Perceived functioning has ethnic-specific associations in systemic sclerosis: another dimension of personalized medicine

OBJECTIVE

To measure self-reported physical and mental functioning and associated clinical features at study entry in 3 ethnic groups with systemic sclerosis (SSc).

METHODS

Sixty Hispanic, 39 African American, and 104 Caucasian patients with recent-onset SSc (< 5 yrs) were assessed for perceived physical and mental functioning, using the Medical Outcomes Study Short Form-36 (SF-36) and Scleroderma-Health Assessment Questionnaire (Scleroderma-HAQ). Socioeconomic, demographic, clinical, immunologic, immunogenetic, behavioral, and psychological variables (Interpersonal Support Evaluation List, ISEL; Illness Behavior Questionnaire, IBQ; and Arthritis Helplessness Index, AHI) were analyzed by linear regression models for associations with SF-36 and mHAQ scores as dependent variables.

RESULTS

Perceived physical functioning scores had ethnic-specific associations with AHI > fatigue scores > IBQ > clinical variables (hypertension, skin score, and percentage predicted DLCO). Scleroderma-HAQ scores had ethnic-specific associations with IBQ > AHI scores > most clinical and laboratory variables. Decreased mental component summary (MCS) scores associated with AHI > ISEL. Ethnic-specific immunogenetic variables HLA-DQB1*0202 (Caucasian) and HLA-DRB 1*11 (African American), and HLA-DQA1*0501 (Hispanic) also associated with MCS. Antinuclear autoantibodies, anti-topoisomerase I, and RNA polymerases I and III also demonstrated associations with functioning in African American and Hispanic groups.

CONCLUSION

Clinical, psychosocial, and immunogenetic variables had ethnic-specific associations with perceived physical and mental functioning. Consideration of ethnic-specific psychological and behavioral support in designing more personalized, relevant therapeutic interventions for the patient may improve therapeutic efficacy in SSc.

Time to neuropsychiatric damage occurrence in LUMINA (LXVI): a multi-ethnic lupus cohort

The aims of this study were to examine the predictors of time to neuropsychiatric (NP) damage and its impact on mortality in 632 systemic lupus erythematosus African-American, Hispanic and Caucasian LUpus in MInorities: NAture versus Nurture (LUMINA) patients, age >or= 16 years and disease duration <or=5 years at baseline (T0). Time-to-NP damage and its impact on mortality were examined by Cox proportional hazards regressions. A total of 185 (29.3%) patients developed NP damage over a mean (SD) disease duration of 5.6 (3.7) years. After adjusting for NP manifestations present, older age [Hazard ratio (HR) = 1.02; 95% Confidence interval (CI) 1.00-1.04], Caucasian ethnicity (HR = 1.87; 95% CI, 1.22-2.87), disease activity over the disease course (HR = 1.16; 95% CI, 1.12-1.21), diabetes (HR = 3.47; 95% CI, 1.44-8.38) and abnormal illness-related behaviours (HR = 1.05; 95% CI, 1.02-1.08) were associated with a shorter time-to-NP damage. Photosensitivity (HR = 0.65; 95% CI, 0.44-0.95), anaemia (HR = 0.56; 95% CI, 0.31-0.98), Raynaud's phenomenon (HR = 0.49; 95% CI, 0.34-0.72), a medium dose of prednisone (HR = 0.56; 95% CI, 0.35-0.92) and hydroxychloroquine use (HR = 0.58; 95% CI, 0.36-0.93) were associated with a longer time. NP damage did not contribute to mortality. Older age, Caucasian ethnicity, disease activity and abnormal illness-related behaviours are associated with a shorter time-to-NP damage; hydroxychloroquine and a medium dose of prednisone with a longer time.

A large-scale replication study identifies TNIP1, PRDM1, JAZF1, UHRF1BP1 and IL10 as risk loci for systemic lupus erythematosus

Genome-wide association studies have recently identified at least 15 susceptibility loci for systemic lupus erythematosus (SLE). To confirm additional risk loci, we selected SNPs from 2,466 regions that showed nominal evidence of association to SLE (P < 0.05) in a genome-wide study and genotyped them in an independent sample of 1,963 cases and 4,329 controls. This replication effort identified five new SLE susceptibility loci (P < 5 x 10(-8)): TNIP1 (odds ratio (OR) = 1.27), PRDM1 (OR = 1.20), JAZF1 (OR = 1.20), UHRF1BP1 (OR = 1.17) and IL10 (OR = 1.19). We identified 21 additional candidate loci with P< or = 1 x 10(-5). A candidate screen of alleles previously associated with other autoimmune diseases suggested five loci (P < 1 x 10(-3)) that may contribute to SLE: IFIH1, CFB, CLEC16A, IL12B and SH2B3. These results expand the number of confirmed and candidate SLE susceptibility loci and implicate several key immunologic pathways in SLE pathogenesis.

Disease activity and damage are not associated with increased levels of fatigue in systemic lupus erythematosus patients from a multiethnic cohort: LXVII

OBJECTIVE

To determine the factors associated with increased levels of fatigue over the course of the disease in systemic lupus erythematosus (SLE) patients from LUpus in MInorities: NAture versus nurture, a longitudinal multiethnic cohort.

METHODS

Patients with SLE (according to the American College of Rheumatology revised and updated criteria) age >/=16 years with a disease duration </=5 years at entry into the cohort, and of Hispanic (Texan or Puerto Rican), African American, or Caucasian ethnicity were studied. The association between socioeconomic/demographic characteristics, health behaviors, behavioral and psychological, functional and clinical characteristics, and fatigue was examined using generalized estimating equations to account for the longitudinal nature of the data.

RESULTS

A total of 515 patients ( approximately 91% female) contributed 2,609 visits to these analyses. Of these patients, 93 (18.1%) were Texan-Hispanic, 101 (19.6%) were Puerto Rican-Hispanic, 169 (32.8%) were African Americans, and 152 (29.5%) were Caucasian. The mean +/- SD patient age and followup time were 37.2 +/- 12.6 years and 4.7 +/- 3.2 years, respectively. Variables associated with increased levels of fatigue in the multivariable analyses were Caucasian ethnicity, the presence of constitutional symptoms (fever, weight loss), and higher levels of pain, abnormal illness-related behaviors, and helplessness (P values between 0.0018 and <0.0001).

CONCLUSION

The presence of pain, abnormal illness-related behaviors, helplessness, and constitutional manifestations were associated with increased levels of fatigue. However, SLE-specific measures, such as disease activity and damage, were not. Interventions aimed at decreasing fatigue need to take into account these findings.

BANK1 functional variants are associated with susceptibility to diffuse systemic sclerosis in Caucasians

OBJECTIVE

To investigate the possible association of the BANK1 gene with genetic susceptibility to systemic sclerosis (SSc) and its subphenotypes.

METHODS

A large multicentre case-control association study including 2380 patients with SSc and 3270 healthy controls from six independent case-control sets of Caucasian ancestry (American, Spanish, Dutch, German, Swedish and Italian) was conducted. Three putative functional BANK1 polymorphisms (rs17266594 T/C, rs10516487 G/A, rs3733197 G/A) were selected as genetic markers and genotyped by Taqman 5 allelic discrimination assay.

RESULTS

A significant association of the rs10516487 G and rs17266594 T alleles with SSc susceptibility was observed (pooled OR=1.12, 95% CI 1.03 to 1.22; p=0.01 and pooled OR=1.14, 95% CI 1.05 to 1.25; p=0.003, respectively), whereas the rs3733197 genetic variant showed no statistically significant deviation. Stratification for cutaneous SSc phenotype showed that the BANK1 rs10516487 G, rs17266594 T and rs3733197 G alleles were strongly associated with susceptibility to diffuse SSc (dcSSc) (pooled OR=1.20, 95% CI 1.05 to 1.37, p=0.005; pooled OR=1.23, 95% CI 1.08 to 1.41, p=0.001; pooled OR=1.15, 95% CI 1.02 to 1.31, p=0.02, respectively). Similarly, stratification for specific SSc autoantibodies showed that the association of BANK1 rs10516487, rs17266594 and rs3733197 polymorphisms was restricted to the subgroup of patients carrying anti-topoisomerase I antibodies (pooled OR=1.20, 95% CI 1.02 to 1.41, p=0.03; pooled OR=1.24, 95% CI 1.05 to 1.46, p=0.01; pooled OR=1.26, 95% CI 1.07 to 1.47, p=0.004, respectively).

CONCLUSION

The results suggest that the BANK1 gene confers susceptibility to SSc in general, and specifically to the dcSSc and anti-topoisomerase I antibody subsets.

Plasma cytokine profiles in systemic sclerosis: associations with autoantibody subsets and clinical manifestations

Introduction

Systemic sclerosis (SSc) (scleroderma) is a complex autoimmune disease that clinically manifests as progressive fibrosis of the skin and internal organs. Anti-centromere antibodies (ACAs), anti-topoisomerase antibodies (ATAs), and anti-RNA polymerase III antibodies (ARAs) are three mutually exclusive SSc-associated autoantibodies that correlate with distinct clinical subsets characterized by extent of cutaneous involvement and pattern of organ involvement. The current report sought to determine whether plasma cytokine profiles differ in SSc patients grouped according to these SSc-associated autoantibody subsets.

Methods

Plasma from 444 SSc patients and 216 healthy controls was obtained from the Scleroderma Family Registry and University of Texas Rheumatology Division. Patients were classified according to the presence of ACAs, ATAs, ARAs, or none of the above (antibody-negative). Levels of 13 cytokines were determined using multiplex assays.

Results

Compared with females, healthy control males had higher plasma levels of IL-2 (P = 0.008), IL-5 (P = 0.01) and IL-8 (P = 0.01). In addition, in controls, IL-6 (P = 0.02) and IL-17 (P = 0.01) levels increased with advancing age. After adjusting for age and gender, SSc patients had higher circulating levels of TNFα (P < 0.0001), IL-6 (P < 0.0001), and IFNγ (P = 0.05) and lower IL-17 (P = 0.0005) and IL-23 (P = 0.014). Additional analyses demonstrated that disease duration also influenced these cytokine profiles. IL-6 was elevated in ATA-positive and ARA-positive patients, but not in ACA-positive patients. IL-8 was uniquely increased in the ATA-positive subset while both ATA-positive and ACA-positive subsets had elevated IFNγ and IL-10. IL-5 was only significantly increased in the ACA-positive subset. Lastly, patients with interstitial lung disease had elevated IL-6 and patients with pulmonary hypertension had elevated IL-6 and IL-13.

Conclusions

Plasma cytokine profiles differ in SSc patients based on the presence of SSc-associated autoantibodies. Plasma cytokine profiles in SSc patients may also be affected by disease duration and the pattern of internal organ involvement.

Association of the C8orf13-BLK region with systemic sclerosis in North-American and European populations

OBJECTIVE

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.

METHODS

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.

RESULTS

The "T" allele at rs2736340 variant was associated with SSc in both the U.S. and Spanish case-control series (P = 6.8 x 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 x 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 x 10(-3); OR 1.20, 95% CI 1.1-1.3). Both variants demonstrated an association with the anti-centromere antibody (P = 2.2 x 10(-6) and P = 5.5 x 10(-4), respectively) and limited SSc (P = 3.3 x 10(-5) and P = 2.9 x 10(-3), respectively) in the combined analysis. Peripheral blood gene expression profiles suggest that B-cell receptor and NFkappaB signaling are dysregulated based on the risk haplotype of these variants.

CONCLUSION

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.

Ultraviolet radiation intensity predicts the relative distribution of dermatomyositis and anti-Mi-2 autoantibodies in women

OBJECTIVE

Because studies suggest that ultraviolet (UV) radiation modulates the myositis phenotype and Mi-2 autoantigen expression, we conducted a retrospective investigation to determine whether UV radiation may influence the relative prevalence of dermatomyositis and anti-Mi-2 autoantibodies in the US.

METHODS

We assessed the relationship between surface UV radiation intensity in the state of residence at the time of onset with the relative prevalence of dermatomyositis and myositis autoantibodies in 380 patients with myositis from referral centers in the US. Myositis autoantibodies were detected by validated immunoprecipitation assays. Surface UV radiation intensity was estimated from UV Index data collected by the US National Weather Service.

RESULTS

UV radiation intensity was associated with the relative proportion of patients with dermatomyositis (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 0.9-5.8) and with the proportion of patients expressing anti-Mi-2 autoantibodies (OR 6.0, 95% CI 1.1-34.1). Modeling of these data showed that these associations were confined to women (OR 3.8, 95% CI 1.3-11.0 and OR 17.3, 95% CI 1.8-162.4, respectively) and suggests that sex influences the effects of UV radiation on autoimmune disorders. Significant associations were not observed in men, nor were UV radiation levels related to the presence of antisynthetase or anti-signal recognition particle autoantibodies.

CONCLUSION

This first study of the distribution of myositis phenotypes and UV radiation exposure in the US showed that UV radiation may modulate the clinical and immunologic expression of autoimmune disease in women. Further investigation of the mechanisms by which these effects are produced may provide insights into pathogenesis and suggest therapeutic or preventative strategies.

A polymorphism within IL21R confers risk for systemic lupus erythematosus

OBJECTIVE

Interleukin-21 (IL-21) is a member of the type I cytokine superfamily that has a variety of effects on the immune system, including B cell activation, plasma cell differentiation, and immunoglobulin production. The expression of IL-21 receptor (IL-21R) is reduced in the B cells of patients with systemic lupus erythematosus (SLE), while serum IL-21 levels are increased both in lupus patients and in some murine lupus models. We recently reported that polymorphisms within the IL21 gene are associated with increased susceptibility to SLE. The aim of this study was to examine the genetic association between single-nucleotide polymorphisms (SNPs) within IL21R and SLE.

METHODS

We genotyped 17 SNPs in the IL21R gene in 2 large cohorts of lupus patients (a European-derived cohort and a Hispanic cohort) and in ethnically matched healthy controls.

RESULTS

We identified and confirmed the association between rs3093301 within the IL21R gene and SLE in the 2 cohorts (meta-analysis odds ratio 1.16 [95% confidence interval 1.08-1.25], P=1.0x10(-4)).

CONCLUSION

Our findings indicate that IL21R is a novel susceptibility gene for SLE.

Association of TNFSF4 (OX40L) polymorphisms with susceptibility to systemic sclerosis

Objective

It is increasingly being appreciated that multiple autoimmune diseases share common susceptibility genes. The tumour necrosis factor ligand superfamily member 4 gene (TNFSF4, OX40L), which encodes for the T cell costimulatory molecule OX40 ligand, has been identified as a susceptibility gene for the development of systemic lupus erythematosus (SLE). Accordingly, the aim of the current study was to investigate the possible association of the TNFSF4 gene region with systemic sclerosis (SSc), an autoimmune disease that leads to the development of cutaneous and visceral fibrosis.

Methods

A total of 9 single nucleotide polymorphisms (SNPs) in the TNFSF4 gene region, previously associated with susceptibility to SLE, were tested for association with SSc in a collection of 1059 patients with SSc and 698 controls.

Results

Case-control comparisons revealed a significant association between susceptibility to SSc and the minor alleles at SNPs rs1234314 (OR 1.20, 95% CI 1.04 to 1.4, p_FDR=0.019), rs2205960 (OR 1.24, 95% CI 1.10 to 1.50, p_FDR=0.019) and rs844648 (OR 1.16, 95% CI 1.01 to 1.30, p_FDR=0.032). The minor allele at rs844644 was protective (OR 0.84, 95% CI 0.70 to 0.97, p_FDR=0.038). Analysis of subsets of patients with SSc demonstrated significant associations of the TNFSF4 SNPs with limited and diffuse SSc as well as specific SNPs that were associated with SSc-associated autoantibodies. Finally, the analyses suggest a potential interaction between two TNFSF4 SNPs, rs2205960 and rs844648, with regards to SSc susceptibility.

Conclusions

Polymorphisms in the TNFSF4 gene region are associated with susceptibility to SSc and its clinical and autoantibody subsets. TNFSF4 may be another gene that confers risk to multiple autoimmune diseases.

Clinical and immunogenetic prognostic factors for radiographic severity in ankylosing spondylitis

OBJECTIVE

To improve prognostic ability in ankylosing spondylitis (AS), we sought to identify demographic, clinical, and immunogenetic characteristics associated with radiographic severity in a large cohort of patients.

METHODS

Patients with AS for > or =20 years were enrolled in a cross-sectional study (n = 398). Pelvic and spinal radiographs were scored using the Bath Ankylosing Spondylitis Radiology Index for the spine (BASRI-s), and radiographic severity was measured as the BASRI-s/duration of AS. Clinical factors and HLA-B, DR, DQ, and DP alleles associated with the highest quartile of the distribution of radiographic severity were identified by first using random forests and then using multivariable logistic regression modeling. Similar procedures were used to identify factors associated with the lowest quartile of radiographic severity.

RESULTS

Radiographic severity (being in the top quartile of BASRI-s/duration of AS) was associated with older age at onset of AS (odds ratio [OR] 1.10 per year), male sex (OR 1.90), current smoker (OR 4.72), and the presence of HLA-B*4100 (OR 11.73), DRB1*0804 (OR 12.32), DQA1*0401 (OR 5.24), DQB1*0603 (OR 3.42), and DPB1*0202 (OR 23.36), whereas the presence of DRB1*0801 was strongly negatively associated (OR 0.03). Being in the lowest quartile of BASRI-s/duration of AS was also less likely among those with an older age at onset of AS (OR 0.94 per year), men (OR 0.28), and current smokers (OR 0.29).

CONCLUSION

The accuracy of the prognosis of radiographic severity in AS is improved by knowing the age at disease onset, sex, smoking history, and the presence of HLA-B*4100, DRB1*0804, DQA1*0401, DQB1*0603, DRB1*0801, and DPB1*0202 alleles.

Entheses and bones in spondyloarthritis: 2008 Annual Research and Education Meeting of the Spondyloarthritis Research and Therapy Network (SPARTAN)

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 6th Annual Research and Education Meeting in July 2008 in Cleveland, Ohio, USA. 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 effect of inflammation on bone; the Th17 axis, HLA-B27, IL23R, and ARTS1; and breakout sessions on epidemiology and registries.

Impact of immigration on the clinical expression of systemic lupus erythematosus: a comparative study of Hispanic patients residing in the USA and Mexico

OBJECTIVE

To compare the socio-economic characteristics, clinical features and health-related quality of life in Hispanic SLE patients residing in Mexico and in the Southwest USA (Mexican and Texan, herein).

METHODS

Mexican and Texan SLE patients (fulfilling ACR criteria) participating in separate longitudinal outcome studies were evaluated. Texan patients were randomly chosen to match total disease duration with the Mexican patients. Cross-sectional data for the Mexican patients were obtained by a US-trained investigator who had previously participated in data collection for the cohort to which the Texan patients belonged. Socio-economic and -demographic characteristics, clinical characteristics, disease activity (with SLAM-Revised), damage accrual (with SLICC/ACR Damage Index) and self-reported function (with Short Form-36) were compared between the two groups.

RESULTS

Seventy Mexican patients were matched with either one or two Texan patients (n = 94) for a total of 164 patients. Mexican patients were younger. In age-adjusted analyses, the Mexican patients were more educated, had better health-related quality of life and overall less systemic SLE manifestations. Mexican patients were exposed more frequently to AZA.

CONCLUSIONS

Texan patients had more severe disease than the Mexican patients. In multivariable analyses, Texan Hispanic ethnicity was significantly associated with high disease activity, but significance was not reached for damage. The discrepant findings observed between these two Hispanic groups of SLE patients may reflect socio-economic or biological factors. Given the global phenomenon of immigration, rheumatologists should be aware of the overall course and outcome of immigrant SLE patients if undesirable outcomes are to be prevented.

Major histocompatibility complex (MHC) class II alleles, haplotypes and epitopes which confer susceptibility or protection in systemic sclerosis: analyses in 1300 Caucasian, African-American and Hispanic cases and 1000 controls

Objective

To determine human leucocyte antigen-class II (HLA-class II) (DRB1, DQB1, DQA1 and DPB1) alleles, haplotypes and shared epitopes associated with scleroderma (systemic sclerosis (SSc)) and its subphenotypes in a large multi-ethnic US cohort by a case–control association study.

Patients and methods

1300 SSc cases (961 white, 178 black and 161 Hispanic subjects) characterised for clinical skin forms (limited vs diffuse), SSc-specific autoantibodies (anticentromere (ACA), anti-topoisomerase I (ATA), anti-RNA polymerase III (ARA), anti-U3 ribonucleoprotein (fibrillarin)) and others were studied using molecular genotyping. Statistical analyses in SSc itself by ethnicity, gender, skin type and autoantibodies were performed using exact logistic regression modelling for dominant, additive and recessive effects from HLA.

Results

The strongest positive class II associations with SSc in white and Hispanic subjects were the DRB1*1104, DQA1*0501, DQB1*0301 haplotype and DQB1 alleles encoding a non-leucine residue at position 26 (DQB1 26 epi), while the DRB1*0701, DQA1*0201, DQB1*0202 haplotype and DRB1*1501 haplotype were negatively correlated and possibly protective in dominant and recessive models, respectively. These associations did not discriminate between limited and diffuse SSc. SSc in black subjects was associated with DRB1*0804, DQA1*0501, DQB1*0301 alleles. DPB1*1301 showed the highest odds ratio for ATA (OR = 14). Moreover, it showed no linkage disequilibrium or gene interaction with DR/DQ. ACA was best explained by DQB1*0501 and DQB1*26 epi alleles and ARA by DRB1*0404, DRB1*11 and DQB1*03 alleles in white and Hispanic subjects but DRB1*08 in black subjects.

Conclusion

These data indicate unique and multiple HLA-class II effects in SSc, especially on autoantibody markers of different subphenotypes.

Anti-scl-70

OBJECTIVE

To develop an overview focusing on the utility of anti-Scl-70 autoantibody determinations in the rheumatic diseases.

METHODS

Articles from electronic literature searches were retrieved, critiqued and data were extracted and pooled on anti-Scl-70 (topoisomerase I) in relation to history, optimal tests used for its detection, sensitivity, specificity, positive and negative likelihood ratios, indications, interpretation and pitfalls.

RESULTS

Anti-Scl 70 antibodies are very useful in distinguishing systemic sclerosis (SSc) patients from healthy controls, from patients with other connective tissue diseases, and from unaffected family members. Among patients with SSc, anti-Scl-70 positivity is useful in predicting those at higher risk for diffuse cutaneous involvement and interstitial fibrosis/restrictive lung disease, though the latter has not been universally observed. Of the four different techniques notably immunodiffusion, immunoblotting, immunoprecipitation and enzyme-linked immunosorbent assay (ELISA) used to assay anti-Scl-70, immunodiffusion has been the most extensively validated. ELISAs are somewhat less specific than other techniques, especially in distinguishing SSc patients from those with other rheumatic diseases, though newer generation ELISAs have been developed to overcome the problem of low specificity inherent with the traditional techniques. As of yet, the need for serial testing of anti-Scl-70 has not been established.

CONCLUSIONS

Evidence-based guidelines suggest that anti-Scl-70 antibodies are very useful in the diagnosis and clinical management of SSc patients and also to establish prognosis in these patients, particularly those with diffuse skin involvement.

Complement receptor 2 polymorphisms associated with systemic lupus erythematosus modulate alternative splicing

Genetic factors influence susceptibility to systemic lupus erythematosus (SLE). A recent family-based analysis in Caucasian and Chinese populations provided evidence for association of single-nucleotide polymorphisms (SNPs) in the complement receptor 2 (CR2/CD21) gene with SLE. Here we confirmed this result in a case-control analysis of an independent European-derived population including 2084 patients with SLE and 2853 healthy controls. A haplotype formed by the minor alleles of three CR2 SNPs (rs1048971, rs17615, rs4308977) showed significant association with decreased risk of SLE (30.4% in cases vs 32.6% in controls, P=0.016, OR=0.90 (0.82-0.98)). Two of these SNPs are in exon 10, directly 5' of an alternatively spliced exon preferentially expressed in follicular dendritic cells (FDC), and the third is in the alternatively spliced exon. Effects of these SNPs and a fourth SNP in exon 11 (rs17616) on alternative splicing were evaluated. We found that the minor alleles of these SNPs decreased splicing efficiency of exon 11 both in vitro and ex vivo. These findings further implicate CR2 in the pathogenesis of SLE and suggest that CR2 variants alter the maintenance of tolerance and autoantibody production in the secondary lymphoid tissues where B cells and FDCs interact.

Challenges comparing functional limitations in rheumatoid arthritis and ankylosing spondylitis

Whether physical functioning in patients with rheumatoid arthritis (RA) differs from that in patients with ankylosing spondylitis (AS) is presently uncertain. Such a comparison poses challenges, not only because the two diseases differ in the domains of functioning affected, but also because of the different instruments used to measure functional limitations. Limiting our analysis to studies using similar self-report questionnaires, we examined published observational studies of unselected cohorts of patients with RA and patients with AS to compare and contrast the severity of functional limitations. Available studies from a few direct comparisons, and mostly indirect comparisons, suggested that patients with RA are generally more severely limited in physical functioning throughout the disease course than patients with AS. Since most studies did not adjust adequately for potentially important confounders, such as age, gender, comorbidity, and disease duration, reported differences in functional disability between patients with RA and patients with AS must be interpreted cautiously.

Genetic associations of LYN with systemic lupus erythematosus

We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case-control association studies using populations of European-American, African-American and Korean subjects. Our combined European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 x 10(-4), odds ratio (OR)=0.81 (95% confidence interval: 0.73-0.90)). This single nucleotide polymorphism (SNP) is located in the 5' untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 x 10(-3), OR=0.75 (95% CI: 0.62-0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets.

High-density genotyping of STAT4 reveals multiple haplotypic associations with systemic lupus erythematosus in different racial groups

OBJECTIVE

Systemic lupus erythematosus (SLE) is the prototypical systemic autoimmune disorder, with complex etiology and a strong genetic component. Recently, gene products involved in the interferon pathway have been under intense investigation in terms of the pathogenesis of SLE. STAT-1 and STAT-4 are transcription factors that play key roles in the interferon and Th1 signaling pathways, making them attractive candidates for involvement in SLE susceptibility.

METHODS

Fifty-six single-nucleotide polymorphisms (SNPs) across STAT1 and STAT4 on chromosome 2 were genotyped using the Illumina platform, as part of an extensive association study in a large collection of 9,923 lupus patients and control subjects from different racial groups. DNA samples were obtained from the peripheral blood of patients with SLE and control subjects. Principal components analyses and population-based case-control association analyses were performed, and the P values, false discovery rate q values, and odds ratios with 95% confidence intervals were calculated.

RESULTS

We observed strong genetic associations with SLE and multiple SNPs located within STAT4 in different ethnic groups (Fisher's combined P = 7.02 x 10(-25)). In addition to strongly confirming the previously reported association in the third intronic region of this gene, we identified additional haplotypic association across STAT4 and, in particular, a common risk haplotype that is found in multiple racial groups. In contrast, only a relatively weak suggestive association was observed with STAT1, probably due to its proximity to STAT4.

CONCLUSION

Our findings indicate that STAT4 is likely to be a crucial component in SLE pathogenesis in multiple racial groups. Knowledge of the functional effects of this association, when they are revealed, might improve our understanding of the disease and provide new therapeutic targets.

Protective effect of hydroxychloroquine on renal damage in patients with lupus nephritis: LXV, data from a multiethnic US cohort

OBJECTIVE

To assess whether hydroxychloroquine can delay renal damage development in lupus nephritis patients.

METHODS

Lupus nephritis patients (n = 256) from the LUpus in MInorities, NAture versus nurture study (n = 635), a multiethnic cohort of African Americans, Hispanics, and Caucasians, age > or =16 years with disease duration < or =5 years at baseline (T0) were studied. Renal damage was defined using the Systemic Lupus International Collaborating Clinics Damage Index (> or =1 of the following lasting at least 6 months: estimated/measured glomerular filtration rate <50%, 24-hour proteinuria > or =3.5 gm and/or end-stage renal disease, regardless of dialysis or transplantation). Patients with renal damage before T0 were excluded (n = 53). The association between hydroxychloroquine use and renal damage (as defined, or omitting proteinuria) was estimated using Cox proportional regression analyses adjusting for potential confounders. Kaplan-Meier survival curves based on hydroxychloroquine intake or the World Health Organization (WHO) class glomerulonephritis were also derived.

RESULTS

Sixty-three (31.0%) of the 203 patients included developed renal damage over a mean +/- SD disease duration of 5.2 +/- 3.5 years. The most frequent renal damage domain item was proteinuria. Patients who received hydroxychloroquine (79.3%) exhibited a lower frequency of WHO class IV glomerulonephritis, had lower disease activity, and received lower glucocorticoid doses than those who did not take hydroxychloroquine. After adjusting for confounders, hydroxychloroquine was protective of renal damage occurrence in full (hazard ratio [HR] 0.12, 95% confidence interval [95% CI] 0.02-0.97, P = 0.0464) and reduced (HR 0.29, 95% CI 0.13-0.68, P = 0.0043) models. Omitting proteinuria provided comparable results. The cumulative probability of renal damage occurrence was higher in those who did not take hydroxychloroquine and those classified as WHO class IV glomerulonephritis (P < 0.0001).

CONCLUSION

After adjusting for possible confounding factors, the protective effect of hydroxychloroquine in retarding renal damage occurrence in systemic lupus erythematosus is still evident.

Predictors of cardiovascular damage in patients with systemic lupus erythematosus: data from LUMINA (LXVIII), a multiethnic US cohort

OBJECTIVE

To determine the features predictive of atherosclerotic cardiovascular damage in patients with SLE.

METHODS

SLE LUMINA (LUpus in MInorities: NAture vs nurture) patients (n = 637), aged >or=16 years, disease duration <or=5 years at baseline (T0), of African-American, Hispanic and Caucasian ethnicity were studied. Atherosclerotic cardiovascular damage was defined by the following items of the SLICC Damage Index (SDI) cardiovascular domain: angina or coronary artery by pass surgery, myocardial infarction and/or congestive heart failure; factors associated with its occurrence were examined by univariable and multivariable regression analyses.

RESULTS

Forty-three (6.8%) of 637 patients developed cardiovascular damage over a mean +/- S.D. total disease duration of 6.6 +/- 3.6 years. Nearly 90% of the patients were women with a mean +/- s.d. age of 36.5 (12.6) years; all ethnic groups were represented. By multivariable analyses, after adjusting for the cardiovascular manifestations present, age [odds ratio (OR) = 1.06; 95% CI 1.03, 1.09], male gender (OR = 3.57; 95% CI 1.35, 9.09) SDI at baseline (OR = 1.28; 95% CI 1.09, 1.50) and CRP levels [highest tertile (OR = 2.63; 95% CI 1.17, 5.91)] were associated with the occurrence of cardiovascular damage, whereas the number of years of education was negatively associated with such outcome (OR = 0.85; 95% CI 0.74, 0.94).

CONCLUSIONS

Our data suggest that atherosclerotic cardiovascular damage in SLE is multifactorial; traditional (age, gender) and disease-related factors (CRP levels, SDI at baseline) appear to be important contributors to such an occurrence. Tight control of the inflammatory process must be achieved to prevent it.

Association of an ERAP1 ERAP2 haplotype with familial ankylosing spondylitis

OBJECTIVES

To assess whether there is excess transmission of alleles from the ERAP1 ERAP2 locus in families with ankylosing spondylitis (AS).

METHODS

199 multiplex families with AS with four non-synonymous single nucleotide polymorphisms (SNPs), three in the endoplasmic reticulum aminopeptidase 1 (ERAP1) gene (rs27044, rs10050860 and rs30187) and one in the endoplasmic reticulum aminopeptidase 2 (ERAP2) gene (rs2549782), were genotyped and family-based association analyses were performed.

RESULTS

Family-based association testing (FBAT -e; empirical variance option) analysis showed that ERAP1 rs30187[T] was associated with AS (additive model: p=0.02; dominant model: p=0.007). Haplotype permutation tests (HBAT-p) showed that a haplotype in the ERAP1 and ERAP2 locus (rs27044[G] rs30187[T] rs2549782[T]) was significantly associated with AS (two-sided p value by permutation test 0.009 for additive and 0.008 for dominant model, respectively).

CONCLUSION

This study shows that one ERAP1 SNP and a haplotype in the ERAP1 and ERAP2 locus are associated with familial AS.

Variants within MECP2, a key transcription regulator, are associated with increased susceptibility to lupus and differential gene expression in patients with systemic lupus erythematosus

OBJECTIVE

Both genetic and epigenetic factors play an important role in the pathogenesis of lupus. The aim of this study was to examine methyl-CpG-binding protein 2 gene (MECP2) polymorphisms in a large cohort of patients with lupus and control subjects, and to determine the functional consequences of the lupus-associated MECP2 haplotype.

METHODS

We genotyped 18 single-nucleotide polymorphisms within MECP2, located on chromosome Xq28, in a large cohort of patients with lupus and control subjects of European descent. We studied the functional effects of the lupus-associated MECP2 haplotype by determining gene expression profiles in B cell lines in female lupus patients with and those without the lupus-associated MECP2 risk haplotype.

RESULTS

We confirmed, replicated, and extended the genetic association between lupus and genetic markers within MECP2 in a large independent cohort of lupus patients and control subjects of European descent (odds ratio 1.35, P = 6.65 x 10(-11)). MECP2 is a dichotomous transcription regulator that either activates or represses gene expression. We identified 128 genes that are differentially expressed in lupus patients with the disease-associated MECP2 haplotype; most ( approximately 81%) were up-regulated. Genes that were up-regulated had significantly more CpG islands in their promoter regions compared with genes that were down-regulated. Gene ontology analysis using the differentially expressed genes revealed significant association with epigenetic regulatory mechanisms, suggesting that these genes are targets for MECP2 regulation in B cells. Furthermore, at least 13 of the 104 up-regulated genes are regulated by interferon. The disease-risk MECP2 haplotype was associated with increased expression of the MECP2 transcription coactivator CREB1 and decreased expression of the corepressor histone deacetylase 1.

CONCLUSION

Polymorphism in the MECP2 locus is associated with lupus and, at least in part, contributes to the interferon signature observed in lupus patients.