SUV39H1 Ablation Enhances Long-term CAR T Function in Solid Tumors.

Unlabelled: 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.

TLR9 ligand sequestration by chemokine CXCL4 negatively affects central B cell tolerance.

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.

Defective Early B Cell Tolerance Checkpoints in Patients With Systemic Sclerosis Allow the Production of Self Antigen-Specific Clones.

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+CD21 CD10+IgM CD27- new emigrant/transitional B cells and 190 CD19+CD21+CD10-IgM+CD27- mature naive B cells from 10 patients with SSc.

Regulatory T Cell Stability and Migration Are Dependent on mTOR.

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.

Disease-associated CTNNBL1 mutation impairs somatic hypermutation by decreasing nuclear AID.

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 β-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.

Publisher Correction: Human DEF6 deficiency underlies an immunodeficiency syndrome with systemic autoimmunity and aberrant CTLA-4 homeostasis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

AIRE expression controls the peripheral selection of autoreactive B cells.

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.

Patients with common variable immunodeficiency with autoimmune cytopenias exhibit hyperplastic yet inefficient germinal center responses.

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.

Impaired TLR9 responses in B cells from patients with systemic lupus erythematosus.

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.

HSC extrinsic sex-related and intrinsic autoimmune disease-related human B-cell variation is recapitulated in humanized mice.

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.

Corrigendum: Germline hypomorphic CARD11 mutations in severe atopic disease.

This corrects the article DOI: 10.1038/ng.3898.

Accumulation of Antigen-Driven Lymphoproliferations in Complement Receptor 2/CD21 B Cells From Patients With Sjögren's Syndrome.

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 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.

Defective Early B Cell Tolerance Checkpoints in Sjögren's Syndrome Patients.

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+CD21 CD10+IgM CD27- newly emigrant/transitional B cells and CD19+CD21+CD10-IgM+CD27- mature naive B cells from 5 SS patients.

Germline hypomorphic CARD11 mutations in severe atopic disease.

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.

Self-reactive VH4-34-expressing IgG B cells recognize commensal bacteria.

The germline immunoglobulin (Ig) variable heavy chain 4-34 () 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, CD27IgG 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.

Deficiency of base excision repair enzyme NEIL3 drives increased predisposition to autoimmunity.

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.

Decreased somatic hypermutation induces an impaired peripheral B cell tolerance checkpoint.

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.

Alterations of circulating lymphoid committed progenitor cellular metabolism after allogeneic stem cell transplantation in humans.

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.

Lentiviral-mediated gene therapy restores B cell tolerance in Wiskott-Aldrich syndrome patients.

Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by microthrombocytopenia, eczema, and high susceptibility to developing tumors and autoimmunity. Recent evidence suggests that B cells may be key players in the pathogenesis of autoimmunity in WAS. Here, we assessed whether WAS protein deficiency (WASp deficiency) affects the establishment of B cell tolerance by testing the reactivity of recombinant antibodies isolated from single B cells from 4 WAS patients before and after gene therapy (GT).

Impact of acute and chronic graft-versus-host disease on human B-cell generation and replication.

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.

CXCR4-related increase of circulating human lymphoid progenitors after allogeneic hematopoietic stem cell transplantation.

Immune recovery after profound lymphopenia is a major challenge in many clinical situations, such as allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recovery depends, in a first step, on hematopoietic lymphoid progenitors production in the bone marrow (BM). In this study, we characterized CD34+Lin-CD10+ lymphoid progenitors in the peripheral blood of allo-HSCT patients.

Lenalidomide consolidation and maintenance therapy after autologous stem cell transplant for multiple myeloma induces persistent changes in T-cell homeostasis.

Whether the efficacy of lenalidomide in the treatment of multiple myeloma (MM) is due to direct tumor toxicity only or to additional immunomodulatory effects is unclear. We studied the effect of lenalidomide treatment on T-cell immune reconstitution in patients with MM who had undergone autologous peripheral blood stem cell transplant (ASCT). Twenty-nine newly diagnosed patients with MM received induction therapy followed by high-dose melphalan and ASCT.