A cross-disease meta-GWAS identifies four new susceptibility loci shared between systemic sclerosis and Crohn’s disease

Abstract: Genome-wide association studies (GWASs) have identified a number of genetic risk loci associated with systemic sclerosis (SSc) and Crohn’s disease (CD), some of which confer susceptibility to both diseases. In order to identify new risk loci shared between these two immune-mediated disorders, we performed a cross-disease meta-analysis including GWAS data from 5,734 SSc patients, 4,588 CD patients and 14,568 controls of European origin. We identified 4 new loci shared between SSc and CD, IL12RB2, IRF1/SLC22A5, STAT3 and an intergenic locus at 6p21.31. Pleiotropic variants within these loci showed opposite allelic effects in the two analysed diseases and all of them showed a significant effect on gene expression. In addition, an enrichment in the IL-12 family and type I interferon signaling pathways was observed among the set of SSc-CD common genetic risk loci. In conclusion, through the first cross-disease meta-analysis of SSc and CD, we identified genetic variants with pleiotropic effects on two clinically distinct immune-mediated disorders. The fact that all these pleiotropic SNPs have opposite allelic effects in SSc and CD reveals the complexity of the molecular mechanisms by which polymorphisms affect diseases

Ribosomal P autoantibodies in systemic lupus erythematosus: Frequencies in different ethnic groups and clinical and immunogenetic associations

Objective. To determine the frequencies and clinical associations of antiribosomal P antibodies (anti-P) in a large multiethnic cohort of patients with systemic lupus erythematosus (SLE), and to assess whether anti-P was associated with any major histocompatibility complex (MHC) class II alleles or shared amino acid sequences. Methods. Sera from 394 SLE patients were studied for anti-P using an enzyme-linked immunosorbent assay, and MHC class II alleles (HLA-DRB1, DQA1, and DQB1) were determined by DNA oligotyping. Results. Anti-P antibodies were found in 13-20% of patients in the majority of ethnic groups, but were perhaps more frequent in Chinese patients (36%) and less common in Bulgarian patients (6%). Neuropsychiatric lupus (psychosis and/or depression) was significantly associated with anti-P. The HLA-DR2, DQ6 haplotypes DRB1*1501 or *1503, DQA1*0102, and DQB1*0602 were increased in anti-P-positive whites, blacks, and Mexican Americans. The HLA-DQB1*0602 allele showed the strongest association with anti-P when these 3 ethnic groups were combined and compared with both race-matched anti-P-negative SLE patients and normal controls. The HLA-DQ8 specificity (DQB1*0302) was increased both in whites and inMexican-Americans with anti-P who were negative for HLA-DQB1*0602, and perhaps also increased in Greeks, but not in blacks, in whom HLA-DQB1*0301 was increased. A shared amino acid sequence in HLA-DQB1 (at position 26 of leucine and position 30 of tyrosine) was strongly associated with anti-P positivity (70%) versus anti-P negativity (42%) across ethnic lines. Conclusion. The anti-P response in SLE patients, occurring in ~15% of patients, was strongly influenced by certain MHC class II alleles and was correlated with diffuse neuropsychiatric dysfunction

Spinal Radiographic Progression and Predictors of Progression in Patients With Radiographic Axial Spondyloarthritis Receiving Ixekizumab Over 2 Years

Objective. To evaluate the long-term effect of ixekizumab (IXE) on radiographic changes in the spine in patients with radiographic axial spondyloarthritis (r-axSpA) by measuring change from baseline through 2 years in modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS), and to identify potential predictors of progression. Methods. This study evaluates patients from COAST-V (ClinicalTrials.gov: NCT02696785, biologic disease-modifying antirheumatic drug-naive) and COAST-W (NCT02696798, tumor necrosis factor inhibitor-experienced) who had mSASSS data at baseline in the originating studies and 108 weeks after baseline in the extension study COAST-Y (NCT03129100). We examined the proportion of patients who did not have spinal radiographic progression through 2 years (108 weeks) of treatment with IXE (80 mg every 2 or 4 weeks) and the change from baseline to year 2 in mSASSS. Potential predictors of spinal radiographic progression were also evaluated. Results. Among patients with evaluable radiographs who were originally assigned to IXE (n = 230), mean (SD) change in mSASSS from baseline at year 2 was 0.3 (1.8). The proportion of nonprogressors over 2 years was 89.6% if defined as mSASSS change from baseline 0) were age >= 40, baseline syndesmophytes, HLA-B27 positivity, and male sex. Week 52 inflammation in Spondyloarthritis Research Consortium of Canada spine was also a predictor of radiographic progression at year 2 in patients with magnetic resonance imaging data in COAST-V (n = 109). Conclusion. The majority of patients with r-axSpA receiving IXE had no radiographic progression in the spine through 2 years of treatment. Predictors were generally consistent with previous studies.Pathophysiology and treatment of rheumatic disease

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Pathophysiology and treatment of rheumatic disease

The chromosome 16q region associated with ankylosing spondylitis includes the candidate gene tumour necrosis factor receptor type 1-associated death domain (TRADD)

Objective: To replicate and refine the reported association of ankylosing spondylitis (AS) with two nonsynonymous single nucleotide polymorphisms (nsSNPs) on chromosome 16q22.1. Methods: 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. Results: 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. Conclusions: 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

Combined analysis of three whole genome linkage scans for Ankylosing Spondylitis

OBJECTIVE: Ankylosing spondylitis (AS) is a debilitating chronic inflammatory condition with a high degree of familiality (lambda(s) = 82) and heritability (>90%) that primarily affects spinal and sacroiliac joints. Whole genome scans for linkage to AS phenotypes have been conducted, although results have been inconsistent between studies and all have had modest sample sizes. One potential solution to these issues is to combine data from multiple studies in a retrospective meta-analysis. METHODS: The International Genetics of Ankylosing Spondylitis Consortium combined data from three whole genome linkage scans for AS (n = 3744 subjects) to determine chromosomal markers that show evidence of linkage with disease. Linkage markers typed in different centres were integrated into a consensus map to facilitate effective data pooling. We performed a weighted meta-analysis to combine the linkage results, and compared them with the three individual scans and a combined pooled scan. RESULTS: In addition to the expected region surrounding the HLA-B27 gene on chromosome 6, we determined that several marker regions showed significant evidence of linkage with disease status. Regions on chromosome 10q and 16q achieved 'suggestive' evidence of linkage, and regions on chromosomes 1q, 3q, 5q, 6q, 9q, 17q and 19q showed at least nominal linkage in two or more scans and in the weighted meta-analysis. Regions previously associated with AS on chromosome 2q (the IL-1 gene cluster) and 22q (CYP2D6) exhibited nominal linkage in the meta-analysis, providing further statistical support for their involvement in susceptibility to AS. CONCLUSION: These findings provide a useful guide for future studies aiming to identify the genes involved in this highly heritable condition

Development of A Health Index for Patients with Ankylosing Spondylitis - First Steps of A Global Initiative Based On the ICF Guided by ASAS

Pathophysiology and treatment of rheumatic disease