Autoreactive T Cells Research Articles

Activation in Autoimmunity: Mechanisms and Clinical Implications

Autoimmunity arises when the immune system mistakenly targets the body’s own tissues, leading to chronic inflammatory diseases that can affect multiple organs. The central event in autoimmunity is the inappropriate activation of immune cells, which normally tolerate self-antigens. This review examines the mechanisms underlying immune activation in autoimmunity, focusing on the loss of immune tolerance, molecular mimicry, bystander activation, and epitope spreading. Genetic predispositions and environmental triggers, such as infections, play key roles in this process, contributing to the dysregulation of immune responses. Specific immune cells, including autoreactive T cells, B cells producing autoantibodies, and dendritic cells presenting self-antigens, drive disease pathogenesis by perpetuating inflammation and tissue damage. Dysfunctions in regulatory T cells (Tregs) further exacerbate immune activation by failing to suppress autoreactive lymphocytes. Clinically, understanding these activation mechanisms is crucial for developing diagnostic biomarkers and targeted therapies. Current treatments focus on modulating immune responses through biologic agents that block pro-inflammatory cytokines (e.g., TNF-α, IL-6), deplete B cells (e.g., rituximab), or restore immune regulation (e.g., Treg therapies). Emerging therapies aim to restore immune tolerance, offering hope for more effective and personalized interventions. This review highlights the critical role of immune activation in autoimmunity and discusses therapeutic strategies to prevent or reverse this process. The ongoing exploration of these mechanisms is key to improving outcomes for patients with autoimmune diseases. Keywords: Autoimmunity, immune tolerance, molecular mimicry, T cells, autoantibodies, targeted therapy

Antigen-specific modulation of chronic experimental autoimmune encephalomyelitis in humanized mice by TCR-like antibody targeting autoreactive T-cell epitope.

The development and application of human TCR-like (TCRL) antibodies recognizing disease-specific MHC-peptide complexes mayprove asan important tool for basic research and therapeutic applications. Multiple sclerosis is characterized by aberrant CD4 T-cell response to self-antigens presented by MHC class II molecules. This led us to select a panel of TCRL Abs targeting the immunodominant autoantigenic epitope MOG35-55 derived from myelin oligodendrocyte glycoprotein (MOG) presented on HLA-DR2, which is associated with multiple sclerosis (MS). We demonstrate that these TCRL Abs bind with high specificity to human HLA-DR2/MOG35-55-derived MHC class II molecules and can detect APCs that naturally present the MS-associated autoantigen in the humanized EAE transgenic mouse model. The TCRL Abs can block ex vivo and in vivo CD4 T-cell proliferation in response to MOG35-55 stimulation in an antigen-specific manner. Most significantly, administration of TCRL Abs to MOG35-55-induced EAE model in HLA-DR2 transgenic mice both prevents and regresses established EAE. TCRL function was associated with a reduction in autoreactive pathogenic T-cell infiltration into the CNS, along with modulation of activated CD11b+ macrophages/microglial APCs. Collectively, these findings demonstrate the combined action of TCRL Abs in blocking TCR-MHC interactions and modulating APC presentation and activation, leading to a profound antigen-specific inhibitory effect on the neuroinflammatory process, resulting in regression of EAE. Our study constitutes an in vivo proof of concept for the utility of TCR-like antibodies as antigen-specific immunomodulators for CD4-mediated autoimmune diseases such as MS, validating the importance of the TCR-MHC axis as a therapeutic target for various autoimmune and inflammatory diseases.

The effect of immunosuppressive agent FTY-720 on coagulation, nitroxidergic lung activity and water balance in experimental antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic acquired autoimmune thrombophilia that leads to impaired non-respiratory lung functions due to the circulation of antiphospholipid antibodies, shifting the balance between the coagulation link of hemostasis and the anti-coagulation system towards hypercoagulation. The research examines the modulating effect of FTY-720 on the water balance, coagulation and NO-activity of the lungs under conditions of experimental APS. The functional activity of FTY-720 is largely due to its ability to bind to S1P1 receptors and block signaling pathways mediated by the interaction of the mediator sphingosine-1-phosphate with them. The main effect of FTY-720 is immunosuppression, which develops as a result of the drug’s receptor interaction predominantly with S1P1 receptors, resulting in the retention of autoreactive lymphocytes in lymph nodes, and prevents further spread of inflammation and damage. The experiments were conducted on 85 male rats, divided into groups as follows: The first group of animals (n = 30) was injected with cardiolipin antigen every other day for three weeks for APS modeling; the rats of the second group (n = 25), which served as a control group, were similarly injected with 0.9% NaCl; APS modeling and FTY-720 injection were combined on the remaining animals (n = 30). Three weeks later, arterial (art) and venous (ven) blood was taken, in which APTT and PT were determined using a hemocoagulometer CGL 2110 “Solar” and the corresponding coefficients of APPT of ven/art, PT of ven/ art were calculated. NO-activity was assessed by the content of plasma NO and NO bronchoalveolar lavage obtained by washing the extraction of the bronchopulmonary complex in anesthetized animals. To study the water balance of the lungs, the mass of moist and dried lungs was measured, were determined the total, extra- and intravascular fluid of the lungs. In APS, an increase in APTT and PT of arterial and venous blood was observed, an increase in the level of NO in bronchoalveolar lavages against the background of worsening nitroxidergic activity of the lungs – the NO index of ven/art decreased. There was a positive effect of FTY- 720 on the restoration of non-respiratory lung functions in APS.

8090 A Gut Commensal, Parabacteroides distasonis, and Molecular Mimicry in Type 1 Diabetes

Abstract Disclosure: A. Randall: None. Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the destruction of pancreatic, insulin-producing beta cells by autoreactive T-cells. The trigger(s) of T1D are unclear and genetics alone cannot explain the recent increase in T1D incidence. The gut microbiome composition in T1D patients is altered and thought to play a key role in T1D pathogenesis. Most longitudinal studies have been descriptive. However, a direct cause-and-effect relationship hasn't been established yet. Insulin is a key autoantigen in T1D autoimmunity, and insulin B-chain amino acids 9-23 (insB:9-23) is an important, commonly recognized T-cell epitope. Molecular mimicry is an autoimmunity mechanism where host-like microbial proteins trigger autoimmune responses. We previously identified a peptide mimic of insB:9-23, amino acids 4-18 of hypoxanthine phosphoribosyl transferase (HPRT:4-18) of Parabacteroides distasonis (Girdhar et al., 2022). HPRT:4-18 stimulated insB:9-23-specific human and non-obese diabetic (NOD) mice T-cells. We hypothesize that P. distasonis HPRT:4-18 is required to accelerate diabetes via molecular mimicry of insB:9-23. By orally gavaging NOD mice (n=40 mice/group), we showed that P. distasonis accelerated diabetes onset. Next, we colonized NOD mice with another common gut commensal, Bacteroides fragilis, as a control, and did not observe any effect on islet infiltration. In addition, P. distasonis colonization increased infiltration of immune cells into the islets of germ-free NOD mice (n=6-8 mice/group), while the diabetes incidence experiment in mice is ongoing. P. distasonis-colonized mice had significantly more splenic CD8 and naïve T-cells, dendritic cells and macrophages but fewer FOXP3 cells (n=3-6 mice/group). To determine whether P. distasonis’s effect is specific to the pancreas, we checked intestinal barrier function and intestinal immune cell composition. Disruption of intestinal barrier function has been associated with diabetes. P. distasonis colonization did not alter gut permeability. Furthermore, P. distasonis did not increase intestinal inflammation. Among the intestinal intraepithelial lymphocytes (IELs), there were fewer naïve, central and effector T-cells and B-cells. The findings indicate that P. distasonis does not stimulate an unspecific immune response and its inflammatory effect is specific to the pancreas, supporting our initial hypothesis. Taken together, our results indicate that exposure to P. distasonis in the first years of life has the potential to stimulate molecular mimicry mechanism and cause T1D onset. Reference: Girdhar, K., Huang, Q., Chow, I. T., Vatanen, T., Brady, C., Raisingani, A., . . . Altindis, E. (2022). A gut microbial peptide and molecular mimicry in the pathogenesis of type 1 diabetes. Proc Natl Acad Sci U S A, 119(31), e2120028119. doi:10.1073/pnas.2120028119 Presentation: 6/2/2024

Decoding the genetic influence of CT60 non-coding polymorphism in CTLA-4 gene and sCTLA-4 biomarker with rheumatoid arthritis in the Indian population.

Cytoplasmic T Lymphocyte Antigen - 4 (CTLA-4) gene encodes an immunoregulatory receptor expressed on surface of activated T-cells to mediate peripheral tolerance against self-antigen. It suppresses auto-reactive T-cell proliferation either by inactivation or apoptosis of T-cells. The CTLA-4 mRNA undergoes alternative splicing to synthesize a native soluble form of CTLA-4 (sCTLA-4) protein, which lacks exon 3 that encodes for transmembrane region. As a result, sCTLA-4 circulates as a soluble serum protein and acts as an immunoregulator molecule to maintain homeostasis in the blood. Techniques coupled with quantitative Polymerase Chain Reaction (qPCR) and High-Resolution Melting Analysis (HRMA) were used to screen CTLA-4 3'Untranslated Region (UTR) CT60 (A/G) rs3087243 Single Nucleotide Polymorphism (SNP) and their association with Rheumatoid Arthritis (RA) in the Indian population. In addition, we also evaluated the concentration of sCTLA-4 serum protein in RA patients carrying rs3087243 SNP with different genotypes (A/A, G/A, and G/G). Statistical analysis of Odds Ratio (OR), Confidence Interval (C.I), and Relative Risk (RR) have shown that frequency of CTLA-4 rs3087243 SNP G/G genotype was significantly associated with RA in the Indian population (OR 1.7140; CI = 1.0765 to 2.7290; RR = 1.5434; p = 0.0232). The sCTLA-4 concentration was also significantly lower in RA patients carrying rs3087243 SNP G/G genotype than control group (p < 0.001). Co-inheritance of CTLA-4 signal peptide and 3'UTR SNPs may activate RAPP pathway. Downregulation of CTLA-4 and sCTLA-4 serum protein by rs3087243 SNP can increase the hyperactivation of T-cells, which causes RA.

Prebiotic inulin controls Th17 cells mediated central nervous system autoimmunity through modulating the gut microbiota and short chain fatty acids

ABSTRACT Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory demyelination occurring in the central nervous system (CNS). Inulin is a common prebiotic that can improve metabolic disorders by modulating the gut microbiota. However, its capacity to affect CNS autoimmunity is poorly recognized. Experimental autoimmune encephalomyelitis (EAE) is a classical mouse model of MS. Herein, we found that oral administration of inulin ameliorated the severity EAE in mice, accompanied by reductions in inflammatory cell infiltration and demyelination in the CNS. These reductions were associated with decreased proportion and numbers of Th17 cells in brain and spleen. Consistent with the findings, the serum concentrations of IL-17, IL-6, and TNF-α were reduced in inulin treated EAE mice. Moreover, the proliferation of auto-reactive lymphocytes, against MOG35-55 antigen, was attenuated ex vivo. Mechanistically, inulin treatment altered the composition of gut microbiota. It increased Lactobacillus and Dubosiella whereas decreased g_Prevotellaceae_NK3B31_group at the genus level, alongside with elevated concentration of butyric acid in fecal content and serum. In vitro, butyrate, but not inulin, could inhibit the activation of MOG35-55 stimulated lymphocytes. Furthermore, fecal microbiota transplantation assay confirmed that fecal contents of inulin-treated normal mice had an ameliorative effect on EAE mice. In contrast, antibiotic cocktail (ABX) treatment diminished the therapeutic effect of inulin in EAE mice as well as the reduction of Th17 cells, while supplementation with Lactobacillus reuteri restored the amelioration effect. These results confirmed that the attenuation of inulin on Th17 cells and inflammatory demyelination in EAE mice was dependent on its modulation on gut microbiota and metabolites. Our findings provide a potential therapeutic regimen for prebiotic inulin supplementation in patients with multiple sclerosis.

Neoself-antigens are the primary target for autoreactive T cells in human lupus

Major histocompatibility complex class II (MHC-II) is the most significant genetic risk factor for systemic lupus erythematosus (SLE), but the nature of the self-antigens that trigger autoimmunity remains unclear. Unusual self-antigens, termed neoself-antigens, are presented on MHC-II in the absence of the invariant chain essential for peptide presentation. Here, we demonstrate that neoself-antigens are the primary target for autoreactive Tcells clonally expanded in SLE. When neoself-antigen presentation was induced by deleting the invariant chain in adult mice, neoself-reactive Tcells were clonally expanded, leading to the development of lupus-like disease. Furthermore, we found that neoself-reactive CD4+ Tcells were significantly expanded in SLE patients. A high frequency of Epstein-Barr virus reactivation is a risk factor for SLE. Neoself-reactive lupus Tcells were activated by Epstein-Barr-virus-reactivated cells through downregulation of the invariant chain. Together, our findings imply that neoself-antigen presentation by MHC-II plays a crucial role in the pathogenesis of SLE.

Association Between the Immune Checkpoint Inhibitor Durvalumab and Myasthenia Gravis: A Comprehensive Review.

Immune checkpoint inhibitors (ICIs), including Imfinzi (durvalumab), have revolutionized cancer treatment by stimulating the body's immune system to target cancerous cells. Although pharmaceuticals offer therapeutic benefits, several drugs have been associated with immune-related adverse events (irAEs), including the uncommon but serious condition known as myasthenia gravis (MG). This review synthesizes data from pertinent research to offer a thorough evaluation of the literature on the underlying mechanisms, clinical manifestations, and therapeutic approaches for durvalumab-induced MG. The incidence of MG in patients on durvalumab and other ICIs is typically low, with less than 1% documented, despite the potential for severe problems associated with the disease. Durvalumab disrupts immunological tolerance by stimulating autoreactive T-cells and inducing the production of autoantibodies. The clinical consequences of MG need meticulous monitoring, prompt identification, and suitable management to efficiently control the condition. Medical practitioners must carefully weigh the positive effects of ICIs against the possible hazards, emphasizing the necessity for more extensive investigation to improve patient results and establish uniform treatment protocols.

Chronic recurrent multifocal osteomyelitis: A challenging diagnosis

Introduction. Chronic recurrent multifocal osteomyelitis (CRMO) is a pediatric autoinflammatory disorder that is characterized by multiple sterile inflammatory bone lesions with a relapsing and remitting course. CRMO belongs to the autoinflammatory family of rheumatologic disorders based on absence of significant titers of autoantibodies and autoreactive T-lymphocytes. In absence of pathognomonic clinical, radiographic or pathological features, diagnosis can be challenging. Case presentation. We report an unusual case of a 3-year-old girl presenting back pain, neurogenic bladder and syringomyelia. A tethered cord was diagnosed and treated, improving urinary function. Despite the surgical treatment, back pain was persistent. A whole body MRI showed multiple lesions compatible with chronic recurrent multifocal osteomyelitis. Conclusion. CRMO shares imaging features with other diseases. It is important for neurosurgeons and radiologists to be able to differentiate other diseases from CRMO because prognosis varies from completely benign to frankly malignant.

Membranous tonsillitis: Aetiology, prevalence and prescribing patterns in patients with upper respiratory tract infection.

Background Membranous tonsillitis is one of the most common forms of acute tonsillitis in childhood. Although many different microorganisms may cause this disease, clinicians generally consider bacterial agents as a possible cause and prescribe a penicillin-group of antibiotic. This study aimed to determine the aetiology of membranous tonsillitis and prescribing errors. In addition, we investigated the effectiveness of epidemiological, clinical and laboratory parameters and their role in guiding treatment. Methods We did this retrospective study at the paediatric emergency department of a tertiary referral hospital including 423 outpatient children aged 0 to 18 years diagnosed with membranous tonsillitis. Results Group A beta-haemolytic streptococcus was found in 132 (31.2%) patients, Epstein-Barr virus (EBV) in 103 (24.3%), and other viral aetiologies in 188 (44.4%). The prescription rate of antibiotics in the EBV-positive group was 27%, and Downey cells were seen at a rate of 98% in this group. Only 7% of patients with a positive throat culture were started on appropriate antibiotics. Conclusion EBV and group A beta-haemolytic streptococcus were the most common causes of membranous tonsillitis. Throat culture and peripheral blood smears are the most useful tests for paediatric emergency clinicians; these are fast and can help ensure correct diagnosis and guide treatment in almost all patients.

Aplastic anemia in association with multiple myeloma: clinical and pathophysiological insights

We investigated immune cytopenia in multiple myeloma (MM) patients with concurrent acquired aplastic anemia (AA), focusing on three clinical cases treated with plasma cell-directed therapy. All three patients achieved partial response in MM and one patient experienced complete resolution of AA. Two patients had partial improvement in transfusion requirement but continued to suffer from severe AA, leading to immunosuppressive therapy (IST) with improvement of transfusion requirement in both patients. In vitro serum testing of these patients demonstrated platelet mitochondrial dysfunction and platelet apoptosis but did not show sera-specific inhibition of erythroid colony formation in progenitor cells. The levels of IL8 and IL15 were elevated in MM patients with AA, implicating their potential roles in this co-occurrence. Response to IST points to the possibility of myeloma-dysregulated immune system leading to autoreactive T-cell destruction of hematopoietic stem and progenitor cells, offering insights for developing new treatment for cytopenia in MM.

Potential role of B- and NK-cells in the pathogenesis of pediatric aplastic anemia through deep phenotyping.

Pediatric patients with unexplained bone marrow failure (BMF) are often categorized as aplastic anemia (AA). Based on the accepted hypothesis of an auto-immune mechanism underlying AA, immune suppressive therapy (IST) might be effective. However, due to the lack of diagnostic tools to identify immune AA and prognostic markers to predict IST response together with the unequaled curative potential of hematopoietic stem cell transplantation (HSCT), most pediatric severe AA patients are momentarily treated by HSCT if available. Although several studies indicate oligoclonal T-cells with cytotoxic activities towards the hematopoietic stem cells, increasing evidence points towards defective inhibitory mechanisms failing to inhibit auto-reactive T-cells. We aimed to investigate the role of NK- and B-cells in seven pediatric AA patients through a comprehensive analysis of paired bone marrow and peripheral blood samples with spectral flow cytometry in comparison to healthy age-matched bone marrow donors. We observed a reduced absolute number of NK-cells in peripheral blood of AA patients with a skewed distribution towards CD56bright NK-cells in a subgroup of patients. The enriched CD56bright NK-cells had a lower expression of CD45RA and TIGIT and a higher expression of CD16, compared to healthy donors. Functional analysis revealed no differences in degranulation. However, IFN-γ production and perforin expression of NK-cells were reduced in the CD56bright-enriched patient group. The diminished NK-cell function in this subgroup might underly the auto-immunity. Importantly, NK-function of AA patients with reduced CD56bright NK-cells was comparable to healthy donors. Also, B-cell counts were lower in AA patients. Subset analysis revealed a trend towards reduction of transitional B-cells in both absolute and relative numbers compared to healthy controls. As these cells were previously hypothesized as regulatory cells in AA, decreased numbers might be involved in defective inhibition of auto-reactive T-cells. Interestingly, even in patients with normal distribution of precursor B-cells, the transitional compartment was reduced, indicating partial differentiation failure from immature to transitional B-cells or a selective loss. Our findings provide a base for future studies to unravel the role of transitional B-cells and CD56bright NK-cells in larger cohorts of pediatric AA patients as diagnostic markers for immune AA and targets for therapeutic interventions.

CAAR NK and T cells to eliminate autoreactive lymphocytes in autoimmune disorders.

CAAR NK and T cells to eliminate autoreactive lymphocytes in autoimmune disorders.

Activation of autoreactive lymphocytes in the lung by radioresistant cells expressing a STING gain-of-function mutation.

Gain-of-function mutations in the dsDNA sensing adaptor STING lead to a severe autoinflammatory syndrome known as STING-associated vasculopathy with onset in infancy (SAVI). Patients with SAVI develop interstitial lung disease (ILD) and produce autoantibodies that are commonly associated with systemic autoimmune diseases. Mice expressing the most common SAVI mutation, STING V154M (VM), similarly develop ILD but exhibit severe T and B cell lymphopenia and low serum Ig titers, and they lack autoantibodies. Importantly, lethally irradiated VM hosts reconstituted with WT stem cells (WT→VM) still develop ILD. In this study, we find that WT→VM chimeras had restored B cell function, produced autoantibodies, and thereby recapitulated the loss of tolerance seen in patients with SAVI. Lymphocytes derived from both WT and BCR or TCR transgenic (Tg) donors accumulated in the extravascular lung tissue of WT+Tg→VM mixed chimeras, but lymphocyte activation and germinal center formation required WT cells with a diverse repertoire. Furthermore, when T cells isolated from the WT→VM chimeras were adoptively transferred to naive Rag1-deficient secondary hosts, they trafficked to the lung and recruited neutrophils. Overall, these findings indicated that VM expression by radioresistant cells promoted the activation of autoreactive B cells and T cells that then differentiated into potentially pathogenic effector subsets.

Detection and characterization of autoreactive memory stem T-cells in children with acute immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by an isolated decrease in platelets below 100 × 109/l after the exclusion of other conditions associated with thrombocytopenia. We investigated the role of different memory T-cell subsets, including T stem cell memory (TSCM), in children diagnosed with primary ITP and its association with therapeutic duration. This case–control study included 39 pediatric patients with acute ITP admitted to the Children's Hospital at Assiut University. Using a FACSCanto flow cytometer, CD8 + and CD4 + T-lymphocytes were gated. Five different subsets were characterized in each of these cells according to CD45RO and CD45RA expression. Afterward, gating was performed based on CCR7, CD95, and CD27. Examination of the CD8 + T cells subpopulation showed that Central memory T (TCM) and CD8+ Naïve T (TN) cells were significantly lower in ITP patients than in healthy children (p < 0.0001) and (p = 0.01), respectively. In addition, CD8 + TEMRA was significantly higher in ITP children than in controls (p = 0.001). CD4 + TCM cells were significantly lower in the ITP patient group (p = 0.04). However, CD4 + TEM was significantly higher in patients than controls (p = 0.04). Our research found that ITP patients had an imbalance in the ratio of CD4+ to CD8+ T cells in the peripheral blood and that TCM cells may be involved in the pathogenetic mechanism of ITP. TCMs could help in prediction of patients with higher risk of developing ITP.

Exploring the Role of PD-1 in the Autoimmune Response: Insights into Its Implication in Systemic Lupus Erythematosus.

Despite advances in understanding systemic lupus erythematosus (SLE), many challenges remain in unraveling the precise mechanisms behind the disease's development and progression. Recent evidence has questioned the role of programmed cell death protein 1 (PD-1) in suppressing autoreactive CD4+ T cells during autoimmune responses. Research has investigated the potential impacts of PD-1 on various CD4+ T-cell subpopulations, including T follicular helper (Tfh) cells, circulating Tfh (cTfh) cells, and T peripheral helper (Tph) cells, all of which exhibit substantial PD-1 expression and are closely related to several autoimmune disorders, including SLE. This review highlights the complex role of PD-1 in autoimmunity and emphasizes the imperative for further research to elucidate its functions during autoreactive T-cell responses. Additionally, we address the potential of PD-1 and its ligands as possible therapeutic targets in SLE.

Understanding Autoimmunity: Mechanisms, Predisposing Factors, and Cytokine Therapies.

Autoimmunity refers to an organism's immune response against its own healthy cells, tissues, or components, potentially leading to irreversible damage to vital organs. Central and peripheral tolerance mechanisms play crucial roles in preventing autoimmunity by eliminating self-reactive T and B cells. The disruption of immunological tolerance, characterized by the failure of these mechanisms, results in the aberrant activation of autoreactive lymphocytes that target self-tissues, culminating in the pathogenesis of autoimmune disorders. Genetic predispositions, environmental exposures, and immunoregulatory disturbances synergistically contribute to the susceptibility and initiation of autoimmune pathologies. Within the realm of immune therapies for autoimmune diseases, cytokine therapies have emerged as a specialized strategy, targeting cytokine-mediated regulatory pathways to rectify immunological imbalances. Proinflammatory cytokines are key players in inducing and propagating autoimmune inflammation, highlighting the potential of cytokine therapies in managing autoimmune conditions. This review discusses the etiology of autoimmune diseases, current therapeutic approaches, and prospects for future drug design.

Scavengers in islets fuel diabetic autoimmunity

Autoreactive lymphocytes that infiltrate the pancreatic islet environment and target β cells are primary drivers of type 1 diabetes. In this issue of Immunity, Srivastava etal.1 examine the role of the islet microenvironment in autoimmunity and find that the scavenging receptor CXCL16 on islet-resident macrophages uptakes oxidized low-density lipoproteins and promotes the differentiation and survival of infiltrating pathogenic CD8+ Tcells.

224-OR: Effect of PD-L1 Overexpression on Autoreactive T-Cell Responses toward Stem Cell–Derived Beta Cells

224-OR: Effect of PD-L1 Overexpression on Autoreactive T-Cell Responses toward Stem Cell–Derived Beta Cells

Integrative profiling of untreated primary membranous nephropathy at the single-cell transcriptome level.

Primary membranous nephropathy (PMN) is an autoimmune kidney disease. Despite the identification of certain autoantigens, the etiology and pathophysiology of PMN are still largely unknown. Five patients with biopsy-proven PMN were enrolled in this study. Their blood, kidney and urine samples were collected respectively to profile cellular, molecular and immunological alterations by using single-cell RNA sequencing (scRNA-seq). Experimental verifications were also implemented in kidney tissue. In the peripheral blood mononuclear cell (PBMC) samples, portions of B cells and plasma cells were increased in PMN patients. Cell-cell communication analysis suggests that APRIL (a proliferation-inducing ligand from B cells) might be a potential molecule that regulates the activity of plasma cells. In the kidney samples, scRNA-seq analysis showed that the infiltration of T cells, as well as the myeloid cells, appears abundant compared with healthy controls, suggesting that immune cells are actively recruited to kidney. Furthermore, we observed an enhanced interaction between inflammatory cells and podocytes, which might contribute to kidney injury. Accordingly, scRNA-seq analysis of urinary samples is partially reminiscent of the kidney cell landscape, especially T cells and myeloid cells, suggesting monitoring urinary samples is a promising method to monitor PMN development. Additionally, integrative analysis across the blood, kidney and urine identified LTB, HERP1, ANXA1, IL1RN and ICAM1 as common regulators of PMN. Finally, immune repertoire in PBMC also showed an elevated diversity of clonal type, implying the existence of autoreactive T-cell receptor/B-cell receptor. Our study comprehensively profiled the transcriptomic landscapes of blood, kidney and urine in patients with PMN using scRNA-seq. We depicted the alterations including cell compositions and cell-cell communication in PMN. These results offer important clues with regard to the diagnosis and pathogenesis of PMN and potential intervention of PMN progression.