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Results for “T-Lymphocytes, Regulatory”

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At least 19 recordsLinked to original sources

PubMed2026

A transient, B cell-targeted tolerance switch using nanoparticles loaded with metabolizable AhR agonists for antigen-specific immune regulation.

Achieving antigen-specific immune tolerance without systemic immunosuppression remains a major challenge in biomaterial-based immunotherapy. Here, we report a simple nanoparticle (NP)-based platform that enables a transient, B cell-targeted tolerance switch. NPs encapsulating metabolizable aryl hydrocarbon receptor (AhR) agonists-FICZ or ITE-preferentially accumulate in splenic marginal zone B cells and convert them into IL-10-producing regulatory B cells (Bregs). This study provides the first in vivo evidence that Bregs can directly present antigen and induce regulatory T cells (Tregs), establishing a NP-controlled Breg-Treg pathway. These Bregs promote antigen-specific Tregs expansion only when co-exposed to antigen, establishing time-gated, antigen-restricted immune regulation. By exploiting the rapid metabolism of AhR agonists, this system provides precise temporal control of tolerance induction while preserving vaccine responses. In mouse models, co-administration of FICZ-containing NP with antigen suppressed anti-drug antibody formation and ameliorated allergic inflammation. This NP platform demonstrates a strategy for safe, antigen-specific immunomodulation and offers a clinically adaptable framework for allergy and biotherapeutic tolerance.

Animals↗

PubMed2026

TGF-β and IL-2 differentially shape T follicular regulatory cell differentiation and stability in vitro.

T follicular helper (Tfh) cells and T follicular regulatory (Tfr) cells play critical roles in regulating the activity of the germinal center (GC), which is essential for the generation of high-affinity antibodies. In the GC, Tfh cells help B cells to proliferate and to differentiate into memory B cells and long-lived plasma cells. In contrast, Tfr cells, a specialized subset of regulatory T cells (Tregs), modulate the humoral immune response by suppressing excessive or autoreactive B-cell activity. Here, we established an in vitro differentiation protocol for mouse CD4⁺ T cells that yielded CXCR5⁺FoxP3⁺ Tfr cells that exhibited a Bcl6hiPD-1hiCD25loGITRint phenotype and were distinct from Treg and Tfh cells. Functionally, in vitro-generated Tfr cells potently suppressed Tfh cell-driven B-cell class switching to IgG1 and downregulated the expression of B-cell costimulatory ligands. While in vitro-generated Bcl6-deficient Tfh cells were impaired in providing help to B cells for efficient class switching to IgG1, in vitro-generated Bcl6-deficient Tfr cells failed to inhibit Tfh cell-driven B-cell class switching to IgG1. Mechanistically, we showed that Tfr cells emerged from FoxP3+ precursors in low-IL-2 environments through a TGF-β- and c-Maf-dependent pathway, allowing for reprogramming and reinforcement of the follicular regulatory cell program in CD4+ T cells in vitro.

Animals↗

PubMed2026

The bidirectional genetic causality between immunocyte phenotypes and dilated cardiomyopathy: A bidirectional Mendelian randomization study.

The association between immunocyte phenotypes and dilated cardiomyopathy (DCM) has been explored, however the exact pathogenesis of the relationship between immune cells and DCM is unclear. This bidirectional two-sample Mendelian randomization (MR) research aims to further validate the causal link between 731 immunocyte phenotypes and DCM. Summary statistics from a genome-wide association study data of individuals with European ancestry were utilized, including 1444 DCM cases and 353,937 controls, as well as 3757 European adults for the 731 immunocyte phenotypes. Causal effects were estimated using inverse variance weighted, MR-Egger regression, weight median estimator, weighted mode, and simple mode. Sensitivity analysis was conducted to confirm data robustness and feasibility. Based on the inverse variance weighted findings, 14 immunocyte phenotypes were risk factors for DCM (P < .05, odds ratio [OR] > 1), while 15 immunocyte phenotypes exhibited a protective effect on DCM (P < .05, OR < 1). The results of reverse MR analysis suggested evidence that DCM occurrence might elevate the levels of 17 immunocyte phenotypes (P < .05, OR > 1) and decrease the levels of 9 immunocyte phenotypes (P < .05, OR < 1). Our research indicated that CD28 on secreting regulatory T cell could mitigate the occurrence of DCM, and reciprocally, the progression of DCM could reduce the level of CD28 on secreting regulatory T cell. This study confirmed the bidirectional genetic predictive relationship between immunocyte phenotypes and DCM, underscoring the complex interplay between DCM and the immune system.

Cardiomyopathy, Dilated↗

PubMed2026

A Functionally Constrained Immune Ecosystem in Microsatellite-stable Colorectal Cancer Resolved by Single-cell and Exome Profiling.

BACKGROUND/AIM: Microsatellite-stable (MSS) colorectal cancer (CRC) generally responds poorly to immune checkpoint blockade, but some MSS tumors are T-cell rich. We examined whether such infiltration reflected effective immunity or functional immune constraint. CASE REPORT: A 77-year-old woman underwent resection of a mismatch repair-proficient (pMMR), MSS, low-mutational-burden CRC with a synchronous adenoma. Whole-exome sequencing of tumor, adenoma and adjacent normal tissue detected no shared high-confidence somatic mutations between tumor and adenoma within the sensitivity of this WES analysis and identified tumor-specific APC, KRAS and TP53 alterations. Tumor single-cell RNA sequencing yielded 7,569 cells, with T-lineage populations comprising 83.5%. Cytotoxic T cells showed cytolytic and dysfunction-associated features, regulatory T cells (Tregs) showed suppressive remodeling, and Th17 cells showed inflammatory/profibrotic programs. CellChat nominated stromal MIF/FN1-CD74/CD44 and extracellular-matrix communication with T-cell compartments. CONCLUSION: This molecular case report shows that T-cell abundance and immune effectiveness can be uncoupled in MSS CRC.

Humans↗

PubMed2026

An inflammatory bowel disease-linked lncRNA suppresses transcription factor T-BET expression in T cells to limit intestinal inflammation.

Among the tens of thousands of annotated long noncoding RNAs (lncRNAs) in the human genome, only a small fraction have been functionally characterized. Here, we show that a well-established inflammatory bowel disease (IBD) risk locus encoded a conserved lncRNA, lnc15 (2310015A10Rik/ENSMUSG00000097729), whose structure was destabilized by risk-associated variants, leading to its degradation. Deletion of lnc15 in mice resulted in molecular features of inflammation under steady-state conditions and conferred heightened susceptibility to experimental colitis. Lnc15 was abundantly expressed in T cells, with highest expression in regulatory T (Treg) cells. Mechanistically, lnc15 suppressed the transcription factor T-BET by recruiting the CCR4-NOT RNA degradation complex to Tbx21 mRNA. Our study identifies that lnc15 simultaneously enhances Treg cell suppressive function and impairs conventional T cell pathogenicity in the context of intestinal inflammation. Collectively, these findings identify lnc15 as a functional lncRNA that links noncoding genetic variation to immune regulation and prevention of mucosal inflammation. VIDEO ABSTRACT.

RNA, Long Noncoding↗

PubMed2026

Defined human Clostridia consortia reverse colitis via dual effects of tryptophan metabolites on microbiota and immunity.

Microbial dysbiosis and disrupted mucosal immune homeostasis are integrally involved in the pathogenesis of inflammatory bowel diseases (IBDs). Live biotherapeutic products (LBPs) offer a potential therapeutic strategy to restore beneficial microbes and mitigate disease. We investigated the therapeutic efficacy of 2 LBPs, human Clostridia consortia 17-mix and 11-mix, by treating established colitis in murine models. Both LBPs exhibited therapeutic effects in T cell-mediated chronic colitis models induced by human microbiota and in pathobiont-driven gnotobiotic colitis models established with combinations of IBD-relevant human-derived strains. Metagenomic and metabolomic analyses elucidated mechanisms that go beyond established functions driven by short-chain fatty acids (SCFAs) and interleukin (IL)-10-producing regulatory T cells. Notably, LBPs exerted therapeutic effects by directly inhibiting resident pathobionts and through IL-10-independent activation of host anti-inflammatory aryl hydrocarbon receptor (AhR) pathways by bacterial tryptophan metabolites. These results elucidate SCFA- and IL-10-independent protective mechanisms exerted by defined resident bacterial strains that are depleted in IBD dysbiosis.

Animals↗

PubMed2026

The future of TCR-Treg therapies is renewables.

Cell therapy has longstanding roots in haematopoietic stem cell transplantation and early immune cell transfers in infectious disease and transplantation, where patient- or donor-derived cells have achieved therapeutic benefit in selected contexts. The modern era has been driven largely by oncology, with engineered modalities such as tumour-infiltrating lymphocytes, CAR-T cells and TCR-engineered T cells delivering transformative responses but requiring complex, costly manufacturing. These platforms are now being adapted for autoimmune diseases to induce durable, antigen-specific immune tolerance, yet broad application is limited by safety concerns, process complexity and access. Non-engineered cell therapies for autoimmunity, including mesenchymal stem cells, polyclonal regulatory T cells and tolerogenic dendritic cells, have shown acceptable safety and proof-of-principle for immune re-education, but clinical responses have been modest and inconsistent, with limited scalability. Engineered approaches such as CAR-T cells can induce reversible B cell depletion in B cell-mediated rheumatic diseases but only addresses antibody-driven pathology and not T cell-mediated autoimmunity. TCR-engineered Tregs have emerged as a promising antigen-specific strategy, offering localized, antigen-linked suppression with bystander tolerance. Preclinical and early clinical data suggest superior potency, stability and disease control compared with polyclonal Tregs at similar or lower doses, but translation is constrained by the rarity and fragility of Tregs and by labour-intensive, CAR-T-like manufacturing. This review highlights emerging solutions for closed, automated and decentralised production, and discusses allogeneic approaches using gene-edited or banked Tregs with HLA engineering or matching. Together, these advances support the development of scalable, "off-the-shelf" TCR-Treg products with potential to provide safe, affordable tolerance-restoring therapies for autoimmune disease.

Humans↗

PubMed2026

Network pharmacological and experimental validation of the mechanism of Chaihu Guizhi Ganjiang decoction regulating T helper cell 17/regulatory T cell balance to improve autoimmune hepatitis.

OBJECTIVE: To elucidate the therapeutic efficacy and mechanism of action of Chaihu Guizhi Ganjiang decoction (, CGGD) in autoimmune hepatitis. METHODS: CGGD components and potential target genes were extracted from previously published databases. The autoimmune hepatitis (AIH)-related regulatory genes were obtained from the DisGeNET database. Intersections were taken, and enrichment analyses were performed on the extracted data. Concanavalin A (ConA)-induced AIH model mice were treated with CGGD via gavage. The results of network pharmacological analysis were experimentally validated. RESULTS: Network pharmacology revealed 228 genes at the intersection of AIH and CGGD. Kyoto Encyclopedia of Genes and Genomes analysis revealed that CGGD primarily regulates the phosphoinositide 3-kinase (PI3K)/ protein kinase B (AKT) signaling pathway and cellular metabolism in AIH. Gene Ontology enrichment analysis revealed that CGGD modulates inflammation through transcription factor-mediated signaling pathways. As predicted, CGGD attenuated ConA-induced AIH in a dose-dependent manner by activating the PI3K/AKT signaling pathway. Histopathological assessment confirmed the protective effects of CGGD against ConA-induced AIH. Further investigation revealed that CGGD regulated the T helper cell 17 (Th17)/regulatory T cell (Treg) balance by modulating the PI3K/Akt/ nuclear factor kappa-B (NF-κB) pathway. CONCLUSIONS: This study demonstrated the therapeutic effect of CGGD on AIH through a combination of network pharmacological prediction and experimental validation. Its mechanism of action involves PI3K/Akt/ NF-κB-mediated regulation of Th17/Treg cells.

Animals↗

PubMed2026

A stromal platform for robust expansion of functional IL-10-producing B cells for immune regulation.

IL-10-producing B cells exert immunosuppressive effects, yet their low abundance and poor in vitro viability have limited their therapeutic application. Here, we developed a stromal coculture system using MS5 cells engineered to express human CD40L, BAFF, and IFN-β1 (MS5-3F, for "3 factors"), which enables robust induction and greater than 1000-fold expansion of human IL-10-producing B cells. The expanded cells showed phenotypic and transcriptional profiles characteristic of unswitched (IgM+) plasmablasts and potently suppressed CD4+ T cell proliferation in an IL-10-dependent manner. MS5-3F-expanded B cells also increased the frequency of regulatory T cells in vitro, an effect that was not abrogated by IL-10/IL-10R blockade, suggesting contributions from additional mechanisms. IL-10 production originated predominantly from naive B cells, rather than memory B cells. Furthermore, B cells from patients with systemic lupus erythematosus, despite impaired IL-10 production under conventional conditions, were efficiently differentiated into IL-10-producing B cells using this system. The expanded cells showed minimal IgG-secreting output. Our platform offers a scalable strategy for generating human regulatory B cells, laying the foundation for B cell-based immunotherapies.

Humans↗

PubMed2026

Role of IFIT1 and IFIT3 in systemic lupus erythematosus: modeling a diagnosis and exploring immune regulation.

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by multi-organ involvement and a protracted clinical course. Current diagnostic strategies, which rely heavily on clinical symptoms and serology, are often insufficient for early detection. Therefore, highly accurate diagnostic biomarkers are urgently needed to facilitate early intervention and optimize personalized treatment strategies. D atasets GSE61635 and GSE135779 were integrated to identify differentially expressed genes. Weighted gene co-expression network analysis (WGCNA) was performed to isolate the module with the strongest clinical relevance. Mendelian randomization and single‑cell RNA‑seq were used to identify key disease‑relevant genes. A diagnostic model was then constructed, and gene set variation analysis (GSVA), along with gene set enrichment analysis (GSEA), was conducted to elucidate the underlying molecular pathways. IFIT1 and IFIT3 were identified as 2 core genes highly expressed in monocytes and T cells of SLE patients. Functional enrichment analysis revealed that these genes were enriched in immune-related pathways, metabolic pathways related to inflammation and genomic stability. The diagnostic model showed good accuracy, with an area under the curve (AUC) of 0.974 on the training set and 0.912 on the validation set. IFIT1 and IFIT3 represent promising biomarkers for diagnosing SLE and appear to mediate key immune and metabolic disturbances. Furthermore, the developed model serves as an accurate and reliable instrument for early diagnosis and personalized therapy. Large-scale clinical studies are warranted to further validate these findings and evaluate their clinical application.

Humans↗

PubMed2026

Localized PD-1 CAR T therapy reprograms neuroinflammation.

B cell-depleting therapies are effective in multiple sclerosis (MS), yet some patients relapse, underscoring the need for more precise interventions. To identify new therapeutic targets, we generated a single-cell RNA sequencing (scRNA-seq) atlas of cerebrospinal fluid (CSF), brain, and blood from non-inflammatory controls and patients with MS or other neuroinflammatory diseases. We found disease-associated enrichment of class-switched immunoglobulin G+ (IgG+) B cells and plasma cells in MS CSF. Unbiased analysis identified a rare disease-enriched subset of activated, T cell receptor (TCR)-restricted, PD-1+ T follicular helper-like cells with B cell-recruiting features. To target this population, we developed PD-1-directed chimeric antigen receptor (CAR) T cells that selectively depleted pathogenic PD-1+ CD4 T cells and locally released IL-10. This strategy attenuated central nervous system (CNS) inflammation, reprogrammed the local immune milieu, and improved clinical outcomes across murine neuroinflammation models. These findings define a CNS-localized adaptive immune circuit in MS and nominate programmable PD-1 CAR T cells as a strategy to disrupt it.

Animals↗

PubMed2026

CAR-T Cell Therapy: Manufacturing Platforms and Clinical Consequences.

Chimeric antigen receptor (CAR) T-cell therapy has transformed hematological cancer care, yet variability in efficacy, durability, and safety cannot be explained solely by antigen selection or patient factors. We propose that manufacturing platforms are active biological determinants of outcome. Viral vectors, used in all licensed products, provide stable genomic integration and durable expression but are limited by cost, cargo capacity, and centralized production. Nonviral strategies, including transposons, CRISPR knock-ins, and messenger RNA delivery, enable faster, less-expensive manufacturing with larger payloads, while introducing distinct safety and persistence profiles. This review presents a three-layer mechanistic framework that reframes manufacturing as biology: integration biology determines genomic risk and transgene stability; clonal fitness shapes persistence, dominance, and exhaustion; and epigenomic imprinting, influenced by gene transfer method, cytokines, and culture stress, preconfigures functional trajectories. Clinical observations link platform choice to immune recovery, where prolonged B-cell aplasia and delayed T-cell reconstitution contribute to infection-related nonrelapse mortality, and hematopoietic reserve at apheresis emerges as a practical predictor. Finally, manufacturing is positioned as the key to democratizing cell therapy. Decentralized, nonviral production aligned with regulatory standards may enable equitable access and transition CAR-T therapy from innovation to sustainable global care.

Humans↗

PubMed2026

Immune Cell-Stratified Regulatory Contexts Associated With BMI-Related Multi-System Disease Risk: A Cell-Stratified Mendelian Randomization Study Using Single-Cell eQTL Data.

AIMS: Body mass index (BMI) is associated with multisystem disease risk, but the immune cell-specific regulatory contexts underlying BMI-related genetic associations with disease outcomes remain unclear. METHODS: We applied a cell-stratified Mendelian randomization framework integrating European-ancestry BMI GWAS data, GWAS datasets for 33 disease outcomes across five disease systems, single-cell cis-eQTL data from 28 peripheral blood immune cell types, and dynamic CD4+ T cell eQTL data. SuSiE-based colocalization was used to identify BMI-associated loci sharing causal variants with immune-cell gene expression. These variants were used as cell-stratified instruments for Mendelian randomization. RESULTS: Across 28 immune cell types, 1326 colocalized variants regulating 1426 genes were identified. In primary MR analyses, genetically predicted BMI showed Bonferroni-significant associations with 26 disease outcomes. Cell-stratified analyses identified 87 Bonferroni-significant associations across 17 disease outcomes. Cardiovascular diseases showed the broadest cell-stratified associations, followed by respiratory and metabolic diseases. CD4+ T cell regulatory contexts contributed one of the largest shares of prioritized associations, and BMI-related effects varied across CD4+ T cell activation states. Cross-disease prioritization highlighted recurrent immune feature genes, including TRAF3 and FGFR1. CONCLUSION: These findings prioritize CD4+ T cell regulatory contexts as potential immunogenetic links between BMI and multi-system disease risk, while requiring further validation in diverse populations and mechanistic models.

Humans↗

PubMed2026

Metadomain and metaloop genome interactions in mammalian T cells.

Recent studies have advanced understanding of chromosomal organization and its role in gene regulation, yet most analyses focus on short-range interactions (<2 Mb), limiting insight into broader architecture. The relationships between topologically associating domains (TADs), sub-TAD loops, cross-TAD interactions, and chromosomal compartmentalization remain poorly understood. Here, using high-resolution Hi-C analysis, we identify extensive multi-megabase and interchromosomal interactions (metaloops) in T lymphocytes that organize into meta-TAD associations (metadomains). These metaloops connect distal promoters and regulatory elements of genes functionally important in T cells, including Ctla4, Ikzf2, Il2ra, Ets1, and Foxo1. Reanalysis of mouse and human datasets confirms their reproducibility and dependence on superenhancers. Genome-wide clustering reveals three distinct interchromosomal hubs, including a superenhancer-enriched hub linked to T cell-specific gene activation. Integrative analysis of regulatory genomics data identifies factors associated with short- versus long-range interactions. This study introduces a broadly applicable computational framework and reveals features of T cell genome organization.

Animals↗

PubMed2026

CD4+T cell metabolic reprogramming as therapeutic targets in neurodegenerative diseases.

Neurodegenerative diseases are a group of disorders characterized by the progressive loss of structure and function of neurons in the brain and/or peripheral nervous system. The main pathological feature of neurodegenerative disease in the central nervous system (CNS) is the selective neuronal loss in the brain and spinal cord, leading to cognitive and/or motor dysfunction. The immune system plays a variety of roles in the pathophysiology of neurodegenerative diseases. CD4+T cells are being recognized as important immunometabolic modulators in the pathophysiology of neurodegenerative disorders (ND), including multiple sclerosis (MS), Parkinson's disease (PD), and Alzheimer's disease (AD). Their varied metabolic patterns provide a special therapeutic window for regulating neuroinflammation, spanning from lipid-dependent regulatory T cells (Tregs) to glycolysis-driven pro-inflammatory subsets (Th1, Th17). Abnormal immune metabolism raises the risk of oxidative stress, mitochondrial malfunction, and neuronal death in neurodegenerative environments. According to recent research, altering CD4 T cell metabolism to favour oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) may help Treg function return and inhibit harmful effector responses. Current research on CD4 T cell immunometabolic pathways, their interactions with CNS-resident cells, and the developing possibility of metabolic intervention to slow neurodegeneration is explained in this review. By examining important signaling pathways including AMPK, mTORC1, and ROS dynamics, we demonstrate how CD4+T cell metabolism may reshape ND treatment approaches.

Humans↗

PubMed2026

Deciphering CD8+ T cell exhaustion in human cancers through single-cell and spatial transcriptomics.

Exhausted CD8+ T cells (Tex) within the tumor microenvironment (TME) represents a critical barrier limiting anti-tumor immune responses. Tex cells are characterized by upregulated inhibitory immune checkpoint receptors, reduced cytotoxicity, and functional heterogeneity. Their genomic features and regulatory networks remain poorly defined, and only a minority of patients respond to immune checkpoint blockade (ICB) therapy. Single-cell RNA sequencing (scRNA-seq), through high-resolution transcriptomic profiling, has revealed diverse Tex subpopulations, identified subpopulation-specific marker genes and regulatory pathways. Spatial transcriptomics has further mapped the spatial distribution of Tex and their interaction networks with immune cells, tumor cells, and stromal cells, elucidating the impact of spatial heterogeneity on Tex functionality. Current studies indicate that the exhausted state of Tex is dynamic and modifiable, with functional differences among subpopulations closely associated with tumor progression and therapeutic response. However, the genomic characteristics, epigenetic regulation, and spatial interaction mechanisms of Tex require further exploration. This review summarizes recent advances in high-resolution omics technologies for precisely dissecting Tex heterogeneity, functional features, and interactions with other cells. It emphasizes the central value of optimizing Tex-targeted tumor immunotherapy strategies, providing theoretical foundations and directional guidance for developing more effective anti-tumor immunotherapies.

Humans↗

PubMed2026

DNA methylation landscape of cerebrospinal fluid cells in multiple sclerosis: an epigenome-wide association study.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system in which DNA methylation may link genetic and environmental risk factors. METHODS: We profiled genome-wide DNA methylation in cerebrospinal fluid (CSF) cells from people with MS (pwMS) and matched controls. Differentially methylated positions (DMPs) and regions (DMRs) were integrated with transcriptomic data, T-cell chromatin annotations, and pathway analyses. Protocadherin gamma (PCDHγ) expression was assessed in primary CD4+ T-cell subsets and confirmed by flow cytometry. FINDINGS: We identified 2710 DMPs and 4330 DMRs associating with genes that were enriched in immune signalling, adhesion and migration processes, and were accompanied by corresponding RNA changes. MS-associated methylation changes enriched in the cohesin chromatin-regulation pathway localised to T-cell regulatory regions, and this pathway included multiple protocadherin (PCDH) genes, which displayed consistent methylation and expression changes in CSF cells of pwMS compared to controls. PCDHγ cluster gene expression was detected in CD4+ T-cell subsets, and flow cytometry confirmed PCDHγ protein expression in peripheral blood T cells. Moreover, co-expression analysis suggests a role of PCDH genes in aryl hydrocarbon receptor (AHR) signalling. Protein-level validation showed fewer PCDHγ-positive CD4+ T cells in pwMS and activation-induced PCDHγ upregulation after T-cell stimulation. INTERPRETATION: DNA methylation changes in CSF resident cells reflect dysregulated T cell activation and migration in pwMS and suggest involvement of protocadherin molecules in MS pathogenesis. FUNDING: European Research Council, Swedish Research Council, Swedish Brain Foundation, Swedish MS Foundation, Knut and Alice Wallenberg Foundation, European Union and others.

Humans↗

PubMed2026

A novel FLNA p.Pro2469Ser variant is associated with impaired T and NK cell function and immune dysregulation.

FLNA encodes filamin A, a ubiquitously expressed actin-binding cytoskeletal protein that cross-links actin filaments and links them to membrane-associated signaling complexes. Although FLNA has been implicated in T-cell signaling and regulatory T-cell development in murine models, its role in human immune-cell function remains incompletely understood. Here, we investigated the immunological phenotype associated with a novel hemizygous FLNA variant identified in a pediatric patient presenting with recurrent infections and inflammatory manifestations. Whole-exome sequencing revealed a hemizygous c.7405C>T (p.Pro2469Ser) variant in FLNA, which was confirmed by Sanger sequencing. Its potential impact on immune-cell function and cytoskeletal organization was evaluated using confocal microscopy, flow cytometry, and molecular assays. Patient-derived T cells showed impaired activation and proliferation following CD3/CD28 and IL-2 stimulation, accompanied by reduced CD25 and CD69 upregulation. CD4+ T cells also exhibited reduced IFN-γ, TNF-α, and IL-2 production after stimulation. Despite elevated basal phospho-STAT5 levels, IL-2-induced STAT5 phosphorylation and TCR-associated signaling responses, including pZAP70, pLCK, and p38 MAPK activation, were attenuated. Confocal imaging together with image-based quantification demonstrated altered cortical cytoskeletal organization in patient T cells despite preserved FLNA expression. In parallel, NK cells showed impaired activation responses and reduced cytotoxic activity under the assay conditions used. Increased apoptosis was observed in CD4⁺, CD8⁺, and NK-cell populations. Inflammatory cytokines were elevated in plasma and colonic tissue, whereas colonic ZO-1 and FLNA expression were reduced. Collectively, these findings indicate that the FLNA p.Pro2469Ser variant is associated with altered immune-cell signaling, disturbed cortical cytoskeletal organization, and immune dysregulation. This study expands the phenotypic spectrum linked to FLNA variants and supports a role for filamin A in human immune-cell regulation.

Humans↗