Publications by authors named "Jahnsen J"

Patients with Inflammatory Bowel Disease (IBD) undergoing immunosuppressive therapies face heightened susceptibility to severe COVID-19. An in-depth understanding of systemic inflammation and cellular immune responses after SARS-CoV-2 vaccination and breakthrough infections (BTI) is required for optimizing vaccine strategies in this population. While the prevalence of high serological responders post- third COVID-19 vaccine dose was lower, and the antibody waning was higher in IBD patients than in healthy donors (HD), IBD patients showed an increase in anti-RBD Wild Type IgG levels and cross-reactive Spike -specific memory B cells following BTI.

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Background: As most people now have established hybrid immunity, the need for regular, updated SARS-CoV-2 vaccine boosters in patients with immune-mediated inflammatory diseases (IMIDs) is unclear. The study aim was to assess humoral and cellular immunogenicity of a fifth bivalent vaccine dose in patients with IMID on tumour necrosis factor inhibitors (TNFi).

Methods: In the longitudinal, observational Nor-vaC study, we assessed anti-spike and neutralising antibodies against Wuhan, Omicron BA.

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With the increasing prevalence of Crohn's disease (CD), treatment options for patients who fail conventional and advanced therapy are highly needed. Therefore, we explored the safety and efficacy of extracorporeal photopheresis (ECP) using 5-aminolevulinic acid (ALA) and blue light (405 nm). Patients with active CD who failed or were intolerant to biological therapy were eligible.

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Background: Inappropriate prescribing may have detrimental consequences for the patient and increase healthcare utilisation and costs. Academic detailing (AD) is an interactive outreach method to deliver non-commercial evidence-based medical information to healthcare professionals, aiming to improve patient care. Performing AD virtually has recently become more relevant, especially with the COVID-19 pandemic.

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Background: Understanding cellular responses to SARS-CoV-2 immunisations is important for informing vaccine recommendations in patients with inflammatory bowel disease (IBD) and other vulnerable patients on immunosuppressive therapies. This study investigated the magnitude and quality of T cell responses after multiple SARS-CoV-2 vaccine doses and COVID-19 breakthrough infection.

Methods: This prospective, observational study included patients with IBD and arthritis on tumour necrosis factor inhibitors (TNFi) receiving up to four SARS-CoV-2 vaccine doses.

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Many antibody responses induced by infection, vaccination or autoimmunity show signs of convergence across individuals with epitope-dependent selection of particular variable region gene segments and complementarity determining region 3 properties. However, not much is known about the relationship between antigen-specific effector cells and antigen-specific precursors present in the naïve B-cell repertoire. Here, we sought to address this relationship in the context of celiac disease, where there is a stereotyped autoantibody response against the enzyme transglutaminase 2 (TG2).

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Objectives: To assess incidence, severity and predictors of COVID-19, including protective post-vaccination levels of antibodies to the receptor-binding domain of SARS-CoV-2 spike protein (anti-RBD), informing further vaccine strategies for patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive medication.

Methods: IMIDs on immunosuppressives and healthy controls (HC) receiving SARS-CoV-2 vaccines were included in this prospective observational study. COVID-19 and outcome were registered and anti-RBD antibodies measured 2-5 weeks post-immunisation.

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Autoantibodies against the enzyme transglutaminase 2 (TG2) are characteristic of celiac disease (CeD), and TG2-specific immunoglobulin (Ig) A plasma cells are abundant in gut biopsies of patients. Here, we describe the corresponding population of autoreactive B cells in blood. Circulating TG2-specific IgA cells are present in untreated patients on a gluten-containing diet but not in controls.

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Background: While indirect comparison of infliximab (IFX) and vedolizumab (VDZ) in adults with Crohn's disease (CD) or ulcerative colitis (UC) shows that IFX has better effectiveness during induction, and comparable efficacy during maintenance treatment, comparative data specific to subcutaneous (SC) IFX (i.e., CT-P13 SC) versus VDZ are limited.

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Background: Antidrug antibodies to TNF inhibitors might affect clinical outcomes. Proactive therapeutic drug monitoring allows for early detection of antidrug antibodies and might reduce negative clinical consequences. We aimed to explore how antidrug antibodies to the TNF inhibitor infliximab influence treatment outcomes, and to assess the effect of proactive therapeutic drug monitoring.

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Dermatitis herpetiformis (DH) is an inflammatory skin disorder often considered as an extra intestinal manifestation of celiac disease (CeD). Hallmarks of CeD and DH are auto-antibodies to transglutaminase 2 (TG2) and transglutaminase 3 (TG3), respectively. DH patients have auto-antibodies reactive with both transglutaminase enzymes.

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Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) which is the precursor of the photosensitizer protoporphyrin IX (PpIX) is an available treatment for several diseases. ALA-PDT induces the apoptosis and necrosis of target lesions. We have recently reported the effects of ALA-PDT on cytokines and exosomes of human healthy peripheral blood mononuclear cells (PBMCs).

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Article Synopsis
  • - The study investigates the characteristics and functions of regulatory T (Treg) CD4 cells in the human small intestine, which are crucial for managing immune responses to harmless substances.
  • - Researchers examined Treg and conventional CD4 T cells from various human gut samples, revealing that Treg cells can be categorized into two subsets based on the expression of the transcription factor Helios, each with distinct cytokine production and suppressive abilities.
  • - The findings indicate that Treg cells are rare in healthy intestines but significantly increase in individuals with active celiac disease, highlighting the potential role of these cells in intestinal immune regulation during pathological conditions.
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Background: Immunogenicity to tumour necrosis factor inhibitors is a significant clinical problem leading to treatment failure and adverse events. The study aimed to assess human leukocyte antigen (HLA) associations with anti-drug antibody (ADAb) formation to infliximab.

Methods: Immune-mediated inflammatory disease patients on infliximab therapy (n = 612) were included.

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CD4 T cells specific for cereal gluten proteins are key players in celiac disease (CeD) pathogenesis. While several CeD-relevant gluten T cell epitopes have been identified, epitopes recognized by a substantial proportion of gluten-reactive T cells remain unknown. The identification of such CeD-driving gluten epitopes is important for the food industry and in clinical settings.

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Background: Data on response and safety of repeated vaccinations and hybrid immunity in patients with immune-mediated inflammatory diseases on immunosuppressive therapy is needed to further develop vaccination strategies in this vulnerable population. This study aimed to evaluate hybrid immunity and humoral immune response and safety of four SARS-CoV-2 vaccine doses in patients with immune-mediated inflammatory diseases on immunosuppressive therapy.

Methods: This prospective observational Norwegian study of vaccine response to COVID-19 (Nor-vaC) included adult patients aged 18 years and older with immune-mediated inflammatory diseases (rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, Crohn's disease, or ulcerative colitis) on immunosuppressive therapy, who had received four SARS-CoV-2 vaccine doses (vaccine group) or three vaccine doses followed by COVID-19 (hybrid group), and healthy controls receiving three vaccine doses (control group).

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Objectives: Humoral vaccine responses to SARS-CoV-2 vaccines are impaired and short lasting in patients with immune-mediated inflammatory diseases (IMID) following two vaccine doses. To protect these vulnerable patients against severe COVID-19 disease, a three-dose primary vaccination strategy has been implemented in many countries. The aim of this study was to evaluate humoral response and safety of primary vaccination with three doses in patients with IMID.

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Antibodies to deamidated gluten peptides are accurate diagnostic markers of celiac disease. However, binding of patient antibodies to all possible gluten epitopes has not previously been investigated. Here, we assess serum antibody specificity across the gluten proteome by use of high-density peptide arrays.

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Article Synopsis
  • This study investigates how long the immune response lasts after vaccination against SARS-CoV-2 in patients with immune-mediated inflammatory diseases (IMIDs) who are on immunosuppressive therapy, compared to healthy individuals.
  • Researchers analyzed blood samples from 1,108 IMID patients and 134 healthy controls at two different times after their second vaccine dose, focusing on antibody levels against the virus.
  • Results showed that IMID patients had significantly lower antibody levels at both time points and experienced a greater decline in these antibodies over time compared to healthy controls, indicating weaker and shorter-lasting vaccine-induced immunity.
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Article Synopsis
  • The study looks at how changes in gene activity, called epigenetic alterations, can help understand inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis.
  • Researchers used blood samples from patients and controls to find 137 specific spots in the genetic code that were different in people with IBD, showing strong genetic influences and ties to immune system activity.
  • The findings showed that certain genetic changes could predict if a patient needed more advanced treatment, like medicine or surgery, indicating the importance of these epigenetic markers for future care.
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Background And Aims: Therapeutic drug monitoring (TDM) may optimize biologic and thiopurine therapies in inflammatory bowel disease (IBD). The study aimed to investigate implementation and utilization of TDM in Scandinavia.

Methods: A web-based questionnaire on the use of TDM was distributed to Scandinavian gastroenterologists via the national societies.

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Celiac disease is an autoimmune disorder in which ingestion of dietary gluten triggers an immune reaction in the small intestine leading to destruction of the lining epithelium. Current treatment focusses on lifelong adherence to a gluten-free diet. Gluten-specific CD4 T cells and cytotoxic intraepithelial CD8 T cells have been proposed to be central in disease pathogenesis.

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BACKGROUND: Whether infliximab therapy can be successfully discontinued after patients with Crohn’s disease have attained sustained, clinical, biochemical, and endoscopic remission is unknown. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled withdrawal study of infliximab in patients with Crohn’s disease who were in clinical, biochemical, and endoscopic remission after standard infliximab maintenance therapy for at least 1 year. Patients were randomly assigned 1:1 to continue infliximab therapy or to receive matching placebo for 48 weeks.

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