Human regulatory B cells in health and disease: therapeutic potential

Quantitative analysis of Tr1 lymphocytes in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is usually accompanied by a low-grade inflammatory phenomenon, which participates in the pathogenesis of different complications of this condition. The inflammatory response is under the regulation of different mechanisms, including T regulatory (Treg) lymphocytes. However, the possible role of type 1 T regulatory (Tr1) cells in T2DM has not been explored so far.

AIM

To carry out a quantitative analysis of Tr1 lymphocytes and other immune cell subsets in patients with T2DM and correlate these results with clinical findings and treatments.

MATERIALS AND METHODS

Sixty patients with T2DM and twenty-three healthy controls were included in the study. Biochemical and anthropometric variables were evaluated, and Tr1 lymphocytes (CD4+CD49+LAG-3+IL-10+) and other cell subsets (Th17, Th22 and Foxp3 + Treg cells) were analyzed in peripheral blood samples by multiparametric flow cytometry.

RESULTS

Significant increased levels of Tr1 cells were detected in patients with severe and mild disease, compared to healthy controls. In addition, CD4+IL-10+ lymphocytes were also increased in patients with T2DM. In contrast, similar levels of Foxp3+ Treg cells, Th17 and Th22 lymphocytes were observed in patients and controls. Likewise, no significant associations were detected between Tr1 cell levels and different clinical and laboratory parameters. However, those patients receiving glucagon-like peptide-1 receptor agonists (GLP-1-RA) showed similar levels of Tr1 cells than healthy controls, and significant lower numbers than untreated patients.

CONCLUSION

We observed an increase in Tr1 and CD4+IL10+ lymphocyte levels in T2DM. Moreover, GLP1-RA treatment was significantly associated with normalization of the Tr1 levels. This highlights another potential immune dysfunction in patients with T2DM, which could participate in the pathogenesis of this condition.

Pathogenic role of different phenotypes of immune cells in airway allergic diseases: a study based on Mendelian randomization

Background

Airway allergic disease (AAD) is a class of autoimmune diseases with predominantly Th2-type inflammation, mainly including allergic rhinitis (AR), allergic asthma (AS), and chronic sinusitis (CRS). There are very complex regulatory mechanisms between immune cells and AAD; however, previous reports found that the functions of the same immune cells in AAD are not identical.

Objective

The aim of this study was to explore the causal relationship between different phenotypic immune cells and their association with AAD.

Method

Utilizing the publicly available Genome-Wide Association Studies (GWAS) database, this study conducted a bidirectional Mendelian randomization (MR) to assess the causal relationship between immune cells of 731 different immunophenotypes and AAD. The primary assessment methods included inverse variance weighting, weighted median, and MR Egger. Additionally, sensitivity analyses such as MR-PRESSO, leave-one-out, and scatter plots were employed to eliminate the interference of heterogeneity and pleiotropy, ensuring the stability of the causal inference.

Result

A total of 38 immune cells with different immunophenotypes were found to be positively and causally associated with AR, of which 26 were protective factors and 12 were risk factors. Positive associations were found between 33 immune cells and AS, of which 14 were protective factors and 19 were risk factors, as well as between 39 immune cells and CRS, of which 22 were protective factors and 17 were risk factors. Finally, the results of all relevant immune cells for the three diseases were taken and intersected, and it was found that CD3 on CD39+-activated Treg (IVWAR = 0.001, IVWCRS = 0.043, IVWAS = 0.027) may be the key immune cell that inhibits the development of AAD (ORAR = 0.940, ORAS = 0.967, ORCRS = 0.976).

Conclusion

This study reveals that different immune phenotypes of immune cells are closely related to AAD at the genetic level, which provides a theoretical basis for future clinical studies.

Oxidative phosphorylation regulates B cell effector cytokines and promotes inflammation in multiple sclerosis

Dysregulated B cell cytokine production contributes to pathogenesis of immune-mediated diseases including multiple sclerosis (MS); however, the underlying mechanisms are poorly understood. In this study we investigated how cytokine secretion by pro-inflammatory (GM-CSF-expressing) and anti-inflammatory (IL-10-expressing) B cells is regulated. Pro-inflammatory human B cells required increased oxidative phosphorylation (OXPHOS) compared with anti-inflammatory B cells. OXPHOS reciprocally modulated pro- and anti-inflammatory B cell cytokines through regulation of adenosine triphosphate (ATP) signaling. Partial inhibition of OXPHOS or ATP-signaling including with BTK inhibition resulted in an anti-inflammatory B cell cytokine shift, reversed the B cell cytokine imbalance in patients with MS, and ameliorated neuroinflammation in a myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalitis mouse model. Our study identifies how pro- and anti-inflammatory cytokines are metabolically regulated in B cells and identifies ATP and its metabolites as a "fourth signal" that shapes B cell responses and is a potential target for restoring the B cell cytokine balance in autoimmune diseases.

Myeloid-derived suppressor cells from tumour-bearing mice induce the population expansion of CD19hiFcγRIIbhi regulatory B cells via PD-L1

Myeloid-derived suppressor cells (MDSCs) increase in number and gain immunosuppressive functions in tumours and many other pathological conditions. MDSCs are characterized by their strong T-cell immunosuppressive capacity. The effects that MDSCs may have on B cells, especially within the tumour microenvironment, are less well understood. Here, we report that either monocytic MDSCs or polymorphonuclear MDSCs can promote increases in interleukin (IL)-10-expressing CD19hiFcγRIIbhi regulatory B cells in vitro and in vivo. Splenic transitional-1, -2, and -3 cells and marginal zone B cells, but not follicular B cells, differentiate into IL-10-expressing CD19hiFcγRIIbhi regulatory B cells. The adoptive transfer of CD19hiFcγRIIbhi regulatory B cells via tail vein injection can promote subcutaneous 3LL tumour growth in mice. The expression of programmed death-ligand 1 on MDSCs was found to be strongly associated with CD19hiFcγRIIbhi regulatory B cell population expansion. Furthermore, the frequency of circulating CD19+FcγRIIhi regulatory B cells was significantly increased in advanced-stage lung cancer patients. Our results unveil a critical role of MDSCs in regulatory B-cell differentiation and population expansion in lung cancer patients.

The activity and immune dynamics of PD-1 inhibition on high-risk pulmonary ground glass opacity lesions: insights from a single-arm, phase II trial

Immune checkpoint inhibitors targeting the programmed cell death-1 (PD-1) protein significantly improve survival in patients with advanced non-small-cell lung cancer (NSCLC), but its impact on early-stage ground-glass opacity (GGO) lesions remains unclear. This is a single-arm, phase II trial (NCT04026841) using Simon's optimal two-stage design, of which 4 doses of sintilimab (200 mg per 3 weeks) were administrated in 36 enrolled multiple primary lung cancer (MPLC) patients with persistent high-risk (Lung-RADS category 4 or had progressed within 6 months) GGOs. The primary endpoint was objective response rate (ORR). T/B/NK-cell subpopulations, TCR-seq, cytokines, exosomal RNA, and multiplexed immunohistochemistry (mIHC) were monitored and compared between responders and non-responders. Finally, two intent-to-treat (ITT) lesions (pure-GGO or GGO-predominant) showed responses (ORR: 5.6%, 2/36), and no patients had progressive disease (PD). No grade 3-5 TRAEs occurred. The total response rate considering two ITT lesions and three non-intent-to-treat (NITT) lesions (pure-solid or solid-predominant) was 13.9% (5/36). The proportion of CD8+ T cells, the ratio of CD8+/CD4+, and the TCR clonality value were significantly higher in the peripheral blood of responders before treatment and decreased over time. Correspondingly, the mIHC analysis showed more CD8+ T cells infiltrated in responders. Besides, responders' cytokine concentrations of EGF and CTLA-4 increased during treatment. The exosomal expression of fatty acid metabolism and oxidative phosphorylation gene signatures were down-regulated among responders. Collectively, PD-1 inhibitor showed certain activity on high-risk pulmonary GGO lesions without safety concerns. Such effects were associated with specific T-cell re-distribution, EGF/CTLA-4 cytokine compensation, and regulation of metabolism pathways.

The immunologic abnormalities in patients with paroxysmal nocturnal hemoglobinuria are associated with disease progression

OBJECTIVES

To suggest the presence of a hyperimmune state in patients, and indicate that immune system attack on glycosylphosphatidylinositol (+) (GPI+) cells while escaping GPI- cell immunity.

METHODS

We retrospective the immune cell subtypes in peripheral blood from 25 patients visiting Tianjin Medical University General Hospital, Tianjin, China, with classical paroxysmal nocturnal hemoglobinuria (PNH) and 50 healthy controls.

RESULTS

The total CD3+ and CD3+CD8+ cell levels were higher in patients with PNH. The CD3+ cells are positively, correlated with lactate dehydrogenase (LDH; r=0.5453, p=0.0040), indirect bilirubin (r=0.4260, p=0.0379) and Flear- cells in monocytes (r=0.4099, p=0.0303). However, a negative correlation was observed between CD3+ cells and hemoglobin (r= -0.4530, p=0.0105). The total CD19+ cells decreased in patients, and CD19+ cells were negatively correlated with LDH (r= -0.5640, p=0.0077) and Flear- cells in monocytes (r= -0.4432, p=0.0341). Patients showed an increased proportion of total dendritic cells (DCs), with a higher proportion of myeloid DCs (mDCs) within the DC population. Moreover, the proportion of mDC/DC was positively correlated with CD59- cells (II + III types) in red cells (r=0.7941, p=0.0004), Flear- cells in granulocytes (r=0.5357, p=0.0396), and monocytes (r=0.6445, p=0.0095).

CONCLUSION

Our results demonstrated that immune abnormalities are associated with PNH development.

Chimeric Antigen Receptor (CAR)-Based Cell Therapy for Type 1 Diabetes Mellitus (T1DM); Current Progress and Future Approaches

Type 1 diabetes mellitus (T1DM) is an autoimmune disease that destroys insulin-producing pancreatic β-cells. Insulin replacement therapy is currently the mainstay of treatment for T1DM; however, treatment with insulin does not ameliorate disease progression, as dysregulated immune response and inflammation continue to cause further pancreatic β-cell degradation. Therefore, shifting therapeutic strategies toward immunomodulating approaches could be effective to prevent and reverse disease progression. Different immune-modulatory therapies could be used, e.g., monoclonal-based immunotherapy, mesenchymal stem cell, and immune cell therapy. Since immune-modulatory approaches could have a systemic effect on the immune system and cause toxicity, more specific treatment options should target the immune response against pancreatic β-cells. In this regard, chimeric antigen receptor (CAR)-based immunotherapy could be a promising candidate for modulation of dysregulated immune function in T1DM. CAR-based therapy has previously been approved for a number of hematologic malignancies. Nevertheless, there is renewed interest in CAR T cells' " off-the-shelf " treatment for T1DM. Several pre-clinical studies demonstrated that redirecting antigen-specific CAR T cells, especially regulatory CAR T cells (CAR Tregs), toward the pancreatic β-cells, could prevent diabetes onset and progression in diabetic mice models. Here, we aim to review the current progress of CAR-based immune-cell therapy for T1DM and the corresponding challenges, with a special focus on designing CAR-based immunomodulatory strategies to improve its efficacy in the treatment of T1DM.

Shift in the B cell subsets between children with type 1 diabetes and/or celiac disease

Our purpose was to characterize the pattern of B cell subsets in children with a combined diagnosis of type 1 diabetes (T1D) and celiac disease (C) since children with single or double diagnosis of these autoimmune diseases may differ in peripheral B cell subset phenotype patterns. B cells were analyzed with flow cytometry for the expression of differentiation/maturation markers to identify transitional, naive, and memory B cells. Transitional (CD24hiCD38hiCD19+) and memory Bregs (mBregs; CD24hiCD27+CD19+, CD1d+CD27+CD19+, and CD5+CD1d+CD19+) were classified as B cells with regulatory capacity. Children with a combined diagnosis of T1D and C showed a pattern of diminished peripheral B cell subsets. The B cells compartment in children with combined diagnosis had higher percentages of memory B subsets and Bregs, including activated subsets, compared to children with either T1D or C. Children with combined diagnosis had a lower percentage of naive B cells (CD27-CD19+; IgD+CD19+) and an increased percentage of memory B cells (CD27+CD19+; IgD-CD19+). A similar alteration was seen among the CD39+ expressing naive and memory B cells. Memory Bregs (CD1d+CD27+CD19+) were more frequent, contrary to the lower percentage of CD5+ transitional Bregs in children with a combined diagnosis. In children with either T1D or C, the peripheral B cell compartment was dominated by naive cells. Differences in the pattern of heterogeneous peripheral B cell repertoire subsets reflect a shifting in the B cell compartment between children with T1D and/or C. This is an immunological challenge of impact on the pathophysiology of these autoimmune diseases.

Immunosuppression withdrawal in living-donor renal transplant recipients following induction with antithymocyte globulin and rituximab: Results of a prospective clinical trial

Durable tolerance in kidney transplant recipients remains an important but elusive goal. We hypothesized that adding B cell depletion to T cell depletion would generate an immune milieu postreconstitution dominated by immature transitional B cells, favoring tolerance. The Immune Tolerance Network ITN039ST Research Study of ATG and Rituximab in Renal Transplantation was a prospective multicenter pilot study of live donor kidney transplant recipients who received induction with rabbit antithymocyte globulin and rituximab and initiated immunosuppression (IS) withdrawal (ISW) at 26 weeks. The primary endpoint was freedom from rejection at 52 weeks post-ISW. Six of the 10 subjects successfully completed ISW. Of these 6 subjects, 4 restarted immunosuppressive medications due to acute rejection or recurrent disease, 1 remains IS-free for over 9 years, and 1 was lost to follow-up after being IS-free for 42 weeks. There were no cases of patient or graft loss. CD19+ B cell frequencies returned to predepletion levels by 26 weeks posttransplant; immunoglobulin D+CD27--naïve B cells predominated. In contrast, memory cells dominated the repopulation of the T cell compartment. A regimen of combined B and T cell depletion did not generate the tolerogenic B cell profile observed in preclinical studies and did not lead to durable tolerance in the majority of kidney transplant recipients.

The role of B cells in systemic sclerosis

Systemic sclerosis (SSc) is a rare and refractory systemic disease characterized by fibrosis and vasculopathy in the presence of autoimmune abnormalities. While the exact cause of SSc is incompletely understood, the specific autoantibodies identified in SSc are closely linked to disease severity and prognosis, indicating a significant role of autoimmune abnormalities in the pathogenesis of SSc. Although the direct pathogenic mechanisms of autoantibodies in SSc are not fully elucidated, numerous prior investigations have demonstrated the involvement of B cells in the pathogenesis of SSc through various mechanisms. Additionally, several clinical trials have explored the efficacy of B-cell depletion therapy for SSc, with many reporting positive outcomes. However, the role of B cells in SSc pathogenesis is multifaceted, as they can both promote inflammation and exert inhibitory functions. This article provides an overview of the involvement of B cells in SSc development, incorporating the latest research findings.

Knowledge mapping of B cell and atherosclerosis over the past 20 years: A bibliometric analysis

Atherosclerosis (AS) is the main underlying cause of cardiovascular disease, and B cells are considered a key immune cell type to regulate AS. So far, there is no bibliometric study on B cell and AS. This study aims to comprehensively analyze the scientific output about B cell and AS, summarize the literature characteristics, explore research hotspots, and point out emerging trends. We searched the literature from 2003 to 2022 from the Web of Science Core Collection (WoSCC) database. CiteSpace, VOSviewer, and the R package "Bibliometrix" were used for literature analysis and visualization. A total of 1,062 articles and reviews were identified. The number of annual publications generally showed an upward trend. The United States and China were the most productive countries. Medical University of Vienna was the most productive research institution, and Binder Christoph J. was the most productive author, who was also from Medical University of Vienna. "Arteriosclerosis Thrombosis and Vascular Biology" was the most published journal and the most frequently cited journal. The most cited reference was written by Caligiuri G (2002) in "Journal of Clinical Investigation." The most frequent keywords were "inflammation," "macrophages," "cardiovascular disease," "T cells," "apoptosis," "immunity," "cytokines," "lymphocytes," etc. The trend topics were mainly focused on "immune infiltration," "immunoglobulins," and "biomarkers." The complex role of B cell subtypes and a variety of B cell mediators is the main research direction at present. In-depth analysis of B cell-specific targets can provide new ideas and methods for the prevention and treatment of AS.

Single-cell RNA sequencing analysis reveals the heterogeneity of IL-10 producing regulatory B cells in lupus-prone mice

Introduction

B cells can have both pathogenic and protective roles in autoimmune diseases, including systemic lupus erythematosus (SLE). Deficiencies in the number or immunosuppressive function of IL-10 producing regulatory B cells (Bregs) can cause exacerbated autoimmune inflammation. However, the exact role of Bregs in lupus pathogenesis has not been elucidated.

Methods

We carried out gene expression analysis by scRNA-seq to characterize differences in splenic Breg subsets and molecular profiles through stages of disease progression in lupus-prone mice. Transcriptome-based changes in Bregs from mice with active disease were confirmed by phenotypic analysis.

Results

We found that a loss of marginal zone (MZ) lineage Bregs, an increase in plasmablast/plasma cell (PB-PC) lineage Bregs, and overall increases in inflammatory gene signatures were characteristic of active disease as compared to Bregs from the pre-disease stage. However, the frequencies of both MZ Bregs and PB-PCs expressing IL-10 were significantly decreased in active-disease mice.

Conclusion

Overall, we have identified changes to the repertoire and transcriptional landscape of Breg subsets associated with active disease that provide insights into the role of Bregs in lupus pathogenesis. These results could inform the design of Breg-targeted therapies and interventions to restore Breg suppressive function in autoimmunity.

Social stress induces autoimmune responses against the brain

Clinical studies have revealed a high comorbidity between autoimmune diseases and psychiatric disorders, including major depressive disorder (MDD). However, the mechanisms connecting autoimmunity and depression remain unclear. Here, we aim to identify the processes by which stress impacts the adaptive immune system and the implications of such responses to depression. To examine this relationship, we analyzed antibody responses and autoimmunity in the chronic social defeat stress (CSDS) model in mice, and in clinical samples from patients with MDD. We show that socially stressed mice have elevated serum antibody concentrations. We also confirm that social stress leads to the expansion of specific T and B cell populations within the cervical lymph nodes, where brain-derived antigens are preferentially delivered. Sera from stress-susceptible (SUS) mice exhibited high reactivity against brain tissue, and brain-reactive immunoglobulin G (IgG) antibody levels positively correlated with social avoidance behavior. IgG antibody concentrations in the brain were significantly higher in SUS mice than in unstressed mice, and positively correlated with social avoidance. Similarly, in humans, increased peripheral levels of brain-reactive IgG antibodies were associated with increased anhedonia. In vivo assessment of IgG antibodies showed they largely accumulate around blood vessels in the brain only in SUS mice. B cell-depleted mice exhibited stress resilience following CSDS, confirming the contribution of antibody-producing cells to social avoidance behavior. This study provides mechanistic insights connecting stress-induced autoimmune reactions against the brain and stress susceptibility. Therapeutic strategies targeting autoimmune responses might aid in the treatment of patients with MDD featuring immune abnormalities.

Distribution characteristics of circulating B cell subpopulations in patients with chronic kidney disease

This study compared the levels of circulating B cell subpopulations in patients with different stages of chronic kidney disease (CKD), investigated the effects of haemodialysis (HD) on the B cell-related immune spectrum in patients with end-stage renal disease, and evaluated the link between renal function and immune homeostasis. Overall, 197 patients with CKD (158 non-dialysis patients with CKD stages I-V and 39 end-stage patients undergoing maintenance HD) and 77 healthy controls were included. Compared to healthy controls, patients with CKD stages I-II showed no significant differences except for the proportion of transitional B cells; patients with CKD stage V showed a significant decrease in the proportions of transitional B cells and CD5+ B cells and a significant increase in double-negative (DN) B cells. Compared with early-stage patients with CKD, the absolute count of various B cell subpopulations in advanced-stage patients with CKD showed a significant decrease. The distribution of circulating B cell subpopulations in patients with CKD was significantly altered and was associated with CKD progression. Furthermore, the proportion of DN B cells and CD5+ B cells was inconsistent pre- and post-HD. This in-depth study of the immune status of patients with CKD may have important clinical value.

Changes in Treg and Breg cells in a healthy pediatric population

The interpretation of clinical diagnostic results in suspected inborn errors of immunity, including Tregopathies, is hampered by the lack of age-stratified reference values for regulatory T cells (Treg) in the pediatric population and a consensus on which Treg immunophenotype to use. Regulatory B cells (Breg) are an important component of the regulatory system that have been poorly studied in the pediatric population. We analyzed (1) the correlation between the three immunophenotypic definitions of Treg (CD4+CD25hiCD127low, CD4+CD25hiCD127lowFoxP3+, CD4+CD25hiFoxP3+), and with CD4+CD25hi and (2) the changes in Treg and Breg frequencies and their maturation status with age. We performed peripheral blood immunophenotyping of Treg and Breg (CD19+CD24hiCD38hi) by flow cytometry in 55 healthy pediatric controls. We observed that Treg numbers varied depending on the definition used, and the frequency ranged between 3.3-9.7% for CD4+CD25hiCD127low, 0.07-1.6% for CD4+CD25hiCD127lowFoxP3+, and 0.24-2.83% for CD4+CD25hiFoxP3+. The correlation between the three definitions of Treg was positive for most age ranges, especially between the two intracellular panels and with CD4+CD25hi vs CD4+CD25hiCD127low. Treg and Breg frequencies tended to decline after 7 and 3 years onwards, respectively. Treg's maturation status increased with age, with a decline of naïve Treg and an increase in memory/effector Treg from age 7 onwards. Memory Breg increased progressively from age 3 onwards. In conclusion, the number of Treg frequencies spans a wide range depending on the immunophenotypic definition used despite a good level of correlation exists between them. The decline in numbers and maturation process with age occurs earlier in Breg than in Treg.

Therapeutic targeting of gut-originating regulatory B cells in neuroinflammatory diseases

Regulatory B cells (Bregs) are immunosuppressive cells that support immunological tolerance by the production of IL-10, IL-35, and TGF-β. Bregs arise from different developmental stages in response to inflammatory stimuli. In that regard, mounting evidence points towards a direct influence of gut microbiota on mucosal B cell development, activation, and regulation in health and disease. While an increasing number of diseases are associated with alterations in gut microbiome (dysbiosis), little is known about the role of microbiota on Breg development and induction in neuroinflammatory disorders. Notably, gut-originating, IL-10- and IgA-producing regulatory plasma cells have recently been demonstrated to egress from the gut to suppress inflammation in the CNS raising fundamental questions about the triggers and functions of mucosal-originating Bregs in systemic inflammation. Advancing our understanding of Bregs in neuroinflammatory diseases could lead to novel therapeutic approaches. Here, we summarize the main aspects of Breg differentiation and functions and evidence about their involvement in neuroinflammatory diseases. Further, we highlight current data of gut-originating Bregs and their microbial interactions and discuss future microbiota-regulatory B cell-targeted therapies in immune-mediated diseases.

Outcomes of hematopoietic stem cell gene therapy for Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterized by combined immunodeficiency, eczema, microthrombocytopenia, autoimmunity, and lymphoid malignancies. Gene therapy (GT) to modify autologous CD34+ cells is an emerging alternative treatment with advantages over standard allogeneic hematopoietic stem cell transplantation for patients who lack well-matched donors, avoiding graft-versus-host-disease. We report the outcomes of a phase 1/2 clinical trial in which 5 patients with severe WAS underwent GT using a self-inactivating lentiviral vector expressing the human WAS complementary DNA under the control of a 1.6-kB fragment of the autologous promoter after busulfan and fludarabine conditioning. All patients were alive and well with sustained multilineage vector gene marking (median follow-up: 7.6 years). Clinical improvement of eczema, infections, and bleeding diathesis was universal. Immune function was consistently improved despite subphysiologic levels of transgenic WAS protein expression. Improvements in platelet count and cytoskeletal function in myeloid cells were most prominent in patients with high vector copy number in the transduced product. Two patients with a history of autoimmunity had flares of autoimmunity after GT, despite similar percentages of WAS protein-expressing cells and gene marking to those without autoimmunity. Patients with flares of autoimmunity demonstrated poor numerical recovery of T cells and regulatory T cells (Tregs), interleukin-10-producing regulatory B cells (Bregs), and transitional B cells. Thus, recovery of the Breg compartment, along with Tregs appears to be protective against development of autoimmunity after GT. These results indicate that clinical and laboratory manifestations of WAS are improved with GT with an acceptable safety profile. This trial is registered at clinicaltrials.gov as #NCT01410825.

Single-cell genomics in acquired bone marrow failure syndromes

Mechanistic studies of immune bone marrow failure are difficult because of the scarcity of residual cells, the involvement of multiple cell types, and the inherent complexities of hematopoiesis and immunity. Single-cell genomic technologies and bioinformatics allow extensive, multidimensional analysis of a very limited number of cells. We review emerging applications of single-cell techniques, and early results related to disease pathogenesis: effector and target cell populations and relationships, cell-autonomous and nonautonomous phenotypes in clonal hematopoiesis, transcript splicing, chromosomal abnormalities, and T-cell receptor usage and clonality. Dense and complex data from single-cell techniques provide insights into pathophysiology, natural history, and therapeutic drug effects.

B Cell Tolerance and Targeted Therapies in SLE

Systemic Lupus Erythematosus (SLE) is a chronic systemic autoimmune disease of high clinical and molecular heterogeneity, and a relapsing-remitting pattern. The disease is currently without cure and more prevalent in women. B cell tolerance and production of autoantibodies are critical mechanisms that drive SLE pathophysiology. However, how the balance of the immune system is broken and how the innate and adaptive immune systems are interacting during lupus-specific autoimmune responses are still largely unknown. Here, we review the latest knowledge on B cell development, maturation, and central versus peripheral tolerance in connection to SLE and treatment options. We also discuss the regulation of B cells by conventional T cells, granulocytes, and unconventional T cells, and how effector B cells exert their functions in SLE. We also discuss mechanisms of action of B cell-targeted therapies, as well as possible future directions based on current knowledge of B cell biology.

Differentially activated B cells develop regulatory phenotype and show varying immunosuppressive features: a comparative study

Regulatory B lymphocytes (Bregs) are B cells with well-pronounced immunosuppressive properties, allowing them to suppress the activity of effector cells. A broad repertoire of immunosuppressive mechanisms makes Bregs an attractive tool for adoptive cell therapy for diseases associated with excessive activation of immune reactions. Such therapy implies Breg extraction from the patient's peripheral blood, ex vivo activation and expansion, and further infusion into the patient. At the same time, the utility of Bregs for therapeutic approaches is limited by their small numbers and extremely low survival rate, which is typical for all primary B cell cultures. Therefore, extracting CD19+ cells from the patient's peripheral blood and specifically activating them ex vivo to make B cells acquire a suppressive phenotype seems to be far more productive. It will allow a much larger number of B cells to be obtained initially, which may significantly increase the likelihood of successful immunosuppression after adoptive Breg transfer. This comparative study focuses on finding ways to efficiently manipulate B cells in vitro to differentiate them into Bregs. We used CD40L, CpG, IL4, IL21, PMA, and ionomycin in various combinations to generate immunosuppressive phenotype in B cells and performed functional assays to test their regulatory capacity. This work shows that treatment of primary B cells using CD40L + CpG + IL21 mix was most effective in terms of induction of functionally active regulatory B lymphocytes with high immunosuppressive capacity ex vivo.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

Germinal center-dependent and -independent immune responses of tumor-infiltrating B cells in human cancers

B cells play essential roles in immunity, mainly through the production of high affinity plasma cells (PCs) and memory B (Bmem) cells. The affinity maturation and differentiation of B cells rely on the integration of B-cell receptor (BCR) intrinsic and extrinsic signals provided by antigen binding and the microenvironment, respectively. In recent years, tumor infiltrating B (TIL-B) cells and PCs (TIL-PCs) have been revealed as important players in antitumor responses in human cancers, but their interplay and dynamics remain largely unknown. In lymphoid organs, B-cell responses involve both germinal center (GC)-dependent and GC-independent pathways for Bmem cell and PC production. Affinity maturation of BCR repertoires occurs in GC reactions with specific spatiotemporal dynamics of signal integration by B cells. In general, the reactivation of high-affinity Bmem cells by antigens triggers GC-independent production of large numbers of PC without BCR rediversification. Understanding B-cell dynamics in immune responses requires the integration of multiple tools and readouts such as single-cell phenotyping and RNA-seq, in situ analyses, BCR repertoire analysis, BCR specificity and affinity assays, and functional tests. Here, we review how those tools have recently been applied to study TIL-B cells and TIL-PC in different types of solid tumors. We assessed the published evidence for different models of TIL-B-cell dynamics involving GC-dependent or GC-independent local responses and the resulting production of antigen-specific PCs. Altogether, we highlight the need for more integrative B-cell immunology studies to rationally investigate TIL-B cells as a leverage for antitumor therapies.

Systemic immune response in young and elderly patients after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of death and long-term disability worldwide. In addition to primary brain damage, systemic immune alterations occur, with evidence for dysregulated immune responses in aggravating TBI outcome and complications. However, immune dysfunction following TBI has been only partially understood, especially in the elderly who represent a substantial proportion of TBI patients and worst outcome. Therefore, we aimed to conduct an in-depth immunological characterization of TBI patients, by evaluating both adaptive (T and B lymphocytes) and innate (NK and monocytes) immune cells of peripheral blood mononuclear cells (PBMC) collected acutely (< 48 h) after TBI in young (18-45 yo) and elderly (> 65 yo) patients, compared to age-matched controls, and also the levels of inflammatory biomarkers.

RESULTS

Our data show that young respond differently than elderly to TBI, highlighting the immune unfavourable status of elderly compared to young patients. While in young only CD4 T lymphocytes are activated by TBI, in elderly both CD4 and CD8 T cells are affected, and are induced to differentiate into subtypes with low cytotoxic activity, such as central memory CD4 T cells and memory precursor effector CD8 T cells. Moreover, TBI enhances the frequency of subsets that have not been previously investigated in TBI, namely the double negative CD27- IgD- and CD38-CD24- B lymphocytes, and CD56dim CD16- NK cells, both in young and elderly patients. TBI reduces the production of pro-inflammatory cytokines TNF-α and IL-6, and the expression of HLA-DM, HLA-DR, CD86/B7-2 in monocytes, suggesting a compromised ability to drive a pro-inflammatory response and to efficiently act as antigen presenting cells.

CONCLUSIONS

We described the acute immunological response induced by TBI and its relation with injury severity, which could contribute to pathologic evolution and possibly outcome. The focus on age-related immunological differences could help design specific therapeutic interventions based on patients' characteristics.

Tolerogenic dendritic cells in type 1 diabetes: no longer a concept

Tolerogenic dendritic cells (tDC) arrest the progression of autoimmune-driven dysglycemia into clinical, insulin-requiring type 1 diabetes (T1D) and preserve a critical mass of β cells able to restore some degree of normoglycemia in new-onset clinical disease. The safety of tDC, generated ex vivo from peripheral blood leukocytes, has been demonstrated in phase I clinical studies. Accumulating evidence shows that tDC act via multiple layers of immune regulation arresting the action of pancreatic β cell-targeting effector lymphocytes. tDC share a number of phenotypes and mechanisms of action, independent of the method by which they are generated ex vivo. In the context of safety, this yields confidence that the time has come to test the best characterized tDC in phase II clinical trials in T1D, especially given that tDC are already being tested for other autoimmune conditions. The time is also now to refine purity markers and to "universalize" the methods by which tDC are generated. This review summarizes the current state of tDC therapy for T1D, presents points of intersection of the mechanisms of action that the different embodiments use to induce tolerance, and offers insights into outstanding matters to address as phase II studies are imminent. Finally, we present a proposal for co-administration and serially-alternating administration of tDC and T-regulatory cells (Tregs) as a synergistic and complementary approach to prevent and treat T1D.

B cell activation via immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease involving multiple organs in which B cells perform important functions such as antibody and cytokine production and antigen presentation. B cells are activated and differentiated by the primary B cell receptor, co-stimulatory molecule signals-such as CD40/CD40L-, the Toll-like receptors 7,9, and various cytokine signals. The importance of immunometabolism in the activation, differentiation, and exerting functions of B cells and other immune cells has been widely reported in recent years. However, the regulatory mechanism of immunometabolism in B cells and its involvement in SLE pathogenesis remain elusive. Similarly, the importance of the PI3K-Akt-mTOR signaling pathway, glycolytic system, and oxidative phosphorylation has been demonstrated in the mechanisms of B cell immunometabolic activation, mainly in mouse studies. However, the activation of the mTOR pathway in B cells in patients with SLE, the induction of plasmablast differentiation through metabolic and transcription factor regulation by mTOR, and the involvement of this phenomenon in SLE pathogenesis are unclear. In our studies using activated B cells derived from healthy donors and from patients with SLE, we observed that methionine, an essential amino acid, is important for mTORC1 activation. Further, we observed that splenic tyrosine kinase and mTORC1 activation synergistically induce EZH2 expression and plasmablasts by suppressing BACH2 expression through epigenomic modification. Additionally, we identified another mechanism by which the glutaminolysis-induced enhancement of mitochondrial function promotes plasmablast differentiation in SLE. In this review, we focused on the SLE exacerbation mechanisms related to the activation of immune cells-especially B cells-and immunometabolism and reported the latest findings in the field.

Added value of lymphocyte subpopulations in the classification of Sjögren's syndrome

Sjögren's Syndrome (SjS) is a chronic systemic immune-mediated inflammatory disease characterized by lymphocytic infiltration and consequent lesion of exocrine glands. SjS diagnosis and classification remains a challenge, especially at SjS onset, when patients may have milder phenotypes of the disease or uncommon presentations. New biomarkers are needed for the classification of SjS, thus, we aimed to evaluate the added-value of lymphocyte subpopulations in discriminating SjS and non-Sjögren Sicca patients. Lymphocyte subsets from 62 SjS and 63 Sicca patients were characterized by flow cytometry. The 2002 AECG and the 2016 ACR/EULAR SjS classification criteria were compared with clinical diagnosis. The added discriminative ability of joining lymphocytic populations to classification criteria was assessed by the area under the Receiver-Operating-Characteristic Curve (AUC). Considering clinical diagnosis as the gold-standard, we obtained an AUC = 0.952 (95% CI: 0.916-0.989) for AECG and an AUC = 0.921 (95% CI: 0.875-0.966) for ACR/EULAR criteria. Adding Tfh and Bm1 subsets to AECG criteria, performance increased, attaining an AUC = 0.985 (95% CI: 0.968-1.000) (p = 0.021). Th1/Breg-like CD24^hiCD27⁺ and switched-memory B-cells maximized the AUC of ACR/EULAR criteria to 0.953 (95% CI: 0.916-0.990) (p = 0.043). Our exploratory study supports the potential use of lymphocyte subpopulations, such as unswitched memory B cells, to improve the performance of classification criteria, since their discriminative ability increases when specific subsets are added to the criteria.

Anorexia Nervosa in Juvenile Systemic Lupus Erythematosus (SLE): A Causality Dilemma

Juvenile-onset systemic lupus erythematosus (jSLE) is an autoimmune disorder with multifaceted clinical findings in different organ systems. Neuropsychiatric manifestations affect more than half of SLE patients, and there is increasing evidence that anorexia nervosa (AN), a feeding and eating disorder (FED) characterized by significantly reduced energy intake, is among them. Herein, a review of the literature on the potential association between jSLE and AN was performed. Reported clinical cases were identified, and putative pathophysiological mechanisms were sought that could potentially explain the observed relationship between these two pathological entities. Four reports of isolated cases and a case series including seven patients were identified. In this limited patient pool, the diagnosis of AN preceded that of SLE in the majority of cases, whereas in all cases both entities were diagnosed within a time span of two years. Many explanations for the observed relationships have been proposed. AN has been associated with the stress of chronic disease diagnosis; on the other hand, the chronic inflammation associated with AN may contribute to the development/appearance of SLE. Adverse childhood experiences, concentrations of leptin, shared autoantibodies, and genetic traits appear to be important factors in this well-established interplay. In essence, it seems important to increase clinician awareness of the concomitant development of AN and SLE and invite further research on the subject.

Regulatory B cells (Bregs) in Helicobacter pylori chronic infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is linked with a wide variety of diseases and was reported in more than half of the world's population. Chronic H. pylori infection and its final clinical outcome depend mainly on the bacterial virulence factors and its ability to manipulate and adapt to human immune responses. Bregs blood levels have been correlated with increased bacterial load and infection chronicity, especially Gram-negative bacterial infection. This study aimed to identify prevalence and virulence factors of chronic H. pylori infection among symptomatic Egyptian patients and to examine its possible correlation to levels of regulatory B cells (Bregs) in blood.

MATERIALS AND METHODS

Gastric biopsies and blood samples from each of 113 adult patients, who underwent upper endoscopy, were examined for the detection of H. pylori by culture and PCR methods. Conventional PCR was used to determine various virulent genes prevalence and association to clinical outcome. Flow cytometry was used to evaluate Bregs levels.

RESULTS

Helicobacter pylori prevalence was 49.1% (55/112). Regarding virulence genes incidence, flaA gene was detected in 73% (40/55), vir B11 in 56.4% (31/55), hopZ1 in 34.5% (19/55), hopZ2 in 89% (49/55), babA2 in 52.7% (29/55), dupA jhp917 in 61.8% (34/55), vacA m1/m2 in 70.9% (39/55), and vacA s1/s2 in 69% (38/55) strains. Bregs levels were significantly lower in H. pylori-infected patients (p = 0.013), while total leukocyte count (TLC) showed no significant differences.

CONCLUSION

Helicobacter pylori infection prevalence was almost 49%, and the infection was found to be related to inflammatory conditions as gastritis and ulcers rather than malignant transformations. Also, we found that CD24⁺ CD38⁺ B cells were downregulated in H. pylori-infected patients.

T cell subsets, regulatory T, regulatory B cells and proinflammatory cytokine profile in Schistosoma haematobium associated bladder cancer: First report from Upper Egypt

BACKGROUND

The function of different populations of the immune system in bladder cancer (BCa) is well established. However, the cohesive role of the immune cell profile of schistosomal BCa at systemic and tissue levels is still lacking, especially in endemic countries. The balance hypothesized between protumorigenic and antitumor molecules determines the prognosis of tumor progression. This study aimed to investigate the frequency of T cell subsets at both blood and tumor tissue, regulatory T(Treg), regulatory B cells (Breg) and proinflammatory cytokines in S. haematobium-related BCa patients in Egypt.

METHODOLOGY/PRINCIPAL FINDINGS

The frequency of T cell subsets at both blood and tumor tissue, regulatory T(Treg), regulatory B cells (Breg) were studied by flow cytometry and proinflammatory cytokines by ELISA in S. haematobium-related BCa patients in Egypt. The results indicated a significant increase in the activity of T-cell populations, particularly CD3+, CD4+, and regulatory T cells (Tregs), and a decrease in cytotoxic CD8+ T cells in the patient group. An increased proportion of CD19+CD24+CD38+ Bregs and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) was also observed. However, T-cell subpopulations in the tumor microenvironment showed a significant reduction in cancer patients compared to controls. Moreover, positive correlations were observed between the frequencies of Bregs and Tregs, suggesting the promotion of cancer progression besides their relation to the intensity of schistosomal infection.

CONCLUSIONS/SIGNIFICANCE

Trapped Schistosoma haematobium eggs in bladder tissue might lead to persistent inflammation that contributes to immunomodulation and promotes tumor progression, as evidenced by the increase in peripheral T helper, Tregs, Bregs and serum tumor-promoting cytokines. Considering the role and integrated functions of specific immune responses in BCa could help future diagnostic and therapeutic implications.

An Ideal Hallmark Closest to Complete Cure of Chronic Hepatitis B Patients: High-sensitivity Quantitative HBsAg Loss

In the era of antiviral therapy, the main goal of treatment has shifted from the persistent inhibition of hepatitis B virus (HBV) replication to the pursuit of serological clearance of HBs surface antigen (HBsAg). Based on the life cycle of HBV, HBsAg originates from covalently closed circular DNA (cccDNA) and integrated HBV DNA, thus reflecting their transcriptional activity. Complete HBsAg loss may mean elimination or persistent inactivity of the HBV genome including cccDNA and integrated HBV DNA. HBsAg loss improves the recovery of abnormal immune function, which in turn, may further promote the clearance of residual viruses. Combined with functional cure and the great improvement of clinical outcomes, the continuous seroclearance of high-sensitivity quantitative HBsAg may represent the complete cure of chronic hepatitis B (CHB). For many other risk factors besides HBV itself, patients with HBsAg loss still need regular monitoring. In this review, we summarized the evolution of CHB treatment, the origin of serum HBsAg, the pattern of HBsAg seroclearance, and the effect of HBsAg loss on immune function and disease outcomes. In addition, we discuss the significance of high-sensitivity HBsAg detection and its possibility as a surrogate of complete cure.

The Role of Immunity in the Pathogenesis of SARS-CoV-2 Infection and in the Protection Generated by COVID-19 Vaccines in Different Age Groups

This study aims to review the available data regarding the central role of immunity in combating SARS-CoV-2 infection and in the generation of protection by vaccination against COVID-19 in different age groups. Physiologically, the immune response and the components involved in it are variable, both functionally and quantitatively, in neonates, infants, children, adolescents, and adults. These immunological differences are mirrored during COVID-19 infection and in the post-vaccination period. The outcome of SARS-CoV-2 infection is greatly dependent on the reaction orchestrated by the immune system. This is clearly obvious in relation to the clinical status of COVID-19 infection, which can be symptomless, mild, moderate, or severe. Even the complications of the disease show a proportional pattern in relation to the immune response. On the contrary, the commonly used anti-COVID-19 vaccines generate protective humoral and cellular immunity. The magnitude of this immunity and the components involved in it are discussed in detail. Furthermore, many of the adverse effects of these vaccines can be explained on the basis of immune reactions against the different components of the vaccines. Regarding the appropriate choice of vaccine for different age groups, many factors have to be considered. This is a cornerstone, particularly in the following age groups: 1 day to 5 years, 6 to 11 years, and 12 to 17 years. Many factors are involved in deciding the route, doses, and schedule of vaccination for children. Another important issue in this dilemma is the hesitancy of families in making the decision about whether to vaccinate their children. Added to these difficulties is the choice by health authorities and governments concerning whether to make children's vaccination compulsory. In this respect, although rare and limited, adverse effects of vaccines in children have been detected, some of which, unfortunately, have been serious or even fatal. However, to achieve comprehensive control over COVID-19 in communities, both children and adults have to be vaccinated, as the former group represents a reservoir for viral transmission. The understanding of the various immunological mechanisms involved in SARS-CoV-2 infection and in the preparation and application of its vaccines has given the sciences a great opportunity to further deepen and expand immunological knowledge. This will hopefully be reflected positively on other diseases through gaining an immunological background that may aid in diagnosis and therapy. Humanity is still in continuous conflict with SARS-CoV-2 infection and will be for a while, but the future is expected to be in favor of the prevention and control of this disease.

The redox protein HMGB1 in cell death and cancer

SIGNIFICANCE

As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer.

RECENT ADVANCES

HMGB1 is a non-histone nuclear protein that acts as a DNA chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depends on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on tumor types and stages.

CRITICAL ISSUES

A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions.

FUTURE DIRECTIONS

Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease.

Impact of folic acid on regulatory B lymphocytes from patients with systemic lupus erythematosus in vitro

BACKGROUND

Epigenetic modifications of genomes are of particular interest as numerous studies indicate the correlation between DNA methylation and the development of systemic lupus. As a major methyl group donor, folic acid is an important participant in this process. The aim of this study is to determine the effect of low or high dose folate co-culturing with peripheral blood mononuclear cells (PBMCs) on the secretion of interleukin (IL)10 from regulatory cells from lupus patients or from healthy volunteers.

METHODS

PBMCs from lupus patients and healthy volunteers were isolated and separated CD19+ B cell populations were cultured in the presence of 4 μg/mL or of 16 μg/mL of folic acid and the DNA methylation level as well as the percentages of B lymphocytes were measured. In another experiment, PBMCs were stimulated in vitro for IL10 production with 1 μg/mL recombinant human CD40L and with 2.5 μg/mL unmethylated CpG dinucleotides and cultured in the presence of 4 μg/mL or of 16 μg/mL of folic acid.

RESULTS

Although co-culturing with low or high folic acid concentrations had no effect on the methylation level of B lymphocytes, particular patients showed an increase in the population of CD19+ IL10+ as well as of CD19- IL10+ cells.

CONCLUSION

The observed increase may be a consequence of additional indirect or direct methylation of DNA in specific loci of the targeted cells. However, further analysis would clarify the exact mechanism of action of folate and would reveal its immunomodulating potential in this autoimmune disease.

Effect of curcumin on regulatory B cells in chronic colitis mice involving TLR/MyD88 signaling pathway

Curcumin (Cur) is a natural active phenolic compound extracted from the root of Curcuma Longa L. It has anti-inflammatory, anti-tumor and other pharmacological activities, and is commonly used to treat ulcerative colitis (UC). However, it is not clear whether curcumin regulates the function and differentiation of Breg cells to treat UC. In this study, mice with chronic colitis were induced by dextran sulfate sodium (DSS), and treated with curcumin for 12 days. Curcumin effectively improved the body weight, colonic weight, colonic length, decreased colonic weight index and pathological injury score under colonoscopy in mice with chronic colitis, and significantly inhibited the production of IL-1β, IL-6, IL-33, CCL-2, IFN-γ, TNF-α, and promoted the secretion of IL-4, IL-10, IL-13 and IgA. Importantly, curcumin markedly upregulated CD3^- CD19⁺ CD1d⁺ , CD3^- CD19⁺ CD25⁺ , CD3^- CD19⁺ Foxp3⁺ Breg cells level and significantly down-regulated CD3^- CD19⁺ PD-L1⁺ , CD3^- CD19⁺ tim-1⁺ , CD3^- CD19⁺ CD27⁺ Breg cells level. In addition, our results also showed that curcumin observably inhibited TLR2, TLR4, TLR5, MyD88, IRAK4, p-IRAK4, NF-κB P65, IRAK1, TRAF6, TAB1, TAB2, TAK1, MKK3, MKK6, p38MAPK, p-p38MAPK and CREB expression in TLR/MyD88 signaling pathway. These results suggest that curcumin can regulate the differentiation and function of Breg cell to alleviate DSS-induced colitis, which may be realized by inhibiting TLR/MyD88 pathway.

Inflammation and autoimmune myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular autoimmune disorder characterized by chronic but intermittent fatigue of the eye- and general body muscles. Muscle weakness is caused primarily by the binding of an autoantibody to the acetylcholine receptors, resulting in blockage of normal neuromuscular signal transmission. Studies revealed substantial contributions of different proinflammatory or inflammatory mediators in the pathogenesis of MG. Despite these findings, compared to therapeutic approaches that target autoantibody and complements, only a few therapeutics against key inflammatory molecules have been designed or tested in MG clinical trials. Recent research focuses largely on identifying unknown molecular pathways and novel targets involved in inflammation associated with MG. A well-designed combination or adjunct treatment utilizing one or more selective and validated promising biomarkers of inflammation as a component of targeted therapy may yield better treatment outcomes. This review briefly discusses some preclinical and clinical findings of inflammation associated with MG and current therapy approaches and suggest the potential of targeting important inflammatory marker(s) along with current monoclonal antibody or antibody fragment based targeted therapies directed to a variety of cell surface receptors.

Standard immunosuppressive treatment reduces regulatory B cells in children with autoimmune liver disease

Introduction

Autoimmune hepatitis (AIH) is a chronic liver disease caused by a perturbed immune system. The scarcity of short- and long-term immune monitoring of AIH hampered us to comprehend the interaction between immunosuppressive medication and immune homeostasis.

Methods and patients

We recruited children with AIH at the time of diagnosis and at the 1st, 3rd, 6th, 12th, 18th, and 24th months of immunosuppression (IS). We also enrolled children with AIH being on IS for >2 years. Children with drug-induced liver injury (DILI), and those receiving tacrolimus after liver transplantation (LT), were enrolled as disease/IS control subjects. Healthy children (HC) were also recruited. Peripheral blood mononuclear cells (PBMCs) were isolated from all participants. Healthy liver tissue from adult donors and from livers without inflammation were obtained from children with hepatoblastoma. By using flow cytometry, we performed multi-parametric immune profiling of PBMCs and intrahepatic lymphocytes. Additionally, after IS with prednisolone, tacrolimus, rapamycin, or 6-mercaptopurine, we carried out an in vitro cytokine stimulation assay. Finally, a Lifecodes SSO typing kit was used to type HLA-DRB1 and Luminex was used to analyze the results.

Results

Untreated AIH patients had lower total CD8 T-cell frequencies than HC, but these cells were more naïve. While the percentage of naïve regulatory T cells (Tregs) (CD4⁺FOXP3^lowCD45RA⁺) and regulatory B cells (Bregs, CD20⁺CD24⁺CD38⁺) was similar, AIH patients had fewer activated Tregs (CD4⁺FOXP3^highCD45RA ^- ) compared to HC. Mucosal-associated-invariant-T-cells (MAIT) were also lower in these patients. Following the initiation of IS, the immune profiles demonstrated fluctuations. Bregs frequency decreased substantially at 1 month and did not recover anymore. Additionally, the frequency of intrahepatic Bregs in treated AIH patients was lower, compared to control livers, DILI, and LT patients. Following in vitro IS drugs incubation, only the frequency of IL-10-producing total B-cells increased with tacrolimus and 6MP. Lastly, 70% of AIH patients possessed HLA-DR11, whereas HLA-DR03/DR07/DR13 was present in only some patients.

Conclusion

HLA-DR11 was prominent in our AIH cohort. Activated Tregs and MAIT cell frequencies were lower before IS. Importantly, we discovered a previously unrecognized and long-lasting Bregs scarcity in AIH patients after IS. Tacrolimus and 6MP increased IL-10+ B-cells in vitro.

Human B-cell subset identification and changes in inflammatory diseases

Our understanding of the B-cell subsets found in human blood and their functional significance has advanced greatly in the past decade. This has been aided by the evolution of high dimensional phenotypic tools such as mass cytometry and single-cell RNA sequencing which have revealed heterogeneity in populations that were previously considered homogenous. Despite this, there is still uncertainty and variation between studies as to how B-cell subsets are identified and named. This review will focus on the most commonly encountered subsets of B cells in human blood and will describe gating strategies for their identification by flow and mass cytometry. Important changes to population frequencies and function in common inflammatory and autoimmune diseases will also be described.

Activated B cells suppress T-cell function through metabolic competition

BACKGROUND

B cells play a pivotal role in regulating the immune response. The induction of B cell-mediated immunosuppressive function requires B cell activating signals. However, the mechanisms by which activated B cells mediate T-cell suppression are not fully understood.

METHODS

We investigated the potential contribution of metabolic activity of activated B cells to T-cell suppression by performing in vitro experiments and by analyzing clinical samples using mass cytometry and single-cell RNA sequencing.

RESULTS

Here we show that following activation, B cells acquire an immunoregulatory phenotype and promote T-cell suppression by metabolic competition. Activated B cells induced hypoxia in T cells in a cell-cell contact dependent manner by consuming more oxygen via an increase in their oxidative phosphorylation (OXPHOS). Moreover, activated B cells deprived T cells of glucose and produced lactic acid through their high glycolytic activity. Activated B cells thus inhibited the mammalian target of rapamycin pathway in T cells, resulting in suppression of T-cell cytokine production and proliferation. Finally, we confirmed the presence of tumor-associated B cells with high glycolytic and OXPHOS activities in patients with melanoma, associated with poor response to immune checkpoint blockade therapy.

CONCLUSIONS

We have revealed for the first time the immunomodulatory effects of the metabolic activity of activated B cells and their possible role in suppressing antitumor T-cell responses. These findings add novel insights into immunometabolism and have important implications for cancer immunotherapy.

The emerging role of regulatory cell-based therapy in autoimmune disease

Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

B Cells at the Cross-Roads of Autoimmune Diseases and Auto-Inflammatory Syndromes

Whereas autoimmune diseases are mediated primarily by T and B cells, auto-inflammatory syndromes (AIFS) involve natural killer cells, macrophages, mast cells, dendritic cells, different granulocyte subsets and complement components. In contrast to autoimmune diseases, the immune response of patients with AIFS is not associated with a breakdown of immune tolerance to self-antigens. Focusing on B lymphocyte subsets, this article offers a fresh perspective on the multiple cross-talks between both branches of innate and adaptive immunity in mounting coordinated signals that lead to AIFS. By virtue of their potential to play a role in adaptive immunity and to exert innate-like functions, B cells can be involved in both promoting inflammation and mitigating auto-inflammation in disorders that include mevalonate kinase deficiency syndrome, Kawasaki syndrome, inflammatory bone disorders, Schnitzler syndrome, Neuro-Behçet's disease, and neuromyelitis optica spectrum disorder. Since there is a significant overlap between the pathogenic trajectories that culminate in autoimmune diseases, or AIFS, a more detailed understanding of their respective roles in the development of inflammation could lead to designing novel therapeutic avenues.

Profiles of host immune impairment in Plasmodium and SARS-CoV-2 infections

Over the past two decades, many countries have reported a steady decline in reported cases of malaria, and a few countries, like China, have been declared malaria-free by the World Health Organization. In 2020 the number of deaths from malaria has declined since 2000. The COVID-19 pandemic has adversely affected overall public health efforts and thus it is feasible that there might be a resurgence of malaria. COVID-19 and malaria share some similarities in the immune responses of the patient and these two diseases also share overlapping early symptoms such as fever, headache, nausea, and muscle pain/fatigue. In the absence of early diagnostics, there can be a misdiagnosis of the infection(s) that can pose additional challenges due to delayed treatment. In both SARS-CoV-2 and Plasmodium infections, there is a rapid release of cytokines/chemokines that play a key role in disease pathophysiology. In this review, we have discussed the cytokine/chemokine storm observed during COVID-19 and malaria. We observed that: (1) the severity in malaria and COVID-19 is likely a consequence primarily of an uncontrolled 'cytokine storm'; (2) five pro-inflammatory cytokines (IL-6, IL-10, TNF-α, type I IFN, and IFN-γ) are significantly increased in severe/critically ill patients in both diseases; (3) Plasmodium and SARS-CoV-2 share some similar clinical manifestations and thus may result in fatal consequences if misdiagnosed during onset.

BLNK mutation associated with T-cell LGL leukemia and autoimmune diseases: Case report in hematology

We present the case of a female patient with a heterozygous somatic BLNK mutation, a T-cell LGL (large granular lymphocyte) leukemia, and multiple autoimmune diseases. Although this mutation seems uncommon especially in this kind of clinical observation, it could represent a new mechanism for autoimmune diseases associated with LGL leukemia. The patient developed several autoimmune diseases: pure red blood cell apalsia, thyroiditis, oophoritis, and alopecia areata. She also presented a T-cell LGL leukemia which required treatment with corticosteroids and cyclophosphamide, with good efficacy. Interestingly, she had no notable infectious history. The erythroblastopenia also resolved, the alopecia evolves by flare-ups, and the patient is still under hormonal supplementation for thyroiditis and oophoritis. We wanted to try to understand the unusual clinical picture presented by this patient. We therefore performed whole-genome sequencing, identifying a heterozygous somatic BLNK mutation. Her total gamma globulin level was slightly decreased. Regarding the lymphocyte subpopulations, she presented a B-cell deficiency with increased autoreactive B-cells and a CD4+ and Treg deficiency. This B-cell deficiency persisted after complete remission of erythroblastopenia and LGL leukemia. We propose that the persistent B-cell deficiency linked to the BLNK mutation can explain her clinical phenotype.

The Regulation between CD4+CXCR5+ Follicular Helper T (Tfh) Cells and CD19+CD24hiCD38hi Regulatory B (Breg) Cells in Gastric Cancer

Purpose

T follicular helper (Tfh) cells and regulatory B (Breg) cells are reported to play essential roles in humoral immunity, especially in inflammation, autoimmune diseases, and cancer. Hence, we sought to investigate the involvement of CXCR5⁺CD4⁺ Tfh cells and CD19⁺CD24^hiCD38^hi Breg cells in gastric cancer.

Methods

The blood samples were obtained from 36 gastric cancer patients and 18 healthy individuals. The percentage of Tfh cells (Tfh%) and Breg cells (Breg%) was detected via flow cytometry, while IL-21, IL-10, and CXCL13 levels were examined with ELISA. The association between them and clinical parameters of patients was also assessed. The in vitro Tfh-B cell coculture experiments were performed for six days, and then, Tfh%, Breg%, and cytokines were valued by flow cytometry and ELISA, respectively.

Results

Tfh%, Breg%, and CXCL13 level were significantly increased among gastric cancer patients. Moreover, higher Tfh% was associated with lymphatic metastasis, patients' worse outcomes and Breg%. Tfh differentiation and CXCL13 were upregulated by cocultured B cells in vitro, while Tfh cells seem to not participate in Breg cell differentiation from B cells.

Conclusion

Altogether, increased Tfh and Breg cells could be involved in immune suppression in gastric cancer. Moreover, B cell may be a potential regulator for Tfh differentiation, while Tfh cells had no significant effects on the regulation of Breg cells.

IL-10 producing regulatory B cells are decreased in blood from smokers and COPD patients

Background

Two opposing B cell subsets have been defined based on their cytokine profile: IL-6 producing effector B cells (B-effs) versus IL-10 producing regulatory B cells (B-regs) that respectively positively or negatively regulate immune responses. B-regs are decreased and/or impaired in many autoimmune diseases and inflammatory conditions. Since there is increasing evidence that links B cells and B cell-rich lymphoid follicles to the pathogenesis of COPD, the aim of this study was to investigate the presence and function of B-regs in COPD.

Methods

First, presence of IL-10 producing regulatory B cells in human lung tissue was determined by immunohistochemistry. Secondly, quantification of IL-10 + B-regs and IL-6 + B-effs in peripheral blood mononuclear cells (PBMCs) from healthy controls, smokers without airflow limitation, and COPD patients (GOLD stage I-IV) was performed by flow cytometry. Thirdly, we exposed blood-derived B cells from COPD patients in vitro to cigarette smoke extract (CSE) and quantified IL-10 + B-regs and IL-6 + B-effs. Furthermore, we aimed at restoring the perturbed IL10 production by blocking BAFF. Fourthly, we determined mRNA expression of transcription factors involved in IL-10 production in FACS sorted memory- and naive B cells upon exposure to medium or CSE.

Results

The presence of IL-10 producing regulatory B cells in parenchyma and lymphoid follicles in lungs was confirmed by immunohistochemistry. The percentage of IL-10 + B-regs was significantly decreased in blood-derived memory B cell subsets from smokers without airflow limitation and patients with COPD, compared to never smokers. Furthermore, the capacity of B cells to produce IL-10 was reduced upon in vitro exposure to CSE and this could not be restored by BAFF-blockade. Finally, upon CSE exposure, mRNA levels of the transcription factors IRF4 and HIF-1α, were decreased in memory B cells.

Conclusion

Decreased numbers and impaired function of B-regs in smokers and patients with COPD might contribute to the initiation and progression of the disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02208-1.

Immune-related 3-lncRNA signature with prognostic connotation in a multi-cancer setting

Background

Advances in our understanding of the tumor microenvironment have radically changed the cancer field, highlighting the emerging need for biomarkers of an active, favorable tumor immune phenotype to aid treatment stratification and clinical prognostication. Numerous immune-related gene signatures have been defined; however, their prognostic value is often limited to one or few cancer types. Moreover, the area of non-coding RNA as biomarkers remains largely unexplored although their number and biological roles are rapidly expanding.

Methods

We developed a multi-step process to identify immune-related long non-coding RNA signatures with prognostic connotation in multiple TCGA solid cancer datasets.

Results

Using the breast cancer dataset as a discovery cohort we found 2988 differentially expressed lncRNAs between immune favorable and unfavorable tumors, as defined by the immunologic constant of rejection (ICR) gene signature. Mapping of the lncRNAs to a coding-non-coding network identified 127 proxy protein-coding genes that are enriched in immune-related diseases and functions. Next, we defined two distinct 20-lncRNA prognostic signatures that show a stronger effect on overall survival than the ICR signature in multiple solid cancers. Furthermore, we found a 3 lncRNA signature that demonstrated prognostic significance across 5 solid cancer types with a stronger association with clinical outcome than ICR. Moreover, this 3 lncRNA signature showed additional prognostic significance in uterine corpus endometrial carcinoma and cervical squamous cell carcinoma and endocervical adenocarcinoma as compared to ICR.

Conclusion

We identified an immune-related 3-lncRNA signature with prognostic connotation in multiple solid cancer types which performed equally well and in some cases better than the 20-gene ICR signature, indicating that it could be used as a minimal informative signature for clinical implementation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03654-7.