Purpose of review
The last decade has seen enormous progress in understanding genetic associations of systemic sclerosis to explain the observed heritability. This review highlights the most recent findings and places them in the context of proposed functional roles.
Over 30 genes and gene regions have now been identified as scleroderma susceptibility loci. These include both human leukocyte antigen (HLA) and non-HLA genes, most of which involve immune-related pathways and modifiers of immune function. Many of these associations have also been reported in other systemic autoimmune diseases and suggest that there are multiple autoimmunity genes resulting in disease occurrence.
In spite of these advances, only a small proportion of the heritability of systemic sclerosis has been explained. Ongoing studies include fine mapping and sequencing studies to identify causal variants, whereas other studies focus on functional consequences of these variants in order to identify the link between these genetic variants and disease susceptibility. Such knowledge should lead to more targeted and effective treatment in this disease.
genetic variants; genome-wide association studies; scleroderma; single nucleotide polymorphisms; systemic sclerosis
Significant advances have been made in understanding the genetic basis of systemic sclerosis (scleroderma) in recent years. Can these discoveries lead to individualized monitoring and treatment? Besides robustly replicated genetic susceptibility loci, several genes have been recently linked to various systemic sclerosis disease manifestations. Furthermore, inclusion of genetic studies in design and analysis of drug trials could lead to development of genetic biomarkers that predict treatment response. Future genetic studies in well-characterized systemic sclerosis cohorts paired with advanced analytic approaches can lead to development of genetic biomarkers for targeted diagnostic and therapeutic interventions in systemic sclerosis.
systemic sclerosis; scleroderma; genetic; biomarker; severity
Psychosocial and rehabilitation interventions are increasingly used to attenuate disability and improve health-related quality of life (HRQL) in chronic diseases, but are typically not available for patients with rare diseases. Conducting rigorous, adequately powered trials of these interventions for patients with rare diseases is difficult. The Scleroderma Patient-centered Intervention Network (SPIN) is an international collaboration of patient organisations, clinicians and researchers. The aim of SPIN is to develop a research infrastructure to test accessible, low-cost self-guided online interventions to reduce disability and improve HRQL for people living with the rare disease systemic sclerosis (SSc or scleroderma). Once tested, effective interventions will be made accessible through patient organisations partnering with SPIN.
Methods and analysis
SPIN will employ the cohort multiple randomised controlled trial (cmRCT) design, in which patients consent to participate in a cohort for ongoing data collection. The aim is to recruit 1500–2000 patients from centres across the world within a period of 5 years (2013–2018). Eligible participants are persons ≥18 years of age with a diagnosis of SSc. In addition to baseline medical data, participants will complete patient-reported outcome measures every 3 months. Upon enrolment in the cohort, patients will consent to be contacted in the future to participate in intervention research and to allow their data to be used for comparison purposes for interventions tested with other cohort participants. Once interventions are developed, patients from the cohort will be randomly selected and offered interventions as part of pragmatic RCTs. Outcomes from patients offered interventions will be compared with outcomes from trial-eligible patients who are not offered the interventions.
Ethics and dissemination
The use of the cmRCT design, the development of self-guided online interventions and partnerships with patient organisations will allow SPIN to develop, rigourously test and effectively disseminate psychosocial and rehabilitation interventions for people with SSc.
Rheumatology; Statistics & Research Methods; Rehabilitation Medicine; Mental Health
A phase II randomized controlled trial of recombinant human relaxin suggested that 25 ug/kg/day was safe and clinically effective in improving skin disease and functional disability in scleroderma. We report the results of a large randomized, double-blind, placebo-controlled clinical trial comparing placebo with recombinant human relaxin, 10 ug/kg of body weight per day and 25 ug/kg per day, given for 24 weeks in patients with stable, diffuse, moderate to severe scleroderma (SSc).
Men and women 18 to 70 years of age with diffuse SSc, disease duration ≤ 5 years since the onset of the first non-Raynaud sign or symptom, a baseline modified Rodnan skin score (MRSS) of 20 or greater, or at least 16 if truncal involvement was present. Recombinant human relaxin (10 or 25 ug/kg/day), or placebo was administered for 24 weeks as a continuous subcutaneous infusion and there was a follow-up safety visit at week 28.
The primary outcome measure, the MRSS, was similar between the 3 groups at baseline and at weeks 4, 12, and 24 (P=NS). Secondary outcomes such as functional disability were similar in all 3 groups and the forced vital capacity significantly decreased in the relaxin groups (p< 0.04). The discontinuation of relaxin (both doses) at week 24 led to statistically significant declines in creatinine clearance and serious renal adverse events (defined as either doubling of baseline serum creatinine, renal crisis, or grade 3 or 4 hypertension) in 7 patients who had received relaxin therapy but in none who had received placebo (p=0.04).
Recombinant relaxin was not significantly better than placebo in improving total skin score, pulmonary function, or functional disability in patients with diffuse SSc. In addition, relaxin was associated with serious renal adverse events, the majority of which occurred after stopping the infusion. If relaxin is used therapeutically for any conditions other than scleroderma, close monitoring of blood pressure and renal function must be performed.
The first genome-wide association study (GWAS) of systemic sclerosis (SSc) demonstrated three non-major histocompatibility complex (MHC) susceptibility loci. The goal of this study was to investigate the impact of these gene variants on survival and severity of interstitial lung disease (ILD) in SSc.
The authors examined 1443 Caucasian SSc patients enrolled in the Genetics versus Environment In Scleroderma Outcome Study (GENISOS) and Scleroderma Family Registry (n = 914 – discovery cohort) and The Johns Hopkins Scleroderma Cohort (n = 529 – replication cohort). Forced vital capacity (FVC)% predicted was used as a surrogate for ILD severity. Five single nucleotide polymorphisms, IRF5 (rs10488631, rs12537284, rs4728142), STAT4 (rs3821236), CD247 (rs2056626) reached genome-wide significance in the SSc-GWAS and were examined in the current study.
Overall, 15.5% of the patients had died over the follow-up period of 5.5 years. The IRF5 rs4728142 minor allele was predictive of longer survival in the discovery cohort (p = 0.021) and in the independent replication cohort (p = 0.047) and combined group (HR: 0.75, 95% CI 0.62 to 0.90, p = 0.002). The association of this SNP with survival was independent of age at disease onset, disease type and autoantibody profile (anticentromere and antitopoisomerase antibodies). The minor allele frequency of IRF5 rs4728142 was 49.4%.
Moreover, IRF5 rs4728142 minor allele correlated with higher FVC% predicted at enrolment (p = 0.019). Finally, the IRF5 rs4728142 minor allele was associated with lower IRF5 transcript expression in patients and controls (p = 0.016 and p = 0.034, respectively), suggesting that the IRF5, rs4728142 SNP, may be functionally relevant.
An SNP in the IRF5 promoter region (rs4728142), associated with lower IRF5 transcript levels, was predictive of longer survival and milder ILD in patients with SSc.
Increased levels of genes in the type I interferon (IFN) pathway have been observed in patients with systemic sclerosis (SSc), or scleroderma. How type I IFN regulates the dermal fibroblast and its participation in the development of dermal fibrosis is not known. We hypothesized that one mechanism by which type I IFN may contribute to dermal fibrosis is through upregulation of specific Toll-like receptors (TLRs) on dermal fibroblasts. Therefore, we investigated the regulation of TLR expression on dermal fibroblasts by IFN.
The expression of TLRs was assessed in cultured dermal fibroblasts from control and SSc patients stimulated with IFNα2. The ability of IFNα2 to regulate TLR-induced interleukin (IL)-6 and CC chemokine ligand 2 production was also assessed. Immunohistochemical analyses were performed to determine whether TLR3 was expressed in skin biopsies in the bleomycin-induced skin fibrosis model and in patients with SSc.
IFNα2 increased TLR3 expression on human dermal fibroblasts, which resulted in enhanced TLR3-induced IL-6 production. SSc fibroblasts have an augmented TLR3 response to IFNα2 relative to control fibroblasts. Pretreatment of fibroblasts with transforming growth factor (TGF)-β increased TLR3 induction by IFNα2, but coincubation of TGF-β did not alter TLR3 induction by IFN. Furthermore, IFNα2 inhibits but does not completely block the induction of connective tissue growth factor and collagen expression by TGF-βin fibroblasts. TLR3 expression was observed in dermal fibroblasts and inflammatory cells from skin biopsies from patients with SSc as well as in the bleomycin-induced skin fibrosis model.
Type I IFNs can increase the inflammatory potential of dermal fibroblasts through the upregulation of TLR3.
To describe the prevalence and clinical correlates of endoscopic gastric antral vascular ectasia (GAVE; “watermelon stomach”) in early diffuse systemic sclerosis (SSc).
Subjects with early, diffuse SSc and evidence of specific internal organ involvement were considered for the Scleroderma: Cyclophosphamide Or Transplant (SCOT) trial. In the screening procedures, all patients underwent upper gastrointestinal endoscopy. Patients were then categorized into those with or without endoscopic evidence of GAVE. Demographic data, clinical disease characteristics, and autoantibody data were compared using Pearson chi-square or Student t tests.
Twenty-three of 103 (22.3%) individuals were found to have GAVE on endoscopy. Although not statistically significant, anti-topoisomerase I (anti-Scl70) was detected less frequently among those with GAVE (18.8% vs 44.7%; p = 0.071). Similarly, anti-RNP antibodies (anti-U1 RNP) showed a trend to a negative association with GAVE (0 vs 18.4%; p = 0.066). There was no association between anti-RNA polymerase III and GAVE. Patients with GAVE had significantly more erythema or vascular ectasias in other parts of the stomach (26.1% vs 5.0%; p = 0.003).
Endoscopic GAVE was present on screening in almost one-fourth of these highly selected patients with early and severe diffuse SSc. While anti-Scl70 and anti-U1 RNP trended toward a negative association with GAVE, there was no correlation between anti-RNA Pol III and GAVE. Patients with GAVE had a higher frequency of other gastric vascular ectasias outside the antrum, suggesting that GAVE may represent part of the spectrum of the vasculopathy in SSc.
GASTRIC ANTRAL VASCULAR ECTASIA; GAVE; SYSTEMIC SCLEROSIS VASCULOPATHY; ENDOSCOPY
A number of genetic loci have been identified that appear to be associated with systemic sclerosis (SSc; scleroderma). There is mounting evidence suggesting that these genetic associations may in fact be associated with distinct phenotypes in SSc based on autoantibody pattern rather than with SSc as a single disease entity. This may ultimately have implications for approaches to therapy as well as responses to therapy. The most promising candidate genes are those involved in pathways that lead to the vascular damage and fibrosis that are the hallmarks of this disease. There is uncertainty, however, regarding the nature of the key pathological mechanisms that link these two disease processes. Recent studies have focused on Fli1 (friend leukaemia integration 1), a transcription factor that is found in immune cells, fibroblasts, and endothelial cells that regulates collagen gene function and angiogenesis. Fli1 is dysregulated in SSc skin and dermal blood vessels, and appears to play a pathological role in SSc skin fibrosis and vessel degeneration. Whether this dysregulation is due to genetic polymorphisms in the Fli1 pathway or to epigenetic mechanisms is not clear.
Systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are related chronic autoimmune diseases of complex aetiology in which the interferon (IFN) pathway plays a key role. Recent studies have reported an association between IRF7 and SLE which confers a risk to autoantibody production. A study was undertaken to investigate whether the IRF7 genomic region is also involved in susceptibility to SSc and the main clinical features.
Two case-control sets of Caucasian origin from the USA and Spain, comprising a total of 2316 cases of SSc and 2347 healthy controls, were included in the study. Five single nucleotide polymorphisms (SNPs) in the PHRF1-IRF7-CDHR5 locus were genotyped using TaqMan allelic discrimination technology. A meta-analysis was performed to test the overall effect of these genetic variants on SSc.
Four out of five analysed SNPs were Significantly associated with the presence of anticentromere autoantibodies (ACA) in the patients with SSc in the combined analysis (rs1131665: pFDR=6.14 × 10−4, OR=0.78; rs4963128: pFDR=6.14 × 10−4, OR=0.79; rs702966: pFDR=3.83 × 10−3, OR=0.82; and rs2246614: pFDR=3.83 × 10−3, OR=0.83). Significant p values were also obtained when the disease was tested globally; however, the statistical significance was lost when the ACA-positive patients were excluded from the study, suggesting that these associations rely on ACA positivity. Conditional logistic regression and allelic combination analyses suggested that the functional IRF7 SNP rs1131665 is the most likely causal variant.
The results show that variation in the IRF7 genomic region is associated with the presence of ACA in patients with SSc, supporting other evidence that this locus represents a common risk factor for autoantibody production in autoimmune diseases.
Osteopontin (OPN) is a matricellular protein with proinflammatory and profibrotic properties. Previous reports demonstrate a role for OPN in wound healing and pulmonary fibrosis. Herein, we determined if OPN levels are increased in a large cohort of systemic sclerosis (SSc) patients and if OPN contributes dermal fibrosis. Plasma OPN levels were increased in SSc patients, including patients with limited and diffuse disease, compared to healthy controls. Immunohistology demonstrated OPN on fibroblast-like and inflammatory cells in SSc skin and lesional skin from mice in the bleomycin-induced dermal fibrosis model. OPN deficient (OPN−/−) mice developed less dermal fibrosis compared to wild-type mice in the bleomycin-induced dermal fibrosis model. Additional in vivo studies demonstrated that lesional skin from OPN−/− mice had fewer Mac-3+ cells, fewer myofibroblasts, decreased TGF-beta (TGFβ) and genes in the TGFβ pathway and decreased numbers of cells expressing phosphorylated SMAD2 (pSMAD) and ERK. In vitro, OPN−/− dermal fibroblasts had decreased migratory capacity but similar phosphorylation of SMAD2 by TGFβ. Finally, TGFβ production by OPN deficient macrophages was reduced compared to wild type. These data demonstrate an important role for OPN in the development of dermal fibrosis and suggest that OPN may be a novel therapeutic target in SSc.
Transforming growth factor-beta (TGF-b) and platelet-derived growth factor (PDGF) may play a critical role in systemic sclerosis- interstitial lung disease (SSc-ILD) and imatinib is a potent inhibitor of TGF-b and PDGF production. We report a phase I/IIa open-label pilot study of imatinib in patients with SSc-ILD. Our primary aim was to assess imatinib’s safety; we also explored efficacy.
We recruited 20 SSc patients with FVC< 85% predicted, dyspnea on exertion, and presence of ground glass appearance on HRCT. Patients received oral imatinib therapy (up to 600 mg/day) for a period of 1 year. Adverse events, pulmonary function tests, and modified Rodnan skin score (MRSS) were captured every 3 months. The course of lung function, HAQ-DI and MRSS were modeled over the length of study to explore efficacy.
The majority of patients were female (65%), Caucasian (75%) and had diffuse SSc (70%). The baseline mean (SD) FVC%predicted was 65.2 (14.0) and MRSS was 18.7 (10.1). Mean(SD) imatinib dose was 445 (125) mg/day. Of 20 patients, 12 completed the study, 7 discontinued due to adverse events (AEs), and 1 patient was lost to follow-up. Common AEs (≥ 20%) included fatigue, facial/lower extremity edema, nausea and vomiting, diarrhea, generalized rash, and new onset proteinuria. Treatment with imatinib showed a trend towards an improvement of FVC%predicted of 1.74% (p>0.05) and MRSS of 3.9 units (p< 0.001).
Use of high-dose daily (600 mg/day) imatinib in SSc-ILD was associated with a large number of AEs. Our AE experience suggests that doses lower than 600 mg/day imatinib may be appropriate and that further dose ranging is needed to understand the therapeutic index of imatinib in SSc.
imatinib; clinical trial; systemic sclerosis; scleroderma-related lung fibrosis
The role of cigarette exposure in susceptibility to systemic sclerosis (SSc) has not been previously studied. Our objective was to investigate the association of smoking with susceptibility to SSc in a large well-defined patient population.
We conducted a review of 1,379 SSc patients enrolled in the Scleroderma Family Registry and DNA Repository and/or the Genetics versus Environment in Scleroderma Outcome Study (GENISOS) cohort. Smoking history was obtained from chart review or via telephone interview. SSc patients were subsequently categorized as never smokers or ever smokers. SSc patients with available smoking data were matched 2:1 by age, gender, ethnicity and state of residence to controls using the Behavioral Risk Factor Surveillance System.
The majority of cases were White (74.2%) with Latinos and Blacks representing 11.3% and 9.7%, respectively. Most patients had limited disease type (54%). For our comparative analyses, 621 patients were matched to controls. There was no significant difference in age, gender, ethnicity and SSc disease type between matched versus unmatched patients. The majority of patients had never smoked (57%), while 43% of patients were ever smokers. The SSc patients did not differ in their smoking behavior from controls (p=0.842, OR: 1.020, 95% CI: 0.839–1.240). Anti-topoisomerase positive patients were more likely to be never smokers (p=0.049, OR=0.648, 95% CI=0.421–0.998) whereas no such association was found with the anti-centromere and anti-RNA Polymerase antibodies.
Unlike in rheumatoid arthritis, smoking does not confer a risk for development of SSc, though it may impact disease severity.
To provide minimally important difference (MID) estimates for the UCLA Scleroderma Clinical Trial Consortium Gastrointestinal Tract 2.0 (UCLA SCTC GIT 2.0) in a longitudinal observational cohort.
We administered the UCLA SCTC GIT 2.0 to 115 patients with SSc at 2 time points 6 months apart. UCLA SCTC GIT 2.0 has 7 multi-item scales: Reflux, Distention/Bloating, Diarrhea, Fecal Soilage, Constipation, Emotional Well-being, and Social Functioning and a Total GIT score. All scales are scored from 0 (better HRQOL) to 3 (worse HRQOL) except the diarrhea and constipation scales (ranges are 0–2 and 0– 2.5, respectively). Patients also rated their overall, upper, and lower GIT involvement during the 2nd visit using a “Much better, somewhat better, almost the same, somewhat worse, or much worse” response scale. The minimally changed group was defined by those reporting they were somewhat better or somewhat worse compared to 1st visit.
Study participants were 84% female and 81% white with a mean disease duration of 6.9 years. The MID estimates for improvement ranged from 0.07 for the Social Functioning scale to 0.36 for Emotional Well-Being scale. For worsening, the MID estimates ranged from 0.06 for Fecal Soilage scale to 0.21 for the Social Functioning Scale.
We provide MID estimates for the UCLA SCTC GIT 2.0 scales. This information can aid in interpreting scale scores in future RCTs and observational studies.
gastrointestinal; scleroderma; systemic sclerosis; UCLA SCTC GIT 2.0; minimally important differences; minimal clinically important differences
Anti-U3-RNP or anti-fibrillarin antibodies (AFA) are detected more frequently among African American (AA) patients with systemic sclerosis (SSc) compared to other ethnic groups and are associated with distinct clinical features. The current study examines the immunogenetic, clinical, and survival correlates of AFA in a large group of AA patients with SSc.
Overall, 278 AA SSc patients and 328 unaffected AA controls were enrolled from three North American cohorts. Clinical features, autoantibody profile, and HLA-class-II genotyping were captured. To compare the clinical manifestations, relevant clinical features were adjusted for disease duration. The Cox proportional hazards regression was used to determine the effect of AFA on survival.
Fifty (18.5%) AA patients had AFA. After Bonferroni correction, HLA-DRB1*08:04 was associated with AFA, compared to unaffected AA controls (OR=11.5, p<0.0001) and AFA negative SSc patients (OR=5.2, p=0.0002). AFA positive AA patients had younger age of disease onset, higher frequency of digital ulcers, diarrhea, pericarditis, higher Medsger Perivascular and lower Lung Severity Indices (p=0.004, p=0.014, p=0.019, p=0.092, p=0.006, and p=0.016, respectively). After adjustment for age at enrollment, AFA positive patients did not have different survival compared with patients without AFA (p=0.493).
These findings demonstrate strong association between AFA and HLA-DRB1*08:04 allele in AA patients with SSc. Moreover, AA SSc patients with AFA had younger age of onset, higher frequency of digital ulcers, pericarditis, and severe lower gastrointestinal involvement, but less severe lung involvement compared to AA patients without AFA. However, presence of AFA did not change survival.
Scleroderma; GENISOS; anti-U3-RNP; digital ulcer; HLA DRB1; and Scleroderma Family Registry
To determine the prevalence, correlates, and predictors of work disability (WD) in the Genetics versus ENvironment In Scleroderma Outcome Study (GENISOS). We hypothesized that WD in systemic sclerosis (SSc) is a function of demographic, clinical, and psychosocial factors.
Patients enrolled in the GENISOS cohort were subdivided in 3 groups: work disabled, working, and retired or homemakers. The latter group (n=29) was excluded from further analysis. We used logistic regression analysis with a forward hierarchical variable selection strategy to investigate the independent correlates of WD at enrollment. Cox regression proportional Hazard’s model with a similar variable selection strategy was utilized to determine the predictors of WD in those working at enrollment.
Overall, 284 patients with mean age of 48.7 years and disease duration of 2.5 (±1.6) years were enrolled into the GENISOS cohort, consisting of 83.5% female, 46.8% Caucasian, 28.9% Hispanic, and 20.4% African American. Patients were longitudinally followed for 3.9 (±3.6) years in 1438 study visits. At enrollment, 124 patients (43.7%) were work disabled whereas 131 (46.1%) were working. Lower education (p<0.001), higher Medsger Lung Severity Index (p=0.012), higher Fatigue Severity Score (FSS) (p=0.008), and less social support (p<0.001) correlated independently with WD. Of those working at baseline, 35 (26.7%) eventually developed WD. Non-Caucasian ethnicity (p=0.038), lower DLCO %predicted value (p=0.038), and higher FSS (p=0.009) at enrollment independently predicted WD on follow-up visits.
Demographic, clinical, and psychosocial factors correlate with WD cross-sectionally and predict WD longitudinally in the patients with SSc.
Work disability; Systemic Sclerosis; Medsger Lung Severity Index; ISEL; SF-36; Fatigue
Accumulating evidence shows that shared autoimmunity is critical for the pathogenesis of many autoimmune diseases. Systemic sclerosis (SSc) belongs to the connective tissue disorders, and recent data have highlighted strong associations with autoimmunity genes shared with other autoimmune diseases. To determine whether novel risk loci associated with systemic lupus erythematosus or multiple sclerosis may confer susceptibility to SSc, we tested single-nucleotide polymorphisms (SNP) from ITGAM, ITGAX, and CD58 for associations.
SNP harboring associations with autoimmune diseases, ITGAM rs9937837, ITGAX rs11574637, and CD58 rs12044852, were genotyped in 2 independent cohorts of European Caucasian ancestry: 1031 SSc patients and 1014 controls from France and 1038 SSc patients and 691 controls from the USA, providing a combined study population of 3774 individuals. ITGAM rs1143679 was additionally genotyped in the French cohort.
The 4 polymorphisms were in Hardy-Weinberg equilibrium in the 2 control populations, and allelic frequencies were similar to those expected in European Caucasian populations. Allelic and genotypic frequencies for these 3 SNP were found to be statistically similar in SSc patients and controls. Subphenotype analyses for subgroups having diffuse cutaneous subtype disease, specific autoantibodies, or fibrosing alveolitis did not reveal any difference between SSc patients and controls.
These results obtained through 2 large cohorts of SSc patients of European Caucasian ancestry do not support the implication of ITGAM, ITGAX, and CD58 genes in the genetic susceptibility of SSc, although they were recently identified as autoimmune disease risk genes.
SYSTEMIC SCLEROSIS; SYSTEMIC LUPUS ERYTHEMATOSUS; AUTOIMMUNITY SINGLE NUCLEOTIDE POLYMORPHISM; ITGAM; ITGAX; CD58
To examine the predictive role of HLA genetic markers for scleroderma renal crisis (SRC) beyond the known clinical correlates in a large population of patients with systemic sclerosis (SSc).
SSc patients from the Scleroderma Family Registry and DNA Repository, Genetics versus Environment in Scleroderma Outcomes Study (GENISOS) and rheumatology divisional registry at the University of Texas Health Science Center at Houston were included in the study. Relevant clinical data were obtained by chart review and autoantibodies were detected utilizing commercially available kits. HLA Class II genotyping was performed on extracted and purified genomic DNA.
Overall, 1519 SSc patients were included in this study, from which 90 patients (6%) had developed SRC. Among the 90 patients with SRC, diffuse cutaneous subtypes were found in 76%, anti-toposiomerase (ATA) in 9%, anti-centromere antibodies(ACA) in 2%, and anti-RNA polymerase III (ARA) in 50% of patients. In the multivariate analysis of clinical and demographic parameters, diffuse disease type and ARA were strong risk factors for presence of SRC, whereas ACA and ATA were protective. In the final multivariate analysis after inclusion of HLA alleles, we identified HLA-DRB1*0407 (OR=3.21, 95% CI 1.27–8.08; P=0.013) and DRB1*1304 (OR=4.51, 95% CI 1.30–15.65; P=0.018) as independent risk factors for SRC. Only 3 clinical characteristics, diffuse disease type, ARA, and ACA remained significant in the final model.
This study suggests that DRB1*0407 and *1304 are independent risk factors for development of SRC beyond the known clinical correlates.
Objectives. SSc-associated gastrointestinal tract involvement (SSc-GIT) is an important predictor of depressive symptoms. University of California at Los Angeles Scleroderma Clinical trial Consortium Gastrointestinal Tract 2.0 (UCLA SCTC GIT 2.0) is a 34-item valid instrument that captures GIT symptom severity and impact on quality of life. It has seven GI-specific scales and a total GIT score. The objectives were to assess: (i) whether there is an association between depressed mood with GI symptom scales as assessed by the UCLA SCTC GIT 2.0 instrument; and (ii) to explore which GI-specific symptom scales are associated with depressed mood in patients with SSc.
Methods. One hundred and fifty-two patients with SSc completed the UCLA SCTC GIT 2.0 and the Center for Epidemiologic Studies Short Depression scale (CES-D10). Patients were divided into depressed (CES-D ≥ 10) or non-depressed group (CES-D < 10) and compared using t-test or chi-square test. Multiple linear regression was used to determine associations between GI scales and depressed mood (CES-D).
Results. Study participants were 84% female, 78% Caucasian and 40% had depressed mood (CES-D10 ≥ 10). Patients with depressed mood had statistically worse GI scale scores (except fecal soilage) and worse total GIT score (P < 0.05). In the multivariable model reflux and constipation scales were independently associated with worse CES-D scores (P = 0.01–0.06)
Conclusion. SSc-GIT involvement is associated with depressed mood. Reflux and constipation scales of UCLA-SCTC GIT 2.0 were independently associated with CES-D. Future studies should assess if treatment of GIT symptoms will improve depressed mood in patients with SSc-GIT.
Scleroderma; Systemic sclerosis; Depression; Center for Epidemiologic Studies Short Depression scale; Gastrointestinal involvement; Reflux; Constipation; University of California at Los Angeles Scleroderma Clinical trial Consortium Gastrointestinal Tract 2.0
Objective. Although the incidence of dcSSc is higher in African-American and Hispanic populations compared with European Caucasian patients, it is not clear whether there are differences in subsequent disease course. Also, the potential impact of gender on the disease course of dcSSc is not well defined. Our objective was to assess the course of modified Rodnan skin score (MRSS), HAQ-disability index (HAQ-DI) and forced vital capacity per cent (FVC%) predicted between men vs women and three ethnic groups with dcSSc participating in three randomized clinical trials (RCTs).
Method. Data from RCTs (n = 495) were pooled and analysed. Baseline characteristics were compared in men vs women and among ethnic groups. A linear mixed effects model was used to assess the predictors of MRSS, HAQ-DI and FVC%. The primary independent variables were time-in-study and its interaction with gender and ethnicity. The models were adjusted for other covariates that were significant at baseline between gender and ethnicity analyses.
Results. Men had lower HAQI-DI scores compared with women (P < 0.05). Among the three ethnic groups, Caucasians were older, African-Americans had lower FVC% predicted and Hispanics had greater tender joint counts (P < 0.05). The course of MRSS, HAQ-DI and FVC% predicted during the study period was not significantly different between gender and three ethnicities. Time-in-study was an independent predictor of improvement in MRSS and HAQ-DI.
Conclusion. Our analysis explores the influence of gender and ethnicity on disease course in RCTs. These findings are relevant to issues of future trial design.
Scleroderma; Randomized clinical trial; Clinical trials; Systemic sclerosis; Gender; Race; Ethnicity; Diffuse cutaneous systemic sclerosis
To identify differentially expressed genes in peripheral blood cells
(PBC) of patients with ankylosing spondylitis (AS) relative to healthy
controls and controls with systemic inflammation.
We investigated PBC samples of 16 patients with AS and 14 matched
controls, in addition to systemic lupus erythematosus (SLE) and systemic
sclerosis (SSc) samples utilizing Illumina Human Ref-8 BeadChips. Candidate genes were confirmed using
quantitative PCR. Subsequently, these genes were also validated in a
separate sample of 27 patients with AS [before and after antitumor necrosis
factor (anti-TNF) treatment] and 27 matched controls.
We identified 83 differentially expressed transcripts between AS
patients and controls. This gene list was filtered through the lists of
differentially expressed transcripts in SLE and SSc, which resulted in
identification of 52 uniquely dysregulated transcripts in AS. Many of the
differentially expressed genes belonged to Toll-like receptor (TLR) and
related pathways. TLR4 and TLR5 were the
only dysregulated TLR subtypes among AS patients. We confirmed the
overexpression of TLR4 and TLR5 in AS
patients in comparison to controls (p = 0.012 and p = 0.006, respectively)
and SLE (p = 0.002, p = 0.008) using quantitative PCR in the same sample.
Similarly, TLR4 (p = 0.007) and TLR5 (p =
0.012) were significantly upregulated among the AS patients before anti-TNF
treatment in the confirmatory sample. TLR4 (p = 0.002) and
TLR5 (p = 0.025) decreased significantly after anti-TNF
PBC gene expression profiling in AS shows an upregulation of
TLR4 and TLR5. This supports the
importance of TLR subtypes in the pathogenesis of AS that are responsible
for the immune response to Gram-negative bacteria.
ANKYLOSING SPONDYLITIS; TOLL-LIKE RECEPTORS; IMMUNE SYSTEM; AUTOIMMUNITY; BACTERIA; GENE EXPRESSION PROFILING
To evaluate changes in vascular and musculoskeletal involvement in subjects in the Scleroderma Lung Study (SLS), a multicenter, double-blind, randomized, controlled trial comparing placebo treatment to oral cyclophosphamide for 1 year in systemic sclerosis (SSc) patients with interstitial lung disease. Subjects were then followed off study agent for an additional 12 months.
The following parameters were noted at baseline and every 6 months for each patient: digital tip ulcers, other dermal ulcers, joint swelling, joint tenderness, large joint contractures, muscle tenderness, muscle weakness, oral aperture, hand extension, and fist closure.
158 patients were enrolled from 13 centers in the United States; 79 were randomized to the cyclophosphamide group (CYC) and 79 to the placebo group. There were no differences in dermal ulcer and musculoskeletal measures between CYC and placebo groups at baseline, 12, and 24 months. Improvement in FVC % predicted was associated with improvement in Rodnan skin score (P<0.05) at 12 and 24 months, and with increased mean oral aperature at 24 months (P=0.005).
These data document the frequency and course of these vascular and musculoskeletal features over time, thus providing essential information for sample size calculations and magnitude of effect in future clinical trials. There was no treatment effect of cyclophosphamide on the vascular and musculoskeletal features described.
Scleroderma; musculoskeletal; joints; vascular; randomized controlled trial; cyclophosphamide
Longitudinal studies examining the baseline predictors of fatigue in SSc have not been reported. Our objectives were to examine the course of fatigue severity over time and to identify baseline clinical, demographic, and psychosocial predictors of sequentially obtained fatigue scores in early SSc. We also examined baseline predictors of change in fatigue severity over time.
We analyzed 1090 longitudinal Fatigue Severity Scale (FSS) scores belonging to 256 patients who were enrolled in the Genetics versus Environment in Scleroderma Outcomes Study (GENISOS). Predictive significance of baseline variables for sequentially obtained FSS scores was examined with generalized linear mixed models. Predictors of change in FSS over time were examined by adding an interaction term between the baseline variable and time-in-study to the model.
The patients' mean age was 48.6 years, 47% were Caucasians, and 59% had diffuse cutaneous involvement. The mean disease duration at enrollment was 2.5 years. The FSS was obtained at enrollment and follow-up visits (mean follow-up time = 3.8 years). Average baseline FSS score was 4.7(±0.96). The FSS was relatively stable and did not show a consistent trend for change over time (p = 0.221). In a multivariable model of objective clinical variables, higher Medsger Gastrointestinal (p = 0.006) and Joint (p = 0.024) Severity Indices, and anti-U1-RNP antibodies (p = 0.024) were independent predictors of higher FSS. In the final model, ineffective coping skills captured by higher Illness Behavior Questionnaire scores (p<0.001), higher self-reported pain (p = 0.006), and higher Medsger Gastrointestinal Severity Index (p = 0.009) at enrollment were independent predictors of higher longitudinal FSS scores. Baseline DLco % predicted was the only independent variable that significantly predicted a change in FSS scores over time (p = 0.013), with lower DLco levels predicting an increase in FSS over time.
This study identified potentially modifiable clinical and psychological factors that predict longitudinal fatigue severity in early SSc.
We describe a novel approach to genetic association analyses with proteins sub-divided into biologically relevant smaller sequence features (SFs), and their variant types (VTs). SFVT analyses are particularly informative for study of highly polymorphic proteins such as the human leukocyte antigen (HLA), given the nature of its genetic variation: the high level of polymorphism, the pattern of amino acid variability, and that most HLA variation occurs at functionally important sites, as well as its known role in organ transplant rejection, autoimmune disease development and response to infection. Further, combinations of variable amino acid sites shared by several HLA alleles (shared epitopes) are most likely better descriptors of the actual causative genetic variants. In a cohort of systemic sclerosis patients/controls, SFVT analysis shows that a combination of SFs implicating specific amino acid residues in peptide binding pockets 4 and 7 of HLA-DRB1 explains much of the molecular determinant of risk.
Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs. Dysregulation of the immune system, including the Th1/Th2 cytokine balance, is central to the pathogenesis of SSc. This study was undertaken to investigate the hypothesis that single-nucleotide polymorphisms (SNPs) in TBX21 and STAT4, both of which are critical transcription factors that regulate the Th1/Th2 balance, are associated with SSc susceptibility.
We tested SNPs in TBX21 and STAT4 for association with SSc in 2 independent cohorts, the SSc Registry cohort (880 SSc cases and 507 controls) and the University of Texas SSc cohort (522 cases and 531 controls). Additional white control genotypes were obtained from public repositories. We also investigated for gene–gene interactions. Plasma cytokines and whole blood gene expression profiles were examined to determine functional effects of these SNPs.
Multiple SNPs in TBX21 and STAT4 were found to be associated with SSc. In a combined analysis of 902 SSc patients and 4,745 controls, TT genotyping of the TBX21 rs11650354 variant revealed a recessive pattern for disease susceptibility (Pcorr = 1.4 × 10−15, odds ratio 3.37, 95% confidence interval 2.4–4.6). In an analysis of 1,039 SSc patients and 3,322 controls, the A allele of the STAT4 variant rs11889341 was associated with increased SSc susceptibility in a dominant pattern (Pcorr = 2.4 × 10−5, odds ratio 1.29, 95% confidence interval 1.2–1.5). Furthermore, we identified gene–gene interaction among the TBX21 and STAT4 variants, such that the STAT4 genotype increased the risk of SSc only in the TBX21 CC genotype group. SSc patients carrying the TBX21 CC genotype had higher interleukin-6 (IL-6) and tumor necrosis factor α levels, and those with the TT genotype had elevated IL-2, IL-5, IL-4, and IL-13 (Th2) levels, compared with controls. Whole blood expression profiles revealed dysregulation of type I interferon pathways in the CC group and T cell pathways in the TT group of the TBX21 SNP.
The present results, from studies of 2 independent cohorts, indicate that SNPs in TBX21 and STAT4 contribute uniquely and interactively to SSc susceptibility, leading to altered cytokine balance and immune dysregulation.