Journal of Autoimmunity

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.

Background VEXAS syndrome is a late onset autoinflammatory disease caused by somatic UBA1 mutations and characterized by heterogeneous systemic and hematologic manifestations. We aimed to describe all identified Belgian cases through a national multicenter cohort. Methods We conducted a retrospective study across four Belgian tertiary centers. Clinical, biological, genetic, therapeutic, and outcome data were collected using standardized anonymized case report forms. Analyses were descriptive. Results Twenty-one male patients were identified between January 2018 and May 2025. General symptoms such as Fatigue, weight loss and sweating occurred in 95% of cases. The most frequent manifestations were cutaneous (85.7%), hematologic (76.2%), articular (66.7%), thromboembolic (57.1%), chondritis (42.9%), ophthalmologic (38.1%), pulmonary (38.1%). Other manifestations also included vasculitis (61.9%). At diagnosis, 95% had anemia, macrocytic in 57%, and 28.6% had thrombocytopenia. Corticosteroids were the main first line therapy. Second line treatments included anti IL 6 agents (46.7%), JAK inhibitors (20%), and azacitidine (14.3%). Complete remission occurred in 50% of patients receiving anti IL 6 therapy and in 33% treated with either JAK inhibitors or azacitidine. Two patients underwent allogeneic stem cell transplantation, one died from infectious complications. Twenty six infectious episodes were recorded, including opportunistic infections. Six patients (28.6%) died during follow-up, four from infectious complications. Conclusion This first Belgian national cohort confirms the clinical heterogeneity of VEXAS syndrome and highlights substantial infectious morbidity and mortality. Access to targeted second-line therapies, particularly anti IL-6 agents and JAK inhibitors, remains challenging despite apparent clinical benefit.

Intrathecal antibody synthesis is a hallmark of multiple sclerosis (MS). Although some intrathecally synthesized antibodies in MS are known to target viral antigens, the spectrum of their antigenic specificities remains incompletely defined. We combined proteome-wide antibody profiling by Phage ImmunoPrecipitation Sequencing (PhIP-Seq) with cross-compartment analytics (MICAR) to study intrathecal antibody synthesis at peptide resolution in paired CSF and serum samples from individuals with MS (n = 40) and non-MS controls (n = 83). While intrathecal antibody responses in MS were polyspecific and included reactivities to various viruses, we identified a subset of individuals with a convergent intrathecal antibody reactivity to a previously described motif within the Epstein-Barr virus (EBV) protein BRRF2 (BRRF2408-415). This motif-directed response showed co-reactivity with multiple CNS-expressed human antigens. In an independent cohort of n = 909 individuals with MS and n = 311 controls, including individuals with NMOSD and MOGAD, serum antibodies to BRRF2408-415 were detected in 8.36% of MS individuals and in 0.64% of non-MS controls, corresponding to an odds ratio for MS of 14.1 (95% CI: 4.4-86.04). Within MS individuals, BRRF2408-415 seropositivity was associated with increased intrathecal IgG synthesis. Cross-reactivity of antibodies to BRRF2408-415 with human targets, including TRIM71 and RTN2, was confirmed by competition ELISA and cell-based assays. Together, these data define an intrathecal EBV BRRF2-linked antibody signature with human target cross-reactivity in a subset of MS individuals. This signature identifies a highly specific serological marker in MS and may support future stratification of the heterogeneous MS spectrum.

Systemic autoimmune connective tissue diseases (CTDs) are characterized by anti-nuclear antibodies, shared HLA-associated genetic risk, and frequent disease overlap, suggesting a central role for CD4+ T cells in pathogenesis. However, defining disease-driving CD4+ T-cell responses remains challenging due to their localization within lymphoid and affected tissues and the lack of approaches linking these responses to circulating counterparts. We combined [18F]-labeled thymidine PET/CT-guided tissue sampling, ex vivo antigen stimulation, and single-cell multiomics to characterize CD4+ T-cell responses in blood, PET-avid locoregional lymph nodes (LNs), and disease-affected tissues from patients with the immunologically distinct CTDs systemic sclerosis and Sjogren's disease. PET-avid LNs from both diseases exhibited enhanced adaptive immune activity and contained an expanded population of interferon-stimulated gene (ISG)-expressing TRAIL+ CD4+ T cells. In Sjogren's disease, active LNs and affected tissues harbored diverse effector CD4+ T-cell populations, including follicular and peripheral helper T cells and Th2/Th17 cells. In contrast, systemic sclerosis tissues lacked effector CD4+ T cells, while active LNs were enriched for naive, regulatory, and TRAIL+ ISG CD4+ T cells. Antigen stimulation of peripheral blood mononuclear cells enriched for expanded effector CD4+ T-cell populations that shared activation profiles and clonal relationships with cells in LNs and affected tissues, many representing autoreactive antigen-specific T cells. TRAIL+ CD4+ T cells suppressed effector T-cell differentiation, autoreactive plasma cell generation, and autoantibody production in vitro, identifying a previously unrecognized immunoregulatory population. Together, this workflow enables comprehensive characterization of pathogenic and regulatory CD4+ T-cell responses across CTDs.

Despite immune-cell infiltration being a hallmark of multiple sclerosis (MS), the interplay between the periphery and central nervous system immune responses is still incompletely characterized. We performed single-cell transcriptomic and V(D)J sequencing of paired blood and cerebrospinal fluid (CSF) immune cells from treatment-naive relapsing-remitting women with MS and compared them to age- and sex-matched healthy controls. Across major immune lineages, we identified coordinated, compartment-specific immune alterations, with enrichment of activated and memory lymphocyte populations in the CSF and concomitant depletion of related populations in peripheral blood, suggesting their recruitment from blood to CSF. Clonally expanded CD4 memory T-cells, together with activated, expanded IgM-positive B-cells, accumulated predominantly in the CSF of people with MS compared to healthy subjects. Interestingly, tissue-primed cytotoxic populations and CXCR3-associated memory populations were depleted from the CSF of MS, implying their recruitment to the target tissue in early disease. These findings reveal coordinated, compartment-specific immune changes in early MS and provide a systems-level view of immune-cell trafficking between peripheral and central nervous system compartments.

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.

Background: Neurodegenerative diseases including Parkinson's disease (PD) are increasingly associated with dysfunction in both central and peripheral immune systems. Pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2) represent a major cause of familial PD, while common polymorphisms are associated with inflammatory diseases. Methods: Here, using immunophenotyping flow cytometry and quantitative PCR (qPCR), we compared immune cell populations and function across both the central and peripheral immune systems in C57BL/6J wild type (WT), Lrrk2 p.G2019S knock-in (GKI) and Lrrk2 knock-out (LKO) models in basal and ex vivo immune-stimulated conditions. Results: With a focus on T cell biology, compared to their WT counterparts at baseline, GKI mice exhibit higher populations of Cd8+ and TH17 T cell subsets in the brain, whereas LKO mice exhibited unique central memory (TCM), follicular helper (TFH), and TH2 lineages. In the periphery, GKI mice demonstrated higher TH1, TH2, and TH17 subset expansions, whereas peripheral alterations in LKO are largely restricted to TH17 subsets. Within mutant genotypes, a striking discrepancy was observed between baseline gene expression and the translated proteins encoded, that reveals a fundamental loss of basal immune homeostasis. This phenomenon was further exposed following an acute (6-hour) ex vivo lipopolysaccharide (LPS) immune challenge. Following stimulation, GKI immune cells had reduced transcription, alongside stalled translation, for almost all effector molecules examined, while LKO immune cells had fewer transcriptional changes compared to wild type. Overall, both mutant lines had stalled or flatline effector molecule production after immune stimulation, suggesting a profound loss of functional responsiveness. This hypothesis was supported by a significant increase in surface protein of the inhibitory receptor Pd-1 on regulatory T cells (TREG) and TH1/TH2 Cd4+ T cell subsets in GKI mice. LKO immune landscapes trended toward similar exhaustion patterns, albeit less evident. Conclusions: These data suggest that bidirectional disruptions to normal Lrrk2 function break immune homeostasis. Immune cell function should be carefully considered when targeting LRRK2 kinase activity in patients with PD.

Myasthenia gravis (MG) is an autoimmune disease caused by pathogenic autoantibodies against proteins at the neuromuscular junction (NMJ). The diagnosis and clinical management of MG patients largely relies on the detection of antigen-specific autoantibodies targeting acetylcholine receptor (AChR) or muscle-specific kinase (MuSK). Yet a subset of patients remains seronegative for known MG autoantibodies, highlighting a critical need for alternative approaches to identify pathogenic NMJ antibodies. We established a new human in vitro model of the NMJ based on primary human muscle cells that recapitulates key features of the NMJ: differentiation to myotubes, expression of key NMJ proteins and formation of postsynaptic AChR clusters in response to agrin stimulation. The model allows new insights into myogenesis and genetic muscle diseases, and the new muscle cell-based assay (CBA) detected autoantibodies in sera from patients with AChR- and MuSK-positive MG with 96.43% sensitivity and 100% specificity, while healthy control sera showed no reactivity. Incubation with patient sera significantly reduced AChR clustering compared to controls, demonstrating functional pathogenic effects. Thus, we established a physiologically relevant human NMJ model that enables detection and functional characterization of neuromuscular autoantibodies. This novel approach addresses a key limitation of current antigen-specific diagnostics and provides a method for improved detection and characterization of MG antibodies, independent of antigen specificity. One Sentence SummaryWe established a postsynaptic human in vitro neuromuscular junction model to assess binding and pathogenicity of MG autoantibodies. Key messagesO_ST_ABSWhat is already known on this topic?C_ST_ABSCurrent diagnosis of myasthenia gravis (MG) relies largely on the detection of antigen-specific autoantibodies against AChR and MuSK, leaving a clinically relevant subset of patients seronegative. What are the new findings?We established a physiologically relevant human in vitro neuromuscular junction model based on primary human muscle cells and developed a novel muscle cell-based assay (CBA) for the detection of neuromuscular autoantibodies. How might this impact on clinical practice or future developments?The CBA detected autoantibodies in patients with AChR- or MuSK-positive MG with high sensitivity and specificity and demonstrated their functional pathogenic effects on AChR clustering. This antigen-independent approach may improve the detection and functional characterization of MG autoantibodies, particularly in patients who are seronegative in current diagnostic assays. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=130 SRC="FIGDIR/small/743478v1_ufig1.gif" ALT="Figure 1000"> View larger version (38K): org.highwire.dtl.DTLVardef@18ed154org.highwire.dtl.DTLVardef@151036corg.highwire.dtl.DTLVardef@1b7ab34org.highwire.dtl.DTLVardef@1490fe9_HPS_FORMAT_FIGEXP M_FIG C_FIG

Epstein-Barr virus (EBV) reprograms B cells in autoimmune disease. Reprogrammed EBV+ B cells activate nearby B and CD4+ T cells, via upregulated antigen presentation and costimulatory machinery, to drive autoimmune pathology. EBV reactivation is a known correlate of long COVID, which is a heterogeneous condition that can bear similarities to autoimmune disease. However, the mechanisms underpinning this association remain unresolved. We report on EBV metabolically reprogrammed B cells in patients with COVID-19. We find EBV+ B cells provide stimulatory signals to bystander B and CD4+ T cells. SARS-CoV-2 infected participants exhibiting elevated fractions of EBV+ B cells present, at convalescence, with dysregulated lipid profiles, increased autoantibody titers, and post-acute symptomology likely reflective of this metabolic reprogramming and cell-cell interactions. Enrichment of our EBV+ B cell signatures seen in patients with COVID-19 is similar in patients with lupus and multiple sclerosis suggesting a potentially shared pathway of EBV-driven dysfunction across diseases.

Inclusion body myositis (IBM) is a progressive inflammatory myopathy characterized by muscle fiber degeneration, immune infiltration, and protein aggregation. Despite the prominent immune infiltrates that characterizes IBM muscle, the factors driving immune infiltration remain unknown, and the repertoire and spatial organization of infiltrating immune populations remain poorly defined. Here, we used high-resolution spatial transcriptomic profiling to define the cellular and spatial architecture of IBM muscle. Immune profiling revealed a complex inflammatory landscape dominated by interferon-responsive CD8+ T cells and interferon-stimulated antigen-presenting macrophages, which organized into spatially localized immune hubs surrounding myofibers. Myofibers within these immune-rich microenvironments exhibited increased expression of interferon-responsive genes and HLA class I and II antigen presentation machinery components across fiber subtypes. In addition, we identified muscle-intrinsic remodeling and regenerative programs that may precede or contribute to immune recruitment, characterized by focal spatial activation of genes involved in proteostasis, cytoskeletal organization, and myofiber repair. Together, these findings define the spatial immune landscape of IBM muscle and reveal coordinated immune and muscle-intrinsic programs that shape disease pathology.

Background: The gradual decline in the functionality of the immune system during aging is commonly referred to as immunosenescence. This study aims to investigate changes in the B-cell receptor immunoglobulin heavy chain (BCR IGH) gene repertoire during natural aging and evaluate the dynamics of emergent low-level BCR IGH clonality in the elderly. We conduct a longitudinal study nested within the Doetinchem Cohort study, comprising 98 participants aged between 31 and 59 years old at study entry who had repeated blood samples drawn at 5 year intervals over a 30 year period (n=548 samples). We sequenced the IGH gene repertoire and evaluated the impact of aging on IGH gene repertoire clonality and diversity using linear mixed effects modeling. Results: Participants older than 60 years exhibited increased BCR IGH clonality and reduced IGH gene repertoire diversity. In a multivariable model, IGH gene repertoire diversity was significantly decreased for individuals with a dominant clonotype ratio greater than 10 (Beta=-0.57, p < 0.001). Additionally, a trend toward reduced IGH gene repertoire diversity was observed in participants aged 60-70 years (Beta =-0.19, p = 0.1) and those aged 70 years or older (Beta =-0.20, p = 0.13). IGH gene repertoire diversity was determined primarily by the naive and transitional B-cell pool, while BCR IGH clonality was influenced by switched memory and age-associated B-cell counts. Conclusions: In summary, our study indicates that IGH gene repertoire diversity decreases significantly after age 60, which coincides with an increased incidence of low-level BCR IGH clonality. This clonality may be driven largely by switched memory and age-associated B-cells. By providing deep insights into age-related dynamic changes in the IGH gene repertoire, these findings lay the groundwork for the molecular assessment and monitoring of incident clonality by clinicians and researchers alike.

Meibomian gland dysfunction (MGD), a disorder of the eyelid's modified sebaceous glands, is the leading cause of dry eye disease and ocular surface morbidity, yet the immune mechanisms driving gland obstruction remain poorly defined. In a cross-sectional study of 66 patients with ocular surface inflammation, we used meibography and spectral flow cytometry of tear washes to identify a disease-associated, remodeled neutrophil state whose abundance is associated with gland atrophy. Using single-cell transcriptomics in a murine model of immune-mediated MGD, we revealed a disease-associated neutrophil state that exhibited ocular surface-enrichment, CD14 and ICAM-1 expression, and elevated IFN-{gamma} response and inflammatory signatures. Spatial transcriptomics localized IFN-{gamma} signaling and neutrophil migration signatures to the periglandular compartment. The remodeled neutrophils exhibited PAD4-dependent histone citrullination, with Padi4 deletion reducing NET-associated obstructive plugging, thus identifying PAD4-dependent NETotic activity as their disease-producing output. Inhibition of IFN-{gamma} signaling phenocopied Padi4 deficiency, yet combined disruption of these pathways provided no additive protection, indicating that IFN-{gamma} and PAD4 function as separable required inputs. Remodeled neutrophils accumulated under both conditions, uncoupling disease severity from cell abundance alone. Our findings support immune-mediated obstructive MGD as a mechanistic endotype driven by the IFN-{gamma}- and PAD4-dependent effector output of a remodeled neutrophil state.

Background: Patients receiving anti-TNF treatment for chronic inflammatory disease display impaired antibody responses, but it remains unclear how immune memory formation is affected. We evaluated antibody responses and memory B cells (Bmem) after COVID-19 booster vaccination in inflammatory bowel disease (IBD) patients receiving anti-TNF treatment. Methodology: Blood was sampled at baseline, 1, and 6 months after WH1/BA.5 bivalent or XBB.1.5 monovalent vaccination from 27 IBD patients receiving intravenous anti-TNF and 44 controls. Neutralizing antibodies were measured using an infectious virus assay. SARS-CoV-2 spike receptor binding domain (RBD)-specific serum IgG was quantified by ELISA, and RBD-specific Bmem were immunophenotyped by flow cytometry using recombinant proteins from ancestral, Omicron BA.1, BA.5, XBB.1.5, and JN.1 variants. Results: Serum IgG to vaccine RBD and neutralizing antibodies in patients increased pre to 1 month post-vaccination, but were lower than controls. Ancestral-, BA.5- and XBB.1.5-specific Bmem increased after vaccination but were significantly lower in patients than controls. Within RBD-specific Bmem, frequencies of recently activated CD21lo cells were increased after vaccination, and were higher in patients than controls. Fewer antigen-specific Bmem in patients expressed IgG4, and more expressed IgG3 or IgD following vaccination. Following vaccination, more RBD-specific Bmem recognized multiple viral variants. However, patients had fewer Bmem that could bind to subvariants than controls. Conclusion: Antibody and Bmem responses to COVID-19 booster vaccination in anti-TNF-treated IBD patients displayed reduced capacity, durability and cross-reactivity, suggesting impaired immune memory for protection against breakthrough infection. This supports the recommendation for annual booster vaccination to prevent severe disease and viral spread.

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: Viral myocarditis presents a significant burden of disease, particularly among children and young adults. However, clinical guidelines and treatment strategies for pediatric patients are derived from those for adult patients due to a lack of pediatric data. Current animal models of viral myocarditis use adult mice, so conclusions from these models cannot necessarily be extrapolated to the pediatric population. We sought to develop a juvenile mouse model of myocarditis to examine differences between these two distinct clinical populations. Methods: Male and female BALB/c 3-4-week-old 'juvenile' and 8-week-old 'adult' mice were infected intraperitoneally with 103 PFU of heart-passaged coxsackievirus B3. Sera was used to evaluate testosterone and estradiol levels. Cardiac histological evaluations included overall inflammation, fibrosis, and specific cell-type infiltration. RNA was extracted from cardiac tissue and evaluated for changes in gene expression of cell-type markers, complement components, and NLRP3 inflammasome components. Results: Juvenile mice exhibited more severe inflammation than adult mice but no sex differences in overall inflammation. Juvenile mice demonstrated increased infiltration of CD11b+ cells, F4/80+ cells, and CD3+ T-cells vs. adults. Inflammasome genes NLRP3 and caspase-1 were significantly increased in juvenile compared with adult myocarditis. Conclusions: This paper is the first to describe a juvenile mouse model of coxsackievirus B3 myocarditis and provides a direct comparison to a translational adult mouse model. Juvenile mice had greater cardiac inflammation than adults. This model replicates clinical populations and provides a valuable tool to study age as a factor in the pathogenesis of myocarditis.

Vascular cognitive impairment and dementia (VCID) is increasingly recognized as a major contributor to cognitive decline; however, the mechanisms through which vascular dysfunction drives innate immune dysregulation remain poorly understood. In this study, we explore the impact of VCID on the cerebral innate immune landscape, focusing on innate lymphoid cells (ILCs) and neutrophils, two key players in neuroinflammation and brain immune homeostasis. Using a murine model of VCID induced by bilateral common carotid artery stenosis (BCAS) with modifications in C57BL/6 mice, we investigated innate immune cell distribution, polarization, and functional profiles using flow cytometry and immunofluorescence staining. Our findings reveal a compartment-specific shift in ILC populations, with a reduction of ILC2s in the meninges and concurrent expansion in the choroid plexus, accompanied by altered cytokine production. Furthermore, VCID drove a marked shift in neutrophil polarization toward a pro-inflammatory N1-like phenotype in both the meninges and choroid plexus. Critically, immunofluorescence staining of hippocampal brain sections confirmed that activated N1-like neutrophils, characterized by elevated IL-1{beta} and MPO and reduced IL-10, infiltrate the hippocampal parenchyma in VCID, suggesting a spatially progressive innate immune response spanning from CNS border compartments to brain tissue. These results identify a novel innate immune signature in VCID, compartment-specific ILC redistribution, pro-inflammatory neutrophil polarization at CNS borders, and parenchymal neutrophil infiltration in the hippocampus, which may collectively amplify neuroinflammation and accelerate cognitive decline, identifying potential therapeutic targets for vascular-related dementia.

Ageing and cytomegalovirus (CMV) infection drive major alterations to T-cell immunity. Age is also associated with an increased risk of cancers including melanoma, which is treated with T-cell modifying immune checkpoint blockade (ICB). However, the extent to which age, CMV, and treatment-induced immune changes interact to shape clinical outcomes remains poorly understood. We investigated this through flow cytometric evaluation of pre- and early on-treatment blood samples of 79 advanced melanoma patients. Age and CMV infection were associated with significant and largely distinct changes to T cell phenotype pre-treatment but had no impact on clinical outcome. Older patients ([&ge;]65 years) had fewer CD8+ Tnaive, CD4+ Tcm, TFH, and B cells, and increased CD8+ TemRA, but similar cytokine and inhibitory marker expression. Conversely, CMV drove expansion of CD8+ and CD4+ TemRA cells with enhanced effector function without reducing naive populations. One cycle of PD-1 and CTLA-4 ICB induced immune cell expansion and phenotype changes of greater magnitude and partially distinct from those seen during PD-1 with or without LAG-3 ICB, but these effects were largely independent of age or CMV serostatus. Hence, neither ageing nor CMV were associated with clinical outcome or immunological response to ICB in advanced melanoma patients.

Advances in immunophenotyping of tumour-infiltrating lymphocytes (TILs) have improved our understanding of prognostic biomarkers and immune targets in human melanoma. However, whether the tumour-immune landscape in canine oral malignant melanoma (COMM) is concordant with that of human melanoma has not been properly defined. To address this gap, we developed a 16-colour spectral flow cytometry panel to characterise TIL phenotypic and functional profiles in COMM. Validation using mitogen-stimulated peripheral blood mononuclear cells from healthy dogs (n = 5) demonstrated robust identification of major T cell lineages, including regulatory T cells (Tregs) and memory subsets, and reliable evaluation of their activation and exhaustion status. COMM patients (n = 8) displayed a distinct protumour microenvironment, characterised by an increased proportion of Tregs, enrichment of tumour-specific exhausted-like T cells co-expressing programmed cell death protein 1 (PD-1) and tumour necrosis factor receptor 2 (TNFR2), and a reduction in cytotoxic CD8 and natural killer T (NKT) cell populations compared with tissue-resident (n = 4) and circulating (n = 8) lymphocytes. Analysis of additional solid tumours, including a mast cell tumour, nerve sheath tumour and adrenal cortical carcinoma, further supported the capability of the panel to identify similar patterns of immune dysregulation across diverse canine tumour landscapes. Collectively, this work describes the first detailed evaluation of canine TIL immunophenotyping using spectral flow cytometry and provides insights into the immunosuppressive mechanisms shaping the tumour microenvironment in COMM. These findings not only increase our understanding of canine tumour immunology but also identify potential immune targets and support ongoing comparative immuno-oncology efforts.

Background The phase 3 ADVOCATE trial evaluated the efficacy and safety of avacopan in patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). Concerns raised regarding the 2019 primary endpoint adjudication process prompted a blinded, independent readjudication of all participants' primary outcomes, the results of which are described here. Methods Patients with GPA or MPA were randomized 1:1 to receive oral avacopan 30 mg twice daily or oral prednisone on a scheduled taper, each in combination with rituximab- or cyclophosphamide-based standard of care. In 2026, the Duke Clinical Research Institute Clinical Events Classification group conducted an independent, blinded committee re-adjudicated the Birmingham Vasculitis Activity Score (BVAS), relapse, and remission from weeks 26 through 52 using procedures aligned with the original adjudication charter. The primary endpoints were remission at week 26 and sustained remission at week 52. As per the original analysis plan, noninferiority and superiority were declared if the lower bounds of the 95% confidence interval (CI) for the difference in the primary outcome rates between avacopan and a prednisone taper were greater than -20.0 and 0.0 percentage points, respectively. Results Among 330 participants in the intent-to-treat population, remission at week 26 was achieved by 68.1% (113/166) and 67.1% (110/164) of participants in the avacopan and prednisone taper groups, respectively, in the 2026 readjudication (adjusted difference: 2.2%; 95% CI, -7.5, 11.9), compared with 72.3% (120/166) and 70.1% (115/164) in the 2019 primary outcome adjudication (adjusted difference: 3.4%; 95% CI, -6.0, 12.8). Sustained remission at week 52 was achieved by 61.4% (102/166) and 52.4% (86/164) of participants, respectively, in the 2026 readjudication (adjusted difference: 9.8%; 95% CI, -0.3, 19.9), compared with 65.7% (109/166) and 54.9% (90/164) in the 2019 readjudication (adjusted difference: 12.5%; 95% CI, 2.6, 22.3). Concordance between the 2019 and 2026 adjudications was 95.2% for remission and 93.6% for sustained remission. Conclusion The re-analysis of ADVOCATE based on the 2026 readjudication further supports the efficacy of avacopan for GPA/MPA. Non-inferiority of avacopan versus a prednisone taper was confirmed at weeks 26 and 52 despite a median 81% reduction in glucocorticoid exposure observed in the avacopan versus prednisone taper groups. While a consistent numerical difference favoring avacopan at week 52 was observed in the 2019 and 2026 analyses, this difference did not reach statistical superiority.

While progress has been made in identifying the true risk-driving single nucleotide polymorphisms (SNPS) on juvenile idiopathic arthritis (JIA) risk haplotypes, the affected cells and target genes largely remain unknown. We used data from a previously published massively parallel reporter assay (MPRA) to query human data in the Database of Immune Cell eQTLs (DICE) and the Gene-Tissue Expression (GTEx) database to identify affected cells and target genes of MPRA-identified SNPs in immune cells and relevant tissues. SNPs identified on MPRA were associated with gene expression levels in a broad range of immune cells in the DICE database, including CD4+ and CD8+ T lymphocytes, monocytes, NK cells, and B cells. MPRA-identified SNPs showed strong associations with gene expression in GTEx whole blood, spleen, and/or EBV-stimulated lymphocytes. Our data show the efficacy of combining MPRA and using human cells/tissue expression data to elucidate complex mechanisms driving genetic risk for JIA.