The liver may act as a firewall mediating mutualism between the host and its gut commensal microbiota.

A prerequisite for establishment of mutualism between the host and the microbial community that inhabits the large intestine is the stringent mucosal compartmentalization of microorganisms. Microbe-loaded dendritic cells trafficking through lymphatics are arrested at the mesenteric lymph nodes, which constitute the firewall of the intestinal lymphatic circulation. We show in different mouse models that the liver, which receives the intestinal venous blood circulation, forms a vascular firewall that captures gut commensal bacteria entering the bloodstream during intestinal pathology. Phagocytic Kupffer cells in the liver of mice clear commensals from the systemic vasculature independently of the spleen through the liver's own arterial supply. Damage to the liver firewall in mice impairs functional clearance of commensals from blood, despite heightened innate immunity, resulting in spontaneous priming of nonmucosal immune responses through increased systemic exposure to gut commensals. Systemic immune responses consistent with increased extraintestinal commensal exposure were found in humans with liver disease (nonalcoholic steatohepatitis). The liver may act as a functional vascular firewall that clears commensals that have penetrated either intestinal or systemic vascular circuits.

[Inflammatory bowel disease]. / Chronisch-entzündliche Darmerkrankungen.

Inflammatory bowel diseases (IBD) show an increase of prevalence in Switzerland. Industrialization and urbanisation correlate with an increase of incidence. IBD are the result of a continuum of interactions between genetic factors, the intestinal microbial flora, the immune system as well as environmental factors. Treatment for active Crohn's disease includes primarily systemically acting steroids for induction of remission, whereas azathioprine, methotrexate and TNF antibodies are used for maintenance of remission. Treatment for ulcerative colitis includes mostly systemic acting steroids for induction of remission and topically and systemically acting 5-ASA products and TNF antibodies for maintenance of remission. For mild active disease 5-ASA drugs are effective.

Les maladies inflammatoires chroniques de l'intestin (MICI) montrent une augmentation de prévalence en Suisse. L'industrialisation et l'urbanisation s'accompagnent d'une augmentation de leur incidence. Les MICI sont le résultat d'interactions entre des facteurs génétiques, la flore microbienne intestinale, le système immunitaire ainsi que les environs ou les influences ambiantes. Pour la maladie de Crohn des stéroïdes sont d'ordinaire utilisés pour l'induction d'une rémission et l'azathioprine et des anti-TNF pour le maintien en rémission. Pour la colite ulcéreuse des stéroïdes sont également utilisés pour l'induction d'une rémission, mais des préparations topiques et systémiques 5-ASA ainsi que des anti-TNF pour le maintien en rémission.

Systemic antibody responses to gut commensal bacteria during chronic HIV-1 infection.

BACKGROUND: Human systemic antibody responses to commensal microbiota are not well characterised during health and disease. Of particular interest is the analysis of their potential modulation caused by chronic HIV-1 infection which is associated with sustained enteropathy and systemic B cell disturbances reflected by impaired B cell responses and chronic B cell hyperactivity. The mechanisms underlying B cell hyperactivation and the specificities of the resulting hypergammaglobulinaemia are only poorly understood. METHODS: By a technique referred to as live bacterial FACS (fluorescence-activated cell sorting), the present study investigated systemic antibody responses to several gut and skin commensal bacteria as well as Candida albicans in longitudinal plasma and serum samples from healthy donors, chronic HIV-1-infected individuals with or without diarrhoea and patients with inflammatory bowel disease (IBD). RESULTS: The data show that systemic antibody responses to the commensal microbiota were abundantly present in humans and remained remarkably stable over years. Overall systemic antibody responses to gut commensal bacteria were not affected during chronic HIV-1 infection, with titres decreasing when normalised to elevated plasma immunoglobulin G (IgG) levels found in patients with HIV. In contrast, increases in the titres of high affinity antimicrobiota antibodies were detected in patients with IBD, demonstrating that conditions with known increased intestinal permeability and aberrant mutualism can induce changes in antibody titres observed in these assays. CONCLUSION: Neither HIV-associated enteropathy nor B cell dysfunction impact on the high-affinity systemic antibody responses to gut commensal bacteria. HIV-associated hypergammaglobulinaemia is therefore unlikely to be driven by induction of antimicrobiota antibodies.

Gastric necrosis complicating lately a Nissen fundoplication. Report of a case.

BACKGROUND: Gastric necrosis after Nissen fundoplication is a rare and life-threatening complication described in paediatric surgery and in some experimental models. Prompt diagnosis and appropriate therapy of acute gastric dilatation is mandatory to avoid potentially fatal gastric necrosis. CASE REPORT: This case report is the first one to describe a gastric necrosis in an adult as a late and very severe complication after Nissen fundoplication. Gastric dilatation and subsequent necrosis occurred 14 years after Nissen fundoplication because of small bowel obstruction based on adhesions. CONCLUSION: Early diagnosis and treatment of gastric dilatation after Nissen fundoplication are essential to prevent from severe secondary complications but can be difficult to establish because of atypical symptoms.

Diagnostic yield of flexible bronchoscopy in current clinical practice.

BACKGROUND: Flexible bronchoscopy is a procedure commonly performed for diagnostic and therapeutic purposes. The aim of this study was to assess the diagnostic yield and the safety of routine bronchoscopy techniques including transbronchial needle aspiration and transbronchial biopsy at a university hospital in Switzerland. METHODS: 616 consecutive bronchoscopies performed at the Pulmonary Medicine Department (University Hospital Basel) over a period of 6 months were analysed retrospectively using bronchoscopy reports and hospital charts. Diagnostic procedures included bronchial washings, bronchoalveolar lavage, bronchial brushings, transbronchial needle aspiration and transbronchial biopsies. RESULTS: 430 bronchoscopies had a diagnostic, 186 a therapeutic indication. The overall diagnostic yield was 57% (245/430). Bronchoscopy performed for suspected tumours confirmed malignancy in 43% of cases. Bronchoscopy in suspected infection and tuberculosis identified pathogenic organisms in 46% and 27% of cases, respectively. The diagnostic yield for central and peripheral TBNA was 37.8 and 43.6%, respectively. Complications were very rare (n = 10, 1.6%) and were only minor. CONCLUSION: This study demonstrates that routine bronchoscopy techniques including transbronchial needle aspiration and transbronchial biopsy are safe and have a high diagnostic yield.