of anti-TNF-alpha antibody in monocyte-derived dendritic cells. Methods: The effect of a specific Fc-glycosylation pattern on antibody uptake by monocyte-derived dendritic cells [mo-DCs] and how this process shapes the immunologic profile of mo-DCs was investigated. Three N-glycoforms of the anti-TNF-alpha antibody adalimumab, that differed in the content of fucose or sialic acid, were tested: [1] mock treated Humira, abbreviated ‘Fuc-G0’, where the N-glycan mainly consist of fucose and N-acetylglucosamine [GlcNAc], without sialic acid; [2] ‘Fuc-G2S1/G2S2’ with fucose and alpha 2,6 linked sialic acid; and [3] ‘G2S1/G2S2’ with alpha 2,6 linked sialic acid, without fucose. Results: Our data demonstrated that neither fucosylation nor sialylation of anti-TNF-Abs [Fuc-G0, FucG2S1/G2S2, G2S1/G2S2] influence their uptake by mo-DCs. Additionally, none of the differentially glycosylated antibodies altered CD80, CD86, CD273, CD274 levels on mo-DCs stimulated in with lipopolysaccharide in the presence of antibodies. Next, we evaluated the levels of cytokines in the supernatant of mo-DCs stimulated with lipopolysaccharide in the presence of Fuc-G0, Fuc-G2S1/G2S2 or G2S1/G2S2-glycosylated anti-TNF antibodies. Only IL-2 and IL-17 levels were downregulated, and IL-5 production was upregulated by uptake of Fuc-G0 antibodies, as compared to control without antibodies. Conclusions: The specific modification in the Fc-glycosylation pattern of anti-TNF-alpha Abs does not affect their immunogenicity under the tested conditions. As this study was limited to mo-DCs, further investigation is required to clarify whether Ab uptake into mo-DCs might change the immunological profile of T- and B-cells, in order to ultimately reduce the formation of anti-drug antibodies and to improve the patient care.

Disruption of epithelial junctional complex (EJC), especially tight junctions (TJ), resulting in increased intestinal permeability, is supposed to activate the enhanced immune response to gluten and to induce the development of celiac disease (CD). This study is aimed to present the role of EJC in CD pathogenesis. To analyze differentially expressed genes the next-generation mRNA sequencing data from CD326+ epithelial cells isolated from non-celiac and celiac patients were involved. Ultrastructural studies with morphometry of EJC were done in potential CD, newly recognized active CD, and non-celiac controls. The transcriptional analysis suggested disturbances of epithelium and the most significant gene ontology enriched terms in epithelial cells from CD patients related to the plasma membrane, extracellular exome, extracellular region, and extracellular space. Ultrastructural analyses showed significantly tighter TJ, anomalies in desmosomes, dilatations of intercellular space, and shorter microvilli in potential and active CD compared to controls. Enterocytes of fetal-like type and significantly wider adherence junctions were observed only in active CD. In conclusion, the results do not support the hypothesis that an increased passage of gluten peptides by unsealing TJ precedes CD development. However, increased intestinal permeability due to abnormality of epithelium might play a role in CD onset.

Total parenteral nutrition (TPN) is a life‐saving therapy administered to millions of patients. However, it is associated with significant adverse effects, namely liver injury, risk of infections, and metabolic derangements. In this review, the underlying causes of TPN‐associated adverse effects, specifically gut atrophy, dysbiosis of the intestinal microbiome, leakage of the epithelial barrier with bacterial invasion, and inflammation are first described. The role of the bile acid receptors farnesoid X receptor and Takeda G protein‐coupled receptor, of pleiotropic hormones, and growth factors is highlighted, and the mechanisms of insulin resistance, namely the lack of insulinotropic and insulinomimetic signaling of gut‐originating incretins as well as the potentially toxicity of phytosterols and pro‐inflammatory fatty acids mainly released from soybean oil‐based lipid emulsions, are discussed. Finally, novel approaches in the design of next generation lipid delivery systems are proposed. Propositions include modifying the physicochemical properties of lipid emulsions, the use of lipid emulsions generated from sustainable oils with favorable ratios of anti‐inflammatory n‐3 to pro‐inflammatory n‐6 fatty acids, beneficial adjuncts to TPN, and concomitant pharmacotherapies to mitigate TPN‐associated adverse effects. ISSN:1613-4125 ISSN:1613-4133

Background Group 2 innate lymphoid cells (ILC2s) play critical roles in induction and exacerbation of allergic airway inflammation. Thus clarification of the mechanisms that underlie regulation of ILC2 activation has received significant attention. Although innate lymphoid cells are divided into 3 major subsets that mirror helper effector T-cell subsets, counterpart subsets of regulatory T cells have not been well characterized. Objective We sought to determine the factors that induce regulatory innate lymphoid cells (ILCregs). Methods IL-10+ ILCregs induced from ILC2s by using retinoic acid (RA) were analyzed with RNA-sequencing and flow cytometry. ILCregs were evaluated in human nasal tissue from healthy subjects and patients with chronic rhinosinusitis with nasal polyps and lung tissue from house dust mite– or saline-treated mice. Results RA induced IL-10 secretion by human ILC2s but not type 2 cytokines. IL-10+ ILCregs, which were converted from ILC2s by means of RA stimulation, expressed a regulatory T cell–like signature with expression of IL-10, cytotoxic T lymphocyte–associated protein 4, and CD25, with downregulated effector type 2–related markers, such as chemoattractant receptor–homologous molecule on TH2 cells and ST2, and suppressed activation of CD4+ T cells and ILC2s. ILCregs were rarely detected in human nasal tissue from healthy subjects or lung tissue from saline-treated mice, but numbers were increased in nasal tissue from patients with chronic rhinosinusitis with nasal polyps and in lung tissue from house dust mite–treated mice. Enzymes for RA synthesis were upregulated in airway epithelial cells during type 2 inflammation in vivo and by IL-13 in vitro. Conclusion We have identified a unique immune regulatory and anti-inflammatory pathway by which RA converts ILC2s to ILCregs. Interactions between airway epithelial cells and ILC2s play an important roles in the generation of ILCregs.

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammation in the intestine. Given their role in regulation of inflammation, long-chain n-3 polyunsaturated fatty acids (PUFAs) represent a potential supplementary therapeutic approach to current drug regimens used for IBD. Mechanistically, there is ample evidence for an anti-inflammatory and pro-resolution effect of long-chain n-3 PUFAs after they incorporate into cell membrane phospholipids. They disrupt membrane rafts and when released from the membrane suppress inflammatory signaling by activating PPAR-γ and free fatty acid receptor 4; furthermore, they shift the lipid mediator profile from pro-inflammatory eicosanoids to specialized pro-resolving mediators. The allocation of long-chain n-3 PUFAs also leads to a higher microbiome diversity in the gut, increases short-chain fatty acid-producing bacteria, and improves intestinal barrier function by sealing epithelial tight junctions. In line with these mechanistic studies, most epidemiological studies support a beneficial effect of long-chain n-3 PUFAs intake on reducing the incidence of IBD. However, the results from intervention trials on the prevention of relapse in IBD patients show no or only a marginal effect of long-chain n-3 PUFAs supplementation. In light of the current literature, international recommendations are supported that adequate diet-derived n-3 PUFAs might be beneficial in maintaining remission in IBD patients. © 2020 Wiley-VCH GmbH ISSN:1613-4125 ISSN:1613-4133

Background Dietary changes are suggested to play a role in the increasing prevalence of allergic diseases and asthma. Short-chain fatty acids (SCFAs) are metabolites present in certain foods and are produced by microbes in the gut following fermentation of fibers. SCFAs have been shown to have anti-inflammatory properties in animal models. Our objective was to investigate the potential role of SCFAs in the prevention of allergy and asthma. Methods We analyzed SCFA levels by high-performance liquid chromatography (HPLC) in fecal samples from 301 one-year-old children from a birth cohort and examined their association with early life exposures, especially diet, and allergy and asthma later in life. Data on exposures and allergic diseases were collected by questionnaires. In addition, we treated mice with SCFAs to examine their effect on allergic airway inflammation. Results Significant associations between the levels of SCFAs and the infant's diet were identified. Children with the highest levels of butyrate and propionate (≥95th percentile) in feces at the age of one year had significantly less atopic sensitization and were less likely to have asthma between 3 and 6 years. Children with the highest levels of butyrate were also less likely to have a reported diagnosis of food allergy or allergic rhinitis. Oral administration of SCFAs to mice significantly reduced the severity of allergic airway inflammation. Conclusion Our results suggest that strategies to increase SCFA levels could be a new dietary preventive option for allergic diseases in children.

Histamine is a biogenic amine with extensive effects on many immune cell types. Histamine and its four receptors (H1R-H4R) represent a complex system of immunoregulation with distinct effects dependent on receptor subtypes and their differential expression. In addition to mammalian cells, bacteria can also secrete histamine and the influence of microbiota-derived histamine on host immunological processes is only beginning to be described. However, it is clear that histamine-secreting microbes are present within the human gut microbiota and their levels are increased in asthma patients. Additional studies are required to fully understand the complex regulatory interactions between histamine and the host immune response to everyday microbial and environmental challenges.

Background Type 3 innate lymphoid cells (ILC3s) are involved in maintenance of mucosal homeostasis; however, their role in immunoregulation has been unknown. Immature transitional regulatory B (itBreg) cells are innate-like B cells with immunosuppressive properties, and the in vivo mechanisms by which they are induced have not been fully clarified. Objective We aimed to investigate the ILC3–B-cell interaction that probably takes place in human tonsils. Methods ILC3s were isolated from peripheral blood and palatine tonsils, expanded, and cocultured with naive B cells. Tonsillar ILC3s and regulatory B cells were visualized with immunofluorescence histology. ILC3 frequencies were measured in tonsil tissue of allergic and nonallergic patients and in peripheral blood of allergic asthmatic patients and healthy control subjects. Results A mutually beneficial relationship was revealed between ILC3s and B cells: ILC3s induced IL-15 production in B cells through B cell–activating factor receptor, whereas IL-15, a potent growth factor for ILC3s, induced CD40 ligand (CD40L) expression on circulating and tonsillar ILC3s. IL-15–activated CD40L + ILC3s helped B-cell survival, proliferation, and differentiation of IL-10–secreting, PD-L1–expressing functional itBreg cells in a CD40L- and B cell–activating factor receptor–dependent manner. ILC3s and regulatory B cells were in close connection with each other in palatine tonsils. ILC3 frequency was reduced in tonsil tissue of allergic patients and in peripheral blood of allergic asthmatic patients. Conclusion Human CD40L + ILC3s provide innate B-cell help and are involved in an innate immunoregulatory mechanism through induction of itBreg cell differentiation, which takes place in palatine tonsils in vivo . This mechanism, which can contribute to maintenance of immune tolerance, becomes insufficient in allergic diseases.

Activity-dependent proteolysis at a synapse has been recognized as a pivotal factor in controlling dynamic changes in dendritic spine shape and function; however, excessive proteolytic activity is detrimental to the cells. The exact mechanism of control of these seemingly contradictory outcomes of protease activity remains unknown. Here, we reveal that dendritic spine maturation is strictly controlled by the proteolytic activity and its inhibition by the endogenous inhibitor (Tissue inhibitor of matrix metalloproteinases-1 – TIMP-1). Excessive proteolytic activity impairs long-term potentiation of the synaptic efficacy (LTP) and this impairment could be rescued by inhibition of protease activity. Moreover LTP is altered persistently when the ability of TIMP-1 to inhibit protease activity is abrogated, further demonstrating the role of such inhibition in the promotion of synaptic plasticity under well-defined conditions. We also show that dendritic spine maturation involves an intermediate formation of elongated spines, followed by their conversion into mushroom shape. The formation of mushroom-shaped spines is accompanied by increase in AMPA/NMDA ratio of glutamate receptors. Altogether, our results identify inhibition of protease activity as a critical regulatory mechanism for dendritic spines maturation.

BACKGROUND Interleukin-22 is produced by certain T helper cells subsets (Th17, Th22) and at lower levels by γ-δ T cells, NKT and innate lymphoid cells. Th22 cells are unique immune cells that regulate tissue responses by IL-22 production. The exact discrimination between Th17 cells that co-produce IL-22 and single IL-22-producing Th22 cells has not been possible until the present study. Isolation of pure Th22 cells without co-expression of cytokines of other T-cell subsets is essential to better understand their function in humans. The aim of this study is the isolation and characterization of viable, human IL-22-producing CD4+ T cells that do not produce IL-17A. METHODS Isolation of viable Th22 cells was performed with the combination of two cytokine secretion assays detecting IL-17A- and IL-22-producing cells in a single purification step. RESULTS The newly developed cytokine secretion assay consists of anti-IL-22 and anti-IL-17A catch antibodies, which via biotin-streptavidin interaction are bound to the biotinylated surface of the target cell, and anti-IL-22 and IL-17A detection antibody labelled with a fluorescent dye, which detects cytokines bound to these catch antibodies. A unique population of human Th22 cells, which do not produce IL-17A, was sorted, and cytokine expression pattern was confirmed by quantitative PCR analysis and ELISA. The presented technique allows the detection and isolation of pure human Th22 cells. CONCLUSIONS This technique may allow the purification of any single cytokine-producing cell subset, and the combination of several different cytokine secretion assays can be used to purify and characterize novel and unique cell subsets.

Background IL-22- and IL-17-producing T cells have important roles in allergic diseases. MicroRNAs (miRNAs) are posttranscriptional regulators of gene expression and modulate numerous biological processes. Little is known about the functions of miRNAs in IL-22/IL-17-producing T cells. Material and Methods IL-22- and IL-17-positive T cells were sorted from human peripheral blood mononuclear cells (PBMCs) by intracellular staining and dual-secretion assay. miRNA expression profiles were detected with TaqMan array microfluidic cards. T cells were transfected with miRNA mimics. Gene expression was analyzed using RT-qPCR and/or enzyme-linked immunosorbent assay in T-cell subsets and PBMCs from patients with asthma and atopic dermatitis. Results The increased expression of miR-323-3p and noncoding RNA nc886 and reduced expression of miR-93, miR-181a, miR-26a, and miR-874 were detected in IL-22-producing T cells. The pathway analysis of the putative targets suggested that these differentially expressed miRNAs could impact the proliferation, differentiation, and effector functions of T cells. Further analyses showed the highest expression for miR-323-3p in IL-22- and IL-17-double-positive T cells and its capacity to suppress multiple genes from the transforming growth factor-β pathway and the production of IL-22 in T cells. An increased expression of miR-323-3p in PBMCs from patients with asthma and reverse correlation between miR-323-3p levels and IL-22 production in PBMCs cultured in T-cell growth conditions was observed. Conclusions Our data suggest that miR-323-3p acts in a negative feedback loop to control the production of IL-22 in IL-22/IL-17-producing T cells and might thus impact the T-cell responses in asthma.

There have been extensive developments on cellular and molecular mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections during the last few years. Better understanding the functions, reciprocal regulation, and counterbalance of subsets of immune and inflammatory cells that interact through interleukins, interferons, TNF-α, and TGF- β offer opportunities for immune interventions and novel treatment modalities in the era of development of biological immune response modifiers particularly targeting these molecules or their receptors. More than 60 cytokines have been designated as interleukins since the initial discoveries of monocyte and lymphocyte interleukins (called IL-1 and IL-2, respectively). Studies of transgenic or gene- deficient mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided essential information about their functions. Here we review recent developments on IL-1 to IL-38, TNF-α, TGF-β, and interferons. We highlight recent advances during the last few years in this area and extensively discuss their cellular sources, targets, receptors, signaling pathways, and roles in immune regulation in patients with allergy and asthma and other inflammatory diseases.

Background Childhood exposure to a farm environment has been shown to protect against the development of inflammatory diseases, such as allergy, asthma, and inflammatory bowel disease. Objective We sought to investigate whether both exposure to microbes and exposure to structures of nonmicrobial origin, such as the sialic acid N-glycolylneuraminic acid (Neu5Gc), might play a significant role. Methods Exposure to Neu5Gc was evaluated by quantifying anti-Neu5Gc antibody levels in sera of children enrolled in 2 farm studies: the Prevention of Allergy Risk factors for Sensitization in Children Related to Farming and Anthroposophic Lifestyle (PARSIFAL) study (n = 299) and the Protection Against Allergy Study in Rural Environments (PASTURE) birth cohort (cord blood [n = 836], 1 year [n = 734], 4.5 years [n = 700], and 6 years [n = 728]), and we associated them with asthma and wheeze. The effect of Neu5Gc was examined in murine airway inflammation and colitis models, and the role of Neu5Gc in regulating immune activation was assessed based on helper T-cell and regulatory T-cell activation in mice. Results In children anti-Neu5Gc IgG levels correlated positively with living on a farm and increased peripheral blood forkhead box protein 3 expression and correlated inversely with wheezing and asthma in nonatopic subjects. Exposure to Neu5Gc in mice resulted in reduced airway hyperresponsiveness and inflammatory cell recruitment to the lung. Furthermore, Neu5Gc administration to mice reduced the severity of a colitis model. Mechanistically, we found that Neu5Gc exposure reduced IL-17+ T-cell numbers and supported differentiation of regulatory T cells. Conclusions In addition to microbial exposure, increased exposure to non–microbial-derived Neu5Gc might contribute to the protective effects associated with the farm environment., published version, peerReviewed

BACKGROUND: Chronic rhinosinusitis (CRS) is characterized by epithelial activation and chronic T-cell infiltration in sinonasal mucosa and nasal polyps. IL-33 is a new cytokine of the IL-1 cytokine family that has a pro-inflammatory and Th2 type cytokine induction property. The role of IL-33 in the pathomechanisms of CRS and its interaction with other T cell subsets remain to be fully understood. METHODS: The main trigger for IL-33 mRNA expression in primary human sinonasal epithelial cells was determined in multiple cytokine and T-cell stimulated cultures. The effects of IL-33 on naive, Th0 and memory T-cells was studied by PCR, ELISA and flow cytometry. Biopsies from sinus tissue were analyzed by PCR and immunofluorescence for the presence of different cytokines and receptors with a special focus on IL-33. RESULTS: IL-33 was mainly induced by IFN-γ in primary sinonasal epithelial cells, and induced a typical CRSwNP Th2 favoring cytokine profile upon co-culture with T-helper cell subsets. IL-33 and its receptor ST2 were highly expressed in the inflamed epithelial tissue of CRS patients. While IL-33 was significantly up-regulated in the epithelium for CRSsNP, its receptor was higher expressed in sinus tissue from CRSwNP. CONCLUSIONS: The present study delineates the influence of IL-33 in upper airway epithelium and a potential role of IL-33 in chronic inflammation of CRSwNP by enhancing Th2 type cytokine production, which could both contribute to a further increase of an established Th2 profile in CRSwNP.

Background: IL 10 producing regulatory B cells suppress immune responses and lack of these cells leads to exacerbated symptoms in mouse models of chronic inflammation transplantation and chronic infection. IgG4 is a blocking antibody isotype with anti inflammatory potential that is induced in human high dose antigen tolerance models. Objective: We sought to characterize human inducible IL 10 secreting B regulatory 1 (BR1) cells and to investigate their immunoregulatory capacity through suppression of cellular immune responses and production of anti inflammatory immunoglobulins. Methods: Highly purified IL 10 secreting B cells were phenotypically and functionally characterized by means of whole genome expression analysis flow cytometry suppression assay and antibody production. B cells specific for the major bee venom allergen phospholipase A2 (PLA) were isolated from beekeepers who displayed tolerance to bee venom antigens and allergic patients before and after specific immunotherapy. Results: Human IL 10+ BR1 cells expressed high surface CD25 and CD71 and low CD73 levels. Sorting of CD73 CD25+CD71+ B cells allowed enrichment of human BR1 cells which produced high levels of IL 10 and potently suppressed antigen specific CD4+ T cell proliferation. IgG 4 was selectively confined to human BR1 cells. B cells specific for the major bee venom allergen PLA isolated from nonallergic beekeepers show increased expression of IL 10 and IgG4. Furthermore the frequency of IL 10+ PLA specific B cells increased in allergic patients receiving allergen specific immunotherapy. Conclusion: Our data show the characterization of IL 10+ BR1 cells and in vivo evidence for 2 essential features of allergen tolerance: the suppressive B cells and IgG4 expressing B cells that are confined to IL 10+ BR1 cells in human subjects. © 2013 American Academy of Allergy Asthma Immunology.

Alterations in the metabolites (i.e. histamine) derived from the gut microbiome may influence host immune responses. Histamine secreting microbes are increased in the gut microbiome of adult asthma patients and histamine from these microbes may contribute to the effector responses in atopic asthma patients. Histamine secreting Escherichia coli Lactobacillus vaginalis and Morganella morganii strains were isolated from the gut microbiome of asthma patients.