Background: Increased prevalence of autoantibody Fab glycosylation has been demonstrated for several autoimmune diseases. Objectives: To study whether elevated Fab glycosylation is a common feature... Show moreBackground: Increased prevalence of autoantibody Fab glycosylation has been demonstrated for several autoimmune diseases. Objectives: To study whether elevated Fab glycosylation is a common feature of autoimmunity, this study investigated Fab glycosylation levels on serum IgG and its subclasses for autoantibodies associated with a range of different B cell- mediated autoimmune diseases, including rheumatoid arthritis, myasthenia gravis subtypes, pemphigus vulgaris, antineutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosus, anti-glomerular basement membrane glomerulonephritis, thrombotic thrombocytopenic purpura, and Guillain-Barre ⠁ syndrome. Methods: The level of Fab glycosylated IgG antibodies was assessed by lectin affinity chromatography and autoantigen-specific immunoassays. Results: In 6 of 10 autoantibody responses, in 5 of 8 diseases, the investigators found increased levels of Fab glycosylation on IgG autoantibodies that varied from 86% in rheumatoid arthritis to 26% in systemic lupus erythematosus. Elevated autoantibody Fab glycosylation was not restricted to IgG4, which is known to be prone to Fab glycosylation, but was also present in IgG1. When autoimmune diseases with a chronic disease course were compared with more acute autoimmune illnesses, increased Fab glycosylation was restricted to the chronic diseases. As a proxy for chronic autoantigen exposure, the investigators determined Fab glycosylation levels on antibodies to common latent herpes viruses, as well as to glycoprotein 120 in individuals who are chronically HIV-1-infected. Immunity to these viral antigens was not associated with increased Fab glycosylation levels, indicating that chronic antigen-stimulation as such does not lead to increased Fab glycosylation levels. Conclusions: These data indicate that in chronic but not acute B cell-mediated autoimmune diseases, disease-specific autoantibodies are enriched for Fab glycans. (J Allergy Clin Immunol 2023;151:16 46-54.) Show less
This thesis aimed to understand the humoral autoimmune response and to translate our knowledge to improve the targeting of autoimmunity in AAV and SLE patients. Our studies demonstrate that NETs... Show moreThis thesis aimed to understand the humoral autoimmune response and to translate our knowledge to improve the targeting of autoimmunity in AAV and SLE patients. Our studies demonstrate that NETs have a pivotal role in both AAV and SLE patients. NETs function as autoantigens, can cause direct glomerular inflammation and can be part of immune-complexes in SLE. Importantly, AAV and SLE-induced NETs are disease specific processes that each encompassed their own unique properties. This should be taken into account when evaluating targeting of NETs in AAV and SLE. In SLE patients, NETs could be targeted through reducing the autoantibody repertoire, specifically high avidity anti-dsDNA and anti-C1q autoantibodies that drive immune complex formation. These autoantibodies were effectively targeted by combined treatment with RTX and BLM. During B-cell targeted therapy in AAV and SLE patients, the presence and reoccurrence of autoreactive B-cells and relevant autoantibodies are components of minimal residual autoimmunity (MRA), which often persists after B-cell therapy. Interestingly, both in AAV and SLE, double negative (DN) B-cells have a key role in the humoral autoimmune response and were associated with reoccurrence of autoantibodies. However, it remains to be established how MRA is associated with disease flares and to find the best way to use it as immunomonitoring tool to guide and personalize treatment. Show less
The primary objective of this thesis is to investigate the role of pharmacogenetics in predicting drug response in treatments for the autoimmune diseases: RA and SLE. For this reason, this thesis... Show moreThe primary objective of this thesis is to investigate the role of pharmacogenetics in predicting drug response in treatments for the autoimmune diseases: RA and SLE. For this reason, this thesis is divided in two parts: pharmacogenetics related with drugs used in RA and pharmacogenetics of rituximab used in SLE and other autoimmune diseases. Part 1: Pharmacogenetics of drugs used in RA MTX is the most common DMARD used in RA. However, its use is hampered by frequent adverse drug events among which gastrointestinal toxicity is most frequent. Hepatotoxicity is a relatively rare but serious adverse event related to the use of MTX and is largely unpredictable. In chapter 2 an overview is presented of the previously performed studies concerning pharmacogenetic predictive biomarkers for MTX-induced hepatotoxicity. Treatment with anti-TNF agents results in a reduction of disease activity in most RA patients. However, a substantial part of patients does not respond to this therapy for unknown reasons. It would be highly beneficial to be able to predict whether or not an individual patient responds to treatment. Chapters 4 and 5 describe the investigations on the role of different candidate SNPs related to the efficacy of the treatment with different anti-TNFs in RA. In addition, in chapter 3 a replication study is presented based on 4 polymorphisms that were found associated with anti-TNF response in RA in a previously published genomewide association study. Part 2: Pharmacogenetics of rituximab used in SLE and other autoimmune diseases In chapters 6–8 the role of different genetic variants related to the pharmacodynamics of the drug or of the diseases are evaluated to study the contribution to differences in the response to rituximab in patients with SLE and other systemic autoimmune diseases. In chapter 6, the possible involvement of the -174 IL-6 polymorphism in the clinical response to rituximab in different systemic autoimmune diseases is assessed. In chapter 7, the aim is to investigate the possible involvement of the FCGR3A-158F/V polymorphism in the clinical response to rituximab in Spanish patients with different systemic autoimmune diseases. In chapter 8, the role of G/T polymorphism at the IL2–IL21 region in the rituximab response in a cohort of SLE patient and different autoimmune disorders is analyzed. Chapter 9 provides a summary of this thesis, chapter 10 the Dutch summary (Nederlandse samenvatting), and chapter 11 the general discussion and future perspective of this thesis. Show less
Objectives To study whether there is an association between body mass index (BMI) category and survival of various tumour necrosis factor inhibitors (TNFi) in rheumatoid arthritis (RA) patients in... Show moreObjectives To study whether there is an association between body mass index (BMI) category and survival of various tumour necrosis factor inhibitors (TNFi) in rheumatoid arthritis (RA) patients in a real-life longitudinal international registry.Methods Data from 5230 patients with RA starting treatment with any TNFi were selected from the METEOR registry. Patients were divided into six BMI categories: 3.7% underweight, BMI<18.5 kg/m(2); 46% normal weight, BMI 18.5-25 kg/m(2); 32% pre-obesity, BMI 25-30 kg/m(2); 13% obesity class I, BMI 30-35 kg/m(2); 3.4% obesity class II, BMI 35-40 kg/m(2); and 1.6% obesity class III, BMI >40 kg/m(2). Time on treatment in the different BMI categories was compared for all TNFi combined and for the infliximab, adalimumab and etanercept separately, using Kaplan-Meier curves and Cox regression analyses. Cox regression analyses were adjusted for potential confounders, with follow-up censored at 5000 days.Results Patients in obesity class II (HR 1.28, 95% CI 1.06 to 1.54) and III (HR 1.67, 95% CI 1.29 to 2.18) and underweight patients (HR 1.30, 95% CI 1.07 to 1.58) showed statistically significantly shorter TNFi survival than normal weight patients. The effect in underweight patients was strongest for infliximab (HR 1.82, 95% CI 1.20 to 2.76), the effect in overweight patients was strongest for infliximab (category II (HR 1.49, 95% CI 0.98 to 2.26); category III (HR 1.46, 95% CI 0.79 to 2.71)) and etanercept (category II (HR 1.27 95% CI 0.98 to 1.65); category III (HR 1.79, 95% CI 1.25 to 2.55)). No significant effect modification from reported pain was found.Conclusion Both underweight and overweight patients discontinued TNFi treatment earlier than normal weight patients, without evidence of reported pain as the main determinant. It remains uncertain what determines TNFi survival in individual patients. Show less
This thesis describes clinical and immunological aspects of immunoablative therapy followed by reinfusion of T-cell depleted autologous stem cells in patients with progressive refractory Juvenile... Show moreThis thesis describes clinical and immunological aspects of immunoablative therapy followed by reinfusion of T-cell depleted autologous stem cells in patients with progressive refractory Juvenile Idiopathic Arthritis (JIA). After an intensive immunoablative therapy in order to eradicate auto-agressive T cells, autologous hematopoietic stem cells of bone marrow, purged of potentially autoreactive mature T lymphocytes, were reinfused as rescue to reduce the aplastic phase after autologous stem cell transplantation (ASCT). Chapter 1 addresses the background and rationale leading to this study. Chapter 2 describes the safety, efficacy, complications and long term clinical outcome after ASCT in 22 patients with JIA, who were refractory to conventional medication. In chapter 3 the efficacy and safety of ASCT in 34 JIA patients transplanted in 9 different centers in Europe were evaluated. In chapter 4 the immunological effects of the conditioning on cellular infiltrates and expression of cytokines in the synovial tissue of two JIA patients were studied before and 6 months after ASCT. The subject of chapter 5 of this thesis is macrophage activation syndrome in systemic JIA patients. The actual effect of conditioning in vivo and graft manipulation ex vivo on the intended elimination of the adaptive (auto)immunological memory after ASCT was studied in 19 JIA/systemic lupus erythematodes (SLE) and 10 multiple sclerosis (MS) patients (chapter 7). In order to obtain reference values for anti-rabies specific humoral and cellular immune responses after a single and booster vaccination, we conducted a study in 18 healthy controls as described in chapter 6. Show less
