TL;DR
A divergent regulation of CD29 and CD49b integrins associated with HLA-B27 status in Iraqi AS patients is suggested and longitudinal validation is required to confirm their clinical utility as diagnostic or therapeutic targets.
Ankylosing spondylitis (AS) is a chronic, immune-mediated inflammatory disorder primarily affecting the axial skeleton. It is characterized by bony fusion and syndesmophyte formation of the spine, leading to compromised mobility, reduced quality of life and increased mortality. However, the underlying immune dysregulation in AS remains poorly understood. We comprehensively profiled the peripheral immune landscape of 30 patients with active AS, all of whom were TNF-α blocker-naïve, capturing the immune profile during the active disease phase without biologic interference. Using advanced 11-color flow cytometry and FlowSOM clustering, 584 immunophenotypes were analyzed in AS and 30 age-and sex-matched healthy controls, with emphasis on both cellular composition and functional characteristics. AS patients displayed a distinctive functional “activated-exhausted” immune phenotype, dominated by CD4 + CD28 + CD38 + PD-1 + T cells and HLA-DR + CD38 + CD4 − CD8 − double-negative (DN) T cells. DN T cells were significantly enriched in HLA-B27-positive patients, suggesting potential as a biomarker. Network analysis revealed seven central immune subsets associated with active disease, while functional assessment demonstrated impaired CD95 + CD8 + T cell apoptosis and disrupted B-cell maturation. These findings provide a detailed functional immune map of biologic-naïve active AS, offering novel mechanistic insights and identifying candidate biomarkers for precision intervention.
Behçet's disease is an uncommon multisystem inflammatory condition characterized by immune-mediated vasculitis affecting vessels of different calibers. Clinically, it presents with recurrent oral and genital ulcerations, dermatological manifestations, and ocular involvement, reflecting its systemic nature. The present study was designed to characterize gut microbial patterns in patients diagnosed with Behçet’s disease and to assess selected immune biomarkers — IL-17A, IL-23, CD4, and CD11b — as potential diagnostic and prognostic indicators. Participants were recruited from Al-Sadr Medical City between December 2024 and September 2025, with ages ranging from 11 to 51 years. Venous blood samples were obtained from patients, and serum concentrations of IL-17A, IL-23, CD4, and CD11b were quantified using the ELISA technique. The study population showed a predominance of male patients, with the highest frequency observed in the 22–31-year age group. Statistical analysis demonstrated significantly elevated serum levels of IL-17A and IL-23 in Behçet’s patients compared with healthy controls. Similarly, CD4 and CD11b expression levels were markedly increased. A strong positive correlation was identified among these immune markers, suggesting coordinated immunological activation. In conclusion, IL-17A, IL-23, CD4, and CD11b may serve as valuable diagnostic and predictive biomarkers in Behçet’s disease, and their interrelationship highlights their potential role in disease pathogenesis and progression.
T cells play a central role in axial spondyloarthritis (axSpA). The serine-threonine kinase DRAK2, encoded by STK17B, modulates T cell activation and survival. In autoimmune models, it promotes autoreactive T cell persistence and reduces regulatory T cell (Treg) abundance.[1,2] We previously found STK17B upregulation in peripheral blood mononuclear cells (PBMCs) of axSpA patients who were non-responders to tumor necrosis factor inhibitors (TNFi).[3] To clarify whether this reflects disease-associated inflammation or treatment resistance, we compared STK17B/DRAK2 expression (i) between axSpA patients and healthy controls and (ii) between responders and non-responders to IL-17 inhibitor (IL-17i) therapy. We also examined STK17B/DRAK2 expression in the SKG mouse model of SpA. Human spinal tissue from axSpA patients and spinal trauma controls was analyzed by immunohistochemistry (IHC) to localize DRAK2 expression, and by immunofluorescence (IF) to compare expression between CD4 + and CD8 + T cells. PBMCs from patients and controls were sorted by fluorescence-activated cell sorting (FACS), and STK17B expression in each subset was quantified by qPCR. Parallel IHC was performed on ankle, tail, and ileum of curdlan-treated and PBS-treated SKG mice. To corroborate findings at higher resolution, STK17B expression in mature CD4 + and CD8 + T cells was queried from our pre-biologic single-cell RNA-sequencing and multiome datasets. In human spinal tissue, DRAK2 + immune infiltrates were more abundant in axSpA than in controls (Figure 1A), with stronger IF staining in CD4 + than CD8 + T cells. In PBMCs, STK17B was preferentially expressed in CD4 + T cells and trended higher in axSpA compared with controls. Single-cell and multiomic analyses confirmed this pattern, showing modest STK17B increases in CD8+ T cells but markedly higher levels in CD4+ T cells of axSpA patients, particularly in effector T cells and Tregs. Notably, pre-biologic STK17B expression was higher among patients who were later identified as non-responders to IL-17i compared with responders (Figure 1B). Consistent with the human findings, curdlan-treated SKG mice exhibited increased DRAK2 + infiltrates in ankle, tail, and ileum relative to PBS-treated controls, paralleling the observation in human tissues (Figure 1C). Figure 1. (A) Histopathology of spinal tissues from AS and control patients with IHC staining for anti-DRAK2. (B) STK17B expression in mature CD4+ T cells of pre-biologic axSpA patients and controls. (C) Histopathology of the tissues from curdlan- vs PBS-SKG mice for anti-DRAK2. Across humans and mouse models, STK17B/DRAK2 expression is increased in inflammatory lesions and enriched in CD4 + effector and regulatory T cells, particularly in patients with inadequate IL-17i response. These findings suggest that DRAK2 upregulation contributes both to axSpA-related inflammation and to treatment resistance, warranting further mechanistic investigation. [1.] Ramos S. J Immunol 2008;181:7606-16. [2.] Mandarano A. Cell Rep 2023;42:112106. [3.] Talukdar A. [Abstract]. Arthritis Rheumatol 2024;76 Suppl 9.
Background Dermatomyositis (DM) and antisynthetase syndrome (ASS) are heterogeneous subsets of idiopathic inflammatory myopathies with persistent unmet needs in disease activity assessment and stratification. Although CD4+ T cells are recognized as important contributors to disease pathogenesis, the role of CD4+ cytotoxic T lymphocytes (CTLs) remains insufficiently defined. Methods Peripheral blood samples were collected from patients with DM (n = 50), patients with ASS (n = 14), and healthy donors (HDs, n = 20). The frequency of CD4+ cytotoxic T lymphocytes with expression of cytotoxic protein granzyme B (GZMB+CD4+ CTLs) was analyzed by flow cytometry to quantify GZMB+CD4+ CTLs and characterize their phenotype. Disease activity and severity were evaluated using standard clinical indices. Multiplex immunohistochemistry was performed on skin biopsy specimens from patients with DM (n = 4) to assess tissue infiltration and endothelial injury. Results The proportion of circulating GZMB+CD4+ CTLs was significantly increased in both DM and ASS compared with HDs. In patients, this population showed phenotypic features consistent with enhanced cytotoxicity and tissue trafficking, including increased fibroblast growth factor binding protein 2 (FGFBP2) expression and reduced circulating fractions of cells positive for C-X3-C motif chemokine receptor 1 (CX3CR1) and C-X-C motif chemokine receptor 3 (CXCR3). GZMB+CD4+ CTL frequency was positively associated with global disease activity and cutaneous activity, and decreased after treatment independently of specific drug regimens. Receiver operating characteristic analysis showed that circulating GZMB+CD4+ CTLs effectively distinguished active from remitting disease in both DM and ASS. In DM skin lesions, GZMB+CD4+ CTLs were abundant and were accompanied by increased endothelial apoptosis and enhanced HLA-DR expression. Conclusions Peripheral GZMB+CD4+ CTLs are expanded in DM and ASS and are closely associated with disease activity. Their accumulation in lesional tissue and association with endothelial injury support a potential pathogenic role, while their diagnostic performance suggests that they may serve as a biomarker and potential therapeutic target in these diseases.
Background: In rheumatoid arthritis (RA), the CD40-CD40L axis plays a key role in immune cell activation and the production of inflammatory mediators. Although the soluble form of CD40 (sCD40) has been identified and investigated in various autoimmune disorders, its significance in RA and its relationship with inflammatory and humoral markers remain to be fully elucidated. Methods: Sixty-two patients with RA, classified according to the 2010 ACR/EULAR criteria, and 31 age- and sex-matched healthy controls were included. Clinical characteristics, disease activity (DAS28-ESR), and acute-phase reactant levels (CRP and ESR) were evaluated in patients with RA. Autoantibodies (RF, ACPA, anti-MCV, and anti-PAD4), serum cytokines, and sCD40 levels were quantified using ELISA and multiplex bead-based assays. Group differences and associations were assessed using nonparametric tests. Multiple linear regression analysis was performed to account for potential confounding variables. Results: Serum sCD40 levels did not differ significantly between patients with RA and healthy controls or among patient subgroups stratified by disease activity or sex. No associations were observed between sCD40 levels and autoantibody seropositivity or titers. sCD40 levels were positively correlated with age (rs = 0.293, p = 0.02). Notably, after adjustment for age, sCD40 showed a significant negative correlation with IL-2 (rs = −0.317, p = 0.01). Conclusions: Serum sCD40 does not reflect disease activity or the humoral immune response in RA. Nevertheless, further studies are needed to evaluate its relevance during early stages of the disease and to further characterize its role in cytokine production.