Annals of the Rheumatic Diseases

The mechanical features of synovial fibroblasts may encode clinically relevant information for the management of rheumatoid arthritis. Indeed, it remains poorly understood the links between cellular and microenvironment mechanics with patient stratification and therapeutic response. Here we show that combining organotypic synovial cultures with multimodal mechanophenotyping and transcriptomics identifies distinct ''soft'' and ''stiff'' fibroblast states. Healthy and rheumatoid arthritis fibroblasts were cultured in two or three dimensions (organotypic cell cultures), alone or with endothelial cells, and characterized by high-throughput nanoindentation, picobalance measurements, digital holographic microscopy, Brillouin microscopy and RNA sequencing. Three-dimensional culture reduced single-cell Young's modulus and total mass while increasing dry-mass surface density; endothelial co-culture increased fibroblast stiffness and the longitudinal modulus of intact organotypic cultures. Stiffness-based grouping revealed transcriptional programmes related to extracellular-matrix remodelling, cytoskeletal contractility, and TGF-beta, WNT, and Hippo signalling. Mapping these signatures to publicly available rheumatoid arthritis clinical transcriptomic datasets associated the ''stiff'' state with fibrotic and myeloid-fibrotic pathotypes and treatment-refractory programmes, whereas the ''soft'' state aligned with lymphoid pathotypes and rituximab- or tocilizumab-responsive programmes. These findings support mechanophenotype-associated transcriptional signatures as potential biomarkers for rheumatoid arthritis stratification.

Introduction: Across major phases of the COVID-19 pandemic (March 2020-April 2023), we compared the burden of severe COVID-19 among individuals with systemic autoimmune rheumatic diseases (SARDs) versus immunocompetent individuals with and without comorbidities. Methods: This population-based cohort study used administrative datasets to estimate crude and age- and sex-standardized SARS-CoV-2 and severe COVID-19 incidences among adults >18 years with SARDs, chronic comorbidities, or no comorbidities. Relative to the latter, we used Cox models to derive adjusted hazard ratios (aHRs) for infection, hospitalization, and intensive care unit admission or death (ICU/death) during the pre-vaccination (March-December 2020), vaccination pre-Omicron (December 2020-December 2021), and Omicron (December 2021-April 2023) periods. Results: We included 81,434 adults with SARDs, and 2,020,356 with comorbidities versus 3,144,700 without comorbidities. Despite similar adjusted infection rates, the SARDS cohort had higher risks of hospitalization and ICU/death during the pre-vaccination period (aHRs: 3.4, 95%CI:2.8-4.1; and 4.0, 95%CI:2.8-5.7, respectively), persisting through the Omicron period (aHRs: 4.5, 95%CI:4.0-4.9; and 4.4, 95%CI:3.6-5.4, respectively). Among SARDS, rheumatoid arthritis, psoriatic arthritis and systemic lupus erythematosus contributed highest burden, with comparable hospitalization and mortality rates among younger rheumatoid arthritis versus healthy older adults. Highly immunosuppressive rituximab- or mycophenolate-treated patients had highest hospitalization and ICU/death risks, particularly during the Omicron period (aHRs: 11.9, 95%CI:9.9-14.3; and 17.6, 95%CI:13.0-23.9, respectively). Conclusion: Individuals with SARDs, especially receiving highly immunosuppressive therapies, experienced elevated COVID-19 burden and severe outcome risks throughout the pandemic, warranting their prioritized consideration during future public health emergencies.

Objectives Juvenile idiopathic arthritis (JIA) is a collection of childhood onset rheumatic conditions that more frequently occur in females in most subtypes. Sex influences disease biology, treatment trajectories, and patient outcomes, however, no study to date has investigated the interaction of sex with autosomal genetic risk to JIA. Methods Genotype data from 3748 JIA cases (2551 female, 1197 male) and 9196 controls (5136 female, 4060 male) were analysed using a sex-stratified genome-wide association analysis. Systemic JIA was excluded. HLA imputation and fine-mapping were performed using SNP2HLA. Sex-specific effects were assessed using an omnibus sex-interaction test for multi-allelic amino acid positions. A subtype specific analysis was repeated in rheumatoid factor (RF) negative polyarthritis and oligoarthritis (1862 female, 718 male). Results A sex-combined analysis identified genome-wide significant (P<5x10-8) loci across the HLA region and nine loci outside the HLA region, including a novel association at rs231977 (NUPR1). Markers within the HLA region were significantly sex-dimorphic (P<5x10-8) and nine loci outside of the HLA region were suggestive for sex dimorphism (P<5x10-6), including SPRY2. HLA fine-mapping identified lysine at position 70 of HLA-B conferring greater male JIA risk, and tyrosine at position 10 of HLA-DRB1 conferring greater female JIA risk. Subtype specific analysis strengthened the association of tyrosine at position 10 of DRB1 in females. Conclusions This study provides the first evidence that autosomal genetic risk factors contribute to JIA risk in a sex-dimorphic manner, mirroring known clinical observations, and highlighting the importance of incorporating sex-stratified methods in future JIA studies.

Systemic sclerosis (SSc) is a devastating fibrosing disorder affecting the skin and internal organs, associated with the highest mortality among all rheumatic diseases. The mechanisms underlying excessive fibrogenesis in SSc are incompletely defined and treatment options are limited. N6-methyladenosine (m6A), the most abundant internal mRNA modification, is a reversible and pharmacologically tractable determinant of RNA fate. Here we mapped the m6A epitranscriptome of peripheral blood mononuclear cells (PBMCs) from patients with SSc using two orthogonal single-nucleotide-resolution platforms, a MazF-based m6A microarray and nanopore direct RNA sequencing. SSc PBMCs showed coordinated upregulation of the m6A writer complex (METTL3, METTL14, WTAP), a two-fold increase in global m6A, and redistribution of m6A marks from 3' untranslated regions toward coding sequences. Both platforms converged on TGF-b signaling as the most enriched pathway among differentially methylated transcripts, with hypermethylation of TGFB1, JUNB and KLF10 transcripts. Pharmacologic inhibition of METTL3 with STM2457 significantly reversed TGF-b-induced transcriptomic changes in skin fibroblasts preventing their transformation into pathological myofibroblasts. Together, these findings uncover an epitranscriptomic signature driving profibrotic transcriptional alterations in SSc, including enhanced TGF-b signaling, which can be effectively reversed by clinically available enzymatic m6A inhibitors. Our data suggest that targeting m6A methylation may offer a novel therapeutic strategy to mitigate fibrosis in SSc.

Objective: Autoantibodies are central for pathology of rheumatoid arthritis (RA) and diabetes mellitus (DM) carrying high predictive and diagnostic value. Here, we explore the frequency and functional potential of DM-related antibodies (DMab) in RA. Methods: DMab targeting glutamic acid decarboxylase (GAD65ab), tyrosine phosphatase-like islet antigen 2 (IA2ab) and zinc transporter 8 (ZnT8ab) were measured in 326 DM-free RA patients (260 females, 66 males), using specific ELISAs. The DMab profile was analysed in relation to 30 clinical and serological variables. ZnT8+ cells were detailed by a public single-cell transcriptome in RA synovial tissue. Results: DMab production was more frequent in females, dominated by ZnT8ab (86%), followed by GAD65ab (26.4%) and IA2ab (7.0%). DMab-positive patients, and specifically ZnT8ab-positive women, had higher levels of insulin and HOMA-IR index and lower serum IL-6, IFN{gamma}, and IL-9. Multivariable logistic regression estimating ZnT8ab, IA2ab, GAD65ab production revealed that BDNF, insulin and DAS28 were positive predictors of ZnT8ab. Increasing ZnT8ab levels were inversely related to RAab in the mixed interaction model. CD14+ cell transcriptome identified association between an activated secretory cell type and increasing ZnT8ab levels. Additionally, ZnT8ab levels were in direct proportion with ZnT8 production in RA CD4+ T cells. Single-cell transcriptome of RA synovial tissue revealed ZnT8+ cells among the lubricin producing lining layer fibroblasts programmed for invasive behaviour. Conclusion: This study reveals frequent production of ZnT8ab in non-diabetic RA patients and identifies their antigenic target expressed in lining synovial fibroblasts of RA joints.

Background and objectivesMyasthenia gravis associated with antibodies against muscle-specific kinase (MuSK-MG) is a well-characterized IgG4-autoimmune disease, however, the mechanisms driving IgG4 predominance remain poorly understood. This study investigated whether promoter DNA methylation of cytokine genes involved in IgG4 class switching is associated with this immune response. MethodsPeripheral blood mononuclear cells were isolated from MuSK-MG patients (n=36), acetylcholine receptor myasthenia gravis (AChR-MG) patients as disease controls (n=7), and sex-matched healthy controls (n=12). Promoter DNA methylation of IL4, IL10, and IL13 was assessed by methylation-sensitive high-resolution melting and relative cytokine mRNA expression by qPCR. Associations with clinical variables, and antibody levels were subsequently evaluated. ResultsMuSK-MG patients showed lower median IL13 promoter methylation compared with healthy controls (p = 0.004). Median IL4 promoter methylation was also reduced in MuSK-MG compared with healthy controls (p < 0.001) and AChR-MG disease controls (p < 0.001), whereas no differences were observed for IL10 promoter methylation. Relative mRNA expression of IL4 (p = 0.0005), IL10 (p = 0.0462), and IL13 (p = 0.0002) was increased in MuSK-MG compared with AChR-MG. Compared with healthy controls, only IL4 expression remained significantly increased (p < 0.0001). Promoter methylation was inversely correlated with relative mRNA expression for IL4 (p < 0.0001), while IL13 showed a similar but non-significant trend (p = 0.054), no association was observed for IL10. Multivariable analysis demonstrated that treatment at sampling was independently associated with lower IL10 and IL13 promoter methylation, whereas no associations were observed with age, sex, disease phase, or disease duration. Promoter methylation did not correlate with total serum IgG4 or anti-MuSK IgG4 levels. DiscussionMuSK-MG is associated with selective hypomethylation of IL4 and IL13 promoters accompanied by increased cytokine gene expression, while IL10 promoter methylation remains unchanged. The association between treatment and IL10 and IL13 promoter methylation suggests that immunosuppressive therapy may influence epigenetic regulation in MuSK-MG. Together, these findings support a role for epigenetic dysregulation of Th2-associated cytokines in the immunological environment associated with IgG4 subclass switch. To our knowledge, this is the first study investigating IL4, IL10, and IL13 promoter DNA methylation in MuSK-MG.

Nociplastic pain features are common in systemic lupus erythematosus (SLE), yet its longitudinal trajectory remain poorly characterized. SLE patients in the FORWARD Databank were classified as Minimal, Type 1, Type 2, or Mixed using the Polysymptomatic Distress Scale (PSD[&ge;]8) and the Systemic Lupus Activity Questionnaire (SLAQ) inflammatory domain score ([&ge;]2). Cross-sectional analyses (N=372) compared clinical outcomes and medication use. Longitudinal analyses (n=301; median 3.7 years) characterized phenotype transitions using continuous-time Markov models and identified latent trajectories using joint group-based trajectory modeling (GBTM). At baseline, 29% were Minimal, 12% Type 1, 13% Type 2, and 47% Mixed. Functional impairment increased stepwise: from Minimal to Mixed, SF-36 physical component scores decreased from 49.7 to 30.0 and PROMIS Pain Interference scores increased from 46.2 to 63.6 (both p<0.001). Organ damage, depression, and opioid use were highest in Mixed. Longitudinally, Minimal and Mixed were persistent (mean duration 2.0 and 1.8 years; one-year retention 70%), while Type 1 and Type 2 were transient (~0.5 years; retention 18% and 28%). Exit trajectories were asymmetric: Type 1 moved preferentially to Minimal (49% of exits), whereas Type 2 moved to Mixed (65%; p<0.001). Population-average PSD was nearly flat (+0.014 SD/year, p=0.07); while opioid use declined to near zero in Minimal and Type 1 but remained high in Type 2 and Mixed. Joint GBTM identified four severity classes along a Minimal-to-Mixed diagonal. Nociplastic phenotypes in SLE are persistent, severity-stratified, with substantial functional, psychological, organ-damage, and opioid burdens. Transient Type 1 and Type 2 states have divergent longitudinal transitions.

Background Fibromyalgia syndrome (FMS) affects 1 to 2 percent of the general population, with higher prevalence estimates in women. Recent evidence supports peripheral immune involvement in disease pathophysiology. Alternative splicing (AS) regulates immune cell function independently of transcript abundance and carries disease-relevant signal in related autoimmune conditions. No study has performed transcriptome-wide differential AS analysis directly in RNA-sequencing data from individuals with FMS. Methods We performed a secondary analysis of GSE221921, restricted to female participants (n = 91 FMS, n = 41 controls). Peripheral immune cell composition was estimated with ABIS, a deconvolution method specifically trained on peripheral blood mononuclear cell signatures. Differential AS was analysed with LeafCutter incorporating cell composition principal components as covariates. Differential gene expression was performed with DESeq2 under the same adjustment framework. Results FMS samples showed lower ABIS-inferred conventional monocyte estimates (Cliff's {delta} = -0.38, FDR = 0.008) and higher memory B-cell estimates (Cliff's {delta} = +0.32, FDR = 0.030). Composition-adjusted LeafCutter analysis identified 14 significant intron clusters, of which 9 were retained for biological interpretation. GNLY (granulysin) was the primary candidate, with a composition-adjusted 5' junction usage shift illustrated by pooled Sashimi visualisation. Composition adjustment substantially reduced significant differentially expressed genes from 10,803 to 3,186 (baseMean [&ge;] 10). Conclusions This first transcriptome-wide differential AS analysis in FMS identifies GNLY, encoding the cytolytic lymphocyte effector granulysin, as a splicing-specific candidate for functional follow-up. AS captures FMS-associated signal not detectable by gene-level expression analysis, and composition adjustment substantially altered the differential expression landscape.

Juvenile systemic sclerosis (jSSc) is a rare autoimmune disease marked by skin fibrosis and multi-organ involvement. Autologous stem cell transplantation (ASCT) is an emerging therapy for severe, treatment-refractory jSSc, but its effects on immune cell dynamics remain poorly understood. PBMCs were collected from three patients with jSSc before ASCT and at 6, 12, and 24 months post-ASCT. Patient and healthy control samples were profiled using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq). We focused on monocytes, given their role in fibrosis-promoting inflammation. To detect longitudinal trends, pseudobulked gene expression (log scale) was regressed against time since ASCT. This approach identified widespread changes in jSSc monocytes, including decreased expression of systemic sclerosis-linked genes, such as SERPINE1. On the pathway level, NF-{kappa}B-associated inflammatory signaling was elevated in jSSc monocytes at baseline relative to healthy controls and decreased progressively post-ASCT. Genes related to mitochondrial function and oxidative phosphorylation progressively increased in expression after ASCT, suggesting a shift in metabolic state. Compositional changes in monocyte subpopulations were also identified and may have contributed to longitudinal gene expression patterns. Together, these findings characterize the dynamic immune changes in jSSc following ASCT and highlight a widely applicable longitudinal modeling framework for single-cell data.

ObjectiveIn the first year after onset of the autoimmune disease RA (RA), 40-60% do not achieve remission on conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs). To understand how autoreactive T cells may contribute to unstable or non-remission, we studied CD4+ T cells, including those recognising citrullinated (Cit) vimentin in participants with RA. MethodsTwo cohorts of drug-naive new-onset participants with RA were treated with csDMARDs. Disease activity score (DAS28-CRP) and peripheral blood (PB) mononuclear cells were collected longitudinally. In HLA-DR-shared epitope+ cohort 1 (n=21), T cells were assessed with a 17-marker spectral flow panel, incorporating HLA-DRB1*04:01/01:01- VimentinCit6459-71 or HLA-DRB1*04:04-VimentinCit7166-78 tetramers. Changes in T cell subsets over time were assessed in remitting and non-remitting participants using a generalized linear mixed model with a negative binomial distribution. In cohort 2 (n=26), the transcriptome of disaggregated synovial tissue (ST) and PB CD4+ T cells were analysed at baseline, and ST biopsy spatial proteomics at baseline and 6 months. ResultsCD4CXCR5-PD1+ peripheral helper T cells (Tph), including Cit-vimentin-reactive Tph, CD4CCR7+CXCR5-PD1+ stem-like Tph and TIGIT+PD1+ Tph were increased with moderate/high DAS28-CRP at any time point. Remission outcome was associated with low CD4 follicular helper T cell (Tfh) and Cit-vimentin-reactive Tfh. In non-remitting participants, Tph/fh infiltrated germinal-centre-like ST aggregates. This decreased in remission. Circulating TIGIT+ Tph genes reflected B lymphoid activation and lymph node egress, while in ST they reflected local differentiation. ConclusionPersistently high circulating TIGIT+ Tph and Tfh, including Cit-vimentin specificities, reflecting antigen-presenting B-cell interactions, are associated with reduced response to csDMARDs in recent-onset RA. Key messagesO_ST_ABSWhat is already known on this topicC_ST_ABSO_LITph and Tfh cells interacting with B cells are implicated in active ACPA+ RA C_LIO_LICitrullinated (Cit)-vimentin is an important neutrophil extracellular trap-derived target of ACPA C_LI What this study addsO_LIHigh circulating TIGIT+ Tph, Cit-vimentin-autoreactive Tph and Tfh associate with failure to reach remission on conventional synthetic DMARDs within the first year in early HLA-DR shared-epitope+ RA C_LIO_LITph/Tfh and adjacent regulatory T cells surround follicular B-cells in lymphoid aggregates in synovial tissue in non-remission C_LIO_LICirculating TIGIT+ Tph bear a transcriptional signature of lymphoid tissue expansion and lymph node egress as compared to functional differentiation and antigen experience in synovial tissue C_LI How this study might affect research, practice or policyO_LIWhen a remission target is not achieved in HLA-DR shared-epitope+ RA patients during the first year of treatment, high circulating TIGIT+ Tph implicate autoreactive T-B-lymphoid expansion in synovial tissue. C_LI

Systemic sclerosis (SSc) is a rare, heterogeneous autoimmune disease characterized by immune dysregulation, vasculopathy and fibrosis. While typically sporadic, SSc can in a minority of cases show familial clustering. Whole exome sequencing (WES), performed on six families with two affected members each, identified a total of 253 genes with rare, disease co-segregating variants predicted to affect protein function. Of these, we prioritized PRKD2, one of only three genes identified in two families. PRKD2 encodes Protein kinase D2: an intracellular serine-threonine kinase that amplifies T cell receptor (TCR) signaling. Both familial SSc-associated PRKD2 missense variants increased kinase activation, exerting overlapping, activating effects on TCR signaling in heterozygous knock-in Jurkat cells. A pan-PRKD inhibitor suppressed T cell activation in peripheral blood mononuclear cells from both familial SSc cases and controls. The enrichment of PRKD2 rare variants in a sporadic SSc cohort provides further support for its relevance to SSc pathogenesis. Together, these findings identify PRKD2 rare variants as potential genetic contributors to SSc, and PRKD2-mediated TCR signaling as a candidate disease-relevant and potentially targetable pathway.

Objectives. Before-and-after transcriptomics in rheumatic disease often yields no reproducible treatment signal, though disease-state stratification is robust. We asked whether exposure and response-prediction labels fall below the detection floor of the designs defining them, while matched disease-state labels do not. Methods. Eight public datasets were analysed (paired juvenile dermatomyositis n = 10; RA before/after methotrexate, n = 28 pairs; lupus nephritis n = 10; controlled exposures; a single-cell dose series). Response labels in current use (one benchmark trajectory, five published signatures) were audited in every analysable source cohort, using effect sizes (dz) against each design's exact minimum detectable effect. Results. Disease-state labels were detectable: the interferon signature declined in 10/10 juvenile dermatomyositis patients (p = 0.002; 59.5% of score variance). No exposure label cleared its design floor in any clinical cohort; a drug-matched methotrexate prior was nominally significant in juvenile dermatomyositis yet did not clear its floor (dz = -0.80; CI spanning it). Exposure became detectable only where prior-context and intensity were jointly favourable (multi-day target tissue dz = 1.24, q = 0.018; well-level pseudobulk dz = +3.70, floor 1.80). Audited response labels failed in 14 of 15 cohorts (93%; descriptive binomial 95% CI 68-100): eleven below their floors, three sign-reversed; the largest training cohort pooled to zero (dz = +0.07; I2 = 69%). Effect size ordered reported AUCs monotonically. Conclusion. Under conventional treatment intensities, exposure and response-prediction labels are either undetectable below the design floor or detected with a sign that does not replicate; disease-state labels are detectable. Part of the negative literature reflects a design floor.

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by symmetric fibrosis of the skin and multiple internal organs. The mechanisms that trigger early fibrotic changes remain unclear. Mast cells are known to infiltrate human SSc lesional skin in early disease stages, yet the role of mast cells in initiating fibrosis and pruritus in SSc remains debated, in part due to unclear pathways of mast cell activation. Here, we show that mast cells, via the receptor Mrgprb2, contribute to fibrosis in the bleomycin (BLM)-induced skin fibrosis mouse model. Mast cells accumulate in the skin of BLM-treated wild-type (WT) but not Mrgprb2-knockout (Mrgprb2-/-) mice. Mrgprb2-/- mice show attenuated disease severity, with reduced collagen deposition and lower expression of matrix metalloproteinases and inflammatory markers associated with fibrosis. BLM treatment also increases pruritus in WT mice in the early stages of the model; an effect reduced in Mrgprb2-/- mice. This is the first report of itch in this model of skin fibrosis, further linking it to clinical SSc, where pruritus is an early and prevalent symptom affecting nearly half of patients. In a parallel human cohort, lesional SSc skin harbors significantly more mast cells than paired non-lesional skin from the same patients, demonstrating that mast cell accumulation is specific to affected tissue. Lesional mast cell counts also track with skin disease severity, correlating with modified Rodnan skin score and patient-reported skin tightness. Together, these findings implicate Mrgprb2-mediated mast cell activity in both fibrosis and pruritus in SSc, highlighting mast cells as a candidate therapeutic target in this understudied disease process.

Background Disease flares in dermatomyositis (DM) are unpredictable and often detected weeks to months after their onset. Interferon (IFN)-related gene signatures are implicated in DM, but their value for longitudinal flare prediction remains unclear. We hypothesized that longitudinal transcriptomic profiling using minimally invasive blood microsampling would detect IFN gene signatures preceding and during DM disease flares. Methods In this feasibility study, patients were included if they had inactive or minimally active disease and at least one of the following criteria: recent diagnosis within 2 years, a documented flare in the prior year, or ongoing tapering of immunosuppressive therapy. Patients self-assessed their disease activity weekly for 6 months using the International Myositis Assessment and Clinical Study group (IMACS) patient global assessment (PtGA; numerical rating scale, range 0-10). Disease flares, defined as a PtGA increase >2 for 2 consecutive weeks, triggered an in-person visit for confirmation by a physician. During the follow-up period, patients also self-collected weekly blood microsamples (125uL) that were shipped by courier to the study center. From those weekly blood microsamples, RNA sequencing was performed on 54 samples collected across 9 timepoints using an Illumina platform. Bioinformatic analyses included alignment, quality assessment, and gene-level quantification to evaluate differential gene expression and RNA processing changes during DM flares. Results Six DM patients were included in this study (2 anti-MDA5, 2 anti-Mi2, 1 anti-NXP2, 1 no myositis-specific antibodies). All were female with ages at study entry ranging from 46 to 72 years. Three of the six patients experienced a flare during their 6-month follow-up. The mean (SD) RNA integrity score for the weekly blood microsamples collected was 7,61 (0,64). IFN scores were significantly higher in flare-associated samples than in no flare samples (linear mixed-effects model with individual patient as a random intercept, P = 5.13 x 10E-4). Gene set enrichment analysis of hallmark gene sets identified enrichment of IFN-related gene sets in pre-flare and flare samples with IFN Alpha Response and IFN Gamma Response showing the highest positive normalized enrichment scores. Conclusion This study demonstrates the technical feasibility of combining home-based longitudinal blood microsampling with transcriptomic profiling in dermatomyositis. IFN gene score were higher in flare-associated than in no-flare samples, supporting further investigation of IFN-related signatures as candidate biomarkers for longitudinal disease monitoring.

Background The ADVOCATE trial evaluated treatment with avacopan for granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). Concerns regarding the 2019 primary outcome adjudication procedures in nine participants prompted readjudication in 2026 of primary outcomes for all participants. Methods Patients with GPA/MPA were randomized 1:1 to prednisone taper or avacopan 30 mg twice daily; participants received treatment with cyclophosphamide or rituximab. An independent, blinded committee readjudicated the primary outcomes of remission at week 26 and sustained remission at week 52. Noninferiority and superiority were established if lower bounds of the 95% confidence interval (CI) for difference in rates were greater than -20.0 and 0.0 percentage points, respectively. Secondary outcomes included glucocorticoid exposure and toxicity, kidney parameters, health-related quality of life, and safety. Results Among 330 participants, remission at week 26 was achieved by 68.1% and 67.1% in the avacopan and prednisone groups, respectively, in the 2026 readjudication (adjusted difference: 2.2%; 95% CI, -7.5, 11.9), compared with 72.3% and 70.1% in the 2019 adjudication (adjusted difference: 3.4%; 95% CI, -6.0, 12.8). Sustained remission at week 52 was achieved by 61.4% and 52.4%, respectively, in the 2026 readjudication (adjusted difference: 9.8%; 95% CI, -0.3, 19.9), compared with 65.7% and 54.9% in the 2019 adjudication (adjusted difference: 12.5%; 95% CI, 2.6, 22.3). Secondary endpoints favored the avacopan group. Conclusions Treatment of GPA/MPA with avacopan in combination with rituximab or cyclophosphamide, when compared with a prednisone taper, resulted in similarly high rates of remission and sustained remission, but reductions in glucocorticoid exposure and toxicity.

Fc{gamma}RIIa, encoded by FCGR2A, is a widely expressed Fc receptor implicated in autoimmunity and infectious disease susceptibility. To fine-map the rheumatoid arthritis (RA) association at the complex FCGR locus, we combined gene-specific resequencing, genetic association studies in UK and Spanish European cohorts, functional genomics, structural biology, biophysical analyses, and cellular assays. We identified a common European FCGR2A haplotype (2A.3), defined by Q27W, H131H, and the RA-associated SNP rs12746613, which showed the strongest association with RA. Multi-omics analyses demonstrated that 2A.3 is associated with reduced expression of the soluble FCGR2A splice variant and lower circulating soluble Fc{gamma}RIIa levels. Functional studies revealed altered IgG interactions and delayed Fc{gamma}RIIa signal transduction associated with Q27W, while structural analyses found no evidence for stable ectodomain dimerisation. Together, these findings identify 2A.3 as an important functional contributor to RA susceptibility and provide mechanistic insight into how FCGR2A variation may influence immune regulation and disease risk in Europeans.

Objective: Tissue-specific biomarkers that are reliable and associated with clinical manifestations of idiopathic inflammatory myopathy (IIM) are lacking. The blood circulation in individuals serves as a central conduit, allowing communication between tissues and facilitating clearance and recycling of tissue-derived proteins. Thus we applied a dual antibody-based proximity extension assay to profile the plasma proteome in subtypes of patients with IIM. Methods: Plasma samples from 201 patients diagnosed with IIM at Karolinska University Hospital were analyzed using Olink. Clinical manifestations, disease activity measurements, and laboratory results were collected. First, we evaluated differential protein abundance across IIM subtypes. Then we calculated tissue scores for each disease subtype using tissue gene expression databases. Finally, interferon (IFN) and complement pathway scores were calculated. Results: Plasma from patients with dermatomyositis was enriched for IFN signaling and skin associated proteins, anti-synthetase syndrome (ASyS) for lung associated proteins, immune-mediated necrotizing myopathy (IMNM) for muscle associated proteins, and inclusion body myositis for T cell response proteins. Patients with IMNM showed the highest tissue score for skeletal muscles, and ASyS for lung tissue score. Skeletal muscle scores correlated strongly with muscle disease activity visual analog scale scores, creatinine kinase levels, and muscle weakness score. Patients with interstitial lung disease along with and those with anti-Jo1 autoantibodies showed differential enrichment of surfactant proteins and IFN pathway activation. Conclusions: Circulatory proteome is a promising tool to capture distinct tissue-specific responses that correlate with disease activity and tissue injury in patients with IIM.

Juvenile idiopathic arthritis (JIA), the most common class of pediatric rheumatic diseases, can lead to joint damage and extra-articular features including uveitis. Early treatment can improve functional outcomes; but many patients do not respond to first-line treatments. We present a JIA Immunochip-based association analysis of rheumatoid factor-negative polyarticular JIA and oligoarticular JIA. This study spans 3,939 cases and 14,412 controls, including 1,123 cases and 1,356 controls not previously analyzed. We identify 41 (14 novel) JIA risk regions and report a JIA polygenic risk score that also associates with age of onset. Functional mechanisms presented include: a novel interaction between HLA-A*02:01 and ERAP2, cluster-based approach for functional amino acid discovery within HLA-DRB1, and sequence-dependent DNA topology for variant prioritization. We present a comprehensive list of curated gene-drug/small molecule interactions for clinically focused studies. These findings provide a deepened understanding of the genetics of JIA and potential mechanisms to inform precision medicine.

Background: Giant cell arteritis (GCA), traditionally considered T cell-driven, exhibits vascular B/plasma-cell infiltrates and altered circulating B-cell homeostasis, suggesting a pathogenic role for B cells. Relapse is common in newly diagnosed GCA (nGCA), yet predictive biomarkers remain elusive. Objective: To characterize circulating B-cell subpopulations in nGCA and assess their association with 12-month relapse. Methods: Baseline multiparametric flow cytometry was performed on peripheral blood samples from consecutive patients with nGCA and sex/age-matched healthy controls (HC). Patients received standard treatment per 2018 EULAR recommendations and were followed longitudinally. Results: 102 patients with nGCA and 102 matched HC were included. One-year outcome data were available for 55 patients, of whom 34 relapsed and 21 remained relapse-free. Baseline B-cell homeostasis differed by disease course. Non-relapsers showed reduced total CD19+ B-cell counts and contraction of most B-cell subsets, while CD27-IgD-double-negative (DN) B-cell counts remained comparable to HC. Conversely, relapsers maintained total B-cell numbers above HC despite reduced memory compartments, driven by expanded naive and DN B cells, alongside preserved plasmablast and transitional B-cell counts. At 6 months, total B-cell counts increased only in non-relapsers. DN B cells showed the greatest divergence between groups and independently predicted relapse. DN B-cell counts also correlated with circulating T peripheral helper cell numbers, supporting extrafollicular immune pathway activation. Conclusion: nGCA is characterized by outcome-dependent disturbances in B-cell homeostasis. Expansion of the DN B-cell compartment identifies a relapse-prone immunophenotype and represents a clinically relevant biomarker for early risk stratification.

Objectives To assess the effects of 24 weeks active treatment with baricitinib, a JAK1/2 inhibitor, in adult idiopathic inflammatory myopathy (IIM). Methods Patients with active dermatomyositis (DM) or polymyositis (PM) were enrolled into a 1:1 randomized treatment delayed-start design clinical trial (NCT04208464). Participants received 24 weeks baricitinib plus 12 weeks follow-up (Immediate-start), or 12 weeks standard of care plus 24 weeks baricitinib (Delayed-start). The primary outcome was clinical response after 24 weeks active treatment, defined as minimal improvement (Total Improvement Score >20 [TIS20]). Secondary outcomes included: TIS40 (moderate), TIS60 (major) response, between-arm comparison, time to achieve response, change in clinical outcome measures. steroid-sparing and cumulative adverse events. Results 14/15 (93%) randomized participants (mean age 43.2 years [11.6 SD]; 13 DM, 2 PM; 11 female) completed the study (baseline to 36 weeks) and all achieved TIS20 at 24 weeks post-active treatment (95% exact CI 0.68-1.00). 9/15 (60%) achieved TIS40 response and 2/15 (13%) TIS60 response. At 12 weeks post-randomization, 11/15 (73%) patients achieved at least TIS20 (95%CI 0.45-0.92), including all Immediate-start arm patients and four Delayed-start arm patients. At the same time point, evidence of a difference was noted for patient global, extramuscular, CDASI skin activity, pain, fatigue and SF-36 mental/physical health scores. Two hospitalisation serious adverse events were documented, neither related to study drug. Conclusions Treatment of IIM with baricitinib resulted in improved clinical outcome after 24 weeks. Significant improvement after 12 weeks treatment was also evident. No significant safety concerns were raised. A randomized placebo-controlled trial is needed to confirm the efficacy in patients with IIM.