A major challenge in human genetics is to devise a systematic strategy to integrate disease-associated variants with diverse genomic and biological datasets to provide insight into disease pathogenesis and guide drug discovery for complex traits such as rheumatoid arthritis (RA)1. Here, we performed a genome-wide association study (GWAS) meta-analysis in a total of >100,000 subjects of European and Asian ancestries (29,880 RA cases and 73,758 controls), by evaluating ~10 million single nucleotide polymorphisms (SNPs). We discovered 42 novel RA risk loci at a genome-wide level of significance, bringing the total to 1012–4. We devised an in-silico pipeline using established bioinformatics methods based on functional annotation5, cis-acting expression quantitative trait loci (cis-eQTL)6, and pathway analyses7–9 – as well as novel methods based on genetic overlap with human primary immunodeficiency (PID), hematological cancer somatic mutations and knock-out mouse phenotypes – to identify 98 biological candidate genes at these 101 risk loci. We demonstrate that these genes are the targets of approved therapies for RA, and further suggest that drugs approved for other indications may be repurposed for the treatment of RA. Together, this comprehensive genetic study sheds light on fundamental genes, pathways and cell types that contribute to RA pathogenesis, and provides empirical evidence that the genetics of RA can provide important information for drug discovery.

BACKGROUND Anifrolumab, a human monoclonal antibody to type I interferon receptor subunit 1 investigated for the treatment of systemic lupus erythematosus (SLE), did not have a significant effect on the primary end point in a previous phase 3 trial. The current phase 3 trial used a secondary end point from that trial as the primary end point. METHODS We randomly assigned patients in a 1:1 ratio to receive intravenous anifrolumab (300 mg) or placebo every 4 weeks for 48 weeks. The primary end point of this trial was a response at week 52 defined with the use of the British Isles Lupus Assessment Group (BILAG)-based Composite Lupus Assessment (BICLA). A BICLA response requires reduction in any moderate-to-severe baseline disease activity and no worsening in any of nine organ systems in the BILAG index, no worsening on the Systemic Lupus Erythematosus Disease Activity Index, no increase of 0.3 points or more in the score on the Physician Global Assessment of disease activity (on a scale from 0 [no disease activity] to 3 [severe disease]), no discontinuation of the trial intervention, and no use of medications restricted by the protocol. Secondary end points included a BICLA response in patients with a high interferon gene signature at baseline; reductions in the glucocorticoid dose, in the severity of skin disease, and in counts of swollen and tender joints; and the annualized flare rate. RESULTS A total of 362 patients received the randomized intervention: 180 received anifrolumab and 182 received placebo. The percentage of patients who had a BICLA response was 47.8% in the anifrolumab group and 31.5% in the placebo group (difference, 16.3 percentage points; 95% confidence interval, 6.3 to 26.3; P = 0.001). Among patients with a high interferon gene signature, the percentage with a response was 48.0% in the anifrolumab group and 30.7% in the placebo group; among patients with a low interferon gene signature, the percentage was 46.7% and 35.5%, respectively. Secondary end points with respect to the glucocorticoid dose and the severity of skin disease, but not counts of swollen and tender joints and the annualized flare rate, also showed a significant benefit with anifrolumab. Herpes zoster and bronchitis occurred in 7.2% and 12.2% of the patients, respectively, who received anifrolumab. There was one death from pneumonia in the anifrolumab group. CONCLUSIONS Monthly administration of anifrolumab resulted in a higher percentage of patients with a response (as defined by a composite end point) at week 52 than did placebo, in contrast to the findings of a similar phase 3 trial involving patients with SLE that had a different primary end point. The frequency of herpes zoster was higher with anifrolumab than with placebo. (Funded by AstraZeneca; ClinicalTrials.gov number, NCT02446899.

Systemic lupus erythematosus (SLE), a complex polygenic autoimmune disease, is associated with increased complement activation. Variants of genes encoding complement regulator factor H (CFH) and five CFH-related proteins (CFHR1-CFHR5) within the chromosome 1q32 locus linked to SLE, have been associated with multiple human diseases and may contribute to dysregulated complement activation predisposing to SLE. We assessed 60 SNPs covering the CFH-CFHRs region for association with SLE in 15,864 case-control subjects derived from four ethnic groups. Significant allelic associations with SLE were detected in European Americans (EA) and African Americans (AA), which could be attributed to an intronic CFH SNP (rs6677604, in intron 11, P meta = 6.6×10−8, OR = 1.18) and an intergenic SNP between CFHR1 and CFHR4 (rs16840639, P meta = 2.9×10−7, OR = 1.17) rather than to previously identified disease-associated CFH exonic SNPs, including I62V, Y402H, A474A, and D936E. In addition, allelic association of rs6677604 with SLE was subsequently confirmed in Asians (AS). Haplotype analysis revealed that the underlying causal variant, tagged by rs6677604 and rs16840639, was localized to a ∼146 kb block extending from intron 9 of CFH to downstream of CFHR1. Within this block, the deletion of CFHR3 and CFHR1 (CFHR3-1Δ), a likely causal variant measured using multiplex ligation-dependent probe amplification, was tagged by rs6677604 in EA and AS and rs16840639 in AA, respectively. Deduced from genotypic associations of tag SNPs in EA, AA, and AS, homozygous deletion of CFHR3-1Δ (P meta = 3.2×10−7, OR = 1.47) conferred a higher risk of SLE than heterozygous deletion (P meta = 3.5×10−4, OR = 1.14). These results suggested that the CFHR3-1Δ deletion within the SLE-associated block, but not the previously described exonic SNPs of CFH, might contribute to the development of SLE in EA, AA, and AS, providing new insights into the role of complement regulators in the pathogenesis of SLE.

Objective. Anticitrullinating autoantibodies are specific markers for rheumatoid arthritis (RA). A functional haplotype of 4 exonic single-nucleotide polymorphisms (SNPs) in a citrullinating enzyme, peptidylarginine deiminase 4 (PADI4), was shown to be associated with susceptibility to RA in a Japanese population and was shown to increase the stability of PADI4 messenger RNA. However, the association was not confirmed in 4 subsequent studies involving Caucasian RA patients living in the UK, a French Caucasian population, and a Spanish population. The aim of the current study was to investigate the association of SNPs in the PADI4 gene with RA in a Korean population.Methods. Four exonic SNPs of the PADI4 gene (padi4_89, padi4_90, padi4_92, and padi4_104) were genotyped in 545 unrelated patients with RA and 392 controls, using the MassArray SNP genotyping system. Allelic, genotypic, and haplotypic associations of the SNPs with RA susceptibility were examined using the chi-square test and multivariate logistic regression analyses.Results. Increased RA susceptibility was significantly associated with the minor alleles of padi4_89 (P ‫؍‬ 2.3 ؋ 10 ؊5 ), padi4_90 (P ‫؍‬ 2.3 ؋ 10 ؊5 ), padi4_92 (P ‫؍‬ 2.1 ؋ 10 ؊5 ), and padi4_104 (P ‫؍‬ 1.1 ؋ 10 ؊3 ) and the haplotype carrying the 4 minor alleles (P ‫؍‬ 1.0 ؋ 10 ؊4 ). Genotypes carrying the minor alleles and HLA-DRB1 shared epitope (SE) alleles (P ‫؍‬ 9.4 ؋ 10 ؊21 ) were also associated with increased RA susceptibility. The genotypic associations were sustained among individuals who did not carry any SE alleles, except in the case of padi4_104. Individuals carrying the risk SNPs and/or SE alleles were more susceptible to RA than were individuals carrying neither risk SNPs nor SE alleles.Conclusion. The PADI4 SNPs and haplotypes are associated with RA susceptibility in Koreans. Thus, the association of PADI4 with RA may depend on genetic heterogeneity between Asians and Europeans.

Objective. To describe vascular events during an 8-year followup in a multicenter systemic lupus erythematosus (SLE) inception cohort and their attribution to atherosclerosis. Methods. Clinical data, including comorbidities, were recorded yearly. Vascular events were recorded and attributed to atherosclerosis or not. All of the events met standard clinical criteria. Factors associated with atherosclerotic vascular events were analyzed using descriptive statistics, t-tests, and chi-square tests. Stepwise multivariate logistic regression was used to assess the association of factors with vascular events attributed to atherosclerosis. Results. Since 2000, 1,249 patients have been entered into the cohort. There have been 97 vascular events in 72 patients, including: myocardial infarction (n ‫؍‬ 13), angina (n ‫؍‬ 15), congestive heart failure (n ‫؍‬ 24), peripheral vascular disease (n ‫؍‬ 8), transient ischemic attack (n ‫؍‬ 13), stroke (n ‫؍‬ 23), and pacemaker insertion (n ‫؍‬ 1). Fifty of the events were attributed to active lupus, 31 events in 22 patients were attributed to atherosclerosis, and 16 events were attributed to other causes. The mean ؎ SD time from diagnosis to the first atherosclerotic event was 2.0 ؎ 1.5 years. Compared with patients followed for 2 years without atherosclerotic events (n ‫؍‬ 615), at enrollment, patients with atherosclerotic vascular events were more frequently white, men, older at diagnosis of SLE, obese, smokers, hypertensive, and had a family history of coronary artery disease. On multivariate analysis, only male sex and older age at diagnosis were associated factors. Conclusion. In an inception cohort with SLE followed for up to 8 years, there were 97 vascular events, but only 31 were attributable to atherosclerosis. Patients with atherosclerotic events were more likely to be men and to be older at diagnosis of SLE.