Marie Vanthuyne

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

The aim of this study was to determine, through a genome-wide association study (GWAS), the genetic components contributing to different clinical sub-phenotypes of systemic sclerosis (SSc). We considered limited (lcSSc) and diffuse (dcSSc) cutaneous involvement, and the relationships with presence of the SSc-specific auto-antibodies, anti-centromere (ACA), and anti-topoisomerase I (ATA). Four GWAS cohorts, comprising 2,296 SSc patients and 5,171 healthy controls, were meta-analyzed looking for associations in the selected subgroups. Eighteen polymorphisms were further tested in nine independent cohorts comprising an additional 3,175 SSc patients and 4,971 controls. Conditional analysis for associated SNPs in the HLA region was performed to explore their independent association in antibody subgroups. Overall analysis showed that non-HLA polymorphism rs11642873 in IRF8 gene to be associated at GWAS level with lcSSc (P = 2.32×10−12, OR = 0.75). Also, rs12540874 in GRB10 gene (P = 1.27 × 10−6, OR = 1.15) and rs11047102 in SOX5 gene (P = 1.39×10−7, OR = 1.36) showed a suggestive association with lcSSc and ACA subgroups respectively. In the HLA region, we observed highly associated allelic combinations in the HLA-DQB1 locus with ACA (P = 1.79×10−61, OR = 2.48), in the HLA-DPA1/B1 loci with ATA (P = 4.57×10−76, OR = 8.84), and in NOTCH4 with ACA P = 8.84×10−21, OR = 0.55) and ATA (P = 1.14×10−8, OR = 0.54). We have identified three new non-HLA genes (IRF8, GRB10, and SOX5) associated with SSc clinical and auto-antibody subgroups. Within the HLA region, HLA-DQB1, HLA-DPA1/B1, and NOTCH4 associations with SSc are likely confined to specific auto-antibodies. These data emphasize the differential genetic components of subphenotypes of SSc.

Lack of evidence of stimulatory autoantibodies to platelet-derived growth factor receptor in patients with systemic sclerosis

OBJECTIVE Systemic sclerosis (SSc) is a severe connective tissue disease of unknown etiology, characterized by fibrosis of the skin and multiple internal organs. Recent findings suggested that the disease is driven by stimulatory autoantibodies to platelet-derived growth factor receptor (PDGFR), which stimulate the production of reactive oxygen species (ROS) and collagen by fibroblasts. These results opened novel avenues of research into the diagnosis and treatment of SSc. The present study was undertaken to confirm the presence of anti-PDGFR antibodies in patients with SSc. METHODS Immunoglobulins from 37 patients with SSc were purified by protein A/G chromatography. PDGFR activation was tested using 4 different sensitive bioassays, i.e., cell proliferation, ROS production, signal transduction, and receptor phosphorylation; the latter was also tested in a separate population of 7 patients with SSc from a different research center. RESULTS Purified IgG samples from patients with SSc were positive when tested for antinuclear autoantibodies, but did not specifically activate PDGFRalpha or PDGFRbeta in any of the tests. Cell stimulation with PDGF itself consistently produced a strong signal. CONCLUSION The present results raise questions regarding the existence of agonistic autoantibodies to PDGFR in SSc.

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.

Hand Radiological Damage in Systemic Sclerosis: Comparison with a Control Group and Clinical and Functional Correlations

OBJECTIVE To define the burden of hand radiological damage in systemic sclerosis (SSc) patients, compared with a control group. METHODS Both hands of 167 SSc patients and 168 hands (82 right and 86 left) of age- and gender-matched controls were imaged by conventional radiograph. Two musculoskeletal radiologists semiquantitatively scored the following lesions: tuft acro-osteolysis, tuft calcinosis, joint space narrowings, marginal erosions, surface erosions, collapse arthropathies, periarticular calcifications, and juxta-articular osteoporosis, at the following areas: tufts, distal interphalangeal, proximal interphalangeal, metacarpophalangeal, carpal, and first carpometacarpal joints. Clinical and functional characteristics of the 167 SSc patients were obtained from the Belgian Systemic Sclerosis Cohort database. RESULTS Tuft acro-osteolysis and calcinosis were the most common findings observed in SSc patients and were almost absent in controls. SSc patients displaying tuft acro-osteolysis/calcinosis suffered from more severe disease. Arthropathies were infrequently detected and mainly consisted of a mixture of osteoarthritis-related changes (joint space narrowing and surface erosions)-also observed in controls-and of 2 types of rare SSc-associated arthropathies: a rheumatoid arthritis-like pattern, characterized by marginal erosions (n = 7 patients), and a collapse arthropathy (n = 6 patients), characterized by pressure erosions and joint subluxation. CONCLUSIONS Although a rheumatoid arthritis-like or a collapse arthropathy can be observed in SSc patients, arthropathies are less common than previously reported.

The Belgian Systemic Sclerosis Cohort: Correlations Between Disease Severity Scores, Cutaneous Subsets, and Autoantibody Profile

Objective. To report baseline and followup data on the first 438 patients with systemic sclerosis (SSc) included in the Belgian Systemic Sclerosis Cohort. Methods. According to LeRoy and Medsger’s classification, 73 patients with limited SSc (lSSc), 279 with limited cutaneous SSc (lcSSc), and 86 with diffuse cutaneous SSc (dcSSc) were included. History was collected and clinical examination, blood tests, and paraclinical investigations were repeated. The Disease Activity Score (DAS) and Disease Severity Score (DSS) of several organ systems were computed. An organ system was considered to demonstrate SSc if the corresponding DSS was ≥ 1. Results. At baseline, patients with dcSSc had more general, joint/tendon, muscle, gastrointestinal, and kidney involvement. Mean DLCO was below normal in patients with lSSc, indicating unsuspected lung involvement. Patients with anti-Scl-70 had more vascular, skin, joint/tendon, and lung involvement. Patients with anti-RNA polymerase III had more skin and joint/tendon involvement compared to patients with anticentromere. Time to death was statistically shorter for patients with dcSSc. New-onset lung disease was the most common complication over time. No changes in DAS were observed. By contrast, the general and the skin DSS worsened in patients with lcSSc and lSSc, respectively. Fifteen percent of patients with lSSc shifted to lcSSc at Month 30, but neither serology nor capillaroscopy findings at baseline were helpful in identifying those at risk. Conclusion. Our data indicate that the DSS can be used to define organ involvement in SSc. Differences can be seen between subsets classified not only according to cutaneous subtypes but also to autoantibody profile.

Validation of a manual ability questionnaire in patients with systemic sclerosis.

OBJECTIVE To adapt and validate a manual ability questionnaire, the ABILHAND, developed through the Rasch methodology in patients with systemic sclerosis (SSc). METHODS The original version of the ABILHAND, which includes 81 manual daily activities, was presented to 156 patients with SSc. They were asked to provide their perceived difficulty in performing each manual activity on a 3-level scale: impossible, difficult, or easy. Items were selected from well-established psychometric criteria. The patients were reassessed 1 month later to test the reproducibility. Concomitantly, they were clinically evaluated for their disease activity/severity, and their functional ability was tested with the Health Assessment Questionnaire (HAQ). RESULTS The 26 selected items defined a unidimensional and linear measure of manual ability and showed a continuous progression in their difficulty. The item difficulty hierarchy was invariant across 12 patient-related factors and the manual ability score was reproducible over time. Finally, the manual ability was significantly poorer in SSc patients with more severe disease, and was negatively correlated with the HAQ score (rho = -0.733). CONCLUSION The SSc-adapted ABILHAND questionnaire is a reliable, valid, reproducible, linear, and unidimensional measure to assess and followup on the manual ability of patients with SSc; therefore, it could become a useful additional tool in clinical trials to assess treatment efficacy.

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.

Two years follow-up of an open-label pilot study of treatment with rituximab in patients with early diffuse cutaneous systemic sclerosis

Abstract Objectives: Following results in open-label studies of rituximab in patients with systemic sclerosis, a Belgian three-centre initiative was launched to explore safety and efficacy of rituximab in early, diffuse cutaneous systemic sclerosis (dcSSc). Methods: Open-label study of 17 patients with early dcSSc, treated with two courses of rituximab, at month 0 and 6. Clinical examination, lung function testing, echocardiography, disease activity score (DAS) and functional status were performed at baseline and over 24 months of follow-up. Results: Modified Rodnan skin score (MRSS) changed significantly over time, with a mean of 25.5 (standard deviation [SD] 6.0) at baseline to 12.6 (SD 5.1) at month 24 (Mixed Model Analysis [MMA] p < 0.0001), which is a decrease of 51% at month 24 vs. baseline. DAS showed significant decrease over the total study period, with a score of 4.1 (SD 1.7) at baseline to 1.5 (SD 1.8) at month 24 (MMA p < 0.0001). Additionally, this was significant at all time points vs. baseline, both for MRSS and DAS. Internal organ status remained clinically stable throughout the study period. No statistically significant differences compared to baseline were found at the follow-up time points. Seven serious adverse events took place, all except for one, considered unrelated to study medication. Conclusions: This is the first multicentre Belgian collaboration investigating potential efficacy of rituximab in early dcSSc. Rituximab appears to be safe and tolerable and it may have beneficial effects on skin involvement, on overall disease activity and on stabilization of internal organ status in early dcSSc.

High prevalence of occupational exposure to solvents or silica in male systemic sclerosis patients: a Belgian cohort analysis

Increasing evidence supports a relation of some occupational exposures to systemic sclerosis pathogenesis. We aimed to evaluate occupational exposure and clinical characteristics in male patients with systemic sclerosis followed in two Belgian academic hospitals. One hundred and three male patients, included in the Belgian Systemic Sclerosis Cohort, were identified. An expert in occupational medicine reviewed the occupational history and allocated the patients to one of the following groups: probable exposure to crystalline silica, probable exposure to solvents, probable exposure to other toxins, or no suspected occupational exposure. Clinical characteristics were extracted from the Belgian Systemic Sclerosis Cohort database. Sufficient data were available for 96/103 patients. Most of these male patients (70/96, 72.9%) had a history of occupational exposure, 55 patients were likely exposed to crystalline silica, 11 patients to solvents, 2 patients to both silica and solvents, and 2 patients to asbestos. Only 26 patients had no suspected occupational exposure (27.1%). We noticed a significant difference in smoking status between exposed and non-exposed patients, with the highest percentage of ever smokers in the group with solvent exposure (p = 0.011). We found no significant differences in disease phenotype between exposed and non-exposed patients. However, we noted a trend to a higher prevalence of anti-Scl70 antibodies, cardiac dysfunction, and higher disease activity score in patients with occupational exposure. We observed a strikingly high prevalence of occupational exposure to both silica and solvents in male systemic sclerosis patients. Occupational exposure to silica or solvents is highly prevalent in male systemic sclerosis patients.