FCGR polymorphisms in the treatment of rheumatoid arthritis with Fc-containing TNF inhibitors.

OBJECTIVES: Reproducible association of a functional polymorphism in FCGR2A with response to a TNF inhibitor (TNFi) in patients with rheumatoid arthritis (RA) led us to explore other FcγR functional polymorphisms. METHODS: Functional polymorphisms FCGR3A F158V, FCGR2B I223T and promoter VNTR in FCGRT were analyzed in up to 429 patients with RA. Response to TNFi was recorded during standard care at 3, 6 and 12 months of follow-up. Fixed effects meta-analysis of studies addressing FCGR3A F158V polymorphism, which is the most studied of these polymorphisms, was conducted with inverse variance weighting. RESULTS: None of the functional polymorphisms were associated with change in DAS28. Meta-analysis of the seven studies (899 patients) with available data addressing association of FCGR3A F158V with response to TNFi in RA showed no association (OR: 1.11, 95% CI: 0.8-1.5; p = 0.5). CONCLUSION: None of the three functional polymorphisms in FcγR genes showed association with response to TNFi in patients with RA. These negative results were obtained in spite of the larger size of this study relative to previous studies addressing the same polymorphisms. In addition, meta-analysis of FCGR3A F158V was also negative against the results provided by previous studies. Original submitted 17 September 2014; Revision submitted 9 December 2014.

Lack of replication of interactions between polymorphisms in rheumatoid arthritis susceptibility: case-control study.

INTRODUCTION: Approximately 100 loci have been definitively associated with rheumatoid arthritis (RA) susceptibility. However, they explain only a fraction of RA heritability. Interactions between polymorphisms could explain part of the remaining heritability. Multiple interactions have been reported, but only the shared epitope (SE) × protein tyrosine phosphatase nonreceptor type 22 (PTPN22) interaction has been replicated convincingly. Two recent studies deserve attention because of their quality, including their replication in a second sample collection. In one of them, researchers identified interactions between PTPN22 and seven single-nucleotide polymorphisms (SNPs). The other showed interactions between the SE and the null genotype of glutathione S-transferase Mu 1 (GSTM1) in the anti-cyclic citrullinated peptide-positive (anti-CCP+) patients. In the present study, we aimed to replicate association with RA susceptibility of interactions described in these two high-quality studies. METHODS: A total of 1,744 patients with RA and 1,650 healthy controls of Spanish ancestry were studied. Polymorphisms were genotyped by single-base extension. SE genotypes of 736 patients were available from previous studies. Interaction analysis was done using multiple methods, including those originally reported and the most powerful methods described. RESULTS: Genotypes of one of the SNPs (rs4695888) failed quality control tests. The call rate for the other eight polymorphisms was 99.9%. The frequencies of the polymorphisms were similar in RA patients and controls, except for PTPN22 SNP. None of the interactions between PTPN22 SNPs and the six SNPs that met quality control tests was replicated as a significant interaction term--the originally reported finding--or with any of the other methods. Nor was the interaction between GSTM1 and the SE replicated as a departure from additivity in anti-CCP+ patients or with any of the other methods. CONCLUSIONS: None of the interactions tested were replicated in spite of sufficient power and assessment with different assays. These negative results indicate that whether interactions are significant contributors to RA susceptibility remains unknown and that strict standards need to be applied to claim that an interaction exists.

Lack of validation of genetic variants associated with anti-tumor necrosis factor therapy response in rheumatoid arthritis: a genome-wide association study replication and meta-analysis.

INTRODUCTION: In this study, our aim was to elucidate the role of four polymorphisms identified in a prior large genome-wide association study (GWAS) in which the investigators analyzed the responses of patients with rheumatoid arthritis (RA) to treatment with tumor necrosis factor inhibitors (TNFi). The authors of that study reported that the four genetic variants were significantly associated. However, none of the associations reached GWAS significance, and two subsequent studies failed to replicate these associations. METHODS: The four polymorphisms (rs12081765, rs1532269, rs17301249 and rs7305646) were genotyped in a total of 634 TNFi-treated RA patients of Spanish Caucasian origin. Four outcomes were evaluated: changes in the Disease Activity Score in 28 joints (DAS28) after 6 and 12 months of treatment and classification according to the European League Against Rheumatism (EULAR) response criteria at the same time points. Association with DAS28 changes was assessed by linear regression using an additive genetic model. Contingency tables of genotype and allele frequencies between EULAR responder and nonresponder patients were compared. In addition, we combined our data with those of previously reported studies in a meta-analysis including 2,998 RA patients. RESULTS: None of the four genetic variants showed an association with response to TNFi in any of the four outcomes analyzed in our Spanish patients. In addition, only rs1532269 yielded a suggestive association (P = 0.0033) with the response to TNFi when available data from previous studies were combined in the meta-analysis. CONCLUSION: Our data suggest that the rs12081765, rs1532269, rs17301249 and rs7305646 genetic variants do not have a role as genetic predictors of TNFi treatment outcomes.

Association of FCGR2A with the response to infliximab treatment of patients with rheumatoid arthritis.

OBJECTIVES: We aimed to assess a functional polymorphism in FCGR2A H131R, for association with the treatment response to Fc-containing inhibitors of tumor necrosis factor (TNF). METHODS: A total of 429 biologic-naive patients with rheumatoid arthritis collected in two sets (299 and 130) were treated during standard care with infliximab (INX), etanercept, or adalimumab. Response to the treatment was evaluated at 3, 6, and 12 months of follow-up as the change in the Disease Activity Score (DAS) 28 from baseline and as the response by the European League Against Rheumatism (EULAR) criteria. These variables were analyzed for association with linear and logistic regression models that included sex, inhibitors of TNF, and baseline DAS28 as covariates. RESULTS: Significant association was found between the FCGR2A H131R polymorphism and the response to treatment with INX, but not with the other two TNF inhibitors. The 131R allele was associated with a lower change in DAS28 (P=0.04-0.008 at different times) in the first set of patients and confirmed in the second group of patients (P=0.026 at 3 months of follow-up). Association was also found in the comparison between nonresponders and responders to INX by the EULAR criteria. CONCLUSION: We found an association of the FCGR2A 131R allele with poor response to INX. This finding could be of utility to understand the mechanisms behind treatment failure and contribute to biomarker panels for INX response prediction.

Lack of association with rheumatoid arthritis of selected polymorphisms in 4 candidate genes: CFH, CD209, eotaxin-3, and MHC2TA.

OBJECTIVE: To investigate associations with rheumatoid arthritis (RA) of single-nucleotide polymorphisms (SNP) in 4 candidate genes, complement factor H (CFH), CD209 or DC-SIGN, eotaxin-3, and the MHC class II Transactivator (MHC2TA) genes. These SNP have been reported as important for RA (eotaxin-3 and MHC2TA) or for other immune-mediated diseases (CFH and CD209). METHODS: Genotypes for the 7 selected SNP were obtained from 1587 patients with RA and 1570 controls of Spanish ancestry. Analyses were carried out after stratification for sex, erosions, rheumatoid factor, shared epitope, anti-cyclic citrullinated peptide antibodies, and the R620W PTPN22 SNP. RESULTS: None of the comparisons between patients with RA and controls or between the different strata of patients according to disease features was significant. CONCLUSION: None of the SNP in CFH and CD209 showed evidence of association with RA. We did not replicate the association of eotaxin-3 with RA described in Koreans, or that of the MHC2T SNP.

Analysis of TNFAIP3, a feedback inhibitor of nuclear factor-kappaB and the neighbor intergenic 6q23 region in rheumatoid arthritis susceptibility.

INTRODUCTION: Genome-wide association studies of rheumatoid arthritis (RA) have identified an association of the disease with a 6q23 region devoid of genes. TNFAIP3, an RA candidate gene, flanks this region, and polymorphisms in both the TNFAIP3 gene and the intergenic region are associated with systemic lupus erythematosus. We hypothesized that there is a similar association with RA, including polymorphisms in TNFAIP3 and the intergenic region. METHODS: To test this hypothesis, we selected tag-single nucleotide polymorphisms (SNPs) in both loci. They were analyzed in 1,651 patients with RA and 1,619 control individuals of Spanish ancestry. RESULTS: Weak evidence of association was found both in the 6q23 intergenic region and in the TNFAIP3 locus. The rs582757 SNP and a common haplotype in the TNFAIP3 locus exhibited association with RA. In the intergenic region, two SNPs were associated, namely rs609438 and rs13207033. The latter was only associated in patients with anti-citrullinated peptide antibodies. Overall, statistical association was best explained by the interdependent contribution of SNPs from the two loci TNFAIP3 and the 6q23 intergenic region. CONCLUSIONS: Our data are consistent with the hypothesis that several RA genetic factors exist in the 6q23 region, including polymorphisms in the TNFAIP3 gene, like that previously described for systemic lupus erythematosus.