Belimumab concentration measurements using a homologous anti-idiotype immunoassay.

Monitoring belimumab concentrations in patients can be a valuable tool for assessing treatment response and for personalizing drug doses. Various assay formats may be used to measure concentrations of therapeutic monoclonal antibodies. A particularly useful format involves the use of anti-idiotype monoclonal antibodies, selected to be highly specific to the antibody of interest.

Longitudinal rheumatoid factor autoantibody responses after SARS-CoV-2 vaccination or infection.

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.

Suppressed IgG4 class switching in dupilumab- and TNF inhibitor-treated patients after mRNA vaccination.

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.

Cardiovascular disease risk in patients with inflammatory arthritis nowadays still substantially elevated.

Objectives: This study aims to assess current cardiovascular disease risk and prevalence of risk factors in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (SpA).

Methods: 2050 consecutive patients with inflammatory arthritis (IA) and 939 controls were included, with 1308 patients with RA, 356 patients with PsA and 386 patients with SpA. In a prospective cohort setting, questionnaires regarding previous cardiovascular events and risk factors were used to assess cardiovascular risk and prevalence in patients with IA by calculating ORs using logistic regression models.

Primary SARS-CoV-2 infection in patients with immune-mediated inflammatory diseases: long-term humoral immune responses and effects on disease activity.

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.

Disease activity in patients with immune-mediated inflammatory diseases after SARS-CoV-2 vaccinations.

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.

Ocrelizumab Concentration Is a Good Predictor of SARS-CoV-2 Vaccination Response in Patients with Multiple Sclerosis.

Ocrelizumab, an anti-CD20 monoclonal antibody, counteracts induction of humoral immune responses after severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) vaccinations in patients with multiple sclerosis (MS). We aimed to assess if serum ocrelizumab concentration measured at the time of vaccination could predict the humoral response after SARS-CoV-2 vaccination. In 52 patients with MS, we found ocrelizumab concentration at the time of vaccination to be a good predictor for SARS-CoV-2 IgG anti-RBD titers after vaccination (comparable to B-cell count).

Evaluation of dose-tapering strategies for intravenous tocilizumab in rheumatoid arthritis patients using model-based pharmacokinetic/pharmacodynamic simulations.

Purpose: Tocilizumab is a humanized monoclonal antibody approved for rheumatoid arthritis treatment. In clinical practice, empirical dose-tapering strategies are implemented in patients showing sustained remission or low disease activity (LDA) to avoid overtreatment and reduce costs. Since rational adaptive-dosing algorithms taking the full pharmacokinetic (PK)/pharmacodynamic (PD) characteristics into account are currently lacking, we aimed to develop novel tapering strategies and compare them with currently used empirical ones.

Divergent chemokine receptor expression and the consequence for human IgG4 B cell responses.

IgG4 antibodies are unique to humans. IgG4 is associated with tolerance during immunotherapy in allergy, but also with pathology, as in pemphigus vulgaris and IgG4-related disease. Its induction is largely restricted to nonmicrobial antigens, and requires repeated or prolonged antigenic stimulation, for reasons poorly understood.

Clinical Impact of Antibodies against Ustekinumab in Psoriasis: An Observational, Cross-Sectional, Multicenter Study.

Ustekinumab is an effective treatment for psoriasis, but response varies between patients. The formation of anti-drug antibodies (ADAs) may explain part of this variation by reducing the free ustekinumab level. Currently, published analyses of the clinical impact of ADAs are incomplete.

Immunogenicity of TNF-Inhibitors.

Tumor necrosis factor inhibitors (TNFi) have significantly improved treatment outcome of rheumatic diseases since their incorporation into treatment protocols two decades ago. Nevertheless, a substantial fraction of patients experiences either primary or secondary failure to TNFi due to ineffectiveness of the drug or adverse reactions. Secondary failure and adverse events can be related to the development of anti-drug antibodies (ADA).

The effect of methotrexate on tumour necrosis factor concentrations in etanercept-treated rheumatoid arthritis patients.

Objectives: Recently, we demonstrated that early low concentrations of circulating, adalimumab-bound TNF in RA patients treated with adalimumab was associated with future anti-drug antibody formation. Furthermore, low TNF was associated with less frequent baseline MTX use. This is remarkable, because of the anti-inflammatory effects of MTX and a potential inhibiting effect on cytokine production.

The effect of certolizumab drug concentration and anti-drug antibodies on TNF neutralisation.

Objectives: Tumour necrosis factor (TNF) inhibitors like certolizumab, elicit an immunogenic response leading to the formation of anti-drug antibodies (ADAs). We sought to mechanistically investigate the relationship between certolizumab concentrations, ADAs, and the effective TNF neutralising capacity in sera of rheumatoid arthritis (RA) patients. TNF neutralising capacity of certolizumab was compared to the neutralising capacity of adalimumab.

Association between concomitant csDMARDs and clinical response to TNF inhibitors in overweight patients with axial spondyloarthritis.

Background: The aim of our study was to investigate the influence of conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) and body mass index (BMI) on circulating drug levels and clinical response to tumour necrosis factor inhibitor (TNFi) therapy in axial spondyloarthritis (axSpA) patients.

Methods: Prospective observational study during 1 year with 2 cohorts (Madrid and Amsterdam) including 180 axSpA patients treated with standard doses of infliximab or adalimumab. Patients were stratified by BMI, being 78 (43%) normal weight (18.

Dynamics of circulating TNF during adalimumab treatment using a drug-tolerant TNF assay.

Patients with rheumatoid arthritis (RA) can be successfully treated with tumor necrosis factor (TNF) inhibitors, including the monoclonal antibody adalimumab. Once in remission, a proportion of patients can successfully discontinue treatment, indicating that blocking TNF is no longer required for disease control. To explore the dynamics of circulating TNF during adalimumab treatment, we developed a competition enzyme-linked immunosorbent assay that can quantify TNF in the presence of large amounts of TNF inhibitor, i.