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Item does not contain fulltext OBJECTIVE: In many rheumatoid arthritis (RA) patients, disease is controlled with anti-tumor necrosis factor (anti-TNF) biologic therapies. However, in a significant number of patients, the disease fails to respond to anti-TNF therapy. We undertook the present study to examine the hypothesis that rare and low-frequency genetic variants might influence response to anti-TNF treatment. METHODS: We sequenced the coding region of 750 genes in 1,094 RA patients of European ancestry who were treated with anti-TNF. After quality control, 690 genes were included in the analysis. We applied single-variant association and gene-based association tests to identify variants associated with anti-TNF treatment response. In addition, given the key mechanistic role of TNF, we performed gene set analyses of 27 TNF pathway genes. RESULTS: We identified 14,420 functional variants, of which 6,934 were predicted as nonsynonymous 2,136 of which were further predicted to be "damaging." Despite the fact that the study was well powered, no single variant or gene showed study-wide significant association with change in the outcome measures disease activity or European League Against Rheumatism response. Intriguingly, we observed 3 genes, of 27 with nominal signals of association (P < 0.05), that were involved in the TNF signaling pathway. However, when we performed a rigorous gene set enrichment analysis based on association P value ranking, we observed no evidence of enrichment of association at genes involved in the TNF pathway (Penrichment = 0.15, based on phenotype permutations). CONCLUSION: Our findings suggest that rare and low-frequency protein-coding variants in TNF signaling pathway genes or other genes do not contribute substantially to anti-TNF treatment response in patients with RA.

Rodent models for arthritis implicate a role for complement in disease development and progression. In humans, complement deposition has been observed in inflamed synovia of rheumatoid arthritis (RA) patients. In this study we analysed whether genetic variants of complement component C1q predispose to RA. We genotyped single nucleotide polymorphisms (SNPs) in and around the C1q genes, C1qA, C1qB and C1qC, in a Dutch set of 845 RA cases and 1046 controls. Replication was sought in a sample set from North America (868 cases/1193 controls), and a meta-analysis was performed in a combined samples set of 8000 cases and 23262 controls of European descent. We determined C1q serum levels in relation to C1q genotypes. In the discovery phase, five of the 13 SNPs tested in the C1q genes showed a significant association with RA. Additional analysis of the genomic area around the C1q genes revealed that the strongest associating SNPs were confined to the C1q locus. Within the C1q locus we observed no additional signal independent of the strongest associating SNP, rs292001 [odds ratio (OR)=0 center dot 72 (0 center dot 58-0 center dot 88), P=0 center dot 0006]. The variants of this SNP were associated with different C1q serum levels in healthy controls (P=0 center dot 006). Interestingly, this SNP was also associated significantly in genome-wide association studies (GWAS) from the North American Rheumatoid Arthritis Consortium study, confirming the association with RA [OR=0 center dot 83 (0 center dot 69-1 center dot 00), P=0 center dot 043]. Combined analysis, including integrated data from six GWAS studies, provides support for the genetic association. Genetic variants in C1q are correlated with C1q levels and may be a risk for the development of RA.

Rheumatoid arthritis (RA) is characterized by inflammatory arthritis and localized destruction of bone and cartilage. The severity of joint destruction is highly variable between patients and, according to the findings of twin studies, substantially influenced by genetic factors (1). Nevertheless, the precise contribution of genetic factors has yet to be determined. To date, only a small number of genetic risk factors have been identified, and apart from HLA, the association of none of these factors with RA severity has been convincingly replicated. In contrast, the genetics of susceptibility to RA has been considerably boosted, largely due to the findings of genome-wide association studies. In addition to the HLA–DRB1 shared epitope alleles, several new susceptibility factors have been identified, and their association with RA has been independently replicated: PTPN22, TRAF1/C5, OLIG3/TNFAIP3, and STAT4. Intriguingly, for many of these genetic risk factors, the associations are confined to RA patients positive for anti–citrullinated protein antibody (ACPA). It remains unknown whether genetic factors also affect the severity of joint destruction in ACPA-positive and ACPA-negative RA in different ways. Nonetheless, compelling evidence demonstrates that ACPA-positive RA patients have a more destructive disease course than do ACPA-negative RA patients. A recent meta-analysis of 2 genome-wide association studies identified 6 new risk loci (rs4810485 [CD40], rs1678542 [KIF5A/PIP4K2C], rs42041 [CDK6], rs2812378 [CCL21], rs4750316 [PRKCQ], and rs3890745 [MMEL1/TNFRSF14]) as susceptibility factors for autoantibody-positive RA (2). In the present study, we investigated the association between these single-nucleotide polymorphisms (SNPs) and the rate of radiologic joint destruction in RA patients and in ACPA-positive RA in particular using a large longitudinal cohort. A cohort of ACPA-positive RA patients was used for replication analysis. We found that a genetic variant in the CD40 gene is associated with the rate of joint destruction in ACPA-positive RA patients.

Objective Recent advances have led to novel identification of genetic polymorphisms that are associated with susceptibility to rheumatoid arthritis (RA). Currently, 5 loci (HLA, PTPN22, TRAF1/C5, TNFAIP3, and STAT4) have been consistently reported, whereas others have been observed less systematically. The aim of the present study was to independently replicate 3 recently described RA susceptibility loci, STAT4, IL2/IL21, and CTLA4, in a large Dutch case–control cohort, and to perform a meta-analysis of all published studies to date and investigate the relevance of the findings in clinically well-defined subgroups of RA patients with or without autoantibodies. Methods The STAT4, IL2/IL21, and CTLA4 gene polymorphisms (rs7574865, rs6822844, and rs3087243, respectively) were genotyped in 877 RA patients and 866 healthy individuals. A meta-analysis of all published studies of disease association with these polymorphisms was performed using the Mantel-Haenszel fixed-effects method. Results An association of STAT4, IL2/IL21, and CTLA4 with RA was detected in Dutch patients (odds ratio [OR] 1.19 [P = 0.031], OR 0.84 [P = 0.051], and OR 0.87 [P = 0.041], respectively). Results from the meta-analysis confirmed an association of all 3 polymorphisms with RA in Caucasians (OR 1.24 [P = 1.66 × 10−11], OR 0.78 [P = 5.6 × 10−5], and OR 0.91 [P = 1.8 × 10−3], respectively). The meta-analysis also revealed that STAT4 predisposed to disease development equally in patients with autoantibodies and those without autoantibodies, and that CTLA4 enhanced the development of anti–citrullinated protein antibody (ACPA)–positive RA as compared with ACPA-negative RA. Conclusion Our results replicate and firmly establish the association of STAT4 and CTLA4 with RA and provide highly suggestive evidence for IL2/IL21 loci as a risk factor for RA. Given the strong statistical power of our meta-analysis to confirm a true-positive association, these findings provide considerable support for the involvement of CTLA4 in distinct subsets of RA patients.

Contains fulltext : 71178.pdf (Publisher’s version ) (Closed access) OBJECTIVE: We recently showed, using a candidate gene approach in a case-control association study, that a 65-kb block encompassing tumor necrosis factor receptor-associated factor 1 (TRAF1) and C5 is strongly associated with rheumatoid arthritis (RA). Compared with case-control association studies, family-based studies have the added advantage of controlling potential differences in population structure and are not likely to be hampered by variation in population allele frequencies, as is seen for many genetic polymorphisms, including the TRAF1/C5 locus. The aim of this study was to confirm this association in populations of European origin by using a family-based approach. METHODS: A total of 1,356 western European white individuals from 452 "trio" families were genotyped for the rs10818488 polymorphism, using the TaqMan allelic discrimination assay. RESULTS: We observed evidence for association, demonstrating departure from Mendel's law, with an overtransmission of the rs10818488 A allele (A = 55%; P = 0.036). By taking into consideration parental phenotypes, we also observed an increased A allele frequency in affected versus unaffected parents (A = 64%; combined P = 0.015). Individuals carrying the A allele had a 1.2-fold increased risk of developing RA (allelic odds ratio 1.24, 95% confidence interval 1.04-1.50). CONCLUSION: Using a family-based study that is robust against population stratification, we provide evidence for the association of the TRAF1/C5 rs10818488 A allele and RA in populations of European descent, further substantiating our previous findings. Future functional studies should yield insight into the biologic relevance of this locus to the pathways involved in RA.