This thesis contains several investigations into the contribution of complement proteins, especially C1q, in several human diseases. Additionally, human autoantibodies against C1q (anti-C1q) are... Show moreThis thesis contains several investigations into the contribution of complement proteins, especially C1q, in several human diseases. Additionally, human autoantibodies against C1q (anti-C1q) are studied, cloned and characterized in order to further the understanding of their role in autoimmune disease. Show less
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... Show moreBackground: 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.e. IMID patients not on ISP and healthy controls) with a confirmed SARS-CoV-2 infection before first vaccination were included from an ongoing prospective cohort study (T2B! study). Clinical data on infections and increased disease activity were registered using electronic surveys and health records. A serum sample was collected before first vaccination to measure SARS-CoV-2 anti-receptor-binding domain (RBD) antibodies. Results: In total, 193 IMID patients on ISP and 113 controls were included. Serum samples from 185 participants were available, with a median time of 173 days between infection and sample collection. The rate of seropositive IMID patients on ISPs was 78% compared to 100% in controls (p < 0.001). Seropositivity rates were lowest in patients on anti-CD20 (40.0%) and anti-tumor necrosis factor (TNF) agents (60.5%), as compared to other ISPs (p < 0.001 and p < 0.001, respectively). Increased disease activity after infection was reported by 68 of 260 patients (26.2%; 95% CI 21.2-31.8%), leading to ISP intensification in 6 out of these 68 patients (8.8%). Conclusion: IMID patients using ISPs showed reduced long-term humoral immune responses after primary SARS-CoV-2 infection, which was mainly attributed to treatment with anti-CD20 and anti-TNF agents. Increased disease activity after SARS-CoV-2 infection was reported commonly, but was mostly mild. Show less
BackgroundPatients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV... Show moreBackgroundPatients 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.MethodsIMID patients on active treatment with ISPs and controls (i.e. IMID patients not on ISP and healthy controls) with a confirmed SARS-CoV-2 infection before first vaccination were included from an ongoing prospective cohort study (T2B! study). Clinical data on infections and increased disease activity were registered using electronic surveys and health records. A serum sample was collected before first vaccination to measure SARS-CoV-2 anti-receptor-binding domain (RBD) antibodies.ResultsIn total, 193 IMID patients on ISP and 113 controls were included. Serum samples from 185 participants were available, with a median time of 173 days between infection and sample collection. The rate of seropositive IMID patients on ISPs was 78% compared to 100% in controls (p < 0.001). Seropositivity rates were lowest in patients on anti-CD20 (40.0%) and anti-tumor necrosis factor (TNF) agents (60.5%), as compared to other ISPs (p < 0.001 and p < 0.001, respectively). Increased disease activity after infection was reported by 68 of 260 patients (26.2%; 95% CI 21.2–31.8%), leading to ISP intensification in 6 out of these 68 patients (8.8%).ConclusionIMID patients using ISPs showed reduced long-term humoral immune responses after primary SARS-CoV-2 infection, which was mainly attributed to treatment with anti-CD20 and anti-TNF agents. Increased disease activity after SARS-CoV-2 infection was reported commonly, but was mostly mild. Show less
For patients with immune-mediated inflammatory diseases (IMIDs), concerns exist about increased disease ac-tivity after vaccination. We aimed to assess changes in disease activity after SARS-CoV-2... Show moreFor patients with immune-mediated inflammatory diseases (IMIDs), concerns exist about increased disease ac-tivity 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 obser-vational cohort study (Target-to-B!), we included patients with IMIDs who received a SARS-CoV-2 vaccine. Patients reported changes in disease activity on a five-point Likert scale every 60 days for up to twelve months after first vaccination. In case of self-reported increased activity, hospital records were screened whether the treating physician reported increased activity, and for potential intensification of immunosuppressive (ISP) treatment. Mixed models were used to study determinants for self-reported increased disease activity. In total, 2111 patients were included for analysis after primary immunization (mean age 49.7 years [SD 13.7], 1329/ 2111 (63.0%) female), from which 1266 patients for analysis after first additional vaccination. Increased disease activity at 60 days after start of primary immunization was reported by 223/2111 (10.6%). In 96/223 (43.0%) the increase was confirmed by the treating physician and in 36/223 (16.1%) ISP treatment was intensified. Increased disease activity at seven to 60 days after additional vaccination, was reported by 139/1266 (11.0%). Vaccinations were not temporally associated with self-reported increased disease activity. Conversely, increased disease activity before first vaccination, neuromuscular disease, and multiple sclerosis were associated. Alto-gether, self-reported increased disease activity after vaccination against SARS-CoV-2 was recorded in a minority of patients and was generally mild. Moreover, multivariate analyses suggest that disease related factors, but not vaccinations are the major determinants for self-reported increased disease activity. Show less
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... Show moreFor 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. Patients reported changes in disease activity on a five-point Likert scale every 60 days for up to twelve months after first vaccination. In case of self-reported increased activity, hospital records were screened whether the treating physician reported increased activity, and for potential intensification of immunosuppressive (ISP) treatment. Mixed models were used to study determinants for self-reported increased disease activity. In total, 2111 patients were included for analysis after primary immunization (mean age 49.7 years [SD 13.7], 1329/2111 (63.0%) female), from which 1266 patients for analysis after first additional vaccination. Increased disease activity at 60 days after start of primary immunization was reported by 223/2111 (10.6%). In 96/223 (43.0%) the increase was confirmed by the treating physician and in 36/223 (16.1%) ISP treatment was intensified. Increased disease activity at seven to 60 days after additional vaccination, was reported by 139/1266 (11.0%). Vaccinations were not temporally associated with self-reported increased disease activity. Conversely, increased disease activity before first vaccination, neuromuscular disease, and multiple sclerosis were associated. Altogether, self-reported increased disease activity after vaccination against SARS-CoV-2 was recorded in a minority of patients and was generally mild. Moreover, multivariate analyses suggest that disease related factors, but not vaccinations are the major determinants for self-reported increased disease activity. Show less
Muscle-specific kinase (MuSK) myasthenia gravis (MG) is a neuromuscular autoimmune disease belonging to a growing group of IgG4 autoimmune diseases (IgG4-AIDs), in which the majority of pathogenic... Show moreMuscle-specific kinase (MuSK) myasthenia gravis (MG) is a neuromuscular autoimmune disease belonging to a growing group of IgG4 autoimmune diseases (IgG4-AIDs), in which the majority of pathogenic autoantibodies are of the IgG4 subclass. The more prevalent form of MG with acetylcholine receptor (AChR) antibodies is caused by IgG1-3 autoantibodies. A dominant role for IgG4 in autoimmune disease is intriguing due to its antiinflammatory characteristics. It is unclear why MuSK autoantibodies are predominantly IgG4. We hypothesized that MuSK MG patients have a general predisposition to generate IgG4 responses, therefore resulting in high levels of circulating IgG4. To investigate this, we quantified serum Ig isotypes and IgG subclasses using nephelometric and turbidimetric assays in MuSK MG and AChR MG patients not under influence of immunosuppressive treatment. Absolute serum IgG1 was increased in both MuSK and AChR MG patients compared to healthy donors. In addition, only MuSK MG patients on average had significantly increased and enriched serum IgG4. Although more MuSK MG patients had elevated serum IgG4, for most the IgG4 serum levels fell within the normal range. Correlation analyses suggest MuSK-specific antibodies do not solely explain the variation in IgG4 levels. In conclusion, although serum IgG4 levels are slightly increased, the levels do not support ubiquitous IgG4 responses in MuSK MG patients as the underlying cause of dominant IgG4 MuSK antibodies. Show less
In order to be able to develop effective medicine and treatments to prevent or cure autoimmune diseases or cancer we need to understand the mechanisms how they arise and what drives their course... Show moreIn order to be able to develop effective medicine and treatments to prevent or cure autoimmune diseases or cancer we need to understand the mechanisms how they arise and what drives their course.Unravelling the fundamental molecular mechanisms influencing the onset and course of diseases such as allergies, rheumatoid arthritis or cancer can be tackled using bioorthogonal antigens – chemically functionalized proteins.To tackle this challenge this thesis uses an inter-disciplinary approach. Combining standard immunological experimental methods with special, highly selective bioorthogonal chemical reactions. These reactions are bioorthogonal because, unlike normal organic chemistry, they are compatible with the physiological environment of a cell. This approach allows for following for example the location of the protein over time within a cell or alterations in the immune response due to disease related changes to the protein without disturbing the processes themself.This is a significant advantage because without changing the method used, new information can be retrieved from the same set of experiments, at any point in time during the process and a plethora of new readout options yielding additional data sets.This promises new insights into the causal relation of time, localisation and factors influencing effective anti-cancer vaccine-design and cancer immunotherapy or new biological drugs to prevent or delay onset and progression of autoimmune diseases. Show less
The distribution of muscle weakness in MG is highly heterogeneous and frequently shifts in patients. In 5% of patients MG was restricted to ocular weakness, whereas 7% of patients never had any... Show moreThe distribution of muscle weakness in MG is highly heterogeneous and frequently shifts in patients. In 5% of patients MG was restricted to ocular weakness, whereas 7% of patients never had any form of ocular weakness throughout their disease course. In 83% of MG patients at least one other extra-ocular muscle was involved at the second visit.Patients with late-onset MG and the presence of additional autoimmune diseases had more exacerbations (OR = 47) and emergency treatments (OR = 26) than early-onset MG patients without other autoimmune diseases.MG-ADL (patient questionnaire on ADL) was found to be relatively insensitive to changes in generalized weakness. This led to the absence of a significant treatment response on MG-ADL in the presence of a significant response on QMG (an objective measure of muscle weakness) in the eculizumab study. A new ADL outcome measure, MGII, was shown to have a higher sensitivity for generalized weakness than MG-ADL.RoVEMP, a novel neurophysiological test, was shown to be a specific measure for myasthenic extra-ocular muscle weakness. In addition, we found a significant correlation between magnitude of decrement and the time since the last intake of pyridostigmine, supporting that RoVEMP decrement reflects reversible neuromuscular transmission failure. Show less
Metsios, G.S.; Moe, R.H.; Esch, M. van der; Zanten, J.J.C.S.V. van; Fenton, S.A.M.; Koutedakis, Y.; ... ; IMPACT-RMD Consortium 2019
Cardiovascular disease (CVD) morbidity and mortality is highly prevalent in patients with rheumatoid arthritis (RA) with debilitating effects for the individual as well as significant healthcare... Show moreCardiovascular disease (CVD) morbidity and mortality is highly prevalent in patients with rheumatoid arthritis (RA) with debilitating effects for the individual as well as significant healthcare impact. Current evidence demonstrates that engaging in aerobic and resistance exercise (i.e. structured physical activity) can significantly improve patient-reported and clinical index-assessed outcomes in RA. In addition to this, engagement in exercise programmes improves, in a dose-dependent manner, the risk of developing CVD as well as CVD symptoms and outcomes. The present narrative review uses evidence from systematic reviews and meta-analyses as well as controlled trials, to synthesize the current state-of-the-art on the potential effects of aerobic and resistance exercise on CVD risk factors as well as on cardiac and vascular function and structure in people with RA. Where there is a lack of evidence in RA to explain potential mechanisms, relevant studies from the general population are also discussed and linked to RA. Show less
The complement system is an important part of the innate immune system and can be divided in three different pathways; the classical, the lectin and the alternative pathway. In this thesis the... Show moreThe complement system is an important part of the innate immune system and can be divided in three different pathways; the classical, the lectin and the alternative pathway. In this thesis the role of C1q is investigated, which is the recognition molecule of the classical pathway. With the usage of epidemiological projects the clinical presentation of C1q deficient patients is investigated and the association of C1q in patients with Neuropsychiatric Systemic Lupus Erythematosus. Furthermore, using cellular based project the production and secretion of C1q by (non) immune cells is determined. Overall, this thesis is a nice overview about the importance of C1q in keeping the homeostasis and the role of C1q in disease. Show less
