ABSTRACT
CD4+ Foxp3+ regulatory T cells (Treg) are essential to maintain immune tolerance, as their loss leads to a fatal autoimmune syndrome in mice and humans. Conflicting findings have been reported concerning their metabolism. Some reports found that Treg have low mechanistic target of rapamycin (mTOR) activity and would be less dependent on this kinase compared with conventional T cells, whereas other reports suggest quite the opposite. In this study, we revisited this question by using mice that have a specific deletion of mTOR in Treg. These mice spontaneously develop a severe and systemic inflammation. We show that mTOR expression by Treg is critical for their differentiation into effector Treg and their migration into nonlymphoid tissues. We also reveal that mTOR-deficient Treg have reduced stability. This loss of Foxp3 expression is associated with partial Foxp3 DNA remethylation, which may be due to an increased activity of the glutaminolysis pathway. Thus, our work shows that mTOR is crucial for Treg differentiation, migration, and identity and that drugs targeting this metabolism pathway will impact on their biology.
Subject(s)
Forkhead Transcription Factors/metabolism , Inflammation/genetics , T-Lymphocytes, Regulatory/immunology , TOR Serine-Threonine Kinases/metabolism , Animals , Autoimmunity/genetics , Cell Differentiation , Cell Movement , DNA Methylation , Forkhead Transcription Factors/genetics , Glutamine/metabolism , Lymphocyte Activation , Mice , Mice, Knockout , Mutation/genetics , Signal Transduction , TOR Serine-Threonine Kinases/geneticsABSTRACT
BACKGROUND: The lack of pathogen-protective, isotype-switched antibodies in patients with common variable immunodeficiency (CVID) suggests germinal center (GC) hypoplasia, yet a subset of patients with CVID is paradoxically affected by autoantibody-mediated autoimmune cytopenias (AICs) and lymphadenopathy. OBJECTIVE: We sought to compare the physical characteristics and immunologic output of GC responses in patients with CVID with AIC (CVID+AIC) and without AIC (CVID-AIC). METHODS: We analyzed GC size and shape in excisional lymph node biopsy specimens from 14 patients with CVID+AIC and 4 patients with CVID-AIC. Using paired peripheral blood samples, we determined how AICs specifically affected B-and T-cell compartments and antibody responses in patients with CVID. RESULTS: We found that patients with CVID+AIC displayed irregularly shaped hyperplastic GCs, whereas GCs were scarce and small in patients with CVID-AIC. GC hyperplasia was also evidenced by an increase in numbers of circulating follicular helper T cells, which correlated with decreased regulatory T-cell frequencies and function. In addition, patients with CVID+AIC had serum endotoxemia associated with a dearth of isotype-switched memory B cells that displayed significantly lower somatic hypermutation frequencies than their counterparts with CVID-AIC. Moreover, IgG+ B cells from patients with CVID+AIC expressed VH4-34-encoded antibodies with unmutated Ala-Val-Tyr and Asn-His-Ser motifs, which recognize both erythrocyte I/i self-antigens and commensal bacteria. CONCLUSIONS: Patients with CVID+AIC do not contain mucosal microbiota and exhibit hyperplastic yet inefficient GC responses that favor the production of untolerized IgG+ B-cell clones that recognize both commensal bacteria and hematopoietic I/i self-antigens.
Subject(s)
Autoantibodies/immunology , B-Lymphocytes/immunology , Common Variable Immunodeficiency/immunology , Germinal Center/immunology , Immunoglobulin G/immunology , T-Lymphocytes/immunology , Adolescent , Adult , Aged , B-Lymphocytes/pathology , Biopsy , Child , Common Variable Immunodeficiency/pathology , Female , Germinal Center/pathology , Humans , Hyperplasia , Male , Middle Aged , T-Lymphocytes/pathologyABSTRACT
Using B-cell rearrangement excision circle measurements, we analyzed B-cell reconstitution in a cohort of 243 patients who underwent allogeneic stem cell transplantation. Acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) transiently increased B-cell replication but decreased overall B-cell neogenesis with a clear difference in terms of kinetics. Moreover, the impact of aGVHD in the absence of cGVHD was transient, recovering at month 6 similar values as in patients who did not suffer from GVHD. Conversely, impact of cGVHD at month 12 in multivariate analysis was independent of the previous aGVHD effect on B-cell output. Finally, we showed in patients affected with cGVHD a higher B-cell division rate that correlates with an elevated BAFF/CD19(+) B-cell ratio, supporting a B-cell hyperactivation state in vivo.
Subject(s)
B-Lymphocytes/immunology , B-Lymphocytes/pathology , Cell Division , Graft vs Host Disease/immunology , Acute Disease , Adult , B-Cell Activating Factor/blood , Cell Proliferation , Chronic Disease , Graft vs Host Disease/blood , Hematopoietic Stem Cell Transplantation , Humans , Transplantation, HomologousABSTRACT
Failure of adoptive T-cell therapies in patients with cancer is linked to limited T-cell expansion and persistence, even in memory-prone 41BB-(BBz)-based chimeric antigen receptor (CAR) T cells. We show here that BBz-CAR T-cell stem/memory differentiation and persistence can be enhanced through epigenetic manipulation of the histone 3 lysine 9 trimethylation (H3K9me3) pathway. Inactivation of the H3K9 trimethyltransferase SUV39H1 enhances BBz-CAR T cell long-term persistence, protecting mice against tumor relapses and rechallenges in lung and disseminated solid tumor models up to several months after CAR T-cell infusion. Single-cell transcriptomic (single-cell RNA sequencing) and chromatin opening (single-cell assay for transposase accessible chromatin) analyses of tumor-infiltrating CAR T cells show early reprogramming into self-renewing, stemlike populations with decreased expression of dysfunction genes in all T-cell subpopulations. Therefore, epigenetic manipulation of H3K9 methylation by SUV39H1 optimizes the long-term functional persistence of BBz-CAR T cells, limiting relapses, and providing protection against tumor rechallenges. SIGNIFICANCE: Limited CAR T-cell expansion and persistence hinders therapeutic responses in solid cancer patients. We show that targeting SUV39H1 histone methyltransferase enhances 41BB-based CAR T-cell long-term protection against tumor relapses and rechallenges by increasing stemness/memory differentiation. This opens a safe path to enhancing adoptive cell therapies for solid tumors. See related article by Jain et al., p. 142. This article is featured in Selected Articles from This Issue, p. 5.
Subject(s)
Neoplasms , Receptors, Chimeric Antigen , Animals , Humans , Mice , Chromatin , Immunotherapy, Adoptive , Methyltransferases/genetics , Methyltransferases/metabolism , Neoplasms/genetics , Neoplasms/therapy , Recurrence , Repressor Proteins/genetics , Repressor Proteins/metabolismABSTRACT
Central B cell tolerance is believed to be regulated by B cell receptor signaling induced by the recognition of self-antigens in immature B cells. Using humanized mice with defective MyD88, TLR7, or TLR9 expression, we demonstrate that TLR9/MYD88 are required for central B cell tolerance and the removal of developing autoreactive clones. We also show that CXCL4, a chemokine involved in systemic sclerosis (SSc), abrogates TLR9 function in B cells by sequestering TLR9 ligands away from the endosomal compartments where this receptor resides. The in vivo production of CXCL4 thereby impedes both TLR9 responses in B cells and the establishment of central B cell tolerance. We conclude that TLR9 plays an essential early tolerogenic function required for the establishment of central B cell tolerance and that correcting defective TLR9 function in B cells from SSc patients may represent a novel therapeutic strategy to restore B cell tolerance.
Subject(s)
Platelet Factor 4 , Scleroderma, Systemic , Toll-Like Receptor 9 , Animals , Humans , Mice , B-Lymphocytes , Ligands , Myeloid Differentiation Factor 88/metabolism , Platelet Factor 4/metabolism , Scleroderma, Systemic/metabolism , Toll-Like Receptor 7 , Toll-Like Receptor 9/metabolismABSTRACT
OBJECTIVE: Early selection steps preventing autoreactive naive B cell production are often impaired in patients with autoimmune diseases, but central and peripheral B cell tolerance checkpoints have not been assessed in patients with systemic sclerosis (SSc). This study was undertaken to characterize early B cell tolerance checkpoints in patients with SSc. METHODS: Using an in vitro polymerase chain reaction-based approach that allows the expression of recombinant antibodies cloned from single B cells, we tested the reactivity of antibodies expressed by 212 CD19+CD21low CD10+IgMhigh CD27- new emigrant/transitional B cells and 190 CD19+CD21+CD10-IgM+CD27- mature naive B cells from 10 patients with SSc. RESULTS: Compared to serum from healthy donors, serum from patients with SSc displayed elevated proportions of polyreactive and antinuclear-reactive new emigrant/transitional B cells that recognize topoisomerase I, suggesting that defective central B cell tolerance contributes to the production of serum autoantibodies characteristic of the disease. Frequencies of autoreactive mature naive B cells were also significantly increased in SSc patients compared to healthy donors, thus indicating that a peripheral B cell tolerance checkpoint may be impaired in SSc. CONCLUSION: Defective counterselection of developing autoreactive naive B cells in SSc leads to the production of self antigen-specific B cells that may secrete autoantibodies and allow the formation of immune complexes, which promote fibrosis in SSc.
Subject(s)
Autoantigens/immunology , B-Lymphocytes/immunology , Immune Tolerance , Scleroderma, Systemic/immunology , Adult , Female , Humans , Male , Middle AgedABSTRACT
Patients with common variable immunodeficiency associated with autoimmune cytopenia (CVID+AIC) generate few isotype-switched B cells with severely decreased frequencies of somatic hypermutations (SHMs), but their underlying molecular defects remain poorly characterized. We identified a CVID+AIC patient who displays a rare homozygous missense M466V mutation in ß-catenin-like protein 1 (CTNNBL1). Because CTNNBL1 binds activation-induced cytidine deaminase (AID) that catalyzes SHM, we tested AID interactions with the CTNNBL1 M466V variant. We found that the M466V mutation interfered with the association of CTNNBL1 with AID, resulting in decreased AID in the nuclei of patient EBV-transformed B cell lines and of CTNNBL1 466V/V Ramos B cells engineered to express only CTNNBL1 M466V using CRISPR/Cas9 technology. As a consequence, the scarce IgG+ memory B cells from the CTNNBL1 466V/V patient showed a low SHM frequency that averaged 6.7 mutations compared with about 18 mutations per clone in healthy-donor counterparts. In addition, CTNNBL1 466V/V Ramos B cells displayed a decreased incidence of SHM that was reduced by half compared with parental WT Ramos B cells, demonstrating that the CTNNBL1 M466V mutation is responsible for defective SHM induction. We conclude that CTNNBL1 plays an important role in regulating AID-dependent antibody diversification in humans.
Subject(s)
Apoptosis Regulatory Proteins , B-Lymphocytes , Common Variable Immunodeficiency , Homozygote , Immunologic Memory/genetics , Mutation, Missense , Nuclear Proteins , Somatic Hypermutation, Immunoglobulin , Amino Acid Substitution , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/immunology , B-Lymphocytes/immunology , B-Lymphocytes/pathology , Cell Line , Child, Preschool , Common Variable Immunodeficiency/genetics , Common Variable Immunodeficiency/immunology , Common Variable Immunodeficiency/pathology , Cytidine Deaminase/genetics , Cytidine Deaminase/immunology , Female , Humans , Nuclear Proteins/genetics , Nuclear Proteins/immunologyABSTRACT
Autoimmune regulator (AIRE) mutations result in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome characterized by defective central T cell tolerance and the production of many autoantibodies targeting tissue-specific antigens and cytokines. By studying CD3- and AIRE-deficient patients, we found that lack of either T cells or AIRE function resulted in the peripheral accumulation of autoreactive mature naïve B cells. Proteomic arrays and Biacore affinity measurements revealed that unmutated antibodies expressed by these autoreactive naïve B cells recognized soluble molecules and cytokines including insulin, IL-17A, and IL-17F, which are AIRE-dependent thymic peripheral tissue antigens targeted by autoimmune responses in APECED. AIRE-deficient patients also displayed decreased frequencies of regulatory T cells (Tregs) that lacked common TCRß clones found instead in their conventional T cell compartment, thereby suggesting holes in the Treg TCR repertoire of these patients. Hence, AIRE-mediated T cell/Treg selection normally prevents the expansion of autoreactive naïve B cells recognizing peripheral self-antigens.
Subject(s)
Autoantibodies/immunology , Autoimmunity/genetics , B-Lymphocytes/immunology , Polyendocrinopathies, Autoimmune/immunology , Transcription Factors/deficiency , Adolescent , Autoantibodies/blood , Autoantibodies/metabolism , Autoantigens/immunology , B-Lymphocytes/metabolism , CD3 Complex/deficiency , CD3 Complex/genetics , CD3 Complex/immunology , Child , Child, Preschool , Cytokines/immunology , Female , Humans , Immune Tolerance/genetics , Lymphocyte Activation/genetics , Male , Middle Aged , Mutation , Polyendocrinopathies, Autoimmune/blood , Polyendocrinopathies, Autoimmune/genetics , Protein Array Analysis , Proteomics/methods , T-Lymphocytes, Regulatory/immunology , Transcription Factors/genetics , Transcription Factors/immunology , AIRE ProteinABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
Immune responses need to be controlled tightly to prevent autoimmune diseases, yet underlying molecular mechanisms remain partially understood. Here, we identify biallelic mutations in three patients from two unrelated families in differentially expressed in FDCP6 homolog (DEF6) as the molecular cause of an inborn error of immunity with systemic autoimmunity. Patient T cells exhibit impaired regulation of CTLA-4 surface trafficking associated with reduced functional CTLA-4 availability, which is replicated in DEF6-knockout Jurkat cells. Mechanistically, we identify the small GTPase RAB11 as an interactor of the guanine nucleotide exchange factor DEF6, and find disrupted binding of mutant DEF6 to RAB11 as well as reduced RAB11+CTLA-4+ vesicles in DEF6-mutated cells. One of the patients has been treated with CTLA-4-Ig and achieved sustained remission. Collectively, we uncover DEF6 as player in immune homeostasis ensuring availability of the checkpoint protein CTLA-4 at T-cell surface, identifying a potential target for autoimmune and/or cancer therapy.
Subject(s)
CTLA-4 Antigen/metabolism , DNA-Binding Proteins/deficiency , Guanine Nucleotide Exchange Factors/deficiency , Primary Immunodeficiency Diseases/genetics , B7-1 Antigen/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/immunology , Gene Knockout Techniques , Guanine Nucleotide Exchange Factors/genetics , Guanine Nucleotide Exchange Factors/immunology , Homeostasis , Humans , Jurkat Cells , T-Lymphocytes/metabolism , T-Lymphocytes/physiology , rab GTP-Binding Proteins/genetics , rab GTP-Binding Proteins/metabolismABSTRACT
OBJECTIVE: Patients with Sjögren's syndrome (SS) are prone to develop malignant lymphomas, and a correlation has been established between the lymphoproliferations occurring in these disorders and the presence in patients' blood of an unusual B cell population that down-regulates complement receptor 2/CD21. This study was undertaken to identify the B cell compartment from which these lymphoproliferations emerge and determine the mechanisms that promote clonal B cell expansion in patients with SS. METHODS: The reactivity of antibodies expressed by CD19+CD10-CD27-IgM+CD21-/low cells isolated from the blood of patients with SS was tested using a polymerase chain reaction-based approach that allows us to clone and express, in vitro, recombinant antibodies produced by single B cells. RESULTS: Clonal expansions were identified in CD21-/low B cells isolated from the peripheral blood of 3 patients with SS. These lymphoproliferations expressed B cell receptors (BCRs) that displayed somatic hypermutation lineage trees characteristic of a strong selection by antigens; one of these antigens was identified as a ribosomal self antigen. When the mutated BCR sequences expressed by the expanded CD21-/low B cell clones from patients with SS were reverted in vitro to their germline counterparts, one clone remained autoreactive. CONCLUSION: Clonal lymphoproliferations in patients with SS preferentially accumulate in the autoreactive CD21-/low B cell compartment often expanded in these subjects, and recognition of self antigens may drive the clonal B cell expansion while further refining BCR self-reactivity.
Subject(s)
B-Lymphocytes/immunology , Lymphoproliferative Disorders/etiology , Sjogren's Syndrome/immunology , Adult , Aged , Autoantibodies/genetics , Autoantibodies/immunology , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Fluorescent Antibody Technique, Indirect , Humans , Immunoprecipitation , Lymphoproliferative Disorders/immunology , Middle Aged , Mutation , Polymerase Chain Reaction , Receptors, Antigen, B-Cell/immunology , Receptors, Antigen, B-Cell/metabolism , Receptors, Complement 3d/immunology , Receptors, Complement 3d/metabolism , Sjogren's Syndrome/complicationsABSTRACT
B cells play a central role in systemic lupus erythematosus (SLE) pathophysiology but dysregulated pathways leading to a break in B cell tolerance remain unclear. Since Toll-like receptor 9 (TLR9) favors the elimination of autoreactive B cells in the periphery, we assessed TLR9 function in SLE by analyzing the responses of B cells and plasmacytoid dendritic cells (pDCs) isolated from healthy donors and patients after stimulation with CpG, a TLR9 agonist. We found that SLE B cells from patients without hydroxychloroquine treatment displayed defective in vitro TLR9 responses, as illustrated by the impaired upregulation of B cell activation molecules and the diminished production of various cytokines including antiinflammatory IL-10. In agreement with CD19 controlling TLR9 responses in B cells, decreased expression of the CD19/CD21 complex on SLE B cells was detected as early as the transitional B cell stage. In contrast, TLR7 function was preserved in SLE B cells, whereas pDCs from SLE patients properly responded to TLR9 stimulation, thereby revealing that impaired TLR9 function in SLE was restricted to B cells. We conclude that abnormal CD19 expression and TLR9 tolerogenic function in SLE B cells may contribute to the break of B cell tolerance in these patients.
Subject(s)
Antigens, CD19/immunology , B-Lymphocytes/immunology , Lupus Erythematosus, Systemic/immunology , Receptors, Complement 3d/immunology , Toll-Like Receptor 9/immunology , Adult , Aged , Aged, 80 and over , Antigens, CD19/metabolism , Autoimmunity , B-Lymphocytes/drug effects , B-Lymphocytes/metabolism , Cells, Cultured , Cytokines/immunology , Cytokines/metabolism , Dendritic Cells/drug effects , Dendritic Cells/immunology , Dendritic Cells/metabolism , Female , Humans , Immune Tolerance , Lupus Erythematosus, Systemic/blood , Male , Middle Aged , Oligodeoxyribonucleotides/pharmacology , Primary Cell Culture , Receptors, Complement 3d/metabolism , Toll-Like Receptor 9/agonists , Toll-Like Receptor 9/metabolism , Up-Regulation , Young AdultABSTRACT
OBJECTIVE: Central and peripheral B cell tolerance checkpoints are defective in many patients with autoimmune diseases, but the functionality of each discrete checkpoint has not been assessed in patients with Sjögren's syndrome (SS). We undertook this study to assess this functionality in SS patients. METHODS: Using a polymerase chain reaction-based approach that allows us to clone and express, in vitro, recombinant antibodies produced by single B cells, we tested the reactivity of recombinant antibodies cloned from single CD19+CD21low CD10+IgMhigh CD27- newly emigrant/transitional B cells and CD19+CD21+CD10-IgM+CD27- mature naive B cells from 5 SS patients. RESULTS: We found that the frequencies of newly emigrant/transitional B cells expressing polyreactive antibodies were significantly increased in SS patients compared to those in healthy donors, revealing defective central B cell tolerance in SS patients. Frequencies of mature naive B cells expressing autoreactive antibodies were also significantly increased in SS patients, thereby illustrating an impaired peripheral B cell tolerance checkpoint in these patients. CONCLUSION: Defective counterselection of developing autoreactive B cells observed in SS patients is a feature common to many other autoimmune diseases and may favor the development of autoimmunity by allowing autoreactive B cells to present self antigens to T cells.
Subject(s)
Autoantibodies/immunology , B-Lymphocytes/immunology , Immune Tolerance/immunology , Sjogren's Syndrome/immunology , Adult , Aged , Antibodies, Antinuclear/immunology , Cell Differentiation , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Fluorescent Antibody Technique , Humans , Middle Aged , Polymerase Chain Reaction , Single-Cell Analysis , Young AdultABSTRACT
The germline immunoglobulin (Ig) variable heavy chain 4-34 (VH4-34) gene segment encodes in humans intrinsically self-reactive antibodies that recognize I/i carbohydrates expressed by erythrocytes with a specific motif in their framework region 1 (FWR1). VH4-34-expressing clones are common in the naive B cell repertoire but are rarely found in IgG memory B cells from healthy individuals. In contrast, CD27+IgG+ B cells from patients genetically deficient for IRAK4 or MYD88, which mediate the function of Toll-like receptors (TLRs) except TLR3, contained VH4-34-expressing clones and showed decreased somatic hypermutation frequencies. In addition, VH4-34-encoded IgGs from IRAK4- and MYD88-deficient patients often displayed an unmutated FWR1 motif, revealing that these antibodies still recognize I/i antigens, whereas their healthy donor counterparts harbored FWR1 mutations abolishing self-reactivity. However, this paradoxical self-reactivity correlated with these VH4-34-encoded IgG clones binding commensal bacteria antigens. Hence, B cells expressing germline-encoded self-reactive VH4-34 antibodies may represent an innate-like B cell population specialized in the containment of commensal bacteria when gut barriers are breached.
Subject(s)
B-Lymphocytes/immunology , Bacteria/immunology , Immunoglobulin G/immunology , Immunoglobulin Heavy Chains/immunology , Immunoglobulin Variable Region/immunology , Adolescent , Adult , Amino Acid Sequence , Antigens, Bacterial/immunology , Autoantibodies/genetics , Autoantibodies/immunology , B-Lymphocytes/metabolism , Child , Child, Preschool , Clonal Selection, Antigen-Mediated , Female , Gastrointestinal Microbiome/immunology , Humans , Immunoglobulin G/genetics , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Variable Region/genetics , Interleukin-1 Receptor-Associated Kinases/deficiency , Interleukin-1 Receptor-Associated Kinases/genetics , Interleukin-1 Receptor-Associated Kinases/immunology , Male , Mutation , Myeloid Differentiation Factor 88/deficiency , Myeloid Differentiation Factor 88/genetics , Myeloid Differentiation Factor 88/immunology , Sequence Homology, Amino Acid , Tumor Necrosis Factor Receptor Superfamily, Member 7/immunology , Tumor Necrosis Factor Receptor Superfamily, Member 7/metabolism , Young AdultABSTRACT
B cells play a major role in antigen presentation and antibody production in the development of autoimmune diseases, and some of these diseases disproportionally occur in females. Moreover, immune responses tend to be stronger in female vs male humans and mice. Because it is challenging to distinguish intrinsic from extrinsic influences on human immune responses, we used a personalized immune (PI) humanized mouse model, in which immune systems were generated de novo from adult human hematopoietic stem cells (HSCs) in immunodeficient mice. We assessed the effect of recipient sex and of donor autoimmune diseases (type 1 diabetes [T1D] and rheumatoid arthritis [RA]) on human B-cell development in PI mice. We observed that human B-cell levels were increased in female recipients regardless of the source of human HSCs or the strain of immunodeficient recipient mice. Moreover, mice injected with T1D- or RA-derived HSCs displayed B-cell abnormalities compared with healthy control HSC-derived mice, including altered B-cell levels, increased proportions of mature B cells and reduced CD19 expression. Our study revealed an HSC-extrinsic effect of recipient sex on human B-cell reconstitution. Moreover, the PI humanized mouse model revealed HSC-intrinsic defects in central B-cell tolerance that recapitulated those in patients with autoimmune diseases. These results demonstrate the utility of humanized mouse models as a tool to better understand human immune cell development and regulation.
ABSTRACT
Few monogenic causes for severe manifestations of common allergic diseases have been identified. Through next-generation sequencing on a cohort of patients with severe atopic dermatitis with and without comorbid infections, we found eight individuals, from four families, with novel heterozygous mutations in CARD11, which encodes a scaffolding protein involved in lymphocyte receptor signaling. Disease improved over time in most patients. Transfection of mutant CARD11 expression constructs into T cell lines demonstrated both loss-of-function and dominant-interfering activity upon antigen receptor-induced activation of nuclear factor-κB and mammalian target of rapamycin complex 1 (mTORC1). Patient T cells had similar defects, as well as low production of the cytokine interferon-γ (IFN-γ). The mTORC1 and IFN-γ production defects were partially rescued by supplementation with glutamine, which requires CARD11 for import into T cells. Our findings indicate that a single hypomorphic mutation in CARD11 can cause potentially correctable cellular defects that lead to atopic dermatitis.
Subject(s)
CARD Signaling Adaptor Proteins/genetics , Dermatitis, Atopic/genetics , Germ-Line Mutation , Guanylate Cyclase/genetics , Amino Acid Transport System ASC/metabolism , Cohort Studies , DNA Mutational Analysis , Dermatitis, Atopic/immunology , Female , Genes, Dominant , Glutamine/metabolism , Humans , Jurkat Cells , Lymphocyte Activation , Male , Mechanistic Target of Rapamycin Complex 1 , Minor Histocompatibility Antigens/metabolism , Multiprotein Complexes/metabolism , NF-kappa B/metabolism , Pedigree , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , TOR Serine-Threonine Kinases/metabolismABSTRACT
This corrects the article DOI: 10.1038/ng.3898.
ABSTRACT
Lymphoid-committed CD34(+)lin(-)CD10(+)CD24(-) progenitors undergo a rebound at month 3 after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the absence of acute graft-versus-host disease (aGVHD). Here, we analyzed transcriptional programs of cell-sorted circulating lymphoid-committed progenitors and CD34(+)Lin(-)CD10(-) nonlymphoid progenitors in 11 allo-HSCT patients who had (n = 5) or had not (n = 6) developed grade 2 or 3 aGVHD and in 7 age-matched healthy donors. Major upregulated pathways include protein synthesis, energy production, cell cycle regulation, and cytoskeleton organization. Notably, genes from protein biogenesis, translation machinery, and cell cycle (CDK6) were overexpressed in progenitors from patients in the absence of aGVHD compared with healthy donors and patients affected by aGVHD. Expression of many genes from the mitochondrial oxidative phosphorylation metabolic pathway leading to ATP production were more specifically increased in lymphoid-committed progenitors in the absence of aGVHD. This was also the case for genes involved in cell mobilization such as those regulating Rho GTPase activity. In all, we found that circulating lymphoid-committed progenitors undergo profound changes in metabolism, favoring cell proliferation, energy production, and cell mobilization after allo-HSCT in humans. These mechanisms are abolished in the case of aGVHD or its treatment, indicating a persistent cell-intrinsic defect after exit from the bone marrow.
Subject(s)
Energy Metabolism , Hematopoietic Stem Cell Transplantation , Lymphoid Progenitor Cells/metabolism , Adult , Biomarkers , Female , Graft vs Host Disease/diagnosis , Graft vs Host Disease/etiology , Hematopoietic Stem Cell Transplantation/adverse effects , Humans , Immunophenotyping , Male , Middle Aged , Phenotype , Transplantation, Homologous , Young AdultABSTRACT
Patients with mutations in AICDA, which encodes activation-induced cytidine deaminase (AID), display an impaired peripheral B cell tolerance. AID mediates class-switch recombination (CSR) and somatic hypermutation (SHM) in B cells, but the mechanism by which AID prevents the accumulation of autoreactive B cells in blood is unclear. Here, we analyzed B cell tolerance in AID-deficient patients, patients with autosomal dominant AID mutations (AD-AID), asymptomatic AICDA heterozygotes (AID+/-), and patients with uracil N-glycosylase (UNG) deficiency, which impairs CSR but not SHM. The low frequency of autoreactive mature naive B cells in UNG-deficient patients resembled that of healthy subjects, revealing that impaired CSR does not interfere with the peripheral B cell tolerance checkpoint. In contrast, we observed decreased frequencies of SHM in memory B cells from AD-AID patients and AID+/- subjects, who were unable to prevent the accumulation of autoreactive mature naive B cells. In addition, the individuals with AICDA mutations, but not UNG-deficient patients, displayed Tregs with defective suppressive capacity that correlated with increases in circulating T follicular helper cells and enhanced cytokine production. We conclude that SHM, but not CSR, regulates peripheral B cell tolerance through the production of mutated antibodies that clear antigens and prevent sustained interleukin secretions that interfere with Treg function.
Subject(s)
B-Lymphocytes/immunology , Cell Cycle Checkpoints/immunology , Cytidine Deaminase/deficiency , Immune Tolerance , Immunologic Memory , Mutation , Somatic Hypermutation, Immunoglobulin/immunology , B-Lymphocytes/pathology , Cell Cycle Checkpoints/genetics , Cytidine Deaminase/immunology , Female , Humans , Male , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/pathologyABSTRACT
Alterations in the apoptosis of immune cells have been associated with autoimmunity. Here, we have identified a homozygous missense mutation in the gene encoding the base excision repair enzyme Nei endonuclease VIII-like 3 (NEIL3) that abolished enzymatic activity in 3 siblings from a consanguineous family. The NEIL3 mutation was associated with fatal recurrent infections, severe autoimmunity, hypogammaglobulinemia, and impaired B cell function in these individuals. The same homozygous NEIL3 mutation was also identified in an asymptomatic individual who exhibited elevated levels of serum autoantibodies and defective peripheral B cell tolerance, but normal B cell function. Further analysis of the patients revealed an absence of LPS-responsive beige-like anchor (LRBA) protein expression, a known cause of immunodeficiency. We next examined the contribution of NEIL3 to the maintenance of self-tolerance in Neil3-/- mice. Although Neil3-/- mice displayed normal B cell function, they exhibited elevated serum levels of autoantibodies and developed nephritis following treatment with poly(I:C) to mimic microbial stimulation. In Neil3-/- mice, splenic T and B cells as well as germinal center B cells from Peyer's patches showed marked increases in apoptosis and cell death, indicating the potential release of self-antigens that favor autoimmunity. These findings demonstrate that deficiency in NEIL3 is associated with increased lymphocyte apoptosis, autoantibodies, and predisposition to autoimmunity.