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Pro-inflammatory autoantigen-specific CD4+ T helper (auto-Th) cells are central orchestrators of autoimmune diseases (AIDs). We aimed to characterize these cells in human AIDs with defined autoantigens by combining human leukocyte antigen (HLA)-tetramer-based and activation-based multidimensional ex vivo analyses. In aquaporin4-antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) patients, auto-Th cells expressed CD154, but proliferative capacity and pro-inflammatory cytokines were strongly reduced. Instead, exhaustion-associated co-inhibitory receptors were expressed together with FOXP3, the canonical regulatory T cell (Treg) transcription factor. Auto-Th cells responded in vitro to checkpoint inhibition and provided potent B cell help. Cells with the same exhaustion-like (ThEx) phenotype were identified in soluble liver antigen (SLA)-antibody-autoimmune hepatitis and BP180-antibody-positive bullous pemphigoid, AIDs of the liver and skin, respectively. While originally described in cancer and chronic infection, our data point to T cell exhaustion as a common mechanism of adaptation to chronic (self-)stimulation across AID types and link exhausted CD4+ T cells to humoral autoimmune responses, with implications for therapeutic targeting.
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OBJECTIVE: Recently, autoantibodies directed against the epithelial adhesion protein integrin αVß6 have been identified which strongly associate with ulcerative colitis (UC). We aimed to elucidate whether anti-integrin αVß6 (anti- αVß6) is present in primary sclerosing cholangitis (PSC), its associated inflammatory bowel disease or other cholestatic liver diseases and their persistence after proctocolectomy. DESIGN: We detected anti- αVß6 by an enzyme-linked immunosorbent assay in sera collected at two German tertiary centers, including healthy controls (N=62), UC (N=36), Crohn's disease (CD, N=65), PSC-IBD (78 samples from N=41 patients), PSC without IBD (PSC, 41 samples from N=18 patients), primary biliary cholangitis (PBC, N=24), autoimmune hepatitis (AIH, N=32), secondary sclerosing cholangitis (SSC, N=12) and metabolic dysfunction-associated steatotic liver disease (MASLD, N=24). Additionally, sera after proctocolectomy were studied (44 samples / N= 10 patients). Immunofluorescent analyses were performed in tissue samples from liver, large bile duct from surgical resections and colon of PSC patients. RESULTS: Anti- αVß6 occurred in 91% of UC, 17% of CD, 73% of PSC-IBD, 39% of PSC, 4% of PBC, 14% of AIH, and 0% of healthy controls, SSC or MASLD. Integrin αVß6 is selectively expressed in disease-associated epithelia of both bile duct and colon. Anti- αVß6 levels correlate moderately with intestinal disease activity in PSC-IBD, but only weakly with biliary disease. CONCLUSION: Anti- αVß6 frequently occur in patients suffering from PSC, especially in PSC-IBD. Anti- αVß6 levels positively correlate to IBD activity in PSC-IBD, but may also occur in the absence of clinically manifest IBD in PSC.
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Aberrant CD4+ T cell reactivity against intestinal microorganisms is considered to drive mucosal inflammation in inflammatory bowel diseases. The disease-relevant microbial species and the corresponding microorganism-specific, pathogenic T cell phenotypes remain largely unknown. In the present study, we identified common gut commensal and food-derived yeasts, as direct activators of altered CD4+ T cell reactions in patients with Crohn's disease (CD). Yeast-responsive CD4+ T cells in CD display a cytotoxic T helper cell (TH1 cell) phenotype and show selective expansion of T cell clones that are highly cross-reactive to several commensal, as well as food-derived, fungal species. This indicates cross-reactive T cell selection by repeated encounter with conserved fungal antigens in the context of chronic intestinal disease. Our results highlighted a role of yeasts as drivers of aberrant CD4+ T cell reactivity in patients with CD and suggest that both gut-resident fungal commensals and daily dietary intake of yeasts might contribute to chronic activation of inflammatory CD4+ T cell responses in patients with CD.
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Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Humanos , Enfermedad de Crohn/microbiología , Linfocitos T CD4-Positivos , Enfermedades Inflamatorias del Intestino/patología , Linfocitos T Colaboradores-Inductores , Células Clonales/patología , Mucosa Intestinal/patología , Células Th17/patología , Células TH1/patologíaRESUMEN
Background: Together with impaired mucociliary clearance, lung disease in cystic fibrosis (CF) is driven by dysregulation of innate and adaptive immunity caused by dysfunctional CFTR (Cystic Fibrosis Transmembrane Conductance Regulator), leading to airway infection and hyperinflamma-tion. The highly effective CFTR modulator therapy (HEMT) elexacaftor/tezacaftor/ivacaftor (ETI) generates substantial improvements in clinical outcomes of people with CF (pwCF) by restoration of CFTR activity. Aberrant immune responses of lymphocytes due to CFTR dysfunction has been described in the past, but not the effects of CFTR restoration by HEMT on these cells. We aimed to examine the effect of ETI on the proliferative activity of antigen-specific CD154 (+) T cells against bacterial and fungal species relevant in CF and on total IgG and IgE as markers of B cell adaptive immunity. Methods: We performed ex vivo analyses of Ki-67 expression in antigen-specific CD154 (+) T cells against Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus fumigatus, Scedosporium apiospermum and Candida albicans from 21 pwCF by cytometric assay based on antigen-reactive T cell enrichment (ARTE), and analysis of total serum IgE and IgG before and after initiation of ETI. Results: Mean Ki-67 expression in antigen-specific CD154 (+) T cells against P. aeruginosa, A. fumigatus, S. apiospermum and C. albicans, but not S. aureus, mean total serum IgG and mean total serum IgE decreased significantly after initiation of ETI. No correlation was found to change in sputum microbiology of the examined pathogens. Mean BMI and FEV1 increased significantly. Conclusion: HEMT is associated with decreased antigen-specific CD154 (+) T cell proliferation activity in our cohort, independent of findings in sputum microbiology of the examined pathogens. Together with the observed clinical improvement and the decrease in total IgE and IgG, this indicates effects due to CFTR restoration on CD154 (+) T cells by ETI and a reduction of B cell activation with subsequent lower immunoglobulin synthesis under HEMT therapy. These results endorse earlier evidence of CFTR dysfunction in T and B cells leading directly to aberrant immune responses with hyperinflammation.
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Antigen-specific T lymphocytes are the central regulators of tolerance versus immune pathology against otherwise innocuous antigens and key targets of antigen-specific immune therapy. Recent advances in the understanding of T cells in tolerance and allergy resulted from improved technologies to directly characterize allergen-specific T cells by multiparameter flow cytometry or single-cell sequencing. This unravelled phenotypically and functionally distinct populations, such as Type 2a T helper cells (Th2a), follicular Th cells (Tfh), regulatory T cells (Treg), Type 1 regulatory T cells (Tr1), and follicular T regulatory cells. Here we will discuss the role of the different Th-cell subsets in the healthy state, during sensitization and development of allergy, and in tolerance induction by allergen immunotherapy (AIT). To date, the mechanisms of AIT as the only causal treatment of allergy are not completely understood. The analyses of allergen-specific T cells directly ex vivo during AIT support the concept of specific-Th2(a) cell deletion rather than an expansion of allergen-specific Tr1 or Treg cells as underlying mechanism.
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Hipersensibilidad , Humanos , Hipersensibilidad/terapia , Subgrupos de Linfocitos T , Desensibilización Inmunológica/métodos , Linfocitos T Reguladores , Tolerancia Inmunológica , AlérgenosRESUMEN
BACKGROUNDThe fungus Aspergillus fumigatus causes a variety of clinical phenotypes in patients with cystic fibrosis (pwCF). Th cells orchestrate immune responses against fungi, but the types of A. fumigatus-specific Th cells in pwCF and their contribution to protective immunity or inflammation remain poorly characterized.METHODSWe used antigen-reactive T cell enrichment (ARTE) to investigate fungus-reactive Th cells in peripheral blood of pwCF and healthy controls.RESULTSWe show that clonally expanded, high-avidity A. fumigatus-specific effector Th cells, which were absent in healthy donors, developed in pwCF. Individual patients were characterized by distinct Th1-, Th2-, or Th17-dominated responses that remained stable over several years. These different Th subsets target different A. fumigatus proteins, indicating that differential antigen uptake and presentation directs Th cell subset development. Patients with allergic bronchopulmonary aspergillosis (ABPA) are characterized by high frequencies of Th2 cells that cross-recognize various filamentous fungi.CONCLUSIONOur data highlight the development of heterogenous Th responses targeting different protein fractions of a single fungal pathogen and identify the development of multispecies cross-reactive Th2 cells as a potential risk factor for ABPA.FUNDINGGerman Research Foundation (DFG), under Germany's Excellence Strategy (EXC 2167-390884018 "Precision Medicine in Chronic Inflammation" and EXC 2051-390713860 "Balance of the Microverse"); Oskar Helene Heim Stiftung; Christiane Herzog Stiftung; Mukoviszidose Institut gGmb; German Cystic Fibrosis Association Mukoviszidose e.V; German Federal Ministry of Education and Science (BMBF) InfectControl 2020 Projects AnDiPath (BMBF 03ZZ0838A+B).
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Aspergilosis Broncopulmonar Alérgica , Fibrosis Quística , Aspergillus fumigatus , Inmunidad , Inmunoglobulina E , InflamaciónRESUMEN
SARS-CoV-2 infection and vaccination generates enormous host-response heterogeneity and an age-dependent loss of immune-response quality. How the pre-exposure T cell repertoire contributes to this heterogeneity is poorly understood. We combined analysis of SARS-CoV-2-specific CD4+ T cells pre- and post-vaccination with longitudinal T cell receptor tracking. We identified strong pre-exposure T cell variability that correlated with subsequent immune-response quality and age. High-quality responses, defined by strong expansion of high-avidity spike-specific T cells, high interleukin-21 production, and specific immunoglobulin G, depended on an intact naive repertoire and exclusion of pre-existing memory T cells. In the elderly, T cell expansion from both compartments was severely compromised. Our results reveal that an intrinsic defect of the CD4+ T cell repertoire causes the age-dependent decline of immune-response quality against SARS-CoV-2 and highlight the need for alternative strategies to induce high-quality T cell responses against newly arising pathogens in the elderly.
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COVID-19 , SARS-CoV-2 , Anciano , Anticuerpos Antivirales , Humanos , Inmunidad , Inmunoglobulina G , Receptores de Antígenos de Linfocitos T , VacunaciónRESUMEN
The current strategy to detect immunodominant T cell responses focuses on the antigen, employing large peptide pools to screen for functional cell activation. However, these approaches are labor and sample intensive and scale poorly with increasing size of the pathogen peptidome. T cell receptors (TCRs) recognizing the same epitope frequently have highly similar sequences, and thus, the presence of large sequence similarity clusters in the TCR repertoire likely identify the most public and immunodominant responses. Here, we perform a meta-analysis of large, publicly available single-cell and bulk TCR datasets from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals to identify public CD4+ responses. We report more than 1,200 αßTCRs forming six prominent similarity clusters and validate histocompatibility leukocyte antigen (HLA) restriction and epitope specificity predictions for five clusters using transgenic T cell lines. Collectively, these data provide information on immunodominant CD4+ T cell responses to SARS-CoV-2 and demonstrate the utility of the reverse epitope discovery approach.
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COVID-19 , SARS-CoV-2 , Linfocitos T CD4-Positivos/química , Epítopos/análisis , Humanos , Receptores de Antígenos de Linfocitos T/genética , Especificidad del Receptor de Antígeno de Linfocitos TRESUMEN
BACKGROUND: Rapid and reliable diagnostic work-up of tuberculosis (TB) remains a major healthcare goal. In particular, discrimination of TB infection from TB disease with currently available diagnostic tools is challenging and time consuming. This study aimed at establishing a standardised blood-based assay that rapidly and reliably discriminates TB infection from TB disease based on multiparameter analysis of TB antigen-reactive CD4+ T-cells acting as sensors for TB stage-specific immune status. METHODS: 157 HIV-negative subjects with suspected TB infection or TB disease were recruited from local tertiary care hospitals in Berlin (Germany). Peripheral blood mononuclear cells were analysed for CD4+ T-cells reactive to the Mycobacterium tuberculosis antigens purified protein derivative and early secretory antigenic target 6â kDa/culture filtrate protein 10. The activation state of TB antigen-reactive T-cells, identified by surface expression of CD154, was evaluated according to the expression profile of proliferation marker Ki-67 and activation markers CD38 and HLA-DR. Using data from 81 subjects with clinically confirmed TB infection (n=34) or culture-proven pulmonary or extrapulmonary TB disease (n=47), 12 parameters were derived from the expression profile and integrated into a scoring system. RESULTS: Using the scoring system, our assay (TB-Flow Assay) allowed reliable discrimination of TB infection from both pulmonary and extrapulmonary TB disease with high sensitivity (90.9%) and specificity (93.3%) as was confirmed by Monte-Carlo cross-validation. CONCLUSION: With low time requirement, ease of sample collection, and high sensitivity and specificity both for pulmonary and extrapulmonary TB disease, we believe this novel standardised TB-Flow Assay will improve the work-up of patients with suspected TB disease, supporting rapid TB diagnosis and facilitating treatment decisions.
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Tuberculosis Latente , Mycobacterium tuberculosis , Tuberculosis , Antígenos Bacterianos , Linfocitos T CD4-Positivos , Humanos , Leucocitos Mononucleares , Tuberculosis/diagnósticoRESUMEN
Repeated direct venous inoculation of Plasmodium falciparum sporozoites (PfSPZ) together with antimalarial chemoprophylaxis (PfSPZ-CVac) is the most potent way to induce sterile immunity against P. falciparum infection in malaria-naive volunteers. However, established schedules are complex and long. Here, we tested two accelerated three-dose schedules (28- and 10-day regimen) assessing efficacy by controlled human malaria infection (CHMI) against placebo, comparing vaccine-specific T cell and antibody responses by antigen-reactive T cell enrichment (ARTE) and protein microarray, respectively. Both regimens were similarly efficacious (67 and 63% vaccine efficacy) but different in the induction of vaccine-specific T cells and antibodies. The 10-day regimen resulted in higher numbers of antigen-specific CD4+ effector memory pro-inflammatory T cells and a broader antibody response compared with the 28-day regimen. Usually in nature, P. falciparum liver stage lasts about 6.5 days. The short vaccination-interval of the 10-day regimen prolongs the time of continuous exposure to liver-stage parasites, which may explain the stronger response. Besides dose and number of vaccinations, duration of liver-stage exposure is a factor to optimize PfSPZ-CVac immunogenicity.
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The cytokine interleukin-2 (IL-2) plays a critical role in controlling the immune homeostasis by regulating the proliferation and differentiation of immune cells, especially T cells. IL-2 signaling is mediated via the IL-2 receptor (IL-2R) complex, which consists of the IL-2Rα (CD25), the IL-2Rß, and the IL-2Rγ. While the latter are required for signal transduction, IL-2Rα controls the ligand-binding affinity of the receptor complex. A soluble form of the IL-2Rα (sIL-2Rα) is found constitutively in human serum, though its levels are increased under various pathophysiological conditions. The sIL-2Rα originates partly from activated T cells through proteolytic cleavage, but neither the responsible proteases nor stimuli that lead to IL-2Rα cleavage are known. Here, we show that the metalloproteases ADAM10 and ADAM17 can cleave the IL-2Rα and generate a soluble ectodomain, which functions as a decoy receptor that inhibits IL-2 signaling in T cells. We demonstrate that ADAM10 is mainly responsible for constitutive shedding of the IL-2Rα, while ADAM17 is involved in IL-2Rα cleavage upon T cell activation. In vivo, we found that mice with a CD4-specific deletion of ADAM10, but not ADAM17, show reduced steady-state sIL-2Rα serum levels. We propose that the identification of proteases involved in sIL-2Rα generation will allow for manipulation of IL-2Rα cleavage, especially as constitutive and induced cleavage of IL-2Rα are executed by different proteases, and thus offer a novel opportunity to alter IL-2 function.
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Proteína ADAM10 , Subunidad alfa del Receptor de Interleucina-2 , Receptores de Interleucina-2 , Proteína ADAM10/genética , Proteína ADAM10/metabolismo , Proteína ADAM17/genética , Proteína ADAM17/metabolismo , Animales , Eliminación de Gen , Interleucina-2/genética , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Activación de Linfocitos , Ratones , Receptores de Interleucina-2/genéticaRESUMEN
OBJECTIVE: One of the current hypotheses to explain the proinflammatory immune response in IBD is a dysregulated T cell reaction to yet unknown intestinal antigens. As such, it may be possible to identify disease-associated T cell clonotypes by analysing the peripheral and intestinal T-cell receptor (TCR) repertoire of patients with IBD and controls. DESIGN: We performed bulk TCR repertoire profiling of both the TCR alpha and beta chains using high-throughput sequencing in peripheral blood samples of a total of 244 patients with IBD and healthy controls as well as from matched blood and intestinal tissue of 59 patients with IBD and disease controls. We further characterised specific T cell clonotypes via single-cell RNAseq. RESULTS: We identified a group of clonotypes, characterised by semi-invariant TCR alpha chains, to be significantly enriched in the blood of patients with Crohn's disease (CD) and particularly expanded in the CD8+ T cell population. Single-cell RNAseq data showed an innate-like phenotype of these cells, with a comparable gene expression to unconventional T cells such as mucosal associated invariant T and natural killer T (NKT) cells, but with distinct TCRs. CONCLUSIONS: We identified and characterised a subpopulation of unconventional Crohn-associated invariant T (CAIT) cells. Multiple evidence suggests these cells to be part of the NKT type II population. The potential implications of this population for CD or a subset thereof remain to be elucidated, and the immunophenotype and antigen reactivity of CAIT cells need further investigations in future studies.
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Enfermedad de Crohn , Células T Asesinas Naturales , Linfocitos T CD8-positivos , Enfermedad de Crohn/genética , Humanos , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Antígenos de Linfocitos T alfa-beta/genéticaRESUMEN
Immunosuppressive Interleukin (IL)-10 production by pro-inflammatory CD4+ T cells is a central self-regulatory function to limit aberrant inflammation. Still, the molecular mediators controlling IL-10 expression in human CD4+ T cells are largely undefined. Here, we identify a Notch/STAT3 signaling-module as a universal molecular switch to induce IL-10 expression across human naïve and major effector CD4+ T cell subsets. IL-10 induction was transient, jointly controlled by the transcription factors Blimp-1/c-Maf and accompanied by upregulation of several co-inhibitory receptors, including LAG-3, CD49b, PD-1, TIM-3 and TIGIT. Consistent with a protective role of IL-10 in inflammatory bowel diseases (IBD), effector CD4+ T cells from Crohn's disease patients were defective in Notch/STAT3-induced IL-10 production and skewed towards an inflammatory Th1/17 cell phenotype. Collectively, our data identify a Notch/STAT3-Blimp-1/c-Maf axis as a common anti-inflammatory pathway in human CD4+ T cells, which is defective in IBD and thus may represent an attractive therapeutic target.
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Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Animales , Enfermedad de Crohn/metabolismo , Humanos , Enfermedades Inflamatorias del Intestino/metabolismo , Interleucina-10/metabolismo , Ratones , Ratones Noqueados , Proteínas Proto-Oncogénicas c-maf/genética , Proteínas Proto-Oncogénicas c-maf/metabolismo , Factor de Transcripción STAT3/metabolismo , Células TH1/metabolismoRESUMEN
A Disintegrin and Metalloproteinases (ADAM)-10 is a member of a family of membrane-anchored proteinases that regulate a broad range of cellular functions with central roles within the immune system. This has spurred the interest to modulate ADAM activity therapeutically in immunological diseases. CD4 T helper (Th) cells are the key regulators of adaptive immune responses. Their development and function is strongly dependent on Notch, a key ADAM-10 substrate. However, Th cells rely on a variety of additional ADAM-10 substrates regulating their functional activity at multiple levels. The complexity of both, the ADAM substrate expression as well as the functional consequences of ADAM-mediated cleavage of the various substrates complicates the analysis of cell type specific effects. Here we provide an overview on the major ADAM-10 substrates relevant for CD4 T cell biology and discuss the potential effects of ADAM-mediated cleavage exemplified for a selection of important substrates.
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Proteína ADAM10/metabolismo , Linfocitos T Colaboradores-Inductores/metabolismo , Proteína ADAM17/metabolismo , Antígeno B7-H1/metabolismo , Diferenciación Celular , Proliferación Celular , Humanos , Receptores de Interleucina-2/metabolismo , Receptores Notch/metabolismo , Transducción de Señal , Linfocitos T Colaboradores-Inductores/citología , Linfocitos T Colaboradores-Inductores/inmunologíaRESUMEN
The amount of scientific data and level of public sharing produced as a consequence of the COVID-19 pandemic, as well as the speed at which these data were produced, far exceeds any previous effort against a specific disease condition. This unprecedented situation allows for development and application of new research approaches. One of the major technical hurdles in immunology is the characterization of HLA-antigen-T cell receptor (TCR) specificities. Most approaches aim to identify reactive T cells starting from known antigens using functional assays. However, the need for a reverse approach identifying the antigen specificity of orphan TCRs is increasing. Utilizing large public single-cell gene expression and TCR datasets, we identified highly public CD4 + T cell responses to SARS-CoV-2, covering >75% of the analysed population. We performed an integrative meta-analysis to deeply characterize these clonotypes by TCR sequence, gene expression, HLA-restriction, and antigen-specificity, identifying strong and public CD4 + immunodominant responses with confirmed specificity. CD4 + COVID-enriched clonotypes show T follicular helper functional features, while clonotypes depleted in SARS-CoV-2 individuals preferentially had a central memory phenotype. In total we identify more than 1200 highly public CD4+ T cell clonotypes reactive to SARS-CoV-2. TCR similarity analysis showed six prominent TCR clusters, for which we predicted both HLA-restriction and cognate SARS-CoV-2 immunodominant epitopes. To validate our predictions we used an independent cohort of TCR repertoires before and after vaccination with ChAdOx1 , a replication-deficient simian adenovirus-vectored vaccine, encoding the SARS-CoV-2 spike protein. We find statistically significant enrichment of the predicted spike-reactive TCRs after vaccination with ChAdOx1 , while the frequency of TCRs specific to other SARS-CoV-2 proteins remains stable. Thus, the CD4-associated TCR repertoire differentiates vaccination from natural infection. In conclusion, our study presents a novel reverse epitope discovery approach that can be used to infer HLA- and antigen-specificity of orphan TCRs in any context, such as viral infections, antitumor immune responses, or autoimmune disease. HIGHLIGHTS: Identification of highly public CD4+ T cell responses to SARS-CoV-2Systematic prediction of exact immunogenic HLA class II epitopes for CD4+ T cell responseMethodological framework for reverse epitope discovery, which can be applied to other disease contexts and may provide essential insights for future studies and clinical applications.
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The detection and functional characterization of antigen-reactive T helper (Th) cells has been challenging due to their low frequency and functional heterogeneity. Antigen-reactive T cell enrichment (ARTE) allows the in-depth characterization of antigen-specific Th lymphocytes as a prerequisite for better understanding the role of adaptive immune responses in health and disease. ARTE is based on detection of the activation markers CD154 (CD40L) (expressed on all conventional Th cell subsets, Tcons) and CD137 (4-1BB) (expressed on regulatory T cells, Tregs), which are upregulated on the surface of CD4+ T cells upon short-term (7 h) in vitro stimulation with antigens in the presence of antigen-presenting cells (APCs). To substantially increase the sensitivity for the detection of antigen-specific Th cells, ARTE combines magnetic pre-enrichment of rare antigen-reactive T cells with multiparameter flow cytometry. Using CD154 and CD137 in combination allows the parallel detection of reactive Tcons and Tregs, after stimulation with the antigen. Thus, the ARTE technology now enables to characterize antigen-specific T cells with increased sensitivity of detection allowing even the investigation of antigen-specific Th cells in the naive T cell repertoire and regardless of prior knowledge of MHC alleles or antigenic epitopes.
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Ligando de CD40/inmunología , Citometría de Flujo , Separación Inmunomagnética , Activación de Linfocitos , Linfocitos T Colaboradores-Inductores/inmunología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunología , Ligando de CD40/metabolismo , Epítopos , Humanos , Fenotipo , Proyectos de Investigación , Linfocitos T Colaboradores-Inductores/metabolismo , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Flujo de TrabajoRESUMEN
Anti-N-methyl-D-aspartate-receptor (NMDAR) encephalitis is the most common autoimmune encephalitis with psychosis, amnesia, seizures and dyskinesias. The disease is mediated by pathogenic autoantibodies against the NR1 subunit that disrupt NMDAR function. Antibody infusion into mouse brains can recapitulate encephalitis symptoms, while active immunization resulted also in strong T cell infiltration into the hippocampus. However, whether T cells react against NMDAR and their specific contribution to disease development are poorly understood. Here we characterized the ex vivo frequency and phenotype of circulating CD4+ T helper (TH) cells reactive to NR1 protein using antigen-reactive T cell enrichment (ARTE) in 24 patients with NMDAR encephalitis, 13 patients with LGI1 encephalitis and 51 matched controls. Unexpectedly, patients with NMDAR encephalitis had lower frequencies of CD154-expressing NR1-reactive TH cells than healthy controls and produced significantly less inflammatory cytokines. No difference was seen in T cells reactive to the synaptic target LGI1 (Leucine-rich glioma-inactivated 1), ubiquitous Candida antigens or neoantigens, suggesting that the findings are disease-specific and not related to therapeutic immunosuppression. Also, patients with LGI1 encephalitis showed unaltered numbers of LGI1 antigen-reactive T cells. The data reveal disease-specific functional alterations of circulating NMDAR-reactive TH cells in patients with NMDAR encephalitis and challenge the idea that increased pro-inflammatory NMDAR-reactive T cells contribute to disease pathogenesis.
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Encefalitis Antirreceptor N-Metil-D-Aspartato , Encefalitis , Animales , Autoanticuerpos , Linfocitos T CD4-Positivos , Citocinas , Humanos , Ratones , Receptores de N-Metil-D-Aspartato , Linfocitos TRESUMEN
Systemic lupus erythematosus is a systemic and chronic autoimmune disease characterized by loss of tolerance towards nuclear antigens with autoreactive CD4+ T cells implicated in disease pathogenesis. However, very little is known about their receptor specificity since the detection of human autoantigen specific CD4+ T cells has been extremely challenging. Here we present an analysis of CD4+ T cells reactive to nuclear antigens using two complementary methods: T cell libraries and antigen-reactive T cell enrichment. The frequencies of nuclear antigen specific CD4+ T cells correlated with disease severity. These autoreactive T cells produce effector cytokines such as interferon-γ, interleukin-17, and interleukin-10. Compared to blood, these cells were enriched in the urine of patients with active lupus nephritis, suggesting an infiltration of the inflamed kidneys. Thus, these previously unrecognized characteristics support a role for nuclear antigen-specific CD4+ T cells in systemic lupus erythematosus.