F. De Keyser

Proteome-wide Analysis and CXCL4 as a Biomarker in Systemic Sclerosis

BACKGROUNDnPlasmacytoid dendritic cells have been implicated in the pathogenesis of systemic sclerosis through mechanisms beyond the previously suggested production of type I interferon.nnnMETHODSnWe isolated plasmacytoid dendritic cells from healthy persons and from patients with systemic sclerosis who had distinct clinical phenotypes. We then performed proteome-wide analysis and validated these observations in five large cohorts of patients with systemic sclerosis. Next, we compared the results with those in patients with systemic lupus erythematosus, ankylosing spondylitis, and hepatic fibrosis. We correlated plasma levels of CXCL4 protein with features of systemic sclerosis and studied the direct effects of CXCL4 in vitro and in vivo.nnnRESULTSnProteome-wide analysis and validation showed that CXCL4 is the predominant protein secreted by plasmacytoid dendritic cells in systemic sclerosis, both in circulation and in skin. The mean (±SD) level of CXCL4 in patients with systemic sclerosis was 25,624±2652 pg per milliliter, which was significantly higher than the level in controls (92.5±77.9 pg per milliliter) and than the level in patients with systemic lupus erythematosus (1346±1011 pg per milliliter), ankylosing spondylitis (1368±1162 pg per milliliter), or liver fibrosis (1668±1263 pg per milliliter). CXCL4 levels correlated with skin and lung fibrosis and with pulmonary arterial hypertension. Among chemokines, only CXCL4 predicted the risk and progression of systemic sclerosis. In vitro, CXCL4 down-regulated expression of transcription factor FLI1, induced markers of endothelial-cell activation, and potentiated responses of toll-like receptors. In vivo, CXCL4 induced the influx of inflammatory cells and skin transcriptome changes, as in systemic sclerosis.nnnCONCLUSIONSnLevels of CXCL4 were elevated in patients with systemic sclerosis and correlated with the presence and progression of complications, such as lung fibrosis and pulmonary arterial hypertension. (Funded by the Dutch Arthritis Association and others.).

Synovial detection and autoantibody reactivity of processed citrullinated isoforms of vimentin in inflammatory arthritides

OBJECTIVESnTo investigate the presence and characteristics of citrullinated vimentin in protein extracts of inflamed synovial tissue.nnnMETHODSnCytosolic protein extracts obtained from RA (n = 14) and SpA patients (n = 14) were analysed by gel electrophoresis and western blotting. Citrullinated vimentin isoforms were visualized by a combination of anti-modified citrulline (AMC) staining and anti-vimentin detections (V9, H-84). This was subsequently confirmed by immunoprecipitation. Autoantibody detection was verified using sera obtained form RA (n = 6) and SpA (n = 6) patients.nnnRESULTSnA specific cluster of spots displayed on the 2D gel images of cytosolic synovial tissue extracts, was identified by mass spectrometry as vimentin. Interestingly, our results suggested that these isoforms could be the result of caspase cleavage. In addition, these cleaved forms of vimentin were found to be citrullinated in synovial cytosolic protein extracts of inflammatory arthritides, mainly in RA patients. Caspase-3 is able to cleave vimentin at amino acid 85. Western blot analysis with a specific antibody against amino acids 1-84 of vimentin (H-84) confirmed that the citrullinated isoforms of vimentin were lacking this part of the protein. These results were also confirmed by immunoprecipitation of vimentin derived from cytosolic protein extracts of RA and SpA patients. Furthermore, the presence of autoantibodies against these citrullinated processed forms of vimentin was found to be predominantly associated with RA patients.nnnCONCLUSIONSnThese findings show the presence of processed citrullinated vimentin in inflammatory arthritides, mainly in RA and suggest a possible origin of the ACPA immune response in RA.

Analysis of the influence of PTPN22 gene polymorphisms in systemic sclerosis

Objective Two functional single nucleotide polymorphisms (SNP) in the PTPN22 gene (rs24746601 and rs33996649) have been associated with autoimmunity. The aim of this study was to investigate the role of the R263Q SNP for the first time and to re-evaluate the role of the R620W SNP in the genetic predisposition to systemic sclerosis (SSc) susceptibility and clinical phenotypes. Methods 3422 SSc patients (2020 with limited cutaneous SSc and 1208 with diffuse cutaneous SSc) and 3638 healthy controls of Caucasian ancestry from an initial case--control set of Spain and seven additional independent replication cohorts were included in our study. Both rs33996649 and rs2476601 PTPN22 polymorphisms were genotyped by TaqMan allelic discrimination assay. A meta-analysis was performed to test the overall effect of these PTPN22 polymorphisms in SSc. Results The meta-analysis revealed evidence of association of the rs2476601 T allele with SSc susceptibility (pFDRcorrected=0.03 pooled, OR 1.15, 95% CI 1.03 to 1.28). In addition, the rs2476601 T allele was significantly associated with anticentromere-positive status (pFDRcorrected=0.02 pooled, OR 1.22, 95% CI 1.05 to 1.42). Although the rs33996649 A allele was significantly associated with SSc in the Spanish population (pFDRcorrected=0.04, OR 0.58, 95% CI 0.36 to 0.92), this association was not confirmed in the meta-analysis (p=0.36 pooled, OR 0.89, 95% CI 0.72 to 1.1). Conclusion The study suggests that the PTPN22 R620W polymorphism influences SSc genetic susceptibility but the novel R263Q genetic variant does not. These data strengthen evidence that the R620W mutation is a common risk factor in autoimmune diseases.

The role of endothelial cells in the vasculopathy of systemic sclerosis: A systematic review

INTRODUCTIONnSystemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by fibroproliferative vasculopathy, immunological abnormalities and progressive fibrosis of multiple organs including the skin. In this study, all English speaking articles concerning the role of endothelial cells (ECs) in SSc vasculopathy and representing biomarkers are systematically reviewed and categorized according to endothelial cell (EC) (dys)function in SSc.nnnMETHODSnA sensitive search on behalf of the EULAR study group on microcirculation in Rheumatic Diseases was developed in Pubmed, The Cochrane Library and Web of Science to identify articles on SSc vasculopathy and the role of ECs using the following Mesh terms: (systemic sclerosis OR scleroderma) AND pathogenesis AND (endothelial cells OR marker). All selected papers were read and discussed by two independent reviewers. The selection process was based on title, abstract and full text level. Additionally, both reviewers further searched the reference lists of the articles selected for reading on full text level for supplementary papers. These additional articles went through the same selection process.nnnRESULTSnIn total 193 resulting articles were selected and the identified biomarkers were categorized according to description of EC (dys)function in SSc. The most representing and reliable biomarkers described by the selected articles were adhesion molecules for EC activation, anti-endothelial cell antibodies for EC apoptosis, vascular endothelial growth factor (VEGF), its receptor VEGFR-2 and endostatin for disturbed angiogenesis, endothelial progenitors cells for defective vasculogenesis, endothelin-1 for disturbed vascular tone control, Von Willebrand factor for coagulopathy and interleukin (IL)-33 for EC-immune system communication. Emerging, relatively new discovered biomarkers described in the selected articles, are VEGF165b, IL-17A and the adipocytokines. Finally, myofibroblasts involved in tissue fibrosis in SSc can derive from ECs or epithelial cells through a process known as endothelial-to-mesenchymal transition.nnnCONCLUSIONnThis systematic review emphasizes the growing evidence that SSc is primarily a vascular disease where EC dysfunction is present and prominent in different aspects of cell survival (activation and apoptosis), angiogenesis and vasculogenesis and where disturbed interactions between ECs and various other cells contribute to SSc vasculopathy.

Identification of novel genetic markers associated with the clinical phenotypes of systemic sclerosis through a genome wide association strategy

Identification of novel genetic markers associated with the clinical phenotypes of systemic sclerosis through a genome wide association strategy O Gorlova, J M Martin, B Rueda, BPC Koeleman, J Ying, M Teruel, L M Diaz-Gallo, J C Broen, M C Vonk, C P Simeon, B Z Alizadeh, MJH Coenen, A E Voskuyl, A J Schuerwegh, PLCM van Riel, M Vanthuyne, R van ‘t Slot, A Italiaander, R A Ophoff, N Hunzelmann, V Fonollosa, N Ortego-Centeno, M A González-Gay, F J García-Hernández, M F González-Escribano, P Airo, J van Laar, J Worthington, R Hesselstrand, V Smith, F De Keyser, F Houssiau, M M Chee, R Madhok, P Shiels, R Westhovens, A Kreuter, E de Baere, T Witte, L Padyukov, A Nordin, R Scorza, C Lunardi, B A Lie, A M Hoffmann-Vold, P García de la Peña, P Carreira, J Varga, M Hinchcliff, A T Lee, P Gourh, C I Amos, G Riemekasten, A Herrick, L Beretta, C Fonseca, C P Denton, P K Gregersen, S Agarwal, S Assassi, F K Tan, F C Arnett, TRDJ Radstake, M D Mayes, J Martin

Over-representation of construction-related occupations in male patients with systemic sclerosis

Aims: Based on preliminary observations, we tested the hypothesis that construction-related occupations are associated with systemic sclerosis (SSc). Methods: The professional occupation of 91 patients with SSc (71 females and 20 males) was recorded. Categorisation into construction-related and other professions was performed. A double definition was used for construction-related occupations. The first (limited) definition was based upon categories of the Belgian National Institute of Statistics (NIS) occupational list. The following occupations were considered construction-related: electricians, joiners, masons and tilers, plumbers and pipefitters. The use of this list also allows us to compare the distribution of professions in these patients with that in the general population. As the NIS occupational list is limitative and leaves out some “real-life” construction-related occupations, a second and broader interpretation was given to the concept of construction-related occupations. Results: The prevalence of construction-related professions in males with SSc, according to the limited definition, was 10-fold higher than in the general working population (50% vs 5%; p<0.001). Interestingly, most of the patients with construction-related occupations were electricians. In the broader interpretation, 75% of the men with SSc fell into the category of construction-related occupations. Conclusions: The data show an association between SSc and professional occupation.

Onset of symptoms of rheumatoid arthritis in relation to age, sex and menopausal transition

In a population of 564 patients with rheumatoid arthritis (RA), the onset of symptoms has been studied in relation to age, sex and last menstrual period for women. Median age of menopause was 49 years (3rd percentile: 32 years and 97th percentile: 56 years). Median age of first symptoms was 45 years in women and 50 in men. The individual interval between menopause and first symptoms has a Gaussian distribution with mean at time 0, implying that the average woman develops the first symptoms at the time of her menopause. The F:M ratio of all patients was 2.3; with increasing age the F:M ratio decreased from 3.7 before 30 years of age to 1 after the 6th decade of life, with a peak at the age of 40-44 years. A possible effect of age related changes in sex hormone levels on the pathogenesis of RA is suggested.

A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with Systemic Sclerosis in a large European cohort

The TNFSF4 gene, which encodes OX40L, is considered as a potential autoimmunity candidate gene. OX40L is expressed on activated antigen presenting cells (APCs) and endothelial cells in acute inflammation [1]. Furthermore, it enhances B-cell proliferation and differentiation, and its binding to OX40 (CD134) promotes proliferation and survival of T-cells and predisposes them to a more permissive proliferative and survival condition [2]. Interestingly, four TNFSF4 promoter single-nucleotide polymorphisms (SNP) were recently implicated in susceptibility to systemic sclerosis (SSc)[3].

Management van reumatoïde artritis bij oudere personen

The prevalence of rheumatoid arthritis (RA) in an aging population is steadily increasing as a consequence of the chronicity of the disease and the increased life expectancy. The phenotype of the disease differs according to the age at which RA first appears. In elderly-onset RA (EORA), the most important differential diagnosis is polymyalgia rheumatica. The use of conventional disease-modifying antirheumatic drugs (DMARDs) and biologicals in older patients is currently not optimal. Literature data indicate that a higher disease activity in this age group is tolerated before adapting the pharmacotherapeutic management. Yet, there is no indication that the safety and efficacy of RA-specific drugs are essentially different between older and younger patients. An important criterion for making a decision is the biological age of the person to be treated. A discrepancy between the biological and the chronological age may be caused by frailty, multimorbidity and the presence of geriatric giant conditions (cognitive limitations, depression, sensory disorders, disturbed mobility and incontinence). In case of a favourable biological age, a sharp therapeutic target should be formulated and pharmacotherapy should be designed to reach such a target. If a person ages less successfully with an unfavourable biological age, drugs with a safety risk should be prescribed with more restraint and more safety surveillance. Non-pharmacotherapeutic care (exercise therapy, occupational therapy), in addition to drug therapy, has an important role for older patients with RA.