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Background: Whipple disease, which is caused by infection with Tropheryma whipplei, can be treated effectively with antimicrobials. Occasionally, inflammation reappears after initial improvement; this is often interpreted as refractory or recurrent disease. However, polymerase chain reaction for T. whipplei in tissue is sometimes negative during reinflammation, indicating absence of vital bacteria, and this reinflammation does not respond to antimicrobials but does respond to steroids. Objective: To demonstrate that the immune reconstitution inflammatory syndrome (IRIS) occurs in patients treated for Whipple disease. Design: Cohort study. (International Standard Randomised Controlled Trial Number Register registration number: ISRCTN45658456) Setting: 2 academic medical centers in Germany. Methods: 142 patients treated for Whipple disease out of a cohort of 187 were observed for reappearance of inflammatory signs after effective antibiotic therapy. Definitions of IRIS in HIV infection, tuberculosis, and leprosy were adapted for application to Whipple disease. Results: On the basis of study definitions, IRIS was diagnosed in 15 of 142 patients. Symptoms included fever, arthritis, pleurisy, erythema nodosum, inflammatory orbitopathy, small-bowel perforation, and a hypothalamic syndrome. Two patients died. There was a positive correlation with previous immunosuppressive treatment and a negative correlation with previous diarrhea and weight loss. Limitations: The study was observational and thus has inherent weaknesses, such as incomplete and potentially selective data recording. Conclusion: The immune reconstitution inflammatory syndrome was diagnosed in about 10% of patients with Whipple disease in the study cohort; the outcome varied from mild to fatal. Patients who had had previous immunosuppressive therapy were at particular risk. An immune reconstitution syndrome should be considered in patients with Whipple disease in whom inflammatory symptoms recur after effective treatment. Early diagnosis and treatment with steroids may be beneficial; prospective studies are needed. Primary Funding Source: European Commission and Deutsche Forschungsgemeinschaft. [ABSTRACT FROM AUTHOR]

Background: Helicobacter pylori remains a global health hazard, and vaccination would be ideal for its control. Natural infection appears not to induce protective immunity. Thus, the feasibility of a vaccine for humans is doubtful. Methods: In two prospective, randomised, double-blind, controlled studies (Paul Ehrlich Institute application nos 0802/02 and 1097/01), live vaccines against H pylori were tested in human volunteers seronegative for, and without evidence of, active H pylori infection. Volunteers (n = 58) were immunised orally with Salmonella enterica serovar Typhi Ty21a expressing H pylori urease or HP0231, or solely with Ty21a, and then challenged with 2×105 cagPAI- H pylori. Adverse events, infection, humoral, cellular and mucosal immune response were monitored. Gastric biopsies were taken before and after vaccination, and postchallenge. Infection was terminated with antibiotics. Results: Vaccines were well tolerated. Challenge infection induced transient, mild to moderate dyspeptic symptoms, and histological and transcriptional changes in the mucosa known from chronic infection. Vaccines did not show satisfactory protection. However, 13 of 58 volunteers, 8 vaccinees and 5 controls, became breath test negative and either cleared H pylori (5/13) completely or reduced the H pylori burden (8/13). H pylori-specific T helper cells were detected in 9 of these 13(69%), but only in 6 of 45 (13%) breath test-positive volunteers (p = 0.0002; Fisher exact test). T cells were either vaccine induced or pre-existing, depending on the volunteer. Conclusion: Challenge infection offers a controlled model for vaccine testing. Importantly, it revealed evidence for T cell-mediated immunity against H pylori infection in humans. [ABSTRACT FROM AUTHOR]

Background and aims: The α2-gliadin-33mer has been shown to be important in the pathogenesis of coeliac disease. We aimed to study mechanisms of its epithelial translocation and processing in respect to transcytotic and paracellular pathways. Methods: Transepithelial passage of a fluorescence-labelled α2-gIiadin-33mer was studied in Caco-2 cells by using reverse-phase high-performance liquid chromatography, mass spectrometry, confocal laser scanning microscopy (LSM) and fluorescence activated cell sorting (FACS). Endocytosis mechanisms were characterised with rab-GFP constructs transiently transfected into Caco-2 cells and in human duodenal biopsy specimens. Results: The α2-gliadin-33mer dose-dependently crossed the epithelial barrier in the apical-to-basal direction. Degradation analysis revealed translocation of the 33mer polypeptide in the uncleaved as well as in the degraded form. Transcellular passage was identified by confocal LSM, inhibitor experiments and FACS. Rab5 but not rab4 or rab7 vesicles were shown to be part of the transcytotic pathway. After pre-incubation with interferon-γ, translocation of the 33mer was increased by 40%. In mucosal biopsies of the duodenum, epithelial 33mer uptake was significantly higher in untreated coeliac disease patients than in healthy controls or coeliac disease patients on a gluten-free diet. Conclusion: Epithelial translocation of the α2-gliadin-33mer occurs by transcytosis after partial degradation through a rab5 endocytosis compartment and is regulated by interferon-γ. Uptake of the 33mer is higher in untreated coeliac disease than in controls and coeliac disease patients on a gluten-free diet. [ABSTRACT FROM AUTHOR]

Patients with first-diagnosed atrial fibrillation (FDAF) exhibit major adverse cardiovascular events (MACEs) during follow-up. Preclinical models have demonstrated that thrombo-inflammation mediates adverse cardiac remodeling and atherothrombotic events. We have hypothesized that thrombin activity (FIIa) links coagulation with inflammation and cardiac fibrosis/dysfunction. Surrogate markers of the thrombo-inflammatory response in plasma have not been characterized in FDAF. In this prospective longitudinal study, patients presenting with FDAF ( n = 80), and 20 matched controls, were included. FIIa generation and activity in plasma were increased in the patients with early AF compared to the patients with chronic cardiovascular disease without AF (controls; p < 0.0001). This increase was accompanied by elevated biomarkers (ELISA) of platelet and endothelial activation in plasma. Pro-inflammatory peripheral immune cells (TNF-α + or IL-6 + ) that expressed FIIa-activated protease-activated receptor 1 (PAR1) (flow cytometry) circulated more frequently in patients with FDAF compared to the controls ( p < 0.0001). FIIa activity correlated with cardiac fibrosis (collagen turnover) and cardiac dysfunction (NT-pro ANP/NT-pro BNP) surrogate markers. FIIa activity in plasma was higher in patients with FDAF who experienced MACE. Signaling via FIIa might be a presumed link between the coagulation system (tissue factor-FXa/FIIa-PAR1 axis), inflammation, and pro-fibrotic pathways (thrombo-inflammation) in FDAF.

Background: Clostridioides difficile toxins TcdA and TcdB are responsible for diarrhea and colitis. Lack of functional studies in organoid models of the gut prompted us to elucidate the toxin's effects on epithelial barrier function and the molecular mechanisms for diarrhea and inflammation., Methods: Human adult colon organoids were cultured on membrane inserts. Tight junction (TJ) proteins and actin cytoskeleton were analyzed for expression via Western blotting and via confocal laser-scanning microscopy for subcellular localization., Results: Polarized intestinal organoid monolayers were established from stem cell-containing colon organoids to apply toxins from the apical side and to perform functional measurements in the organoid model. The toxins caused a reduction in transepithelial electrical resistance in human colonic organoid monolayers with sublethal concentrations. Concomitantly, we detected increased paracellular permeability fluorescein and FITC-dextran-4000. Human colonic organoid monolayers exposed to the toxins exhibited redistribution of barrier-forming TJ proteins claudin-1, -4 and tricellulin, whereas channel-forming claudin-2 expression was increased. Perijunctional F-actin cytoskeleton organization was affected., Conclusions: Adult stem cell-derived human colonic organoid monolayers were applicable as a colon infection model for electrophysiological measurements. The TJ changes noted can explain the epithelial barrier dysfunction and diarrhea in patients, as well as increased entry of luminal antigens triggering inflammation.

Background and Purpose: To assess the clinical spectrum of central nervous system (CNS) involvement as well as cerebrospinal fluid (CSF) and neuroimaging findings in patients with Whipple's disease (WD) and to analyze the association of neurological symptoms with CSF and imaging findings., Methods: Neurological involvement was retrospectively analyzed in a series of 36 patients diagnosed with WD at a single center between 1992 and 2019. Findings of 81 comprehensive CSF examinations from 36 patients, including polymerase chain reaction (PCR) tests for Tropheryma whipplei (TW) in CSF from 35 patients, were systematically evaluated. The prevalence of ischemic stroke in patients with WD was compared to a matched control cohort., Results: Neurological symptoms occurred in 23 of 36 (63.9%) patients, with cognitive, motor, and oculomotor dysfunction being most frequent. TW was detected by PCR in CSF of 13 of 22 (59.1%) patients with and four of 13 (30.8%, p = 0.0496) patients without neurological symptoms. Total CSF protein (p = 0.044) and lactate (p = 0.035) were moderately elevated in WD with neurologic symptoms compared with WD without. No intrathecal immunoglobulin synthesis was observed. Three of 36 (8.3%) patients had hydrocephalus due to aqueductal stenosis. Patients with WD had an unexpectedly high prevalence of ischemic stroke (10/36, 27.7%) compared to matched controls (10/360, 3.2%)., Conclusions: Neurological involvement in patients with WD is common. Detection of TW DNA in CSF is only partly associated with neurological symptoms. Elevated CSF parameters suggest CNS parenchymal infection. Stroke is a hitherto underrecognized manifestation of WD. These findings suggest that mechanisms beyond CNS infection contribute to the spectrum of CNS involvement in WD., (© 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Little is known about the CD8 + T cell functionality in the coronavirus disease 2019 (COVID-19). Therefore, we examined twenty-five hospitalized COVID-19 patients with moderate (MD) or severe disease (SD) as well as seventeen SARS-CoV-2-unexposed persons regarding the cytolytic and cytokine-producing reactivity of their CD8 + T cells. Reactive CD8 + T cells were detectable in 90% of the unexposed persons, confirming high cross-reactive immune memory in the general population. Compared to unexposed persons and MD patients, SD patients had higher numbers of SARS-CoV-2 reactive CD8 + T cells with cytolytic function that can simultaneously produce inflammatory cytokines. In addition, SD patients showed higher CD8 + T cell reactivity against non-SARS-CoV-2-related viruses, which was mainly mediated by cytolytic response. Sequence alignments showed that cross-reactivities with the Spike protein could contribute to the expansion of such cells. Since insufficiently regulated cytolytic CD8 + T cells can damage peripheral and vascular tissue structures, high levels of both SARS-CoV-2-reactive and heterologously activated cytolytic CD8 + T cells could favor severe disease progression., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Tropheryma whipplei ( TW ) can cause different pathologies, e.g., Whipple's disease and transient gastroenteritis. The mechanism by which the bacteria pass the intestinal epithelial barrier, and the mechanism of TW -induced gastroenteritis are currently unknown., Methods: Using ex vivo disease models comprising human duodenal mucosa exposed to TW in Ussing chambers, various intestinal epithelial cell (IEC) cultures exposed to TW and a macrophage/IEC coculture model served to characterize endocytic uptake mechanisms and barrier function., Results: TW exposed ex vivo to human small intestinal mucosae is capable of autonomously entering IECs, thereby invading the mucosa. Using dominant-negative mutants, TW uptake was shown to be dynamin- and caveolin-dependent but independent of clathrin-mediated endocytosis. Complementary inhibitor experiments suggested a role for the activation of the Ras/Rac1 pathway and actin polymerization. TW -invaded IECs underwent apoptosis, thereby causing an epithelial barrier defect, and were subsequently subject to phagocytosis by macrophages., Conclusions: TW enters epithelia via an actin-, dynamin-, caveolin-, and Ras-Rac1-dependent endocytosis mechanism and consecutively causes IEC apoptosis primarily in IECs invaded by multiple TW bacteria. This results in a barrier leak. Moreover, we propose that TW -packed IECs can be subject to phagocytic uptake by macrophages, thereby opening a potential entry point of TW into intestinal macrophages.

Background: Campylobacter jejuni ( C. jejuni ) is one of the most common causes of bacterial gastroenteritis worldwide. One sequela of this infection is the development of post-infectious irritable bowel syndrome (PI-IBS). It has been suggested that a dysfunctional intestinal barrier may promote IBS development. We aimed to test this hypothesis against the background of the leaky gut concept for low-grade inflammation in PI-IBS., Methods: We identified patients with persistent PI-IBS symptoms after C. jejuni infection. During sigmoidoscopy, forceps biopsies were obtained for electrophysiological measurements of epithelial transport and barrier function in miniaturized Ussing devices. C. jejuni absence was checked by PCR and cytokine production with immunohistochemistry., Results: In PI-IBS, the epithelial resistance of the colon epithelium was unaltered, reflecting an intact paracellular pathway. In contrast, temperature-dependent horseradish peroxidase (HRP, 44 kDa) permeation increased. Short-circuit current (Isc) reflecting active anion secretion and ENaC-dependent electrogenic sodium absorption was unaffected. Early endosome antigen-1 (EEA1) and IL-4 levels increased. C. jejuni is not incorporated into the resident microbiota of the colon mucosa in PI-IBS., Conclusions: In PI-IBS after C. jejuni infection, macromolecule uptake via endocytosis was enhanced, leading to low-grade inflammation with pro-inflammatory cytokine release. The findings will allow C. jejuni -induced pathomechanisms to be targeted during infection and, thereafter to reduce sequelae such as PI-IBS.

Class I histone deacetylases (HDACs) are important regulators of cellular functions in health and disease. HDAC1, HDAC2, HDAC3, and HDAC8 are promising targets for the treatment of cancer, neurological, and immunological disorders. These enzymes have both catalytic and non-catalytic functions in the regulation of gene expression. We here describe the generation of a genetic toolbox by the CRISPR/Cas9 methodology in nearly haploid human tumor cells. This novel model system allows to discriminate between catalytic and structural functions of class I HDAC enzymes and to mimic the treatment with specific HDAC inhibitors., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)