Arthritis & Rheumatology

Background: Itch in systemic sclerosis (SSc) is thought to be most significant in early disease, but no longitudinal studies have examined itch course. We estimated itch presence and severity from SSc disease onset, accounting for participant age and time since onset at each assessment. Methods: People with SSc from the multinational Scleroderma Patient-centred Intervention Network Cohort completed past-week itch severity assessments (0 to 10 numerical rating scale) at enrolment and longitudinally at 3-month intervals. To estimate itch probability (score > 0) and, if present, itch severity, we used two-stage mixed effects models with basis splines to address non-linearity. The primary predictor was age at each assessment, partitioned into age at non-Raynaud phenomenon symptom onset and time since onset. We estimated prevalence and severity for onset ages of 20, 30, 40, 50 and 60 years and, for each onset age, at 2 years, 3 years, 4 years, 5 years, 7 years, and 5-year intervals 10 years to 35 years post-onset. Findings: We included 2173 participants with 19 733 itch assessments (mean [standard deviation] 9.1 [6.9] assessments). 1896 of 2173 (87.3%) participants were women. Mean age at enrolment was 54.7 (SD 12.7) years. 873 (40.2%) participants had diffuse cutaneous SSc. Predicted itch probability was between 35.0% (95% CI 31.8% to 38.5%) and 36.8% (95% CI 33.3% to 40.4%) at all onset age and disease duration combinations. Mean itch severity, when present, was moderate, between 4.1 (95% CI 4.1 to 4.1) and 4.4 (95% CI 4.3 to 4.4), for all age and duration combinations. Interpretation: Itch prevalence and mean severity were stable across onset ages and over time within onset ages. Findings suggest that itch is common in SSc and not as closely related to disease duration as previously thought. Research is needed to elucidate itch pathophysiology and identify effective management strategies.

Background: immune dysregulation underlies cardiovascular risk excess in systemic autoimmune diseases, such as rheumatoid arthritis (RA) and Sjogren disease (SjD). However, exact mediators are unknown. Regulatory autoantibodies targeting G protein coupled receptors, including CXCR3, have emerged as modulators of immune and vascular homeostasis, but their role in autoimmunity remains ill defined. Our aim was to evaluate antiCXCR3 levels in systemic autoimmunity and their potential value as biomarkers. Methods: antiCXCR3 IgG serum levels were quantified in early RA (n=84), clinically suspect arthralgia (n=12), and controls (n=65). Established RA (n=103) and SjD (n=44) were recruited for validation. Atherosclerosis was assessed by carotid ultrasound. Cytokines were measured by multiplex immunoassays. Cardiometabolic related proteins were evaluated using high-throughput targeted proteomics. Publicly available datasets were used for validation. Results: antiCXCR3 antibodies were significantly reduced in early RA and arthralgia compared with controls, independently of disease activity, autoantibodies, or systemic inflammation. This finding was confirmed in validation cohorts. AntiCXCR3 were negatively associated with good therapeutic outcomes upon csDMARD at 6 and 12 months. Lower anti-CXCR3 levels were independently associated with atherosclerosis occurrence and extent across conditions. Incorporating antiCXCR3 into mSCORE improved risk stratification. AntiCXCR3 were related to proteomic signatures linked to immune activation and to apoptosis, chemotaxis, and cell adhesion in an atherosclerosis dependent manner. Transcriptomic analyses indicated compartment specific CXCR3 dysregulation. Conclusion: reduced antiCXCR3 antibodies represent a shared hallmark bridging systemic autoimmunity and atherosclerosis burden, shaping our understanding on the regulatory role of antibodies at the vascular immune interface. Clinical translation of anti-CXCR3 antibodies hold promise to improve risk stratification.

BackgroundGastroesophageal reflux disease (GERD) is highly prevalent in systemic sclerosis (SSc) and frequently persists despite proton pump inhibitor (PPI) therapy. However, the mechanisms underlying PPI-refractory GERD in SSc remain incompletely understood. MethodsWe conducted a singlel7lcentre, retrospective study of adults with SSc who underwent ambulatory pH-multichannel intraluminal impedance (pH/MII) monitoring while receiving twicel7ldaily PPI therapy (2021-2025). Esophageal motility (highl7lresolution manometry, HREM) and gastric emptying scintigraphy were integrated to examine associations between gastro-esophageal dysmotility and reflux phenotypes. ResultsThirty patients were included, of whom 67% had PPI-refractory reflux symptoms and 33% were undergoing pre-lung transplantation evaluation. Refractory GERD was present in 29/30 patients (97%) based on Lyon 2.0 classification, with conclusive evidence in 53% and borderline evidence in 43%. Esophageal dysmotility was identified in 80%, most commonly absent contractility (67%), and was associated with impaired reflux clearance, reflected by longer acid clearance times (2.20 [1.15-3.75] vs 1.15 [0.43-1.90] min) and prolonged reflux episode duration (16.60 [4.38-40.63] vs 1.95 [0.53-20.43] min). Gastric dysmotility was identified in 60.7% and was associated with an increased reflux episode burden (51.00 [30.00-81.50] vs 25.00 [21.00-54.00] episodes/24h). ConclusionsPPIl7lrefractory GERD is nearly universal in this SSc cohort and reflects heterogeneous, quantifiable abnormalities across the foregut, including impaired esophageal clearance and increased reflux burden related to gastric retention. These findings support integrated physiologic evaluation to define reflux mechanisms, inform risk stratification (including lung transplantation), and guide targeted, mechanism-based therapies beyond acid suppression.

Objectives: Knee osteoarthritis (KOA) is a leading cause of disability, yet which patients will experience structural decline remains unclear. Body mass index (BMI) and lower limb alignment are established risk factors for KOA, but their independent and interactive effects on compartment-specific cartilage loss and total knee replacement (TKR) have not been characterized at scale. Methods: We analyzed 5,832 limbs from 3,016 participants in the Osteoarthritis Initiative followed over 7 years. Cartilage thickness in the weight-bearing medial and lateral femur and tibia was quantified, and lower limb alignment was measured using hip-knee-ankle (HKA) angle obtained from full-limb radiographs. Linear mixed-effects models estimated the independent and interactive effects of BMI and lower limb alignment on longitudinal cartilage thinning, and mixed-effects logistic regression modeled TKR risk. Results: In the medial compartment, BMI and varus alignment interacted multiplicatively, with their combined effect exceeding the sum of independent contributions (femur: p = 0.011; tibia: p < 0.001). At +10 kg/m2 BMI and +10 degrees varus, the rate of medial femur cartilage thinning was 243.5% faster than the reference rate. In the lateral compartment, BMI and valgus alignment were independently associated with faster cartilage thinning, with no significant interaction. TKR risk increased exponentially with HKA deviation (odds ratio [OR] = 1.38 per 1 degree; ~five-fold at 5 degrees malalignment) but was not associated with BMI. Conclusion: BMI and lower limb alignment influence structural KOA progression through compartment-specific pathways. The multiplicative interaction in the medial compartment identifies high BMI combined with varus malalignment as a discrete high-risk phenotype, with implications for clinical risk stratification and disease-modifying intervention design.

Rheumatoid arthritis is a prototypical autoimmune disease, characterised by prolonged systemic autoimmunity prior to organ-specific tissue inflammation. To achieve the contemporary goal of autoimmune disease prevention, a nuanced understanding of the transition from systemic autoimmunity to tissue-specific inflammation is critical. Here, we sought to identify immune signatures associated with the transition to subclinical joint inflammation detected by multi-joint ultrasound in anti-citrullinated protein antibodies (ACPA+)-positive individuals who imminently progress to RA. To achieve this, we performed single-cell transcriptomic and proteomic profiling on prospectively collected blood samples from high-risk ACPA+ imminent progressors, who were further stratified by the presence or absence of ultrasound (US)-detectable subclinical synovitis and compared them with ACPA+ non-progressors. We found type-1 interferon (IFN-I) activation in circulating CD14+ classical monocyte and GZMK+ CD8+ T cells preceding subclinical joint inflammation in ultrasound-negative (USneg) future progressors. In contrast, US-positive (USpos) future progressors exhibited a phenotypic shift in CD14+ classical monocytes towards IL1B+ expression and clonal expansion of GZMB+ cytotoxic CD8+ T cells at the onset of subclinical synovitis. Plasma proteomics also revealed a shift from Toll-like receptor-associated innate pathways in USneg future progressors toward effector and tissue-remodeling signatures in USpos future progressors. These findings suggest IFN-I-driven immune priming in specific immune subsets precedes the onset of subclinical joint inflammation, whereas tissue-directed inflammatory and cytotoxic programmes emerge at the onset of joint inflammation when clinical RA is imminent.

Peptidase inhibitor 16 (Pi16)-expressing fibroblasts are found across tissues and species, but their functional role is unclear. As fibroblasts and macrophages have been proposed to exist in a reciprocal circuit, we hypothesized Pi16+ fibroblasts may regulate macrophage homeostasis. Flow cytometry revealed [~]80% of skin fibroblasts express Pi16, leading us to investigate the role of these cells in maintaining a macrophage niche in this tissue. We generated an in vivo system where fibroblast-derived Colony Stimulating Factor 1 (Csf1) was constitutively eliminated in Pi16+ fibroblasts by crossing animals with a Csf1fl/fl allele to mice in which the gene Pi16 drives an IresCre cassette. Deletion of Csf1 in Pi16+ fibroblasts resulted in significant diminishment of CD64+ and CD11c+ macrophages alongside expansion of PDPN+YFP+ fibroblasts. Alterations in cell population dynamics coincided with thickening of both the dermis and fascial compartments of the skin. Deletion of Csf1 in Pi16+ fibroblasts delayed early wound healing in a unsplinted mouse model. Loss of PI16+ fibroblasts was observed in individuals with limited (lSSc) and diffuse (dSSc) systemic Scleroderma compared to healthy controls. These findings suggest that loss of Csf1 in Pi16+ fibroblasts elicit changes in the population dynamics of skin macrophages and modifications to tissue architecture.

Objectives: Juvenile systemic lupus erythematosus (JSLE) and juvenile dermatomyositis (JDM) are systemic autoimmune rheumatic diseases (RMDs) with childhood-onset associated with increased risk of damage accumulation and cardiovascular disease (CVD) over the life course. Methods: Damage associated with JSLE and JDM has been assessed using validated outcome measures in a longitudinal single-centre cohort study with long-term follow-up, involving data collected both retrospectively and prospectively. Descriptive statistics, sensitivity and regression analyses have been used to evaluate predictors of damage and CVD-risk. Results: We assessed comparatively a JSLE cohort (n=76), with a mean age of 24.3 +/- 4.2 years and a JDM cohort (n=79) with a mean 20.1 +/-5.0 years (p<0.001), with matched duration of follow-up (10.0 +/- 4.2 vs. 11.0 +/- 5.1, respectively, p=0.68). Traditional CVD-risk factors, including hypertension (p=0.02), dyslipidaemia (p=0.0005), and higher total cholesterol (p=0.01) and LDL-cholesterol (p=0.02) levels at the last assessment were higher in JSLE vs. JDM. Over the disease course, 39 (51.3%) AYA with JSLE vs. 47 (59.4%) AYA with JDM accumulated damage (p=0.307), which was independently predicted by the body mass index in both cohorts (p=0.038 and p=0.026, respectively). The PDAY score was the only tool able to stratify AYA based on CVD-risk (median = 5 (4-13) points in JSLE vs. 0 (0-3) points in JDM, p=0.0001), as all the adult CVD-risk scores were very low in both cohorts. Conclusions: This is the first comparative evaluation of JSLE vs. JDM in adulthood, which highlighted increased damage burden and CVD-risk in JSLE that warrants further investigation.

Sarcoidosis is a heterogenous disease of unknown etiology characterized by non-caseating granulomas. Disease prevalence and presentation vary significantly by ancestry and ranges from acute, self-resolving disease to severe, chronic disease. Following previous reports suggesting B cells in the development and pathogenesis of sarcoidosis, we present here results of single-cell RNA sequencing, supporting B cell involvement in sarcoidosis through altered immediate early response, rewiring of MAPK signaling, and ancestry-specific preferential expansion of B cell receptors. Peripheral blood mononuclear cells were obtained from individuals of African or European Ancestry (AA and EA, respectively) including 48 healthy controls, 59 sarcoidosis patients, and 28 systemic lupus erythematosus (SLE) patients. SLE samples were used as a disease control. Differential expression analysis highlighted many differentially expressed genes (DEGs) with almost 5x more in the AA sarcoidosis versus AA control group compared to the EA sarcoidosis versus EA control group. B cells had the most DEGs of all cell types and expression patterns were similar between ancestries, however, sarcoidosis had an opposite transcription pattern than SLE, demonstrating an alternative immune response to acute activation than that seen in a prototypical autoinflammatory disease. This trend was maintained when examining specialized B cell subsets, with the most pronounced effect in the AA sarcoidosis versus AA control comparison. Our results strongly support further investigation of the role of humoral immune response in sarcoidosis and the potential to highlight patient groups likely to benefit from existing B cell therapies.

Over half of patients with rheumatoid arthritis (RA) report clinically meaningful pain, despite treatment with disease-modifying antirheumatic drugs (DMARDs). While joint inflammation is a known cause of pain in patients with rheumatic diseases, emerging data indicate that many patients also suffer from centralized or nociplastic pain. There is a critical unmet need to characterize the altered cellular state that distinguishes patients with centralized pain. In the IMPACT study, 39 RA patients with minimal joint inflammation but varying levels of pain underwent quantitative sensory testing (QST) to assess nociplastic pain, completed patient-reported outcome (PRO) surveys, and provided blood samples for immune profiling. Supervised and unsupervised analysis of the multi-parameter spectral flow cytometry data identified immune cell populations correlated with nociplastic pain and patient-reported pain intensity. Moreover, analyses of single-cell RNA-seq from a subset of 22 patients revealed differences in cell type proportions and differential expression between the high and low pain groups. These studies provide novel insights into the role of circulating immune cells in altered central nervous system (CNS) pain regulation in adults with RA.

Red blood cell (RBC) alloimmunization is a clinically significant complication in transfused patients whose immunological determinants remain incompletely understood. Type I interferon (IFN-I) signaling drives RBC alloimmunization in murine models, and systemic lupus erythematosus (SLE) is characterized by constitutive IFN-I hyperactivation alongside elevated alloimmunization rates. We analyzed three publicly available SLE RNA-seq cohorts (GSE72509, GSE112087, GSE122459; whole blood and PBMC; total n = 150 SLE) in a pre-specified discovery-replication-validation design. A 14-gene IFN-I signature score was computed per sample; differential expression, gene set enrichment analysis, and Spearman correlation were performed independently per cohort. IFN-I scores were significantly elevated in SLE versus healthy controls in all three cohorts (p < 0.01 each). IFN-high SLE patients showed 665 differentially expressed genes, with enrichment of alloimmunization-associated and plasmablast differentiation gene sets confirmed by GSEA. The alloimmunization signature score correlated significantly with IFN-I score across all three independent cohorts ({rho} = +0.77, +0.51, +0.60; all FDR q < 0.05); Tfh differentiation showed no association in any cohort. To our knowledge, this represents the first human transcriptomic evidence that IFN-I pathway activity in SLE is coupled to alloimmunization-associated immune programs in vivo. These findings identify IFN-I score as a candidate biomarker of alloimmunization susceptibility in SLE and provide translational rationale for prospective studies incorporating transfusion outcome data.

BackgroundDespite advances in therapy, optimal management of juvenile idiopathic arthritis (JIA) remains challenging. The ability to predict disease progression in JIA can improve personalized treatment decisions, but few reliable clinical predictors have been identified. We developed machine learning approaches to predict disease trajectories in children with JIA. MethodsUsing data from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry (years 2015-2024), we developed machine learning models to predict attainment of inactive disease in children with non-systemic JIA. We applied Dynamic Bayesian Networks (DBN) to model temporal dependencies and causal relationships, and Convolutional Neural Networks (CNN) to capture complex non-linear patterns. Model input included demographic factors, longitudinal clinical factors, and medication use in the preceding 12 months. FindingsA total of 8,093 participants were included. When tested on an independent test cohort, both DBN (AUC:0.76; precision:0.73; recall:0.83; F1-score:0.78; accuracy:0.71) and CNN (AUC:0.76; precision:0.71; recall:0.63; F1-score:0.67; accuracy:0.70) models achieved comparable performance in predicting inactive disease. Disease activity levels in the preceding 12 months, presence of enthesitis and uveitis were the strongest predictors. Causal relationships captured in the DBN model revealed suboptimal care patterns, likely shaped by insurance constraints and a predominantly reactive approach to JIA management. InterpretationOur study demonstrates that machine learning approaches can predict disease trajectories in JIA with good discriminative performance. Unlike prior studies that predict outcomes at single timepoints, our models are the first to predict inactive disease longitudinally. However, suboptimal care patterns in retrospective data limit models capacity to learn treatment-outcome relationships, underscoring critical opportunities to improve JIA care and the need for prospective comparative studies to better inform prediction models. FundingPatient-Centered Outcomes Research Institute (PCORI) Award (ME-2022C2-25573-IC). RESEARCH IN CONTEXT Evidence before this studyNumerous studies have sought to identify clinical predictors of JIA progression and outcomes. However, few reliable predictors have emerged and existing prediction models demonstrate limited performance. As a result, our ability to personalize treatment decisions based on individual risk of severe disease course remains limited. Added value of this studyWe developed novel machine learning models that predict individualized disease trajectories in children with polyarticular and oligoarticular JIA using data from their preceding 12-month clinical course. These models demonstrated strong discriminative performance and outperformed previously published machine learning approaches in JIA. Unlike prior studies limited to single time-point predictions, our models are the first to predict inactive disease longitudinally, enabling a patient-specific projection of disease progression over time. Importantly, our findings also bright to light patterns of suboptimal care, likely driven by insurance constraints and a reactive treatment paradigm, underscoring critical opportunities to improve JIA management. Implications of all the available evidenceOur models have the potential to support clinical decision-making by enabling early identification of children with JIA at risk for unfavorable disease trajectories. In addition, the suboptimal care patterns and systems-level barriers identified through our analyses highlight priority areas for quality improvement initiatives and policy interventions to reduce gaps in JIA care delivery.

Inflammatory diseases cause significant morbidity and mortality, but their pathobiology is often difficult to dissect due to complex genetic-environmental interactions. Genetic forms of heterotopic ossification, such as fibrodysplasia ossificans progressiva (FOP), reduce genetic variability, allowing careful dissection of non-genetic drivers of inflammation. While >95% of FOP patients harbor the ACVR1R206H mutation, patients exhibit significant variability in disease progression, suggesting a role of environmental drivers. Here, we identify the gut microbiome as a regulator of inflammation-driven HO in FOP. Metagenomic profiling of cohabitating FOP/unaffected sibling pairs revealed a pathogenic gut microbiome profile in FOP patients (Bray-Curtis, p < 0.05). In Pdgfr-Cre/Acvr1R206H (FOP) mice, gut microbiome ablation by antibiotics reduced spontaneous HO formation (47.4% reduction, p < 0.05) and reduced plasma IL-1 pathway activity. IL-1{beta} blockade in FOP mice suppressed trauma-induced HO formation. These findings identify a gut microbiome-IL-1-HO axis with modifiable targets for developing treatments for HO and related inflammatory conditions. One Sentence SummaryAntibiotic disruption of the gut microbiome reduces HO in FOP mice via an IL-1 mediated pathway.

In multiple sclerosis (MS), autoreactive B cells play a central role in driving CD4 T cell-mediated inflammatory damage to myelin (1). Here we investigated how disrupting Brutons tyrosine kinase (BTK) signaling exclusively in B cells shapes the course of experimental autoimmune encephalomyelitis (EAE), a model for MS, through alterations in B cell development and activity. B cell-specific BTK deletion significantly ameliorated both human MOG (hMOG) induced EAE (p = 0.0087) as well as spontaneous disease in 2D2+IgHMOG mice (p = 0.0004). Additionally, MOG-specific cells were found to be more sensitive to loss of BTK than tolerant clones (p = 0.0002) and production of anti-MOG immunoglobulins was also found to be diminished (p < 0.004) while overall IgG was unchanged (p = 0.44). B cells isolated from conditional knockout mice did not upregulate expression of co-stimulatory receptors or MHC II to the same extent as controls when cultured alongside MOG-specific CD4 T cells (p < 0.005) and were inferior at driving T cell proliferation (p < 0.0001) in vitro. Lastly, while BTK deletion diminished the proliferative and survival response of B cells following mitogen stimulation, B cell trafficking to the leptomeninges and organization into ectopic lymphoid tissues (ELTs) in 2D2+IgHMOG mice continued unabated. We identified that BTK signaling regulates several features adopted by autoreactive B cells that contribute to EAE pathogenesis. This study provides mechanistic insights into the therapeutic benefits of BTK inhibitors observed in clinical trials exploring BTK as a therapeutic target in the context of MS. Significance statementAutoreactive B cells contribute to the neuroinflammation that drives multiple sclerosis (MS) and related diseases, yet the molecular mechanisms enabling their pathogenicity remain incompletely understood. This study demonstrates that B cell-specific deletion of Brutons tyrosine kinase (BTK) markedly reduces disease severity in two complementary versions of experimental autoimmune encephalomyelitis (EAE), a widely used animal model for MS. Loss of BTK impairs autoreactive B cell survival, antibody production, antigen presentation to encephalitogenic T cells, and T cell activation, while leaving meningeal ectopic lymphoid tissue formation intact. These findings provide direct mechanistic evidence that BTK signaling in B cells promotes neuroinflammatory damage and supports the therapeutic targeting of BTK to limit B cell-driven pathology in MS.

Purpose To determine whether clinically significant weight loss (>5% of body weight) is associated with slower 2-year knee cartilage degeneration in individuals with and without radiographic osteoarthritis. This study used a cartilage structural assessment score derived from the spatial distribution of cartilage thickness, referred to as the Cartilage Thickness Score (CTh-Score). It is based on cartilage thickness patterns and scores the cartilage between 0 and 100, with higher scores indicating greater severity. Methods We conducted a retrospective matched cohort study within the Osteoarthritis Initiative. High-resolution cartilage thickness maps (CTh-Maps), along with their corresponding CTh-Score, were extracted from a public repository. Participants with complete radiographic and MRI data at baseline and 24 months were stratified by baseline Kellgren-Lawrence (KL) grade into non-radiographic OA (non-ROA; KL<2) and radiographic OA (ROA; KL>=2). Within strata, cases (>5% 2-year weight loss) were propensity score-matched 1:2 to weight-stable controls on age, sex, height, weight, KL grade, joint space width (JSW), KOOS Pain, baseline CTh-Score, and mean cartilage thickness in the medial and lateral femoral and tibial compartments. The primary outcome was 2-year change (delta) in CTh-Score, where higher values indicate worsening. Secondary outcomes were delta JSW, delta regional mean cartilage thickness, and delta KOOS Pain. Non-parametric tests were used. Results We included 164 cases and 328 controls in non-ROA, and 266 cases and 532 controls in ROA. Median (interquartile range) weight loss was -6.10 kg (-8.90, -4.70) versus +0.30 kg (-1.30, 2.20) in non-ROA and -6.80 kg (-9.10, -5.02) versus +0.40 kg (-1.40, 2.82) in ROA (both p<0.001). Weight loss was associated with significantly smaller 2-year increases in CTh-Score: in non-ROA, median 1.58 (0.61, 6.53) vs 3.14 (0.44, 7.12) (p=0.005); in ROA, median 1.69 (0.97, 6.71) vs 2.90 (0.19, 7.38) (p=0.004). No between-group differences were detected for delta JSW or delta regional mean cartilage thickness in any of the 4 ROIs. A trend toward greater KOOS Pain improvement with weight loss was observed in ROA: 2.75 (-3.35, 13.40) vs 0.00 (-5.60, 8.40) (p=0.06). Conclusions Achieving >5% weight loss over 2 years is associated with approximately 50% lower progression in median cartilage degeneration, as assessed by CTh-Score, in both non-ROA and ROA. No change was observed with conventional structural metrics. These findings support weight management as a structural disease-modifying strategy and highlight CTh-Score as a sensitive endpoint.

BackgroundExcessive accumulation of fibrillar collagen causes pathological scarring and fibrosis. A promising anti-fibrotic strategy targets the extracellular assembly of collagen fibrils rather than intracellular synthesis pathways. We previously developed a chimeric monoclonal antibody targeting the C-terminal telopeptide of the 2(I) chain of human collagen I that effectively disrupts fibrillogenesis. This study details the engineering of a humanized antibody variant optimized for therapeutic application, augmented with a collagen-binding peptide (CBP) to enhance targeted retention in fibrotic tissues. MethodsA humanized ACA was engineered by in silico homology modeling, complementarity-determining region grafting, and sequence optimization to eliminate chemical liabilities. Variants were expressed in mammalian cells and evaluated for binding kinetics and specificity. To improve spatial localization, the CBP was fused to the antibody. The lead variant was assessed for in vitro cytotoxicity, matrix retention, and in vivo efficacy using a rabbit model of post-traumatic knee arthrofibrosis. ResultsThe humanized ACA variants maintained high specificity and affinity for the 2Ct target domain. Fusing the CBP to the C-terminus of the light chain (C-cbpACA) successfully enhanced matrix retention without compromising target engagement or causing cellular toxicity. In the rabbit arthrofibrosis model, intra-articular C-cbpACA delivery significantly reduced flexion contracture and decreased total collagen deposition in the joint capsule compared to untreated controls. ConclusionWe successfully engineered a clinically viable, humanized, and matrix-targeted anti-fibrotic antibody that specifically inhibited extracellular collagen assembly and exhibited enhanced localization within fibrotic tissues. This construct represents a promising therapeutic strategy for mitigating pathological scarring and improving post-traumatic functional outcomes.

IntroductionSystemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by loss of immune tolerance, autoantibody production, and multi-organ damage. Current therapies, including glucocorticoids and CAR-T/CAR-NK cell therapies, are limited by adverse effects, high cost, and safety concerns. ObjectivesTo develop engineered NK-92 cell-derived extracellular vesicles displaying CD19 single-chain variable fragment (V-CD19-Exo) and evaluate their therapeutic efficacy in an MRL/lpr mouse model of SLE. MethodsThe CD19scFv-LAMP-2B fusion construct was stably expressed in NK-92 cells via lentiviral transduction. Extracellular vesicles were isolated by differential centrifugation and characterized by NTA, TEM, and Western Blot. In vivo efficacy was assessed in MRL/lpr mice through B cell depletion analysis, renal function monitoring, cytokine profiling, autoantibody detection, and survival observation. ResultsV-CD19-Exo significantly reduced splenic CD19{square}CD20{square} B cells from 10.53% to 1.51% (p < 0.0001). Treatment attenuated proteinuria, ameliorated lupus nephritis pathology, reversed splenomegaly, and downregulated serum IgE, IL-17A, IFN-{gamma}, anti-dsDNA, and ANA levels. Notably, V-CD19-Exo improved survival to approximately 80% compared to 25% in untreated controls. ConclusionEngineered NK-92 cell-derived extracellular vesicles represent a novel, safe, and effective cell-free therapeutic strategy for SLE, offering advantages over conventional cell therapies including lower immunogenicity, scalable production, and no requirement for lymphodepletion.

Interleukin-10 (IL-10) is a potent immunoregulatory cytokine that suppresses pro-inflammatory cytokine production, reduces antigen presentation by myeloid cells, promotes M2 macrophage polarization, and inhibits T cell activation. Despite these well-established immunoregulatory functions, efforts to harness recombinant IL-10 therapeutically have been limited by its short plasma half-life and poor retention in the secondary lymphoid organs (SLOs), key sites of autoreactive T cell priming in autoimmune disease. Previously, we engineered a fusion of serum albumin and IL-10 (SA-IL-10) with extended half-life and enhanced exposure in the SLOs following intravenous administration. Here, we integrate human transcriptomic analyses and a murine model of neuroinflammation, experimental autoimmune encephalomyelitis (EAE), to investigate how sustained IL-10 exposure in the SLOs modulates immune responses under inflammatory conditions. Human single-cell RNA sequencing analyses revealed reduced IL-10 expression alongside increased IL-10 receptor expression across multiple immune cell populations in treatment-naive patients with multiple sclerosis (MS), motivating the investigation of IL-10-based immunomodulatory strategies. Prophylactic SA-IL-10 administration prevented the development and progression of EAE with superior efficacy to wild type IL-10 and comparable protection to fingolimod, an FDA-approved MS therapy. Immunophenotyping of the SLOs revealed that SA-IL-10 suppressed pathogenic, antigen-specific ROR{gamma}t+ Foxp3- TH17 T cells, CD86+ M1-like macrophages, CD86+ dendritic cells, and pro-inflammatory cytokine production, while expanding immunoregulatory CD206+ M2-like macrophages and increasing the frequency of multiple checkpoint markers (CTLA-4, PD-1, TIGIT, ICOS) on GATA3+ Foxp3- TH2 cells. Despite the absence of direct central nervous system targeting, SA-IL-10 treatment also reduced the infiltration of macrophages, dendritic cells, and CD4+ T cells into the spinal cord. Repeated SA-IL-10 administration was well tolerated, as treated EAE mice gained significantly more body weight over the course of treatment compared to PBS- and WT IL-10-treated controls, and exhibited plasma biochemistry parameters comparable to control animals at study endpoint. Together, these findings demonstrate that increasing IL-10 exposure in the SLOs suppresses neuroinflammation by promoting immunoregulation. One Sentence SummarySubcutaneously administered serum albumin-fused interleukin-10 prevents experimental autoimmune encephalomyelitis by suppressing pathogenic TH17 cells and pro-inflammatory myeloid cells in the secondary lymphoid organs and spinal cord, while expanding immunoregulatory cells in the secondary lymphoid organs.

Objective To evaluate the Cartilage Thickness Score (CTh-Score) as a quantitative measure of cartilage damage severity by assessing its association with three osteoarthritis (OA) milestones and comparing its performance with conventional morphometric measures (radiographic minimum joint space width (JSW) and regional average cartilage thickness). Methods Data were obtained from the Osteoarthritis Initiative (OAI) and the publicly available OAI CTh-Maps and CTh-Score dataset. Three matched case-control designs were used to represent major OA milestones: (i) incident radiographic OA onset, (ii) combined pain and structural progression, and (iii) knee replacement (KR) in the coming 2 years. Progression subjects were extracted from the FNIH Biomarkers Consortium cohort. Cases and controls were compared at 4 years (T-4Y), 2 years (T-2Y), and 0 years (T0) before the milestone. MRI-based CTh-Score and regional average cartilage thickness, as well as JSW, were analyzed cross-sectionally and longitudinally. Associations with case status were assessed using adjusted logistic regression models, and responsiveness was evaluated using longitudinal change and standardized response means. Results The onset cohort included 307 matched case-control pairs, the progression cohort 164 cases and 369 controls, and the KR cohort 81 cases and 324 controls. Across all three study designs, the CTh-Score significantly differentiated cases from controls at all timepoints. In the onset cohort, the CTh-Score was higher in future cases than controls at T-4Y (16.2 vs 12.6, p=0.007), T-2Y (23.5 vs 16.7, p<0.001), and T0 (39.8 vs 18.6, p<0.001), whereas JSW and regional thickness measures showed limited or later discrimination. Similar findings were observed for progression (43.2 vs 33.0 at T-4Y; p<0.001) and KR (55.4 vs 46.1 at T-4Y; p=0.02) cohorts. Longitudinally, CTh-Score changes differentiated cases from controls earlier and more consistently than JSW or regional average thickness, and its responsiveness was consistently the highest across OA milestones and time intervals. In adjusted models, the CTh-Score was independently associated with all outcomes at T-4Y and T-2Y, with odds ratios per standard deviation increase ranging from 1.3 to 2.2. Conclusion The CTh-Score captures high-resolution cartilage thickness patterns associated with OA onset, progression, and future knee replacement, outperforming conventional morphometric measures in early discrimination, responsiveness, and predictive association. These findings support CTh-Score as a sensitive quantitative marker of cartilage damage severity across the OA continuum.

Abstract Background Spontaneous coronary artery dissection (SCAD) is a well-recognised cause of acute coronary syndrome particularly among women without conventional cardiovascular risk factors. Increasing evidence indicates a genetic contribution; however, the underlying genetic architecture of SCAD remains insufficiently understood. Objective The aim of this study was to assess the prevalence of rare variants in previously reported SCAD associated genes and to explore the potential presence of novel genetic alterations in well-characterised Swedish patients with SCAD. Methods The study comprised 201 patients enrolled in SweSCAD, a national project examining the clinical characteristics, aetiology, and outcomes of SCAD. All individuals had a confirmed diagnosis based on invasive coronary angiography. Comprehensive exome sequencing was performed to identify rare variants contributing to disease susceptibility. Results Genetic variants that have been associated with SCAD according to current clinical genetics practice for variant reporting were identified in approximately 4 % of patients. In addition, rare potentially relevant variants were detected in almost 60 % of patients in genes associated with vascular integrity and vascular remodelling. Conclusion This study supports SCAD as a genetically complex arteriopathy, driven by rare high?impact variants together with broader polygenic susceptibility. Variants in collagen, vascular extracellular matrix, and oestrogen?responsive pathways provide biologically plausible links to female?predominant disease. Although the diagnostic yield of clearly actionable variants is modest, these findings support broader genomic evaluation beyond overt syndromic presentations and highlight the need for larger integrative genomic and functional studies to refine risk stratification and management.

Saul-Wilson syndrome (SWS) is a skeletal dysplasia characterized by primordial dwarfism and progeroid features caused by a recurrent dominant COG4 variant (p.G516R). We previously showed that this mutation accelerates Golgi retrograde trafficking and disrupts glycosylation of the proteoglycan decorin, while zebrafish models revealed defects in chondrocyte elongation and intercalation. We have also shown that the SW1353 chondrosarcoma cells carrying the SWS variant exhibit reduced secretion of extracellular matrix (ECM) components. While these results indicate a critical function of COG4 in Golgi processing, the developmental process leading to skeletal dysplasia in SWS patients remains unknown. Here, we generated patient-derived iPSC cartilage organoids (SWS organoids), modeling early human chondrogenesis. SWS organoids failed to produce cartilage structures and displayed poor expression of chondrogenic markers. Time-course RNA-seq analysis of the chondrogenic process revealed reduced activation of gene networks involved in skeletal development, ECM organization, ossification, and glycosaminoglycan metabolism. Spatial multiomic analysis of protein and glycosylation by CODEX and GLYPH imaging revealed an altered chondrogenic trajectory, persistence of mesenchymal states, global glycosylation changes, and reduced deposition of chondroitin sulfate proteoglycans. These results indicate that the COG4 mutation disrupts ECM glycosylation and chondrogenic commitment, and that SWS organoids model early defects in cartilage formation underlies impaired skeletal growth in SWS. HighlightsO_LIPatient iPSC-derived cartilage organoids model development defects in Saul-Wilson syndrome C_LIO_LISWS organoids show defective extracellular matrix deposition and attenuated chondrogenic gene expression C_LIO_LIGlycan profiling reveals global glycosylation defects and deficient proteoglycan GAG chains C_LIO_LIAn early developmental impairment in chondrogenesis alters skeletal formation in Saul-Wilson syndrome C_LI