Publications by authors named "Jim B D Keijser"

Background: Rheumatoid factors (RFs) are autoantibodies that target the Fc region of IgG, and are found in patients with rheumatic diseases as well as in the healthy population. Many studies suggest that an immune trigger may (transiently) elicit RF responses. However, discrepancies between different studies make it difficult to determine if and to which degree RF reactivity can be triggered by vaccination or infection.

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Background: The noninflammatory immunoglobulin G4 (IgG4) is linked to tolerance and is unique to humans. Although poorly understood, prolonged antigenic stimulation and IL-4-signaling along the T helper 2-axis may be instrumental in IgG4 class switching. Recently, repeated SARS-CoV-2 mRNA vaccination has been linked to IgG4 skewing.

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IgG antibodies are important mediators of vaccine-induced immunity through complement- and Fc receptor-dependent effector functions. Both are influenced by the composition of the conserved -linked glycan located in the IgG Fc domain. Here, we compared the anti-Spike (S) IgG1 Fc glycosylation profiles in response to mRNA, adenoviral, and protein-based COVID-19 vaccines by mass spectrometry (MS).

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Background: Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV-2 infection. We aimed to investigate long-term humoral immune responses against SARS-CoV-2 and increased disease activity after a primary SARS-CoV-2 infection in unvaccinated IMID patients on ISPs.

Methods: IMID patients on active treatment with ISPs and controls (i.

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For patients with immune-mediated inflammatory diseases (IMIDs), concerns exist about increased disease activity after vaccination. We aimed to assess changes in disease activity after SARS-CoV-2 vaccination in patients with IMIDs, and determine risk factors for increased disease activity. In this substudy of a prospective observational cohort study (Target-to-B!), we included patients with IMIDs who received a SARS-CoV-2 vaccine.

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Introduction: During the COVID-19 pandemic, certain disease modifying therapies (DMTs) used in multiple sclerosis (MS), such as anti-CD20 therapies, have been associated with decreased humoral responses after SARS-CoV-2 vaccination. Hybrid immunity, referring to immunity after both vaccination and SARS-CoV-2 infection might increase humoral responses.

Methods: This was a substudy of two prospective cohort studies on SARS-CoV-2 antibodies after SARS-CoV-2 infection and vaccination.

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Objectives: To compare the cumulative incidence and disease severity of reported SARS-CoV-2 omicron breakthrough infections between patients with immune-mediated inflammatory diseases (IMID) on immunosuppressants and controls, and to investigate determinants for breakthrough infections.

Methods: Data were used from an ongoing national prospective multicentre cohort study on SARS-CoV-2 vaccination responses in patients with IMID in the Netherlands (Target-to-B! (T2B!) study). Patients wih IMID on immunosuppressants and controls (patients with IMID not on immunosuppressants and healthy controls) who completed primary immunisation were included.

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Article Synopsis
  • - The study investigates how specific immunosuppressive therapies affect the immune response to SARS-CoV-2 vaccination in patients with immune-mediated inflammatory disorders, focusing on the humoral immune response.
  • - Conducted in the Netherlands with over 3,200 participants, the research compares the immune responses of patients on immunosuppressants to controls, including healthy individuals and those without systemic immunosuppressants.
  • - Findings indicate that certain immunosuppressive treatments, like anti-CD20 therapy and S1P modulators, result in lower chances of achieving adequate immunity post-vaccination, regardless of the type of immune disorder present.
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