Many challenges have made it difficult to determine the prevalence of spondyloarthritis (SpA) in North America. They include the ethnic heterogeneity of the population, the lack of feasibility of applying current criteria (such as requirements for HLA-B27 testing and imaging studies such are pelvic radiographs and MRI scanning) and the transient nature of some SpA symptoms (ie, peripheral arthritis, enthesitis). Current estimates of the prevalence of SpA in the United States range between 0.2% and 0.5% for ankylosing spondylitis, 0.1% for psoriatic arthritis, 0.065% for enteropathic peripheral arthritis, between 0.05% and 0.25% for enteropathic axial arthritis, and an overall prevalence of SpA as high as over one percent. With newer population-based instruments becoming available, the availability of the widely validated European Spondyloarthropathy Study Group (ESSG) criteria and the lower cost and greater feasibility of genetic testing, opportunities for true population-based studies of SpA are possible and will likely soon ensue.
Epidemiology; ankylosing spondylitis; psoriatic arthritis; enteropathic arthritis; spondyloarthritis
Objectives. To explore whether helplessness, internality and depression would mediate the relationship between disease activity and functional limitations in patients with AS in a 12-month longitudinal study.
Methods. A total of 294 participants with AS meeting modified New York criteria completed clinical and psychological assessments at 6-month intervals. Psychological measures evaluated helplessness, depression and internality. Path analysis evaluated the direct and indirect effects of baseline disease activity on 12-month functional limitations via the psychological measures of helplessness, internality and depression at 6 months.
Results. Baseline disease activity demonstrated direct and indirect effects on 12-month functional limitations. Helplessness and depression, but not internality, served as mediators of the relationship between disease activity and functional limitations.
Conclusion. Higher baseline disease activity predicted greater functional limitations at 12 months through helplessness and depression. Our findings suggest that helplessness and depression may constitute future treatment targets in reducing functional limitations in patients with AS.
Ankylosing spondylitis; Disease activity; Functional limitations; Depression; Internality; Helplessness
The Spondyloarthritis Research and Therapy Network (SPARTAN), founded in 2003 to promote research, education, and treatment of ankylosing spondylitis (AS) and related forms of spondyloarthritis (SpA), held its sixth Annual Research and Education Meeting in July 2008 in Cleveland, Ohio. The overall theme of the meeting was entheses and bones in SpA, which included presentations on the anatomy and physiology of the synovial-entheseal complex; bone formation and destruction, and the impact of inflammation on bone; the Th17 axis, HLA-B27, IL23R, and ARTS1; and breakout sessions on epidemiology and registries.
ankylosing spondylitis; epidemiology; spondyloarthritis; spondyloarthropathies
Systemic lupus erythematosus is a clinically heterogeneous autoimmune disease. A number of genetic loci that increase lupus susceptibility have been established. This study examines if these genetic loci also contribute to the clinical heterogeneity in lupus.
Materials and methods
4001 European-derived, 1547 Hispanic, 1590 African-American and 1191 Asian lupus patients were genotyped for 16 confirmed lupus susceptibility loci. Ancestry informative markers were genotyped to calculate and adjust for admixture. The association between the risk allele in each locus was determined and compared in patients with and without the various clinical manifestations included in the ACR criteria.
Renal disorder was significantly correlated with the lupus risk allele in ITGAM (p=5.0×10−6, OR 1.25, 95% CI 1.12 to 1.35) and in TNFSF4 (p=0.0013, OR 1.14, 95% CI 1.07 to 1.25). Other significant findings include the association between risk alleles in FCGR2A and malar rash (p=0.0031, OR 1.11, 95% CI 1.17 to 1.33), ITGAM and discoid rash (p=0.0020, OR 1.20, 95% CI 1.06 to 1.33), STAT4 and protection from oral ulcers (p=0.0027, OR 0.89, 95% CI 0.83 to 0.96) and IL21 and haematological disorder (p=0.0027, OR 1.13, 95% CI 1.04 to 1.22). All these associations are significant with a false discovery rate of <0.05 and pass the significance threshold using Bonferroni correction for multiple testing.
Significant associations were found between lupus clinical manifestations and the FCGR2A, ITGAM, STAT4, TNSF4 and IL21 genes. The findings suggest that genetic profiling might be a useful tool to predict disease manifestations in lupus patients in the future.
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
The aim of this study was to develop a clinical-grade, automated, multiplex system for the differential diagnosis and molecular stratification of rheumatoid arthritis (RA).
We profiled autoantibodies, cytokines, and bone-turnover products in sera from 120 patients with a diagnosis of RA of < 6 months' duration, as well as in sera from 27 patients with ankylosing spondylitis, 28 patients with psoriatic arthritis, and 25 healthy individuals. We used a commercial bead assay to measure cytokine levels and developed an array assay based on novel multiplex technology (Immunological Multi-Parameter Chip Technology) to evaluate autoantibody reactivities and bone-turnover markers. Data were analyzed by Significance Analysis of Microarrays and hierarchical clustering software.
We developed a highly reproducible, automated, multiplex biomarker assay that can reliably distinguish between RA patients and healthy individuals or patients with other inflammatory arthritides. Identification of distinct biomarker signatures enabled molecular stratification of early-stage RA into clinically relevant subtypes. In this initial study, multiplex measurement of a subset of the differentiating biomarkers provided high sensitivity and specificity in the diagnostic discrimination of RA: Use of 3 biomarkers yielded a sensitivity of 84.2% and a specificity of 93.8%, and use of 4 biomarkers a sensitivity of 59.2% and a specificity of 96.3%.
The multiplex biomarker assay described herein has the potential to diagnose RA with greater sensitivity and specificity than do current clinical tests. Its ability to stratify RA patients in an automated and reproducible manner paves the way for the development of assays that can guide RA therapy.
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.
High serum interferon α (IFNα) activity is a heritable risk factor for systemic lupus erythematosus (SLE). Auto-antibodies found in SLE form immune complexes which can stimulate IFNα production by activating endosomal Toll-like receptors and interferon regulatory factors (IRFs), including IRF5. Genetic variation in IRF5 is associated with SLE susceptibility; however, it is unclear how IRF5 functional genetic elements contribute to human disease.
1034 patients with SLE and 989 controls of European ancestry, 555 patients with SLE and 679 controls of African–American ancestry, and 73 patients with SLE of South African ancestry were genotyped at IRF5 polymorphisms, which define major haplotypes. Serum IFNα activity was measured using a functional assay.
In European ancestry subjects, anti-double-stranded DNA (dsDNA) and anti-Ro antibodies were each associated with different haplotypes characterised by a different combination of functional genetic elements (OR > 2.56, p >003C; 1.9×10−14 for both). These IRF5 haplotype-auto-antibody associations strongly predicted higher serum IFNα in patients with SLE and explained > 70% of the genetic risk of SLE due to IRF5. In African–American patients with SLE a similar relationship between serology and IFNα was observed, although the previously described European ancestry-risk haplotype was present at admixture proportions in African–American subjects and absent in African patients with SLE.
The authors define a novel risk haplotype of IRF5 that is associated with anti-dsDNA antibodies and show that risk of SLE due to IRF5 genotype is largely dependent upon particular auto-antibodies. This suggests that auto-antibodies are directly pathogenic in human SLE, resulting in increased IFNα in cooperation with particular combinations of IRF5 functional genetic elements.
SLE is a systemic autoimmune disorder affecting multiple organ systems including the skin, musculoskeletal, renal and haematopoietic systems. Humoral autoimmunity is a hallmark of SLE, and patients frequently have circulating auto-antibodies directed against dsDNA, as well as RNA binding proteins (RBP). Anti-RBP autoantibodies include antibodies which recognize Ro, La, Smith (anti-Sm), and ribonucleoprotein (anti-nRNP), collectively referred to as anti-retinol-binding protein). Anti-retinol-binding protein and anti-dsDNA auto-antibodies are rare in the healthy population.1 These auto-antibodies can be present in sera for years preceding the onset of clinical SLE illness2 and are likely pathogenic in SLE.34
The Xq28 region containing IRAK1 and MECP2 has been identified as a risk locus for systemic lupus erythematosus (SLE) in previous genetic association studies. However, due to the strong linkage disequilibrium between IRAK1 and MECP2, it remains unclear which gene is affected by the underlying causal variant(s) conferring risk of SLE.
We fine-mapped ≥136 SNPs in a ~227kb region on Xq28, containing IRAK1, MECP2 and 7 adjacent genes (L1CAM, AVPR2, ARHGAP4, NAA10, RENBP, HCFC1 and TMEM187), for association with SLE in 15,783 case-control subjects derived from 4 different ancestral groups.
Multiple SNPs showed strong association with SLE in European Americans, Asians and Hispanics at P<5×10−8 with consistent association in subjects with African ancestry. Of these, 6 SNPs located in the TMEM187-IRAK1-MECP2 region captured the underlying causal variant(s) residing in a common risk haplotype shared by all 4 ancestral groups. Among them, rs1059702 best explained the Xq28 association signals in conditional testings and exhibited the strongest P value in trans-ancestral meta-analysis (Pmeta=1.3×10−27, OR=1.43), and thus was considered to be the most-likely causal variant. The risk allele of rs1059702 results in the amino acid substitution S196F in IRAK1 and had previously been shown to increase NF-κB activity in vitro. We also found that the homozygous risk genotype of rs1059702 was associated with lower mRNA levels of MECP2, but not IRAK1, in SLE patients (P=0.0012) and healthy controls (P=0.0064).
These data suggest contributions of both IRAK1 and MECP2 to SLE susceptibility.
Systemic Lupus Erythematosus; Gene Polymorphism; Xq28; IRAK1; MECP2
We previously reported that the G allele of rs3853839 at 3′untranslated region (UTR) of Toll-like receptor 7 (TLR7) was associated with elevated transcript expression and increased risk for systemic lupus erythematosus (SLE) in 9,274 Eastern Asians [P = 6.5×10−10, odds ratio (OR) (95%CI) = 1.27 (1.17–1.36)]. Here, we conducted trans-ancestral fine-mapping in 13,339 subjects including European Americans, African Americans, and Amerindian/Hispanics and confirmed rs3853839 as the only variant within the TLR7-TLR8 region exhibiting consistent and independent association with SLE (Pmeta = 7.5×10−11, OR = 1.24 [1.18–1.34]). The risk G allele was associated with significantly increased levels of TLR7 mRNA and protein in peripheral blood mononuclear cells (PBMCs) and elevated luciferase activity of reporter gene in transfected cells. TLR7 3′UTR sequence bearing the non-risk C allele of rs3853839 matches a predicted binding site of microRNA-3148 (miR-3148), suggesting that this microRNA may regulate TLR7 expression. Indeed, miR-3148 levels were inversely correlated with TLR7 transcript levels in PBMCs from SLE patients and controls (R2 = 0.255, P = 0.001). Overexpression of miR-3148 in HEK-293 cells led to significant dose-dependent decrease in luciferase activity for construct driven by TLR7 3′UTR segment bearing the C allele (P = 0.0003). Compared with the G-allele construct, the C-allele construct showed greater than two-fold reduction of luciferase activity in the presence of miR-3148. Reduced modulation by miR-3148 conferred slower degradation of the risk G-allele containing TLR7 transcripts, resulting in elevated levels of gene products. These data establish rs3853839 of TLR7 as a shared risk variant of SLE in 22,613 subjects of Asian, EA, AA, and Amerindian/Hispanic ancestries (Pmeta = 2.0×10−19, OR = 1.25 [1.20–1.32]), which confers allelic effect on transcript turnover via differential binding to the epigenetic factor miR-3148.
Systemic lupus erythematosus (SLE) is a debilitating autoimmune disease contributed to by excessive innate immune activation involving toll-like receptors (TLRs, particularly TLR7/8/9) and type I interferon (IFN) signaling pathways. TLR7 responds against RNA–containing nuclear antigens and activates IFN-α pathway, playing a pivotal role in the development of SLE. While a genomic duplication of Tlr7 promotes lupus-like disease in the Y-linked autoimmune accelerator (Yaa) murine model, the lack of common copy number variations at TLR7 in humans led us to identify a functional single nucleotide polymorphism (SNP), rs3853839 at 3′ UTR of the TLR7 gene, associated with SLE susceptibility in Eastern Asians. In this study, we fine-mapped the TLR7-TLR8 region and confirmed rs3853839 exhibiting the strongest association with SLE in European Americans, African Americans, and Amerindian/Hispanics. Individuals carrying the risk G allele of rs3853839 exhibited increased TLR7 expression at the both mRNA and protein level and decreased transcript degradation. MicroRNA-3148 (miR-3148) downregulated the expression of non-risk allele (C) containing transcripts preferentially, suggesting a likely mechanism for increased TLR7 levels in risk-allele carriers. This trans-ancestral mapping provides evidence for the global association with SLE risk at rs3853839, which resides in a microRNA–gene regulatory site affecting TLR7 expression.
Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease with a strong genetic component. African-Americans (AA) are at increased risk of SLE, but the genetic basis of this risk is largely unknown. To identify causal variants in SLE loci in AA, we performed admixture mapping followed by fine mapping in AA and European-Americans (EA). Through genome-wide admixture mapping in AA, we identified a strong SLE susceptibility locus at 2q22–24 (LOD = 6.28), and the admixture signal is associated with the European ancestry (ancestry risk ratio ∼1.5). Large-scale genotypic analysis on 19,726 individuals of African and European ancestry revealed three independently associated variants in the IFIH1 gene: an intronic variant, rs13023380 [Pmeta = 5.20×10−14; odds ratio, 95% confidence interval = 0.82 (0.78–0.87)], and two missense variants, rs1990760 (Ala946Thr) [Pmeta = 3.08×10−7; 0.88 (0.84–0.93)] and rs10930046 (Arg460His) [Pdom = 1.16×10−8; 0.70 (0.62–0.79)]. Both missense variants produced dramatic phenotypic changes in apoptosis and inflammation-related gene expression. We experimentally validated function of the intronic SNP by DNA electrophoresis, protein identification, and in vitro protein binding assays. DNA carrying the intronic risk allele rs13023380 showed reduced binding efficiency to a cellular protein complex including nucleolin and lupus autoantigen Ku70/80, and showed reduced transcriptional activity in vivo. Thus, in SLE patients, genetic susceptibility could create a biochemical imbalance that dysregulates nucleolin, Ku70/80, or other nucleic acid regulatory proteins. This could promote antibody hypermutation and auto-antibody generation, further destabilizing the cellular network. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis.
African-Americans (AA) are at increased risk of systemic lupus erythematosus (SLE), but the genetic basis of this risk increase is largely unknown. We used admixture mapping to localize disease-causing genetic variants that differ in frequency across populations. This approach is advantageous for localizing susceptibility genes in recently admixed populations like AA. Our genome-wide admixture scan identified seven admixture signals, and we followed the best signal at 2q22–24 with fine-mapping, imputation-based association analysis and experimental validation. We identified two independent coding variants and a non-coding variant within the IFIH1 gene associated with SLE. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis.
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 identify susceptibility loci for ankylosing spondylitis, we undertook a genome-wide association study in 2,053 unrelated ankylosing spondylitis cases among people of European descent and 5,140 ethnically matched controls, with replication in an independent cohort of 898 ankylosing spondylitis cases and 1,518 controls. Cases were genotyped with Illumina HumHap370 genotyping chips. In addition to strong association with the major histocompatibility complex (MHC; P < 10−800), we found association with SNPs in two gene deserts at 2p15 (rs10865331; combined P = 1.9 × 10−19) and 21q22 (rs2242944; P = 8.3 × 10−20), as well as in the genes ANTXR2 (rs4333130; P = 9.3 × 10−8) and IL1R2 (rs2310173; P = 4.8 × 10−7). We also replicated previously reported associations at IL23R (rs11209026; P = 9.1 × 10−14) and ERAP1 (rs27434; P = 5.3 × 10−12). This study reports four genetic loci associated with ankylosing spondylitis risk and identifies a major role for the interleukin (IL)-23 and IL-1 cytokine pathways in disease susceptibility.
To examine the clinical and radiographic features in men and women in the Prospective Study of Outcomes in Ankylosing Spondylitis cohort, a large well‐defined cross‐sectional study of patients with AS, in order to understand the influence of gender in determining the severity of ankylosing spondylitis.
Extensive clinical assessments and spine radiographs were performed in 302 men and 100 women with AS of ⩾20 years duration. Radiographs were scored using the Bath Ankylosing Spondylitis Radiographic Index Spine (BASRI‐spine) score (range 2–12). Functional impairment was measured by the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Health Assessment Questionnaire for the Spondyloarthropathies (HAQ‐S).
Radiographic severity was worse among men. The unadjusted median BASRI‐spine score for men was 10, compared with 6.5 for women (p<0.001). Functional disability, as measured by the BASFI and HAQ‐S, was not different between men and women. However, after adjusting for radiographic spinal damage, women were found to report worse functioning than men at any given level of radiographic damage. Women had a slightly earlier age of disease onset; however, disease duration was identical in both groups. Women more frequently reported family histories of AS in first‐degree relatives and were more likely to be treated with intra‐articular steroids, sulphasalazine and prednisone.
Among patients with longstanding AS, men have more severe radiographic changes; findings of treatment differences suggest that women may have more peripheral arthritis. At any given level of radiographic damage, self‐reported functional limitations were worse for women.
Several confirmed genetic susceptibility loci for lupus have been described. To date, no clear evidence for genetic epistasis is established in lupus. We test for gene-gene interactions in a number of known lupus susceptibility loci.
Eighteen SNPs tagging independent and confirmed lupus susceptibility loci were genotyped in a set of 4,248 lupus patients and 3,818 normal healthy controls of European descent. Epistasis was tested using a 2-step approach utilizing both parametric and non-parametric methods. The false discovery rate (FDR) method was used to correct for multiple testing.
We detected and confirmed gene-gene interactions between the HLA region and CTLA4, IRF5, and ITGAM, and between PDCD1 and IL21 in lupus patients. The most significant interaction detected by parametric analysis was between rs3131379 in the HLA region and rs231775 in CTLA4 (Interaction odds ratio=1.19, z-score= 3.95, P= 7.8×10−5 (FDR≤0.05), PMDR= 5.9×10−45). Importantly, our data suggest that in lupus patients the presence of the HLA lupus-risk alleles in rs1270942 and rs3131379 increases the odds of also carrying the lupus-risk allele in IRF5 (rs2070197) by 17% and 16%, respectively (P= 0.0028 and 0.0047).
We provide evidence for gene-gene epistasis in systemic lupus erythematosus. These findings support a role for genetic interaction contributing to the complexity of lupus heritability.
To determine the features predictive of time-to-integument damage in patients with systemic lupus erythematosus (SLE) from a multiethnic cohort (LUMINA).
SLE LUMINA patients (n=580), age ≥16 years, disease duration ≤5 years at baseline (T0), of African American, Hispanic and Caucasian ethnicity were studied. Integument damage was defined per the SLICC damage index (scarring alopecia, extensive skin scarring and skin ulcers lasting at least six months); factors associated with time-to-its occurrence were examined by Cox proportional univariable and multivariable (main model) hazards regression analyses. Two alternative models were also examined; in model 1 all patients, regardless of when integument damage occurred (n=94), were included; in model 2 a time-varying approach (GEE) was employed.
Thirty-nine (6.7%) of 580 patients developed integument damage over a mean (SD) total disease duration of 5.9 (3.7) years and were included in the main multivariable regression model. After adjusting for discoid rash, nailfold infarcts, photosensitivity and Raynaud’s phenomenon (significant in the univariable analyses), disease activity over time [Hazard ratio (HR)=1.17; 95% Confidence interval (CI) 1.09–1.26)] was associated with a shorter time-to-integument damage whereas hydroxychloroquine use (HR=0.23, 95% CI 0.12–0.47) and Texan-Hispanic (HR=0.35; 95% CI 0.14–0.87) and Caucasian ethnicities (HR=0.37; 95% CI 0.14–0.99) were associated with a longer time. Results of the alternative models were consistent with those of the main model albeit in model 2 the association with hydroxychloroquine was not significant.
Our data indicate that hydroxychloroquine use is possibly associated with a delay in integument damage development in patients with SLE.
Integument; skin; lupus; LUMINA Hispanics; African Americans; damage; hydroxychloroquine
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.
Functional status is an integral component of health-related quality of life in patients with ankylosing spondylitis (AS). The purpose of this study was to investigate the role of psychological variables in self-reported functional limitation in patients with AS, while controlling for demographic and medical variables.
294 AS patients meeting modified New York Criteria completed psychological measures evaluating depression, resilience, active and passive coping, internality and helplessness at the baseline visit. Demographic, clinical, and radiologic data were also collected. Univariate and multivariate analyses were completed to determine the strength of correlation of psychological variables with functional limitation, as measured by the Bath AS Functional Index (BASFI).
In the multivariate regression analysis, the psychological variables contributed significantly to the variance in BASFI scores, adding an additional 24% to the overall R-square beyond that accounted by demographic and medical variables (R-square 32%), resulting in a final R-square of 56%. Specifically, arthritis helplessness, depression and passive coping beside age, ESR and the Bath AS Radiograph Index accounted for a significant portion of the variance in BASFI scores in the final model.
Arthritis helplessness, depression, and passive coping accounted for significant variability in self-reported functional limitation beyond demographic and clinical variables in patients with AS. Psychological health should be examined and accounted for when assessing functional status in the AS patients.
Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) share similarities and are classified as spondyloarthropathies. In IBD, anti-Saccharomyces cerevisiae antibody (ASCA), anti-I2 (associated with anti-Pseudomonas activity), anti-Escherichia coli outer membrane porin C (anti-OmpC), anti-flagellin (anti-CBir1), and antineutrophil cytoplasmic antibodies (ANCA) possess clinical significance. Because of the overlap between the two conditions, a pilot study was designed to compare the frequency of these antibodies in AS patients compared to normal controls.
Serum stored from 80 AS patients and 80 control subjects was available for analysis. ASCA, anti-I2, anti-OmpC, anti-CBir1, and ANCA studies were completed on all serum samples using Enzyme-Linked Immunosorbent Assay (ELISA) methodology. The following analyses were performed: comparison of positivity based on the established values in IBD, median values, the number of subjects in each serology in the 4th quartile of a normal distribution, and the mean quartile sum of all the antibodies.
There was no difference in positivity rates between AS and control groups with the established IBD values. The median anti-I2 response was significantly higher in AS than in controls (11.78 vs 7.86, p = 0.017). Significantly more AS patients had quartile scores of 4 for the following antibody responses: ASCA IgG (26% vs 13%, p = 0.016, OR = 2.49, CI 1.168 - 5.313), ASCA IgG and IgA (27% vs 12%, p = 0.006, OR = 2.9, CI: 1.342 - 6.264), and anti - I2 (25% vs 14%, p = 0.0424, OR = 2.15, CI: 1.018 - 4.538). The mean quartile sum of the antibody responses was elevated in AS patients when ANCA was excluded (10.526 vs 9.519, p = 0.03). When ANCA was included, this difference lost significance.
The data from this pilot study points towards mucosal dysregulation as an important pathway in AS. We were able to demonstrate that anti-I2 could play a pathologic role in AS. The elevated mean total antibody response being significant only with ANCA exclusion is consistent with the histopathological evidence that intestinal inflammation in AS is similar to Crohn's disease. To better define the roles of these antibodies in AS, larger studies with more precisely defined patient characteristics are required.
Objective. Thrombosis is an important cause of morbidity and mortality in SLE. We have explored the factors associated with time to the occurrence of thrombotic events in SLE patients to expand our cohort’s previous observations.
Method. SLE patients (ACR criteria), age ≥16 years, disease duration ≤5 years at enrolment (T0), African-American, Hispanic (Texan or Puerto Rican) or Caucasian ethnicity, from LUMINA, a longitudinal cohort, were studied. An event was defined as the presence of arterial or venous thrombosis. Time to the first thrombotic event was examined by univariable and multivariable (MV) Cox models adjusting for pertinent baseline clinical and socio-demographic variables.
Results. A total of 643 patients were studied; mean (s.d.) age was 36.4 (12.6) years and disease duration at T0 was 1.4 (1.3) years; 90% were female. After T0, 81 (12.6%) patients had developed a thrombotic event. In the MV model, age [hazard ratio (HR) = 1.06; 95% CI 1.03, 1.08; P < 0.0001], health insurance (HR = 0.53; 95% CI 0.30, 0.94; P = 0.029), smoking (HR = 1.85; 95% CI 1.01, 3.40; P = 0.048), damage (T0) (HR = 1.44; 95% CI 1.20, 1.71; P < 0.0001), aPL (HR = 2.12; 95% CI 1.19, 3.76; P = 0.011) and glucocorticoid (highest dose) (HR = 1.01; 95% CI 1.01, 1.02; P < 0.0001) were significant.
Conclusions. Age, poverty, smoking, damage accrual, aPL and higher doses of glucocorticoids were independently associated with a shorter time to the first thrombotic event; health insurance had a protective effect. Acting upon modifiable risk factors at the personal (smoking, high-dose glucocorticoids) and societal (poverty, health insurance) levels may prevent these events and improve the long-term outcome of SLE patients.
Systemic lupus erythematosus; Thrombotic events; Risk factors
Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse clinical manifestations characterized by the development of pathogenic autoantibodies manifesting in inflammation of target organs such as the kidneys, skin and joints. Genome-wide association studies have identified genetic variants in the UBE2L3 region that are associated with SLE in subjects of European and Asian ancestry. UBE2L3 encodes an ubiquitin-conjugating enzyme, UBCH7, involved in cell proliferation and immune function. In this study, we sought to further characterize the genetic association in the region of UBE2L3 and use molecular methods to determine the functional effect of the risk haplotype. We identified significant associations between variants in the region of UBE2L3 and SLE in individuals of European and Asian ancestry that exceeded a Bonferroni corrected threshold (P < 1 × 10−4). A single risk haplotype was observed in all associated populations. Individuals harboring the risk haplotype display a significant increase in both UBE2L3 mRNA expression (P = 0.0004) and UBCH7 protein expression (P = 0.0068). The results suggest that variants carried on the SLE associated UBE2L3 risk haplotype influence autoimmunity by modulating UBCH7 expression.
Systemic Lupus Erythematosus; UBE2L3; Multi Ethnic Association Study; UBCH7 Expression
To replicate and refine the reported association of ankylosing spondylitis (AS) with two non-synonymous single nucleotide polymorphisms (nsSNPs) on chromosome 16q22.1.
Firstly, 730 independent UK patients with AS were genotyped for rs9939768 and rs6979 and allele frequencies were compared with 2879 previously typed historic disease controls. Secondly, the two data sets were combined in meta-analyses. Finally, 5 tagging SNPs, located between rs9939768 and rs6979, were analysed in 1604 cases and 1020 controls.
The association of rs6979 with AS was replicated, p=0.03, OR=1.14 (95% CI 1.01 to 1.28), and a trend for association with rs9939768 detected, p=0.06, OR=1.25 (95% CI 0.99 to 1.57). Meta-analyses revealed association of both SNPs with AS, p=0.0008, OR=1.31 (95% CI 1.12 to 1.54) and p=0.0009, OR=1.15 (95% CI 1.06 to 1.23) for rs9939768 and rs6979, respectively. New associations with rs9033 and rs868213 (p=0.00002, OR=1.23 (95% CI 1.12 to 1.36) and p=0.00002 OR=1.45 (95% CI 1.22 to 1.72), respectively, were identified.
The region on chromosome 16 that has been replicated in the present work is interesting as the highly plausible candidate gene, tumour necrosis factor receptor type 1 (TNFR1)-associated death domain (TRADD), is located between rs9033 and rs868213. It will require additional work to identify the primary genetic association(s) with AS.
To investigate the role of psychological variables in self-reported disease activity in patients with Ankylosing Spondylitis (AS), while controlling for demographic and medical variables.
Patients and Methods
294 AS patients meeting modified New York Criteria completed psychological measures evaluating depression, resilience, active and passive coping, internality and helplessness. Demographic, clinical, and radiologic data were also collected. Univariate and multivariate analyses were completed to determine the strength of the correlation of psychological variables with disease activity, as measured by the Bath AS Disease Activity Index (BASDAI).
In the multivariate regression analysis, the psychological variables contributed significantly to the variance in BASDAI scores, adding an additional 33% to the overall R-square beyond that accounted for by demographic and medical variables (combined R-square 18%). Specifically, Arthritis Helplessness and Depression accounted for the most significant portion of the variance in BASDAI scores in the final model.
Arthritis helplessness and depression accounted for significant variability in self-reported disease activity beyond clinical and demographic variables in patients with AS. These findings have important clinical implications in the treatment and monitoring of disease activity in AS, and suggest potential avenues of intervention.
Ankylosing Spondylitis; disease activity; psychosocial factors
Genetic studies in the systemic sclerosis (SSc), an autoimmune disease that clinically manifests with dermal and internal organ fibrosis and small vessel vasculopathy, have identified multiple susceptibility genes including HLA-class II, PTPN22, IRF5, and STAT4 which have also been associated with other autoimmune diseases, such as systemic lupus erythematosus (SLE). These data suggest that there are common autoimmune disease susceptibility genes. The current report sought to determine if polymorphisms in the C8orf13-BLK region (chromosome 8p23.1-B lymphoid tyrosine kinase), which is associated with SLE, are associated also with SSc.
Two variants in the C8orf13-BLK region (rs13277113 & rs2736340) were tested for association with 1050 SSc cases and 694 controls of North Americans of European descent and replicated in a second series 589 SSc cases and 722 controls from Spain.
The “T” allele at rs2736340 variant was associated with SSc in both the U.S. and Spanish case-control series (P=6.8×10−5, OR 1.27, 95%CI 1.1–1.4). The “A” allele at rs13277113 variant was associated with SSc in the U.S. series only (P=3.6×10−4, OR 1.32, 95%CI 1.1–1.6) and was significant in the combined analyses of the two series (P=2.0×10−3; OR 1.20, 95%CI 1.1–1.3). Both variants demonstrated an association with the anti-centromere antibody (P=2.2×10−6 and P=5.5×10−4, respectively) and limited SSc (P=3.3×10−5 and P=2.9×10−3, respectively) in the combined analysis. Peripheral blood gene expression profiles suggest that B-cell receptor and NFκB signaling are dysregulated based on the risk haplotype of these variants.
We identify and replicate the association of the C8orf13-BLK region as a novel susceptibility factor for SSc, placing it in the category of common autoimmune disease susceptibility genes.
Scleroderma; Systemic Sclerosis/SSc; Polymorphism/SNP; BLK; C8orf13; Anti- Topoisomerase-I; Anti-Centromere; Genetics; Autoantibody; rs13277113; rs2736340