Lower body mass and lower adiposity are associated with differential responses to two treatment strategies for rheumatoid arthritis.

PURPOSE: To determine if body mass index (BMI) and adipokine levels identify rheumatoid arthritis (RA) patients most likely to benefit from initiation of tumour necrosis factor inhibitors (TNFi) after methotrexate inadequate response. METHODS: This is a secondary analysis of the Rheumatoid Arthritis Comparison of Active Treatments (RACAT) trial and the (TEAR) trial. Both studies compared treatment strategies starting with conventional disease-modifying anti-rheumatic drugs (DMARDs) (triple therapy) versus etanercept plus methotrexate. We compared response rates between TNFi and triple therapy among patients with different BMI. Adipokines were measured at enrolment and associations with treatment response were examined using regression, adjusting for age, sex, BMI and baseline disease activity. RESULTS: In RACAT (n=306), participants who were normal/underweight were more likely to benefit from TNFi versus triple therapy, with greater change in Disease Activity Score in 28 and greater ACR20 response (ACR 20: 64% vs 23%, p=0.001). In contrast, overweight/obese participants had similar response to TNFi versus triple therapy (p-for-interaction=0.001). Similarly, but modest patterns were observed in TEAR (n=601; ACR20: 67% vs 52%, p=0.05). In RACAT, adipokine scores consistent with lower adiposity also predicted greater response to TNFi (ACR20: 58% vs 37%, p=0.01) with better model fit compared with BMI alone. CONCLUSIONS: Lower BMI and evidence of lower adiposity based on adipokine profiles were associated with a superior response to TNFi compared with triple therapy. There was no difference between treatments among overweight/obese participants. The results support TNFi being a particularly important therapeutic among normal/underweight patients, with implications for clinical decisions and trial design.

Muscle Inflammation Susceptibility: A Potential Phenotype for Guiding Precision Rehabilitation After Total Hip Arthroplasty in End-Stage Osteoarthritis.

The progression of osteoarthritis of the hip to its end stage and ultimately to total hip arthroplasty (THA) is complex; the multifactorial pathophysiology involves myriad collaborating tissues in and around the diseased joint. We have named the heightened state of periarticular muscle inflammation at the time of surgery "muscle inflammation susceptibility" (MuIS) because it is distinct from systemic inflammation. In this review article, we discuss how MuIS and heightened atrophy-associated signaling in the periarticular skeletal muscles may contribute to reduced muscle mass, impaired muscle quality (ie, through fibrosis), and a muscle microenvironment that challenges regenerative capacity and thus functional recovery from THA. We also review directions for future research that should advance understanding of the key determinants of precision for optimized success of THA for each individual.

Cystic fibrosis autoantibody signatures associate with Staphylococcus aureus lung infection or cystic fibrosis-related diabetes.

Introduction: While cystic fibrosis (CF) lung disease is characterized by persistent inflammation and infections and chronic inflammatory diseases are often accompanied by autoimmunity, autoimmune reactivity in CF has not been studied in depth. Methods: In this work we undertook an unbiased approach to explore the systemic autoantibody repertoire in CF using autoantibody microarrays. Results and discussion: Our results show higher levels of several new autoantibodies in the blood of people with CF (PwCF) compared to control subjects. Some of these are IgA autoantibodies targeting neutrophil components or autoantigens linked to neutrophil-mediated tissue damage in CF. We also found that people with CF with higher systemic IgM autoantibody levels have lower prevalence of S. aureus infection. On the other hand, IgM autoantibody levels in S. aureus-infected PwCF correlate with lung disease severity. Diabetic PwCF have significantly higher levels of IgA autoantibodies in their circulation compared to nondiabetic PwCF and several of their IgM autoantibodies associate with worse lung disease. In contrast, in nondiabetic PwCF blood levels of IgA autoantibodies correlate with lung disease. We have also identified other autoantibodies in CF that associate with P. aeruginosa airway infection. In summary, we have identified several new autoantibodies and associations of autoantibody signatures with specific clinical features in CF.

Genetic, social, and environmental risk factors in rheumatoid arthritis-associated interstitial lung disease.

OBJECTIVE: MUC5B and TOLLIP single nucleotide polymorphisms (SNPs) and cigarette smoking were associated with rheumatoid arthritis-interstitial lung disease (RA-ILD) in a predominantly Northern European population. We evaluated whether RA-ILD is associated with these genetic variants and HLA-DRB1 shared epitope (SE) alleles in a large RA cohort stratified by race and smoking history. METHODS: HLA-DRB1 SE alleles and MUC5B rs35705950 and TOLLIP rs5743890 SNPs were genotyped in U.S. veterans with RA. ILD was validated through medical record review. Genetic associations with ILD were assessed in logistic regression models overall and in subgroups defined by race and smoking status, with additive interactions assessed by the relative excess risk of interaction (RERI). RESULTS: Of 2,556 participants (88% male, 77% White), 238 (9.3%) had ILD. The MUC5B variant was associated with ILD (OR 2.25 [95% CI 1.69, 3.02]), whereas TOLLIP and HLA-DRB1 SE were not. The MUC5B variant was less frequent among Black/African American participants (5.8% vs. 22.6%), though its association with RA-ILD was numerically stronger (OR 4.23 [1.65, 10.86]) compared to all other participants (OR 2.32 [1.70, 3.16]). Those with the MUC5B variant and a smoking history had numerically higher odds of ILD (OR 4.18 [2.53, 6.93]) than non-smokers (OR 2.41 [1.16, 5.04]). Additive interactions between MUC5B-race and MUC5B-smoking were not statistically significant. CONCLUSION: In this large RA cohort, the MUC5B promoter variant was associated with >2-fold higher odds of RA-ILD. While this variant is less common among Black/African American patients, its presence in this population carried >4-fold higher odds of RA-ILD.

A genome-wide association study for rheumatoid arthritis replicates previous HLA and non-HLA associations in a cohort from South Africa.

The complex pathogenesis of rheumatoid arthritis (RA) is not fully understood, with few studies exploring the genomic contribution to RA in patients from Africa. We report a genome-wide association study (GWAS) of South-Eastern Bantu-Speaking South Africans (SEBSSAs) with seropositive RA (n = 531) and population controls (n = 2653). Association testing was performed using PLINK (logistic regression assuming an additive model) with sex, age, smoking and the first three principal components as covariates. The strong association with the Human Leukocyte Antigen (HLA) region, indexed by rs602457 (near HLA-DRB1), was replicated. An additional independent signal in the HLA region represented by the lead SNP rs2523593 (near the HLA-B gene; Conditional P-value = 6.4 × 10-10) was detected. Although none of the non-HLA signals reached genome-wide significance (P < 5 × 10-8), 17 genomic regions showed suggestive association (P < 5 × 10-6). The GWAS replicated two known non-HLA associations with MMEL1 (rs2843401) and ANKRD55 (rs7731626) at a threshold of P < 5 × 10-3 providing, for the first time, evidence for replication of non-HLA signals for RA in sub-Saharan African populations. Meta-analysis with summary statistics from an African-American cohort (CLEAR study) replicated three additional non-HLA signals (rs11571302, rs2558210 and rs2422345 around KRT18P39-NPM1P33, CTLA4-ICOS and AL645568.1, respectively). Analysis based on genomic regions (200 kb windows) further replicated previously reported non-HLA signals around PADI4, CD28 and LIMK1. Although allele frequencies were overall strongly correlated between the SEBSSA and the CLEAR cohort, we observed some differences in effect size estimates for associated loci. The study highlights the need for conducting larger association studies across diverse African populations to inform precision medicine-based approaches for RA in Africa.

Perioperative assessment of muscle inflammation susceptibility in patients with end-stage osteoarthritis.

Many individuals with end-stage osteoarthritis (OA) undergo elective total hip/knee arthroplasty (THA/TKA) to relieve pain, improve mobility and quality of life. However, ∼30% suffer long-term mobility impairment following surgery. This may be in part due to muscle inflammation susceptibility (MuIS+), an overt proinflammatory pathology localized to skeletal muscle surrounding the diseased joint, present in some patients with TKA/THA. We interrogated the hypothesis that MuIS+ status results in a perturbed perioperative gene expression profile and decreases skeletal muscle integrity in patients with end-stage OA. Samples were leveraged from the two-site, randomized, controlled trial R01HD084124, NCT02628795. Participants were dichotomized based on surgical (SX) muscle gene expression of TNFRSF1A (TNF-αR). MuIS+/- samples were probed for gene expression and fibrosis. Paired and independent two-tailed t tests were used to determine differences between contralateral (CTRL) and surgical (SX) limbs and between-subject comparisons, respectively. Significance was declared at P < 0.05. Seventy participants (26M/44F; mean age 62.41 ± 8.86 yr; mean body mass index 31.10 ± 4.91 kg/m2) undergoing THA/TKA were clustered as MuIS+ (n = 24) or MuIS- (n = 46). Lower skeletal muscle integrity (greater fibrosis) exists on the SX versus CTRL limb (P < 0.001). Furthermore, MuIS+ versus MuIS- muscle exhibited higher proinflammatory (IL-6R and TNF-α) and catabolic (TRIM63) gene expression (P < 0.001, P = 0.004, and 0.024 respectively), with a trend for greater fibrosis (P = 0.087). Patients with MuIS+ exhibit more inflammation and catabolic gene expression in skeletal muscle of the SX limb, accompanied by decreased skeletal muscle integrity (Trend). This highlights the impact of MuIS+ status emphasizing the potential value of perioperative MuIS assessment to inform optimal postsurgical care.NEW & NOTEWORTHY This study assessed the skeletal muscle molecular characteristics associated with end-stage osteoarthritis and refined an important phenotype, in some patients, termed muscle inflammation susceptibility (MuIS+) that may be an important consideration following surgery. Furthermore, we provide evidence of differential inflammatory and catabolic gene expression between the contralateral and surgical limbs along with differences between the skeletal muscle surrounding the diseased hip versus knee joints.

The Safety and Immunologic Effectiveness of the Live Varicella-Zoster Vaccine in Patients Receiving Tumor Necrosis Factor Inhibitor Therapy : A Randomized Controlled Trial.

BACKGROUND: The safety and effectiveness of live virus vaccines, such as the varicella-zoster vaccine, are unknown in patients with inflammatory diseases receiving immunomodulatory therapy such as tumor necrosis factor inhibitors (TNFis). OBJECTIVE: To evaluate the safety and immunogenicity of the live attenuated zoster vaccine (ZVL) in patients receiving TNFis. DESIGN: Randomized, blinded, placebo-controlled trial. (ClinicalTrials.gov: NCT02538341). SETTING: Academic and community-based rheumatology, gastroenterology, and dermatology practices. PATIENTS: Adults aged 50 years or older receiving TNFis for any indication. INTERVENTION: Random assignment to ZVL versus placebo. MEASUREMENTS: Glycoprotein enzyme-linked immunosorbent assay (gpELISA) and enzyme-linked immunosorbent spot (ELISpot) from serum and peripheral blood mononuclear cells measured at baseline and 6 weeks after vaccination. Suspected varicella infection or herpes zoster was clinically assessed using digital photographs and polymerase chain reaction on vesicular fluid. RESULTS: Between March 2015 and December 2018, 617 participants were randomly assigned in a 1:1 ratio to receive ZVL (n = 310) or placebo (n = 307) at 33 centers. Mean age was 62.7 years (SD, 7.5); 66.1% of participants were female, 90% were White, 8.2% were Black, and 5.9% were Hispanic. The most common TNFi indications were rheumatoid arthritis (57.6%) and psoriatic arthritis (24.1%); TNFi medications were adalimumab (32.7%), infliximab (31.3%), etanercept (21.2%), golimumab (9.1%), and certolizumab (5.7%). Concomitant therapies included methotrexate (48.0%) and oral glucocorticoids (10.5%). Through week 6, no cases of confirmed varicella infection were found; cumulative incidence of varicella infection or shingles was 0.0% (95% CI, 0.0% to 1.2%). At 6 weeks, compared with baseline, the mean increases in geometric mean fold rise as measured by gpELISA and ELISpot were 1.33 percentage points (CI, 1.17 to 1.51 percentage points) and 1.39 percentage points (CI, 1.07 to 1.82 percentage points), respectively. LIMITATION: Potentially limited generalizability to patients receiving other types of immunomodulators. CONCLUSION: This trial informs safety concerns related to use of live virus vaccines in patients receiving biologics. PRIMARY FUNDING SOURCE: The National Institute of Arthritis and Musculoskeletal and Skin Diseases and the American College of Rheumatology.

A novel Mendelian randomization method with binary risk factor and outcome.

BACKGROUND: Mendelian randomization (MR) applies instrumental variable (IV) methods to observational data using a genetic variant as an IV. Several Monte-Carlo studies investigate the performance of MR methods with binary outcomes, but few consider them in conjunction with binary risk factors. OBJECTIVE: To develop a novel MR estimator for scenarios with a binary risk factor and outcome; and compare to existing MR estimators via simulations and real data analysis. METHODS: A bivariate Bernoulli distribution is adapted to the IV setting. Empirical bias and asymptotic coverage probabilities are estimated via simulations. The proposed method is compared to the Wald method, two-stage predictor substitution (2SPS), two-stage residual inclusion (2SRI), and the generalized method of moments (GMM). An analysis is performed using existing data from the CLEAR study to estimate the potential causal effect of smoking on rheumatoid arthritis risk in African Americans. RESULTS: Bias was low for the proposed method and comparable to 2SPS. The Wald method was often biased towards the null. Coverage was adequate for the proposed method, 2SPS, and 2SRI. Coverage for the Wald and GMM methods was poor in several scenarios. The causal effect of ever smoking on rheumatoid arthritis risk was not statistically significant using a variety of genetic instruments. CONCLUSIONS: Simulations suggest the proposed MR method is sound with binary risk factors and outcomes, and comparable to 2SPS and 2SRI in terms of bias. The proposed method also provides more natural framework for hypothesis testing compared to 2SPS or 2SRI, which require ad-hoc variance adjustments.

Effect of Serum Urate Lowering With Allopurinol on Blood Pressure in Young Adults: A Randomized, Controlled, Crossover Trial.

OBJECTIVE: To determine whether serum urate reduction with allopurinol lowers blood pressure (BP) in young adults and the mechanisms mediating this hypothesized effect. METHODS: We conducted a single-center, randomized, double-blind, crossover clinical trial. Adults ages 18-40 years with baseline systolic BP ≥120 and <160 mm Hg or diastolic BP ≥80 and <100 mm Hg, and serum urate ≥5.0 mg/dl for men or ≥4.0 mg/dl for women were enrolled. Main exclusion criteria included chronic kidney disease, gout, or past use of urate-lowering therapies. Participants received oral allopurinol (300 mg daily) or placebo for 1 month followed by a 2-4 week washout and then were crossed over. Study outcome measures were change in systolic BP from baseline, endothelial function estimated as flow-mediated dilation (FMD), and high-sensitivity C-reactive protein (hsCRP) levels. Adverse events were assessed. RESULTS: Ninety-nine participants were randomized, and 82 completed all visits. The mean ± SD age was 28.0 ± 7.0 years, 62.6% were men, and 40.4% were African American. In the primary intent-to-treat analysis, systolic BP did not change during the allopurinol treatment phase (mean ± SEM -1.39 ± 1.16 mm Hg) or placebo treatment phase (-1.06 ± 1.08 mm Hg). FMD increased during allopurinol treatment periods compared to placebo treatment periods (mean ± SEM 2.5 ± 0.55% versus -0.1 ± 0.42%; P < 0.001). There were no changes in hsCRP level and no serious adverse events. CONCLUSION: Our findings indicate that urate-lowering therapy with allopurinol does not lower systolic BP or hsCRP level in young adults when compared with placebo, despite improvements in FMD. These findings do not support urate lowering as a treatment for hypertension in young adults.

Osteoarthritis Progression: Mitigation and Rehabilitation Strategies.

Osteoarthritis is the most common form of arthritis and is a substantial burden for patients with the disease. Currently, there is no cure for osteoarthritis, but many emerging therapies have been developed to aid in the mitigation of disease progression. When osteoarthritis reaches the end-stage of disease many patients undergo total joint arthroplasty to improve quality of life, yet some experience persistent pain and mobility limitations for extended periods following surgery. This review highlights recent therapeutic advancements in osteoarthritis treatment consisting of pharmacologics, nutraceuticals, biologics, and exercise while emphasizing the current state of post-arthroplasty rehabilitation.

HLA and autoantibodies define scleroderma subtypes and risk in African and European Americans and suggest a role for molecular mimicry.

Systemic sclerosis (SSc) is a clinically heterogeneous autoimmune disease characterized by mutually exclusive autoantibodies directed against distinct nuclear antigens. We examined HLA associations in SSc and its autoantibody subsets in a large, newly recruited African American (AA) cohort and among European Americans (EA). In the AA population, the African ancestry-predominant HLA-DRB1*08:04 and HLA-DRB1*11:02 alleles were associated with overall SSc risk, and the HLA-DRB1*08:04 allele was strongly associated with the severe antifibrillarin (AFA) antibody subset of SSc (odds ratio = 7.4). These African ancestry-predominant alleles may help explain the increased frequency and severity of SSc among the AA population. In the EA population, the HLA-DPB1*13:01 and HLA-DRB1*07:01 alleles were more strongly associated with antitopoisomerase (ATA) and anticentromere antibody-positive subsets of SSc, respectively, than with overall SSc risk, emphasizing the importance of HLA in defining autoantibody subtypes. The association of the HLA-DPB1*13:01 allele with the ATA+ subset of SSc in both AA and EA patients demonstrated a transancestry effect. A direct correlation between SSc prevalence and HLA-DPB1*13:01 allele frequency in multiple populations was observed (r = 0.98, P = 3 × 10-6). Conditional analysis in the autoantibody subsets of SSc revealed several associated amino acid residues, mostly in the peptide-binding groove of the class II HLA molecules. Using HLA α/ß allelic heterodimers, we bioinformatically predicted immunodominant peptides of topoisomerase 1, fibrillarin, and centromere protein A and discovered that they are homologous to viral protein sequences from the Mimiviridae and Phycodnaviridae families. Taken together, these data suggest a possible link between HLA alleles, autoantibodies, and environmental triggers in the pathogenesis of SSc.

HLA-C: An Accomplice in Rheumatic Diseases.

Human leukocyte antigen c (HLA-C) is a polymorphic membrane protein encoded by the HLA-C gene in the class I major histocompatibility complex. HLA-C plays an essential role in protection against cancer and viruses but has also been implicated in allograft rejection, preeclampsia, and autoimmune disease. This review summarizes reports and proposed mechanisms for the accessory role of HLA-C in rheumatic diseases. Historically, contributions of HLA-C to rheumatic diseases were eclipsed by the stronger association with HLA-DRB1 alleles containing the "shared epitope" with rheumatoid arthritis. Larger genetic association studies and more powerful analytical approaches have revealed independent associations of HLA-C with rheumatic disease-associated phenotypes, including development of anticitrullinated peptide antibodies. HLA-C functions by presenting antigens to T cells and by binding activatory and inhibitory receptors on natural killer (NK) cells, but the exact mechanisms by which the HLA-C locus contributes to autoimmunity are largely undefined. Studies have suggested that HLA-C and NK cell receptor polymorphisms may predict responsiveness to pharmacotherapy. Understanding the mechanisms of the role of HLA-C in rheumatic disease could uncover therapeutic targets or guide precision pharmacologic treatments.

IFNγ induces epigenetic programming of human T-bethi B cells and promotes TLR7/8 and IL-21 induced differentiation.

Although B cells expressing the IFNγR or the IFNγ-inducible transcription factor T-bet promote autoimmunity in Systemic Lupus Erythematosus (SLE)-prone mouse models, the role for IFNγ signaling in human antibody responses is unknown. We show that elevated levels of IFNγ in SLE patients correlate with expansion of the T-bet expressing IgDnegCD27negCD11c+CXCR5neg (DN2) pre-antibody secreting cell (pre-ASC) subset. We demonstrate that naïve B cells form T-bethi pre-ASCs following stimulation with either Th1 cells or with IFNγ, IL-2, anti-Ig and TLR7/8 ligand and that IL-21 dependent ASC formation is significantly enhanced by IFNγ or IFNγ-producing T cells. IFNγ promotes ASC development by synergizing with IL-2 and TLR7/8 ligands to induce genome-wide epigenetic reprogramming of B cells, which results in increased chromatin accessibility surrounding IRF4 and BLIMP1 binding motifs and epigenetic remodeling of IL21R and PRDM1 loci. Finally, we show that IFNγ signals poise B cells to differentiate by increasing their responsiveness to IL-21.

Association of response to TNF inhibitors in rheumatoid arthritis with quantitative trait loci for CD40 and CD39.

OBJECTIVES: We sought to investigate whether genetic effects on response to TNF inhibitors (TNFi) in rheumatoid arthritis (RA) could be localised by considering known genetic susceptibility loci for relevant traits and to evaluate the usefulness of these genetic loci for stratifying drug response. METHODS: We studied the relation of TNFi response, quantified by change in swollen joint counts ( Δ SJC) and erythrocyte sedimentation rate ( Δ ESR) with locus-specific scores constructed from genome-wide assocation study summary statistics in 2938 genotyped individuals: 37 scores for RA; scores for 19 immune cell traits; scores for expression or methylation of 93 genes with previously reported associations between transcript level and drug response. Multivariate associations were evaluated in penalised regression models by cross-validation. RESULTS: We detected a statistically significant association between Δ SJC and the RA score at the CD40 locus (p=0.0004) and an inverse association between Δ SJC and the score for expression of CD39 on CD4 T cells (p=0.00005). A previously reported association between CD39 expression on regulatory T cells and response to methotrexate was in the opposite direction. In stratified analysis by concomitant methotrexate treatment, the inverse association was stronger in the combination therapy group and dissipated in the TNFi monotherapy group. Overall, ability to predict TNFi response from genotypic scores was limited, with models explaining less than 1% of phenotypic variance. CONCLUSIONS: The association with the CD39 trait is difficult to interpret because patients with RA are often prescribed TNFi after failing to respond to methotrexate. The CD39 and CD40 pathways could be relevant for targeting drug therapy.

Systemic levels of anti-PAD4 autoantibodies correlate with airway obstruction in cystic fibrosis.

Cystic fibrosis (CF) airway disease is characterized by the long-term presence of neutrophil granulocytes. Formation of neutrophil extracellular traps (NETs) and/or autoantibodies directed against extracellular components of NETs are possible contributors to neutrophil-mediated lung damage in CF. The goal of this study was to measure their levels in CF adults compared to healthy controls and subjects with rheumatologic diseases known to develop NET-related autoantibodies and pathologies, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Sera were analyzed from the following number of subjects: 37 CF, 23 healthy controls (HC), 20 RA, and 21 SLE. CF had elevated serum myeloperoxidase (MPO) concentrations (347.5±56.1 ng/ml, mean+/-S.E.M., p = .0132) compared to HC (144.5±14.6 ng/ml) but not of neutrophil elastase (NE) complexed with alpha-1-antitrypsin, cell-free DNA or NE-DNA complexes. The peptidylarginine deiminase 4 (PAD4) enzyme is required for NET formation and associated DNA release in neutrophils. Serum levels of anti-PAD4 antibodies (Ab) were elevated in CF (p = .0147) compared to HC and showed an inverse correlation with a measure of lung function, FEV1% predicted (r = -0.5020, p = .015), as did MPO levels (r = -0.4801, p = .0026). Anti-PAD4 Ab levels in CF sera associated with lung infection by P. aeruginosa, but not that by S. aureus, age, sex, CF-related diabetes or the presence of musculoskeletal pain. Serum levels of anti-citrullinated protein Abs (ACPAs) and anti-nucleosome Abs were not elevated in CF compared to HC (p = .7498, p = .0678). In summary, adult CF subjects develop an autoimmune response against NET components that correlates with worsening lung disease.

Beyond Autoantibodies: Biologic Roles of Human Autoreactive B Cells in Rheumatoid Arthritis Revealed by RNA-Sequencing.

OBJECTIVE: To obtain the comprehensive transcriptome profile of human citrulline-specific B cells from patients with rheumatoid arthritis (RA). METHODS: Citrulline- and hemagglutinin-specific B cells were sorted by flow cytometry using peptide-streptavidin conjugates from the peripheral blood of RA patients and healthy individuals. The transcriptome profile of the sorted cells was obtained by RNA-sequencing, and expression of key protein molecules was evaluated by aptamer-based SOMAscan assay and flow cytometry. The ability of these proteins to effect differentiation of osteoclasts and proliferation and migration of synoviocytes was examined by in vitro functional assays. RESULTS: Citrulline-specific B cells, in comparison to citrulline-negative B cells, from patients with RA differentially expressed the interleukin-15 receptor α (IL-15Rα) gene as well as genes related to protein citrullination and cyclic AMP signaling. In analyses of an independent cohort of cyclic citrullinated peptide-seropositive RA patients, the expression of IL-15Rα protein was enriched in citrulline-specific B cells from the patients' peripheral blood, and surprisingly, all B cells from RA patients were capable of producing the epidermal growth factor ligand amphiregulin (AREG). Production of AREG directly led to increased migration and proliferation of fibroblast-like synoviocytes, and, in combination with anti-citrullinated protein antibodies, led to the increased differentiation of osteoclasts. CONCLUSION: To the best of our knowledge, this is the first study to document the whole transcriptome profile of autoreactive B cells in any autoimmune disease. These data identify several genes and pathways that may be targeted by repurposing several US Food and Drug Administration-approved drugs, and could serve as the foundation for the comparative assessment of B cell profiles in other autoimmune diseases.

Brief Report: Whole-Exome Sequencing to Identify Rare Variants and Gene Networks That Increase Susceptibility to Scleroderma in African Americans.

OBJECTIVE: Whole-exome sequencing (WES) studies in systemic sclerosis (SSc) patients of European American (EA) ancestry have identified variants in the ATP8B4 gene and enrichment of variants in genes in the extracellular matrix (ECM)-related pathway that increase SSc susceptibility. This study was undertaken to evaluate the association of the ATP8B4 gene and the ECM-related pathway with SSc in a cohort of African American (AA) patients. METHODS: SSc patients of AA ancestry were enrolled from 23 academic centers across the US under the Genome Research in African American Scleroderma Patients consortium. Unrelated AA individuals without serologic evidence of autoimmunity who were enrolled in the Howard University Family Study were used as unaffected controls. Functional variants in genes reported in the 2 WES studies in EA patients with SSc were selected for gene association testing using the optimized sequence kernel association test (SKAT-O) and pathway analysis by Ingenuity Pathway Analysis in 379 patients and 411 controls. RESULTS: Principal components analysis demonstrated that the patients and controls had similar ancestral backgrounds, with roughly equal proportions of mean European admixture. Using SKAT-O, we examined the association of individual genes that were previously reported in EA patients and none remained significant, including ATP8B4 (P = 0.98). However, we confirmed the previously reported association of the ECM-related pathway with enrichment of variants within the COL13A1, COL18A1, COL22A1, COL4A3, COL4A4, COL5A2, PROK1, and SERPINE1 genes (corrected P = 1.95 × 10-4 ). CONCLUSION: In the largest genetic study in AA patients with SSc to date, our findings corroborate the role of functional variants that aggregate in a fibrotic pathway and increase SSc susceptibility.

Transcriptional Profiling of Synovial Macrophages Using Minimally Invasive Ultrasound-Guided Synovial Biopsies in Rheumatoid Arthritis.

OBJECTIVE: Currently, there are no reliable biomarkers for predicting therapeutic response in patients with rheumatoid arthritis (RA). The synovium may unlock critical information for determining efficacy, since a reduction in the numbers of sublining synovial macrophages remains the most reproducible biomarker. Thus, a clinically actionable method for the collection of synovial tissue, which can be analyzed using high-throughput strategies, must become a reality. This study was undertaken to assess the feasibility of utilizing synovial biopsies as a precision medicine-based approach for patients with RA. METHODS: Rheumatologists at 6 US academic sites were trained in minimally invasive ultrasound-guided synovial tissue biopsy. Biopsy specimens obtained from patients with RA and synovial tissue from patients with osteoarthritis (OA) were subjected to histologic analysis, fluorescence-activated cell sorting, and RNA sequencing (RNA-seq). An optimized protocol for digesting synovial tissue was developed to generate high-quality RNA-seq libraries from isolated macrophage populations. Associations were determined between macrophage transcriptional profiles and clinical parameters in RA patients. RESULTS: Patients with RA reported minimal adverse effects in response to synovial biopsy. Comparable RNA quality was observed from synovial tissue and isolated macrophages between patients with RA and patients with OA. Whole tissue samples from patients with RA demonstrated a high degree of transcriptional heterogeneity. In contrast, the transcriptional profile of isolated RA synovial macrophages highlighted different subpopulations of patients and identified 6 novel transcriptional modules that were associated with disease activity and therapy. CONCLUSION: Performance of synovial tissue biopsies by rheumatologists in the US is feasible and generates high-quality samples for research. Through the use of cutting-edge technologies to analyze synovial biopsy specimens in conjunction with corresponding clinical information, a precision medicine-based approach for patients with RA is attainable.

Dense Genotyping of Immune-Related Regions Identifies Loci for Rheumatoid Arthritis Risk and Damage in African Americans.

Over 100 risk loci for rheumatoid arthritis (RA) have been identified in individuals of European and Asian descent, but the genetic basis for RA in African Americans is less well understood. We genotyped 610 African Americans with autoantibody positive RA and 933 African American controls on the ImmunoChip (iChip) array. Using multivariable regression we evaluated the association between iChip markers and the risk of RA and radiographic severity. The single nucleotide polymorphism (SNP) rs1964995 (OR = 1.97, p = 1.28 × 10-15) near HLA-DRB1 was the most strongly associated risk SNP for RA susceptibility; SNPs in AFF3, TNFSF11, and TNFSF18 loci were suggestively associated (10-4 < p < 3.1 × 10-6). Trans-ethnic fine mapping of AFF3 identified a 90% credible set containing previously studied variants including rs9653442, rs7608424, and rs6712515 as well as the novel candidate variant rs11681966; several of these likely influence AFF3 gene expression level. Variants in TNFRSF9, CTLA4, IL2RA, C5/TRAF1, and ETS1 - but no variants within the major histocompatibility complex - were associated with RA radiographic severity. Conditional regression and pairwise linkage disequilibrium (LD) analyses suggest that additional pathogenic variants may be found in ETS1 and IL2RA beyond those found in other ethnicities. In summary, we use the dense genotyping of the iChip array and unique LD structure of African Americans to validate known risk loci for RA susceptibility and radiographic severity, and to better characterize the associations of AFF3, ETS1, and IL2RA.

Rationale and design of the randomized evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) Study.

BACKGROUND: Despite the availability of effective therapies, most gout patients achieve suboptimal treatment outcomes. Current best practices suggest gradual dose-escalation of urate lowering therapy and serial serum urate (sUA) measurement to achieve sUA<6.0mg/dl. However, this strategy is not routinely used. Here we present the study design rationale and development for a pharmacist-led intervention to promote sUA goal attainment. METHODS: To overcome barriers in achieving optimal outcomes, we planned and implemented the Randomized Evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) study. This is a large pragmatic cluster-randomized trial designed to assess a highly automated, pharmacist-led intervention to optimize allopurinol treatment in gout. Ambulatory clinics (n=101) from a large health system were randomized to deliver either the pharmacist-led intervention or usual care to gout patients over the age of 18years newly initiating allopurinol. All participants received educational materials and could opt-out of the study. For intervention sites, pharmacists conducted outreach primarily via an automated telephone interactive voice recognition system. The outreach, guided by a gout care algorithm developed for this study, systematically promoted adherence assessment, facilitated sUA testing, provided education, and adjusted allopurinol dosing. The primary study outcomes are achievement of sUA<6.0mg/dl and treatment adherence determined after one year. With follow-up ongoing, study results will be reported subsequently. CONCLUSION: Ambulatory care pharmacists and automated calling technology represent potentially important, underutilized resources for improving health outcomes for gout patients.