The probability of atherosclerotic plaque rupture and its thrombotic sequelae are thought to be i... more The probability of atherosclerotic plaque rupture and its thrombotic sequelae are thought to be increased at sites of macrophage accumulation. Folate receptor b (FR-b) is present on activated macrophages but not on quiescent macrophages or other immune cells. By conjugating the ligand folate with a fluorescent contrast agent, fluorescein isothiocyanate (FITC), we aimed to explore the potential role of FR-b fluorescence imaging in the distinction of vulnerable sites from more stable regions. Methods: Carotid specimens were taken from 20 patients and incubated with folate-FITC for 30 min. Ex vivo fluorescence imaging was performed to determine the exact location of folate-FITC uptake. Sections displaying regions of high uptake (determined as hot spots) were compared with sections showing low uptake (cold spots) through immunohistochemistry and real-time quantitative reverse-transcription polymerase chain reaction for FR-b. Results: Hot spots showed significantly higher folate-FITC uptake than cold spots (P , 0.001). Hot spots tended to contain more macrophages and areas of hypoxia than cold spots. A positive correlation between messenger RNA levels of CD68 (marker for macrophages), FR-b (r 5 0.53, P 5 0.045), and hypoxia-inducible factor-1a expression (marker for intraplaque hypoxia; r 5 0.55, P 5 0.034) was found. Conclusion: Compared with areas with low folate-FITC uptake, areas of high folate-FITC uptake within human atherosclerotic plaques had an increased number of activated macrophages and higher areas of hypoxia. These characteristics of vulnerability imply that molecular imaging of FR-b through folate conjugates might be a good indicator for plaque vulnerability in future noninvasive imaging studies.
Objective. To ,investigate the effect of the ,p38 mitogen ,activated protein kinase (MAPK) inhibi... more Objective. To ,investigate the effect of the ,p38 mitogen ,activated protein kinase (MAPK) inhibitor RWJ 67657 on inflammatory mediator ,production by rheumatoid synovial fibroblasts (RSF). Methods.RSF were pretreated with RWJ 67657 and stimulated with TNF-αand/or IL- 1β. Protein levels and mRNA expression of MMP-1, MMP-3, TIMP-1, IL-6 and IL-8 were determined, as was mRNA expression of COX-2 and ADAMTS-4.
Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging, Jan 16, 2015
In this study, the potential of matrix metalloproteinase (MMP) sense for detection of atheroscler... more In this study, the potential of matrix metalloproteinase (MMP) sense for detection of atherosclerotic plaque instability was explored. Secondly, expression of MMPs by macrophage subtypes and smooth muscle cells (SMCs) was investigated. Twenty-three consecutive plaques removed during carotid endarterectomy were incubated in MMPSense™ 680 and imaged with IVIS® Spectrum. mRNA levels of MMPs, macrophage markers, and SMCs were determined in plaque specimens, and in in vitro differentiated M1 and M2 macrophages. There was a significant difference between autofluorescence signals and MMPSense signals, both on the intraluminal and extraluminal sides of plaques. MMP-9 and CD68 messenger RNA (mRNA) expression was higher in hot spots, whereas MMP-2 and αSMA expression was higher in cold spots. In vitro M2 macrophages had higher mRNA expression of MMP-1, MMP-9, MMP-12, and TIMP-1 compared to M1 macrophages. MMP-9 is most dominantly MMP present in atherosclerotic plaques and is produced by M2 ra...
High mobility group box 1 (HMGB1) has been suggested to be involved in the pathogenesis of many a... more High mobility group box 1 (HMGB1) has been suggested to be involved in the pathogenesis of many autoimmune diseases. In addition to its nuclear functions, extracellular HMGB1 released from activated, injured or dying cells becomes a proinflammatory mediator via binding to various receptors on the surface of responding cells. HMGB1 interacts with various systems involved in inflammation, such as the complement system and the coagulation system. Thus, HMGB1 could amplify inflammation and enhance immune responses in pathophysiology of certain diseases. In the past years, HMGB1 has been studied in several vasculitides including antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, Kawasaki disease, Henoch-Schönlein purpura, Takayasu arteritis and giant cell arteritis. Several studies showed that circulating HMGB1 levels are higher in patients with active disease compared with healthy controls, and levels are associated with disease severity. Further studies on pathogenetic m...
High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released into... more High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released into the extracellular milieu. HMGB1 is a biomarker of active disease in several systemic autoimmune diseases. Behçet's disease (BD) is a systemic inflammatory disorder with a waxing/waning course. The objective of this study is to evaluate serum HMGB1 levels as a possible biomarker for disease activity in BD. A cross-sectional study measuring serum HMGB1 levels was performed in 26 BD patients and 20 healthy controls. The Brazilian version of the simplified BD Current Activity Form (BR-BDCAFs) was used to measure disease activity. Serum HMGB1 levels were higher in patients with active disease [3.82 (2.54-6.11) ng/ml], in patients with BD without active disease but still on therapy [2.76 (1.89-5.78) ng/ml] and in patients in remission without treatment [2.66 (1.86-4.70) ng/ml] than in healthy controls [0.96 (0.59-1.39) ng/ml], P < 0.001. Levels were comparable between BD patients with active disease, BD without active disease but still on therapy and those in remission without treatment (P = 0.432). There was no correlation between serum HMGB1 levels and BR-BDCAF(s) (ρ = 0.195; P = 0.339). No association could be found between serum HMGB1 levels and specific disease involvement or therapy. So serum HMGB1 levels cannot be used as a biomarker in BD. Serum HMGB1 levels are increased in patients with BD as compared with healthy controls. However, no association was found with disease activity, specific organ involvement or therapy in BD.
Currently, in the field of rheumatology, there is much attention given towards the possible causa... more Currently, in the field of rheumatology, there is much attention given towards the possible causality between periodontitis and rheumatoid arthritis (RA), specifically regarding the role of Porphyromonas gingivalis (Pg). This bacterium is unique, having a citrullinating enzyme. Antibodies against citrullinated proteins are rather specific for RA. Because causality is ultimately tested in longitudinal cohort studies which currently do not exist for periodontitis and RA, this commentary applied Bradford Hill criteria on the existing literature to assess causality as the most likely interpretation of this association. From an epidemiologic point of view, patients with RA have a higher incidence of periodontal disease than individuals without RA. In addition, there is a dose-response pattern in the association between the severity of periodontitis and RA disease activity. There are indications that periodontitis precedes RA, but there is no evidence yet available to show that Pg plays a direct role in this temporal relationship. The role of the unique characteristic of citrullination by Pg remains unexplained. However, in animal models, citrullination by Pg plays a distinct role in the development and aggravation of experimental arthritis. Although the role of Pg in RA remains speculative, a causative role for periodontitis as a chronic inflammatory disease caused by infectious agents in RA seems biologically plausible.
Monoclonal gammopathy of undetermined significance (MGUS) arises from a clonal expansion of plasm... more Monoclonal gammopathy of undetermined significance (MGUS) arises from a clonal expansion of plasma cells in the bone marrow, secreting monoclonal (M) paraprotein. MGUS is associated with increased susceptibility to infections, which may reflect altered B-cell repertoire. To investigate this, we examined the IgM, IgG and IgA B-cell repertoire diversity in MGUS at baseline and after influenza vaccination (n=16) in comparison to healthy controls (HCs) (n=16). The CDR3 region of the immunoglobulin heavy chain variable (IGHV) region gene was amplified and B-cell spectratypes analyzed by high-resolution electrophoresis. Spectratype Gaussian distribution, kurtosis and skewness were quantified to measure repertoire shifts. Both HC and MGUS baseline spectratypes show inter-individual variability that is more pronounced in the IGHG and IGHA repertoires. Overall, baseline B cell repertoire is more altered in MGUS, with oligoclonality observed in 50% (p=0.01). Post-vaccination, significant diff...
Patients with autoimmune inflammatory rheumatic diseases (AIRDs) are at increased risk of infecti... more Patients with autoimmune inflammatory rheumatic diseases (AIRDs) are at increased risk of infections. This risk has been further increased by the introduction of biologic agents over the past two decades. One of the most effective strategies to prevent infection is vaccination. However, patients with an AIRD have a compromised immune system, which is further impaired by medication. Another important issue is the possibility of triggering a broad nonspecific response by vaccination, potentially resulting in increased activity of the underlying autoimmune disease. In this Review, we provide an analysis of data on vaccination of patients with an AIRD. Both the efficacy and the safety of vaccination are addressed, together with the epidemiology of vaccine-preventable infectious diseases in different subgroups of adults with AIRDs. Special attention is given to vaccination of patients who are treated with biologic agents.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2014
In atherosclerotic plaques, the risk of rupture is increased at sites of macrophage accumulation.... more In atherosclerotic plaques, the risk of rupture is increased at sites of macrophage accumulation. Activated macrophages express folate receptor-β (FR-β), which can be targeted by folate coupled to radioactive ligands to visualize vulnerability. The aim of this study was to explore the presence of activated macrophages in human atherosclerotic plaques by (99m)Tc-folate imaging and to evaluate whether this technique can discriminate between an M1-like and M2-like macrophage phenotype. Carotid endarterectomy specimens of 20 patients were incubated with (99m)Tc-folate, imaged using micro-SPECT, and divided into 3-mm slices. The mean accumulation was calculated per slice, and the distribution of M1-like and M2-like macrophages per slice was quantified by immunohistochemical staining for CD86 as well as inducible nitric oxide synthase (iNOS) for M1 and CD163 and FR-β for M2 macrophages. Monocytes from healthy donors were differentiated toward M1-like or M2-like phenotype by in vitro cultu...
High-mobility group box 1 (HMGB1) is an important molecule for several nuclear processes. Recentl... more High-mobility group box 1 (HMGB1) is an important molecule for several nuclear processes. Recently, HMGB1 has gained much attention as a damage-associated molecular pattern (DAMP) and has been implicated in the pathogenesis of several (auto)-immune diseases, in particular, systemic lupus erythematosus (SLE). A main pathogenic feature in SLE is the accumulation of apoptotic cells. Since HMGB1 is released from apoptotic cells it has been hypothesized that HMGB1 might fuel the inflammatory processes, as seen in this disease, and play a fundamental role in the pathogenesis. In this review, we discuss evidence in support of the theory that HMGB1 is an important mediator in SLE and may be considered a new autoantigen.
The incidence of cardiovascular disease (CVD) is increased in RA. This study was designed to eval... more The incidence of cardiovascular disease (CVD) is increased in RA. This study was designed to evaluate whether a reduction in disease activity influences early markers of CVD. In a prospective longitudinal study, 58 newly diagnosed RA patients and 58 age- and sex-matched healthy controls (HCs) were included. Endothelial dysfunction was measured by small artery elasticity (SAE) and endothelial cell activation was assessed by measuring soluble vascular cellular activation molecule 1(sVCAM-1) and von Willebrand factor (vWF). Advanced glycation end products (AGEs) were quantified by skin autofluorescence. After 1 year, measurements were repeated in all RA patients. At entry, SAE was decreased in RA vs HCs [median 3.4 ml/mmHg100 (range 1.2-9.0) vs 6.1 (range 5.0-15.3), P < 0.0001] and sVCAM-1 and vWF were increased: 391 ng/ml (range 256-680) vs 341 (range 223-691) (P = 0.0015) and 120 ng/ml (range 26.5-342) vs 99 (range 22-298) (P = 0.02), respectively. SAE was inversely correlated wit...
Objective: Differential gene expression in CD177 + and CD177 2 neutrophils was investigated, in o... more Objective: Differential gene expression in CD177 + and CD177 2 neutrophils was investigated, in order to detect possible differences in neutrophil function which could be related to the pathogenesis of ANCA-associated Vasculitides (AAV).
The objective of this study was to evaluate whether levels of high mobility group box 1 (HMGB1) i... more The objective of this study was to evaluate whether levels of high mobility group box 1 (HMGB1) in granulomatosis with polyangiitis (GPA) patients are associated with carotid atherosclerosis, related to levels of soluble receptor for advanced glycation end-products (sRAGE) and influenced by immunosuppressive or lipid-lowering therapy. Twenty-three GPA patients and 20 controls were evaluated for HMGB1- and sRAGE levels and for carotid atherosclerosis using ultrasound to determine intima-media thickness (IMT). In vitro the effect of atorvastatin on the production of HMGB1 by lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVEC) was assessed. Serum HMGB1 and sRAGE levels did not differ between patients and controls. A negative correlation was found between sRAGE and maximum IMT but HMGB1 and carotid IMT were not related. HMGB1 levels were reduced in GPA patients on statins and prednisolone. In vitro, atorvastatin reduced HMGB1 levels in supernatants of acti...
In inflammatory processes, the p38 mitogen-activated protein kinase (MAPK) signal transduction ro... more In inflammatory processes, the p38 mitogen-activated protein kinase (MAPK) signal transduction route regulates production and expression of cytokines and other inflammatory mediators. Tumor necrosis factor α (TNF-α) is a pivotal cytokine in rheumatoid arthritis and its production in macrophages is under control of the p38 MAPK route. Inhibition of the p38 MAPK route may inhibit production not only of TNF-α, but also of other inflammatory mediators produced by macrophages, and indirectly of inflammatory mediators by other cells induced by TNF-α stimulation. Here we investigate the effects of RWJ 67657, a p38 MAPK inhibitor, on mRNA expression and protein production of TNF-α and other inflammatory mediators, in monocyte-derived macrophages. A strong inhibition of TNF-α was seen at pharmacologically relevant concentrations of RWJ 67657, but also inhibition of mRNA expression of IL-1β, IL-8, and cyclooxygenase-2 was shown. Furthermore, it was shown that monocyte-derived macrophages have a high constitutive production of matrix metalloproteinase 9, which is not affected by p38 MAPK inhibition. The results presented here may have important implications for the treatment of rheumatoid arthritis.
Objective. In SLE, a decreased antibody response on influenza vaccination has been reported. In t... more Objective. In SLE, a decreased antibody response on influenza vaccination has been reported. In this study, we assessed whether a booster vaccination could improve antibody responses, as determined by seroprotection rates, in SLE patients. Methods. SLE patients (n ¼ 52) with quiescent disease (SLEDAI 44) and healthy controls (HCs) (n ¼ 28) received subunit influenza vaccine in October-December 2007. After 4 weeks, only SLE patients received a second dose of vaccination. Sera were obtained before both vaccinations, and 4 weeks after the second vaccination. At each visit, SLE disease activity was recorded. The haemagglutination inhibition test was used to measure antibody titres. Seroprotection was defined as a titre 540. Results. Following the first vaccination, seroprotection rates and geometric mean titres (GMTs) to each vaccine strain increased in both SLE patients and controls to comparable levels. Seroprotection rates in SLE patients after the first vaccination were 86.5% to A/H1N1, 80.8% to A/H3N2 and 61.5% to the B-strain while GMTs were 92.6, 56.2 and 39.2, respectively. Overall, the booster vaccination did not lead to a further rise of seroprotection rates and GMTs in SLE patients. However, in patients not vaccinated in the previous year, GMT and seroconversion rate to A/H1N1 did rise following the booster vaccination. Both influenza vaccinations did not increase SLEDAI scores. Conclusions. Additional value of a booster influenza vaccination in SLE is limited to patients who were not vaccinated in the previous year.
Objective. To investigate whether serum levels of endothelial cell activation markers in early RA... more Objective. To investigate whether serum levels of endothelial cell activation markers in early RA patients can serve as biomarkers for inflammation and disease activity, and are associated with radiological progression and development of cardiovascular disease (CVD).
Background: In patients with end stage renal disease (ESRD) we observed protection from inflammat... more Background: In patients with end stage renal disease (ESRD) we observed protection from inflammation-associated mortality in CCR5D32 carriers, leading to CCR5 deficiency, suggesting impact of CCR5D32 on inflammatory processes. Animal studies have shown that CCR5 deficiency is associated with a more pronounced Th2 type immune response, suggesting that in human CCR5D32 carriers the immune response may be more Th2 type directed. So, in the present study we determined the Th1-Th2 type directed immune response in ESRD patients carrying and not carrying the CCR5D32 genetic variant after stimulation.
The prevalence of anti-endothelial cell autoantibodies (AECA) in patients with anti-neutrophil cy... more The prevalence of anti-endothelial cell autoantibodies (AECA) in patients with anti-neutrophil cytoplasmic autoantibody-associated systemic vasculitis (ASV) has been reported by several groups with conflicting results ranging from 8% to 100%. Types of substrate cells used for AECA testing partially explain this variation. Endothelial cells from kidney origin have been reported to be predominant in AECA binding. Therefore, we investigated AECA prevalence using a human glomerular endothelial cell line compared with primary human umbilical vein endothelial cells, which have frequently been used for AECA detection. Methods: Sera from 43 ASV patients (29 Wegener's granulomatosis (WG), 14 microscopic polyangiitis (MPA)) with active disease were assessed for AECA positivity using cell-based enzyme-linked immunosorbent assay. Forty serum samples from healthy controls were tested in parallel. To evaluate endothelial activation levels, soluble intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were measured with capture enzyme-linked immunosorbent assay. Results: The AECA were detected in 4 of 29 WG patients (14%), but none of 14 MPA patients was positive for AECA using glomerular endothelial cell as a substrate, whereas AECA were positive in 10% of WG patients and 14% of MPA patients on human umbilical vein endothelial cells. No significant differences were found between ASV patients and controls in AECA test. Serum levels of vascular cell adhesion molecule-1 and soluble intercellular cell adhesion molecule-1 in ASV patients were significantly higher than in controls. However, there were no differences between AECA-positive and -negative patients for both of the activation markers. Conclusion: The AECA, directed against glomerular endothelial cells, have a low prevalence in ASV patients with active disease and are not correlated with endothelial activation.
The probability of atherosclerotic plaque rupture and its thrombotic sequelae are thought to be i... more The probability of atherosclerotic plaque rupture and its thrombotic sequelae are thought to be increased at sites of macrophage accumulation. Folate receptor b (FR-b) is present on activated macrophages but not on quiescent macrophages or other immune cells. By conjugating the ligand folate with a fluorescent contrast agent, fluorescein isothiocyanate (FITC), we aimed to explore the potential role of FR-b fluorescence imaging in the distinction of vulnerable sites from more stable regions. Methods: Carotid specimens were taken from 20 patients and incubated with folate-FITC for 30 min. Ex vivo fluorescence imaging was performed to determine the exact location of folate-FITC uptake. Sections displaying regions of high uptake (determined as hot spots) were compared with sections showing low uptake (cold spots) through immunohistochemistry and real-time quantitative reverse-transcription polymerase chain reaction for FR-b. Results: Hot spots showed significantly higher folate-FITC uptake than cold spots (P , 0.001). Hot spots tended to contain more macrophages and areas of hypoxia than cold spots. A positive correlation between messenger RNA levels of CD68 (marker for macrophages), FR-b (r 5 0.53, P 5 0.045), and hypoxia-inducible factor-1a expression (marker for intraplaque hypoxia; r 5 0.55, P 5 0.034) was found. Conclusion: Compared with areas with low folate-FITC uptake, areas of high folate-FITC uptake within human atherosclerotic plaques had an increased number of activated macrophages and higher areas of hypoxia. These characteristics of vulnerability imply that molecular imaging of FR-b through folate conjugates might be a good indicator for plaque vulnerability in future noninvasive imaging studies.
Objective. To ,investigate the effect of the ,p38 mitogen ,activated protein kinase (MAPK) inhibi... more Objective. To ,investigate the effect of the ,p38 mitogen ,activated protein kinase (MAPK) inhibitor RWJ 67657 on inflammatory mediator ,production by rheumatoid synovial fibroblasts (RSF). Methods.RSF were pretreated with RWJ 67657 and stimulated with TNF-αand/or IL- 1β. Protein levels and mRNA expression of MMP-1, MMP-3, TIMP-1, IL-6 and IL-8 were determined, as was mRNA expression of COX-2 and ADAMTS-4.
Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging, Jan 16, 2015
In this study, the potential of matrix metalloproteinase (MMP) sense for detection of atheroscler... more In this study, the potential of matrix metalloproteinase (MMP) sense for detection of atherosclerotic plaque instability was explored. Secondly, expression of MMPs by macrophage subtypes and smooth muscle cells (SMCs) was investigated. Twenty-three consecutive plaques removed during carotid endarterectomy were incubated in MMPSense™ 680 and imaged with IVIS® Spectrum. mRNA levels of MMPs, macrophage markers, and SMCs were determined in plaque specimens, and in in vitro differentiated M1 and M2 macrophages. There was a significant difference between autofluorescence signals and MMPSense signals, both on the intraluminal and extraluminal sides of plaques. MMP-9 and CD68 messenger RNA (mRNA) expression was higher in hot spots, whereas MMP-2 and αSMA expression was higher in cold spots. In vitro M2 macrophages had higher mRNA expression of MMP-1, MMP-9, MMP-12, and TIMP-1 compared to M1 macrophages. MMP-9 is most dominantly MMP present in atherosclerotic plaques and is produced by M2 ra...
High mobility group box 1 (HMGB1) has been suggested to be involved in the pathogenesis of many a... more High mobility group box 1 (HMGB1) has been suggested to be involved in the pathogenesis of many autoimmune diseases. In addition to its nuclear functions, extracellular HMGB1 released from activated, injured or dying cells becomes a proinflammatory mediator via binding to various receptors on the surface of responding cells. HMGB1 interacts with various systems involved in inflammation, such as the complement system and the coagulation system. Thus, HMGB1 could amplify inflammation and enhance immune responses in pathophysiology of certain diseases. In the past years, HMGB1 has been studied in several vasculitides including antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, Kawasaki disease, Henoch-Schönlein purpura, Takayasu arteritis and giant cell arteritis. Several studies showed that circulating HMGB1 levels are higher in patients with active disease compared with healthy controls, and levels are associated with disease severity. Further studies on pathogenetic m...
High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released into... more High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released into the extracellular milieu. HMGB1 is a biomarker of active disease in several systemic autoimmune diseases. Behçet&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (BD) is a systemic inflammatory disorder with a waxing/waning course. The objective of this study is to evaluate serum HMGB1 levels as a possible biomarker for disease activity in BD. A cross-sectional study measuring serum HMGB1 levels was performed in 26 BD patients and 20 healthy controls. The Brazilian version of the simplified BD Current Activity Form (BR-BDCAFs) was used to measure disease activity. Serum HMGB1 levels were higher in patients with active disease [3.82 (2.54-6.11) ng/ml], in patients with BD without active disease but still on therapy [2.76 (1.89-5.78) ng/ml] and in patients in remission without treatment [2.66 (1.86-4.70) ng/ml] than in healthy controls [0.96 (0.59-1.39) ng/ml], P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001. Levels were comparable between BD patients with active disease, BD without active disease but still on therapy and those in remission without treatment (P = 0.432). There was no correlation between serum HMGB1 levels and BR-BDCAF(s) (ρ = 0.195; P = 0.339). No association could be found between serum HMGB1 levels and specific disease involvement or therapy. So serum HMGB1 levels cannot be used as a biomarker in BD. Serum HMGB1 levels are increased in patients with BD as compared with healthy controls. However, no association was found with disease activity, specific organ involvement or therapy in BD.
Currently, in the field of rheumatology, there is much attention given towards the possible causa... more Currently, in the field of rheumatology, there is much attention given towards the possible causality between periodontitis and rheumatoid arthritis (RA), specifically regarding the role of Porphyromonas gingivalis (Pg). This bacterium is unique, having a citrullinating enzyme. Antibodies against citrullinated proteins are rather specific for RA. Because causality is ultimately tested in longitudinal cohort studies which currently do not exist for periodontitis and RA, this commentary applied Bradford Hill criteria on the existing literature to assess causality as the most likely interpretation of this association. From an epidemiologic point of view, patients with RA have a higher incidence of periodontal disease than individuals without RA. In addition, there is a dose-response pattern in the association between the severity of periodontitis and RA disease activity. There are indications that periodontitis precedes RA, but there is no evidence yet available to show that Pg plays a direct role in this temporal relationship. The role of the unique characteristic of citrullination by Pg remains unexplained. However, in animal models, citrullination by Pg plays a distinct role in the development and aggravation of experimental arthritis. Although the role of Pg in RA remains speculative, a causative role for periodontitis as a chronic inflammatory disease caused by infectious agents in RA seems biologically plausible.
Monoclonal gammopathy of undetermined significance (MGUS) arises from a clonal expansion of plasm... more Monoclonal gammopathy of undetermined significance (MGUS) arises from a clonal expansion of plasma cells in the bone marrow, secreting monoclonal (M) paraprotein. MGUS is associated with increased susceptibility to infections, which may reflect altered B-cell repertoire. To investigate this, we examined the IgM, IgG and IgA B-cell repertoire diversity in MGUS at baseline and after influenza vaccination (n=16) in comparison to healthy controls (HCs) (n=16). The CDR3 region of the immunoglobulin heavy chain variable (IGHV) region gene was amplified and B-cell spectratypes analyzed by high-resolution electrophoresis. Spectratype Gaussian distribution, kurtosis and skewness were quantified to measure repertoire shifts. Both HC and MGUS baseline spectratypes show inter-individual variability that is more pronounced in the IGHG and IGHA repertoires. Overall, baseline B cell repertoire is more altered in MGUS, with oligoclonality observed in 50% (p=0.01). Post-vaccination, significant diff...
Patients with autoimmune inflammatory rheumatic diseases (AIRDs) are at increased risk of infecti... more Patients with autoimmune inflammatory rheumatic diseases (AIRDs) are at increased risk of infections. This risk has been further increased by the introduction of biologic agents over the past two decades. One of the most effective strategies to prevent infection is vaccination. However, patients with an AIRD have a compromised immune system, which is further impaired by medication. Another important issue is the possibility of triggering a broad nonspecific response by vaccination, potentially resulting in increased activity of the underlying autoimmune disease. In this Review, we provide an analysis of data on vaccination of patients with an AIRD. Both the efficacy and the safety of vaccination are addressed, together with the epidemiology of vaccine-preventable infectious diseases in different subgroups of adults with AIRDs. Special attention is given to vaccination of patients who are treated with biologic agents.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2014
In atherosclerotic plaques, the risk of rupture is increased at sites of macrophage accumulation.... more In atherosclerotic plaques, the risk of rupture is increased at sites of macrophage accumulation. Activated macrophages express folate receptor-β (FR-β), which can be targeted by folate coupled to radioactive ligands to visualize vulnerability. The aim of this study was to explore the presence of activated macrophages in human atherosclerotic plaques by (99m)Tc-folate imaging and to evaluate whether this technique can discriminate between an M1-like and M2-like macrophage phenotype. Carotid endarterectomy specimens of 20 patients were incubated with (99m)Tc-folate, imaged using micro-SPECT, and divided into 3-mm slices. The mean accumulation was calculated per slice, and the distribution of M1-like and M2-like macrophages per slice was quantified by immunohistochemical staining for CD86 as well as inducible nitric oxide synthase (iNOS) for M1 and CD163 and FR-β for M2 macrophages. Monocytes from healthy donors were differentiated toward M1-like or M2-like phenotype by in vitro cultu...
High-mobility group box 1 (HMGB1) is an important molecule for several nuclear processes. Recentl... more High-mobility group box 1 (HMGB1) is an important molecule for several nuclear processes. Recently, HMGB1 has gained much attention as a damage-associated molecular pattern (DAMP) and has been implicated in the pathogenesis of several (auto)-immune diseases, in particular, systemic lupus erythematosus (SLE). A main pathogenic feature in SLE is the accumulation of apoptotic cells. Since HMGB1 is released from apoptotic cells it has been hypothesized that HMGB1 might fuel the inflammatory processes, as seen in this disease, and play a fundamental role in the pathogenesis. In this review, we discuss evidence in support of the theory that HMGB1 is an important mediator in SLE and may be considered a new autoantigen.
The incidence of cardiovascular disease (CVD) is increased in RA. This study was designed to eval... more The incidence of cardiovascular disease (CVD) is increased in RA. This study was designed to evaluate whether a reduction in disease activity influences early markers of CVD. In a prospective longitudinal study, 58 newly diagnosed RA patients and 58 age- and sex-matched healthy controls (HCs) were included. Endothelial dysfunction was measured by small artery elasticity (SAE) and endothelial cell activation was assessed by measuring soluble vascular cellular activation molecule 1(sVCAM-1) and von Willebrand factor (vWF). Advanced glycation end products (AGEs) were quantified by skin autofluorescence. After 1 year, measurements were repeated in all RA patients. At entry, SAE was decreased in RA vs HCs [median 3.4 ml/mmHg100 (range 1.2-9.0) vs 6.1 (range 5.0-15.3), P < 0.0001] and sVCAM-1 and vWF were increased: 391 ng/ml (range 256-680) vs 341 (range 223-691) (P = 0.0015) and 120 ng/ml (range 26.5-342) vs 99 (range 22-298) (P = 0.02), respectively. SAE was inversely correlated wit...
Objective: Differential gene expression in CD177 + and CD177 2 neutrophils was investigated, in o... more Objective: Differential gene expression in CD177 + and CD177 2 neutrophils was investigated, in order to detect possible differences in neutrophil function which could be related to the pathogenesis of ANCA-associated Vasculitides (AAV).
The objective of this study was to evaluate whether levels of high mobility group box 1 (HMGB1) i... more The objective of this study was to evaluate whether levels of high mobility group box 1 (HMGB1) in granulomatosis with polyangiitis (GPA) patients are associated with carotid atherosclerosis, related to levels of soluble receptor for advanced glycation end-products (sRAGE) and influenced by immunosuppressive or lipid-lowering therapy. Twenty-three GPA patients and 20 controls were evaluated for HMGB1- and sRAGE levels and for carotid atherosclerosis using ultrasound to determine intima-media thickness (IMT). In vitro the effect of atorvastatin on the production of HMGB1 by lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVEC) was assessed. Serum HMGB1 and sRAGE levels did not differ between patients and controls. A negative correlation was found between sRAGE and maximum IMT but HMGB1 and carotid IMT were not related. HMGB1 levels were reduced in GPA patients on statins and prednisolone. In vitro, atorvastatin reduced HMGB1 levels in supernatants of acti...
In inflammatory processes, the p38 mitogen-activated protein kinase (MAPK) signal transduction ro... more In inflammatory processes, the p38 mitogen-activated protein kinase (MAPK) signal transduction route regulates production and expression of cytokines and other inflammatory mediators. Tumor necrosis factor α (TNF-α) is a pivotal cytokine in rheumatoid arthritis and its production in macrophages is under control of the p38 MAPK route. Inhibition of the p38 MAPK route may inhibit production not only of TNF-α, but also of other inflammatory mediators produced by macrophages, and indirectly of inflammatory mediators by other cells induced by TNF-α stimulation. Here we investigate the effects of RWJ 67657, a p38 MAPK inhibitor, on mRNA expression and protein production of TNF-α and other inflammatory mediators, in monocyte-derived macrophages. A strong inhibition of TNF-α was seen at pharmacologically relevant concentrations of RWJ 67657, but also inhibition of mRNA expression of IL-1β, IL-8, and cyclooxygenase-2 was shown. Furthermore, it was shown that monocyte-derived macrophages have a high constitutive production of matrix metalloproteinase 9, which is not affected by p38 MAPK inhibition. The results presented here may have important implications for the treatment of rheumatoid arthritis.
Objective. In SLE, a decreased antibody response on influenza vaccination has been reported. In t... more Objective. In SLE, a decreased antibody response on influenza vaccination has been reported. In this study, we assessed whether a booster vaccination could improve antibody responses, as determined by seroprotection rates, in SLE patients. Methods. SLE patients (n ¼ 52) with quiescent disease (SLEDAI 44) and healthy controls (HCs) (n ¼ 28) received subunit influenza vaccine in October-December 2007. After 4 weeks, only SLE patients received a second dose of vaccination. Sera were obtained before both vaccinations, and 4 weeks after the second vaccination. At each visit, SLE disease activity was recorded. The haemagglutination inhibition test was used to measure antibody titres. Seroprotection was defined as a titre 540. Results. Following the first vaccination, seroprotection rates and geometric mean titres (GMTs) to each vaccine strain increased in both SLE patients and controls to comparable levels. Seroprotection rates in SLE patients after the first vaccination were 86.5% to A/H1N1, 80.8% to A/H3N2 and 61.5% to the B-strain while GMTs were 92.6, 56.2 and 39.2, respectively. Overall, the booster vaccination did not lead to a further rise of seroprotection rates and GMTs in SLE patients. However, in patients not vaccinated in the previous year, GMT and seroconversion rate to A/H1N1 did rise following the booster vaccination. Both influenza vaccinations did not increase SLEDAI scores. Conclusions. Additional value of a booster influenza vaccination in SLE is limited to patients who were not vaccinated in the previous year.
Objective. To investigate whether serum levels of endothelial cell activation markers in early RA... more Objective. To investigate whether serum levels of endothelial cell activation markers in early RA patients can serve as biomarkers for inflammation and disease activity, and are associated with radiological progression and development of cardiovascular disease (CVD).
Background: In patients with end stage renal disease (ESRD) we observed protection from inflammat... more Background: In patients with end stage renal disease (ESRD) we observed protection from inflammation-associated mortality in CCR5D32 carriers, leading to CCR5 deficiency, suggesting impact of CCR5D32 on inflammatory processes. Animal studies have shown that CCR5 deficiency is associated with a more pronounced Th2 type immune response, suggesting that in human CCR5D32 carriers the immune response may be more Th2 type directed. So, in the present study we determined the Th1-Th2 type directed immune response in ESRD patients carrying and not carrying the CCR5D32 genetic variant after stimulation.
The prevalence of anti-endothelial cell autoantibodies (AECA) in patients with anti-neutrophil cy... more The prevalence of anti-endothelial cell autoantibodies (AECA) in patients with anti-neutrophil cytoplasmic autoantibody-associated systemic vasculitis (ASV) has been reported by several groups with conflicting results ranging from 8% to 100%. Types of substrate cells used for AECA testing partially explain this variation. Endothelial cells from kidney origin have been reported to be predominant in AECA binding. Therefore, we investigated AECA prevalence using a human glomerular endothelial cell line compared with primary human umbilical vein endothelial cells, which have frequently been used for AECA detection. Methods: Sera from 43 ASV patients (29 Wegener's granulomatosis (WG), 14 microscopic polyangiitis (MPA)) with active disease were assessed for AECA positivity using cell-based enzyme-linked immunosorbent assay. Forty serum samples from healthy controls were tested in parallel. To evaluate endothelial activation levels, soluble intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were measured with capture enzyme-linked immunosorbent assay. Results: The AECA were detected in 4 of 29 WG patients (14%), but none of 14 MPA patients was positive for AECA using glomerular endothelial cell as a substrate, whereas AECA were positive in 10% of WG patients and 14% of MPA patients on human umbilical vein endothelial cells. No significant differences were found between ASV patients and controls in AECA test. Serum levels of vascular cell adhesion molecule-1 and soluble intercellular cell adhesion molecule-1 in ASV patients were significantly higher than in controls. However, there were no differences between AECA-positive and -negative patients for both of the activation markers. Conclusion: The AECA, directed against glomerular endothelial cells, have a low prevalence in ASV patients with active disease and are not correlated with endothelial activation.
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Papers by Johanna Westra