Reduced Circulating Memory B-Cells Account for Humoral Immune Defects in Multiple Myeloma, Associated with Infective Risk and Poor Vaccination Responses

Abstract Multiple myeloma (MM) is characterized by an increased risk of infection due to the immunosuppressive effect of the disease and conjointly of therapy. Furthermore, there is impaired responses to vaccination to counter the infection risk. The factors that underpin defective B-cell homeostasis and effective humoral immunity are not clear, nor are the extent of the defects. Also, the level of impaired humoral immunity in MGUS is not fully understood. The aim of this study was to delineate the circulating B-cell populations and recall antibody responses in patients with MGUS & MM, compared to age-matched controls, correlating with the responsiveness to vaccinations, incidence of infective complications and concomitant therapy. We performed comprehensive B-cell immunophenotyping by multi-parameter flow cytometry of peripheral blood samples from patients with MGUS (n=16), asymptomatic MM (n=18) and MM (n=108) with a median age of 63 years (range 38-94) comparing them to age-matched controls (n=9). B-cell subsets included naïve (CD19+CD27-), memory (CD19+CD27+; non-switch CD19+IgD+CD27+, switch CD19+IgD-CD27+), transitional (CD19+CD27-CD24hiCD38hi) & regulatory (CD19+CD27+CD24hi) B-cells. Serum uninvolved total IgG, IgM & IgA levels along with vaccine-specific antibody responses were analysed. There is a progressive decrease in the uninvolved immunoglobulin classes with significant reduction in total IgA (p=0.006) and IgM levels (p=0.007) in aMM/MM compared to MGUS & control (Figure 1). When anti-pneumococcal antibodies were measured, only 30% of aMM/MM patients had adequate protective levels compared to 79% of age-matched controls, with 40% of aMM/MM patients with inadequate levels experiencing recurrent respiratory tract infections compared to 25% of aMM/MM patients with adequate proactive antibodies. Patients with MGUS, aMM and MM have lower total B-cell numbers compared to controls (1-way ANOVA p=0.004; Figure 1). The reduction in B-cell numbers were primarily the consequence of reduced memory B-cells (percentage and absolute 1-way ANOVA p<0.0001), noted in both MGUS and aMM/MM but a progressive reduction with increasing disease activity (MGUS>aMM>MM). Furthermore, a correlation with total IgG levels & memory B-cell numbers is evident (r2=-0.053) & progressive reduction in memory B-cell numbers is seen with advancing cycles of therapy. The ratio of switch:non-switch memory B-cells is unaltered (control 1.05, MGUS 0.53, aMM 1.41 & MM 1.49; 1-way ANOVA p=ns). Conversely, there is a compensatory increase in the percentage of transitional B-cells when increasing disease stage is compared to controls (control 7.38% (95%ci 4.9,9.9) vs MGUS 14.0% (95%ci 7.4, 20.7) vs aMM 14.95% (95%ci 8, 21.9); 1-way ANOVA p<0.001) but a reduction is noted in MM (5.82%, 95%ci 4.5,7.2; p<0.0001), primarily being driven by sequential lines of therapy. As a consequence, the ratio of Memory:transitional B-cells is significantly reduced in aMM/MM compared to MGUS & controls (control 10.35, MGUS 20.46, aMM 7.74 & MM 4.57; 1-way ANOVA p=0.006), associated with increasing incidence of bacterial infections. A non-significant correlation is seen between transitional B-cells and total uninvolved immunoglobulin levels and with recall responses to vaccinations. There is a progressive decrease in the CD19+CD27+CD24hi B-cell subset between control and plasma cell dyscrasias (control 20.4% (95%ci 15.5,25.2), MGUS 14.0% (95%ci 7.4, 20.7), aMM 14.95% (95%ci 8, 21.9) & MM 5.82%, 95%ci 4.5,7.2; p<0.0001), primarily being driven by sequential lines of therapy and associated with increased incidence of infection. This study illustrates that patients with myeloma demonstrate reduced total circulating B-cells primarily as a consequence of reduced memory B-cells, associated with reduced immunoglobulin and recall antibody responses. This is associated with increased incidence of bacterial infections and is worsened by sequential exposure to lymphodepleting therapies. Of particular importance is the identified aberration in B-cell subsets seen in MGUS compared with age-matched control, indicative of humoral immune dysregulation highlighting that MGUS may not be an immunologically inert disorder. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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B Cell With Regulatory Function Are Enriched Within Transitional and IgM Memory B Cell Subsets In Healthy Donors But Are Reduced and Functionally Impaired In Patients With Chronic Graft-Versus-Host Disease

Blood ◽

10.1182/blood.v122.21.4478.4478 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4478-4478

Author(s):

Anushruti Sarvaria ◽

Ahmad Khoder ◽

Abdullah Alsuliman ◽

Claude Chew ◽

Takuya Sekine ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cd4 T Cells ◽

Memory B Cells ◽

Regulatory Function ◽

Healthy Controls ◽

Transitional B Cells ◽

B Cell Subsets

The immunosuppressive function of IL10 producing regulatory B cells (Bregs) has been shown in several murine models of inflammation and autoimmune disease. However, there is a paucity of data regarding the existence of an equivalent regulatory B cell subset in healthy individuals and their potential role in the pathogenesis of chronic graft-versus-host disease (cGVHD) remains unknown. Here, we examined the functional regulatory properties of peripheral blood (PB)-derived human B cell subsets from healthy individuals. In addition, we carried out studies to explore their role in cGVHD, using B cells from patients following allogeneic stem cell transplantation (HSCT). We first determined whether human IL-10 producing B cells are enriched within any othe previously described human B cell subsets: CD19+IgM+CD27+ IgM memory, CD19+IgM-CD27+ switched memory, CD19+IgM+CD27- naive, and and transitional CD19+CD24hiCD38hi. Following in vitro stimulation with CD40 ligand, the majority of IL-10 producing B cells were found within the CD24hiCD38hi transitional and CD19+IgM+CD27+B cell subsets. We next assessed the regulatory properties of the PB-derived B cell subsets, by sort-purifying IgM memory (CD19+IgM+CD27+), switched memory (CD19+IgM-CD27+), naïve (CD19+IgM+CD27-) and transitional (CD19+CD24hiCD38hi) B cells from healthy controls, and cultured them 1:1 with autologous magnetic-bead purified CD4+ T cells. CD3/CD28 stimulated CD4+ T cells cultured with either CD19+IgM+CD27- naïve or CD19+IgM-CD27+ switched memory B cells proliferated to the same extent and produced equivalent amounts of IFN-γ to cultures containing CD4+ T cells alone. In contrast, culture of CD4+ T cells with IgM memory and transitional B cells significantly suppressed CD4+ T cell proliferation [median percent proliferating CD4+ T cells 52.5%; (33%-75%)] and 51% (25%-63%)], respectively when compared with CD3/CD28 stimulated CD4+ T cells (positive control) [89.5% (75%-92%], p=0.0001. The inhibitory effect of IgM memory and transitional B cells on CD4+ T cell proliferation was cell dose dependent with the highest suppression observed at a ratio of 1:1. These data suggest that human PB transitional and IgM memory B cells are endowed with regulatory function. We next examined if the in vitro suppressive effect of transitional and IgM memory B cells is mediated by regulatory T cells (Tregs). For this purpose, CD4+ T cells were depleted of CD127lo CD25hi CD4+ T cells by magnetic cell purification. B cell subsets were cultured with CD3/CD28 stimulated CD4+ CD25- T cells at a ratio of 1:1. IgM memory and transitional B cells were able to significantly suppress the proliferation and Th1 cytokine response by CD4+ CD25- T cells compared to cultures containing CD4+ CD25-T cells alone, indicating that the suppressive activity of Bregs is independent of Tregs. To further understand the underlying mechanims though which Bregs exert T-cell suppression, we used antibody blockade experiments and showed that this suppressive effect was mediated partially via the provision of IL-10, but not TGF-ß. Using transwell experiments, we further determined that the suppressive function of Bregs is also partly dependent on direct T cell/B cell contact. We next assessed whether the activity of Breg cells might be altered in patients with cGVHD. B cells from patients with cGVHD were refractory to CD40 stimulation and produced less IL-10 when compared to patients without cGVHD post-SCT and healthy controls, [1.02% (0.22-2.26) vs.1.72% (0.8-5.52) vs. 2.16 (1.3- 5.6), p=0.001]. Likewise, the absolute number of IL-10 producing B cells was significantly lower in cGvHD patients compared to patients without cGVHD and healthy controls (p=0.007), supporting both a qualitative and quantitative defect in IL-10 producing B cells in cGvHD. Our combined studies provide important new data defining the phenotype of B cell populations enriched in regulatory B cells in healthy humans and provide evidence for a defect in the activity of such cells in patients with cGVHD post-SCT. In association with previous reports showing defects in Treg cell activity in GVHD, our results suggest the existence of a broad range of deficiencies in immune regulatory cell function in cGvHD patients. * Both Anushruti Sarvaria and Ahmad K contributed equally. Disclosures: No relevant conflicts of interest to declare.

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Impaired Response to Influenza Vaccination in AML Patients Post-Chemotherapy Associated with a Highly Atypical B-Cell Profile

Blood ◽

10.1182/blood.v126.23.3427.3427 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3427-3427

Author(s):

Meghali Goswami ◽

Gabrielle T. Prince ◽

Angelique Biancotto ◽

Susan Moir ◽

Foo Cheung ◽

...

Keyword(s):

Immune System ◽

T Cell ◽

B Cells ◽

B Cell ◽

Specific Antibody ◽

Memory B Cells ◽

Post Treatment ◽

Humoral Immune ◽

Transitional B Cells ◽

Cell Profile

Abstract The immunotherapy of cancer is arguably the most promising therapy under development, and vaccination against cancer antigens is a promising strategy to stimulate adaptive immune responses against malignant clones. However, the ability of patients treated with chemotherapy to respond appropriately to immune challenge may be suboptimal. This study was designed to determine the functional capacity of the immune system in adult acute myeloid leukemia (AML) patients who have completed chemotherapy and are potential candidates for immunotherapy. We used the response to influenza vaccination as a surrogate for the health of the immune system in AML patients in a complete remission (CR) post-chemotherapy. Ten adult AML patients in CR after completion of intensive chemotherapy were recruited to the clinical protocol J1293. They were on average 37 weeks post-treatment (range 4-148) when receiving the 2012-2013 inactivated seasonal influenza vaccine. Peripheral blood samples were collected at baseline and 30 days post-vaccination. Ten age and sex matched healthy donors (HD) served as baseline controls. Serological response to vaccination was assessed via microneutralization assays; multi-parameter flow cytometry was used to characterize lymphocyte subsets. ELISPOT assays were used to evaluate lymphocyte function, microarrays were used to assess gene expression, and deep sequencing of the B-cell receptor heavy chain (IGH) was performed to determine expansion and clonality of B-cells. Wilcoxon rank-sum tests were used to assess statistical significance. Only 2/10 (20%) patients seroconverted (AML responders, or AML-R) with a four-fold increase or greater in influenza-specific antibody. One responder was 148 weeks post-treatment; the other had acute promyelocytic leukemia (APL) and was 4 weeks post-treatment. Deep immunophenotyping revealed no striking differences in T-cell compartments between AML at baseline and HD, indicating rapid T-cell recovery after chemotherapy. In contrast, we observed a highly atypical B-cell profile. AML non-responders (AML-NR) at day 0 versus HD had significantly reduced frequencies of mature IgA+ (4.5% vs. 11%) and IgG+ (2.4% vs. 5.9%) B-cells (as a percentage of CD19+CD20+). Further dissection exposed markedly higher frequencies of CD10+CD27- transitional B-cells (36% vs. 16%, p<0.005) and dramatically fewer memory (resting, tissue-like, activated) B-cells (5% vs. 25%, p<0.005) (as a percentage of CD19+CD20+) in AML-NR at day 0 versus HD. There were no significant changes in any B-cell population at day 30 over baseline in any patient. Examining frequencies of transitional, naive, and memory B-cells in AML patients at day 0 when ranked by time since treatment showed a decrease in transitional B-cells with a corresponding increase in naive B-cells over time but no concurrent increase in memory B-cell frequencies (Fig 1). These data suggest B-cell deficiencies of several types: loss of the memory B-cell compartment due to chemotherapy, a subsequent excess of transitional B-cells, and a lack of naive B-cell development into specific, class-switched effectors of the antibody response, which together likely lead to humoral immune incompetence. Interestingly, functional T-cell assays revealed that of 5 evaluable patients, including the 2 AML-R and 3 AML-NR, 5/5 (100%) patients had an increase in influenza-specific cytokine production (1.24 - 4.40x higher on day 30 over baseline), suggesting a functional T-cell response even with deficient influenza-specific antibody production. Supervised clustering of microarray data identified many upregulated genes in AML-NR related to apoptosis, BCR, IL2, IL-4, IL-8, and IL-12 signaling pathways, indicative of developing B-cells. IGH sequencing demonstrated AML-NR had greater variability in CDR3 length than seen in HD, consistent with an antigen inexperienced B-cell repertoire. These data suggest that while some aspects of cellular immunity recover comparatively quickly, the humoral immune system is incompletely reconstituted in the year following intensive cytotoxic chemotherapy for AML. Abnormal frequencies of transitional and memory B-cells may explain the poor response to vaccination often seen in patients after chemotherapy. Furthermore, the uncoupled recovery of B-cell and T-cell immune capacity observed here might have implications for the success of immunotherapies based on vaccination. Figure 1. Figure 1. Disclosures Noonan: Celgene: Speakers Bureau. Borrello:Celgene: Research Funding.

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Impact of deranged B cell subsets distribution in the development of HCV-related cirrhosis and HCC in type two diabetes mellitus

Scientific Reports ◽

10.1038/s41598-020-77416-0 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Fadwa A. Abdelwahab ◽

Khaled M. Hassanein ◽

Helal F. Hetta ◽

Mohamed O. Abdelmalek ◽

Asmaa M. Zahran ◽

...

Keyword(s):

Liver Disease ◽

Hepatitis C ◽

B Cells ◽

B Cell ◽

Disease Progression ◽

Memory B Cells ◽

Diabetic Patients ◽

Transitional B Cells ◽

Liver Disease Progression ◽

B Cell Subsets

AbstractType II diabetes (T2D) may worsen the course of hepatitis C virus infection with a greater risk of liver cirrhosis (LC) and hepatocellular carcinoma (HCC). In chronic viral infections, the deranged B cell subset signifies uncontrolled disease. The study aimed to verify the relation between B cell subsets’ distribution and liver disease progression in chronic hepatitis C (CHC) patients with T2D. A total of 67 CHC patients were divided into two groups; 33 non-diabetic and 34 with T2D. Each group was subdivided into CHC-without LC or HCC (N-CHC), CHC-with LC (CHC-LC), and CHC-with HCC (CHC-HCC). Twenty-seven healthy individuals also participated as controls. Flow cytometry was used to analyze CD19+ B cell subsets based on the expression of CD24 and CD38. CD19+CD24hiCD38hi Immature/transitional B cells elevated in diabetic than non-diabetic patients. In diabetic patients, while CD19+CD24+CD38− primarily memory B cells were higher in CHC-N and CHC-HCC groups than LC with a good predictive accuracy of LC, the opposite was observed for CD19+CD24−CD38− new memory B cells. Only in diabetic patients, the CD19+CD24intCD38int naïve mature B cells were high in CHC-HCC patients with good prognostic accuracy of HCC. Merely in diabetic patients, several correlations were observed between B cell subsets and liver function. Immature/transitional B cells increase remarkably in diabetic CHCpatients and might have a role in liver disease progression. Memory and Naïve B cells are good potential predictors of LC and HCCin diabetic CHCpatients, respectively. Further studies are needed to investigate the role of the CD19+CD24−CD38− new memory B cells in disease progression in CHC patients.

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Circulating B Cell Subsets from Untreated Diffuse Large B Cell Lymphoma (DLBCL) Patients Resemble Those of Patients with Autoimmune Disease

Blood ◽

10.1182/blood-2018-99-119031 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4221-4221

Author(s):

Jean L. Koff ◽

Kevin S. Cashman ◽

Vivien Warren ◽

Kira Smith ◽

Christopher R Flowers ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Research Funding ◽

B Cell Lymphoma ◽

Memory B Cells ◽

Transitional B Cells ◽

Large B Cell Lymphoma ◽

Pre Treatment ◽

B Cell Subsets ◽

Cell Profile

Abstract Introduction Diffuse large B cell lymphoma (DLBCL) is a clinically and genetically heterogeneous malignancy that can arise from B cell-mediated autoimmune (AI) diseases such as systemic lupus erythematosus (SLE). Profiling B cell subsets by multicolor flow cytometry can delineate SLE pts from healthy controls and correlates with differences in SLE outcomes (Tipton CM, Nat Immunol 2015). Emerging data suggest that expansions of IgD-CD27- ("double-negative," DN) memory B cells in SLE are comprised of a novel subset representing pre-plasma cell effector B cells (Sanz MS under review), with at least 15% of DN B cells expressing autoantibodies. Given the etiologic link between autoimmunity and DLBCL, we hypothesized that B cell profiling in DLBCL patients (pts) with and without concomitant AI disease could identify variations in B cell repertoire similar to those observed in SLE patients and reveal links to distinct subtype variations based on biology and etiology. Methods Pts with DLBCL were prospectively identified and consented to participate. All pts were followed longitudinally for clinical data annotation and sample re-collection. Peripheral blood mononuclear cells were isolated from whole blood using density-gradient centrifugation, stained with a 13-color cocktail that included fluorochrome-conjugated mouse monoclonal antibodies to CD3, CD11c, CD19, CD20, CD21, CD24, CD27, CD38, IgD, and Ig light chain kappa and lambda, and then analyzed via flow cytometry with gating analysis using FlowJo. After excluding dead cells, doublets, and non-lymphocytes, we gated on CD19+ B cells and assessed subpopulations based first on expression of IgD and CD27 to distinguish mature-naïve B cells (IgD+CD27-) from switched (IgD-CD27+), unswitched (IgD+CD27+), and DN (IgD-CD27-) memory B cells. Additional cell surface markers (e.g., CD24, CD38) defined other subsets such as antibody-secreting cells and transitional B cells. We examined pre-treatment B cell profile to characterize baseline variations in DLBCL. To examine changes in B cell profile relative to treatment, DLBCL pt samples were evaluated: after completion of standard first-line chemoimmunotherapy; in remission ≥ 1 year from treatment; and at relapse. The Kruskal-Wallis test was used to compare B cell subset distributions between samples. Results Peripheral blood was collected from a total of 59 DLBCL pts, with 8 pts contributing samples at >1 time-point. B cell profiling of pre-treatment samples (n=12) revealed two distinct phenotypes according to CD27 and IgD expression: 7 pts' profiles resembled those of healthy controls (42%), and 5 exhibited diminished unswitched memory B cells (<10% of CD19+ cells), similar to SLE pts (Figures 1 and 2). Within the latter group, 4 pts also exhibited DN expansion (>10% of CD19+ cells), a phenotype similar to SLE pts with poor outcomes. Plasmablasts, transitional B cells, switched memory and naïve B cells in untreated DLBCL were not significantly expanded. As expected, CD19+ B cells were uniformly depleted following chemoimmunotherapy, constituting <1% lymphocytes until about 9 months post-treatment. Prior to B cell reconstitution, this small B cell population consisted predominantly of DN cells (Figure 3). Conclusions Intriguingly, a subset of untreated DLBCL pts exhibit diminished unswitched memory B cells and DN expansion characteristic of SLE pts. It is unclear whether the DN expansion we detected in non-AI-associated DLBCL represents an immune response to tumor or a state of subclinical immune dysregulation that predisposes to DLBCL development, perhaps via chronic antigen stimulation as postulated in AI-associated lymphomas. Longitudinal studies are ongoing to evaluate associations between abnormal B cell profiles, clinical factors, and survival outcomes Disclosures Flowers: BeiGene: Research Funding; TG Therapeutics: Research Funding; Gilead: Research Funding; Abbvie: Research Funding; Pharmacyclics/ Janssen: Consultancy; Bayer: Consultancy; Acerta: Research Funding; Karyopharm: Consultancy; Genentech/Roche: Consultancy; National Cancer Institute: Research Funding; Celgene: Research Funding; Millennium/Takeda: Research Funding; Spectrum: Consultancy; Genentech/Roche: Research Funding; Janssen Pharmaceutical: Research Funding; V Foundation: Research Funding; OptumRx: Consultancy; Burroughs Wellcome Fund: Research Funding; Pharmacyclics: Research Funding; Abbvie: Consultancy, Research Funding; Eastern Cooperative Oncology Group: Research Funding; Gilead: Consultancy; Denovo Biopharma: Consultancy.

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Toll-Like Receptor Homolog CD180 Expression Is Diminished on Natural Autoantibody-Producing B Cells of Patients with Autoimmune CNS Disorders

Journal of Immunology Research ◽

10.1155/2021/9953317 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Zsófia Hayden ◽

Szabina Erdő-Bonyár ◽

Beáta Bóné ◽

Noémi Balázs ◽

Kornélia Bodó ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Peripheral Blood ◽

Bacterial Infections ◽

Citrate Synthase ◽

Memory B Cells ◽

Igg Antibody ◽

Autoantibody Production ◽

B Cell Subsets ◽

Natural Autoantibody

Purpose. Decreased expression of TLR homolog CD180 in peripheral blood B cells and its potential role in antibody production have been described in autoimmune diseases. Effectiveness of anti-CD20 therapy in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) strengthens the role of B cells in the pathogenesis. Therefore, we aimed to investigate the CD180 expression of peripheral blood B cell subsets in NMOSD and MS patients and analyze the levels of natural anti-citrate synthase (CS) IgG autoantibodies and IgG antibodies induced by bacterial infections reported to play a role in the pathogenesis of NMOSD or MS. Methods. We analyzed the distribution and CD180 expression of peripheral blood B cell subsets, defined by CD19/CD27/IgD staining, and measured anti-CS IgM/G natural autoantibody and antibacterial IgG serum levels in NMOSD, RRMS, and healthy controls (HC). Results. We found decreased naïve and increased memory B cells in NMOSD compared to MS. Among the investigated four B cell subsets, CD180 expression was exclusively decreased in CD19+CD27+IgD+ nonswitched (NS) memory B cells in both NMOSD and MS compared to HC. Furthermore, the anti-CS IgM natural autoantibody serum level was lower in both NMOSD and MS. In addition, we found a tendency of higher anti-CS IgG natural autoantibody levels only in anti-Chlamydia IgG antibody-positive NMOSD and MS patients. Conclusions. Our results suggest that reduced CD180 expression of NS B cells could contribute to the deficient natural IgM autoantibody production in NMOSD and MS, whereas natural IgG autoantibody levels show an association with antibacterial antibodies.

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A splenic IgM memory subset with antibacterial specificities is sustained from persistent mucosal responses

Journal of Experimental Medicine ◽

10.1084/jem.20180977 ◽

2018 ◽

Vol 215 (8) ◽

pp. 2035-2053 ◽

Cited By ~ 15

Author(s):

Simon Le Gallou ◽

Zhicheng Zhou ◽

Lan-Huong Thai ◽

Remi Fritzen ◽

Alba Verge de los Aires ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Bacterial Infections ◽

Plasma Cells ◽

Memory B Cells ◽

Endogenous Retroviruses ◽

Lymphoid Tissues ◽

Gut Flora ◽

Protective Capacity ◽

B Cell Subsets

To what extent immune responses against the gut flora are compartmentalized within mucosal tissues in homeostatic conditions remains a much-debated issue. We describe here, based on an inducible AID fate-mapping mouse model, that systemic memory B cell subsets, including mainly IgM+ B cells in spleen, together with IgA+ plasma cells in spleen and bone marrow, are generated in mice in the absence of deliberate immunization. While the IgA component appears dependent on the gut flora, IgM memory B cells are still generated in germ-free mice, albeit to a reduced extent. Clonal relationships and renewal kinetics after anti-CD20 treatment reveal that this long-lasting splenic population is mainly sustained by output of B cell clones persisting in mucosal germinal centers. IgM-secreting hybridomas established from splenic IgM memory B cells showed reactivity against various bacterial isolates and endogenous retroviruses. Ongoing activation of B cells in gut-associated lymphoid tissues thus generates a diversified systemic compartment showing long-lasting clonal persistence and protective capacity against systemic bacterial infections.

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Hyper‐metabolic B cells in the spleens of old mice make antibodies with autoimmune specificities

Immunity & Ageing ◽

10.1186/s12979-021-00222-3 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Daniela Frasca ◽

Maria Romero ◽

Denisse Garcia ◽

Alain Diaz ◽

Bonnie B. Blomberg

Keyword(s):

B Cells ◽

B Cell ◽

Inflammatory Markers ◽

Cell Subset ◽

Antibody Responses ◽

Metabolic Phenotype ◽

Cellular Mechanisms ◽

Autoimmune Antibodies ◽

B Cell Subsets ◽

Old Mice

Abstract Background Aging is associated with increased intrinsic B cell inflammation, decreased protective antibody responses and increased autoimmune antibody responses. The effects of aging on the metabolic phenotype of B cells and on the metabolic programs that lead to the secretion of protective versus autoimmune antibodies are not known. Methods Splenic B cells and the major splenic B cell subsets, Follicular (FO) and Age-associated B cells (ABCs), were isolated from the spleens of young and old mice and left unstimulated. The RNA was collected to measure the expression of markers associated with intrinsic inflammation and autoimmune antibody production by qPCR. B cells and B cell subsets were also stimulated with CpG and supernatants collected after 7 days to measure autoimmune IgG secretion by ELISA. Metabolic measures (oxygen consumption rate, extracellular acidification rate and glucose uptake) were performed using a Seahorse XFp extracellular flux analyzer. Results Results have identified the subset of ABCs, whose frequencies and numbers increase with age and represent the most pro-inflammatory B cell subset, as the cell type mainly if not exclusively responsible for the expression of inflammatory markers and for the secretion of autoimmune antibodies in the spleen of old mice. Hyper-inflammatory ABCs from old mice are also hyper-metabolic, as compared to those from young mice and to the subset of FO B cells, a feature needed not only to support their higher expression of RNA for inflammatory markers but also their higher autoimmune antibody secretion. Conclusions These results identify a relationship between intrinsic inflammation, metabolism and autoimmune B cells and suggest possible ways to understand cellular mechanisms that lead to the generation of pathogenic B cells, that are hyper-inflammatory and hyper-metabolic, and secrete IgG antibodies with autoimmune specificities.

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AB0025 B-CELL SUBSETS AS ADDITIONAL DIAGNOSTIC TOOL FOR PRIMARY SJOGREN’S SYNDROME AND SYSTEMIC LUPUS ERYTHEMATOSUS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.5332 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1315.1-1316

Author(s):

S. Benevolenskaya ◽

I. Kudryavtsev ◽

M. Serebriakova ◽

I. Grigor’eva ◽

A. Budkova ◽

...

Keyword(s):

B Cells ◽

Discriminant Analysis ◽

B Cell ◽

Sjögren’S Syndrome ◽

Sjögren's Syndrome ◽

Sjogren’S Syndrome ◽

Sjogren's Syndrome ◽

Transitional B Cells ◽

B Cell Subsets ◽

Sjögren‘S Syndrome

Background:Systemic lupus erythematosus (SLE) and primary Sjögren’s syndrome (pSS) are chronic complex disorders with an autoimmune background, multifactorial etiology, multiple circulating antinuclear antibodies and damage of various organs. SLE and pSS have several similar clinical and serological aspects; likewise, SLE and Sjögren’s syndrome may coexist (so-called secondary Sjögren’s syndrome). However, applied classification criteria do not differentiate SLE and pSS. It is known that humoral immunity plays significant part in pathogenesis of those diseases; hereby, we can expect imbalances in B cell subset frequencies during SLE and pSS.Objectives:To investigate clinical utility of B cell subsets in distinguish SLE and pSS during diagnosis.Methods:A total of 25 SLE patients, 25 SS patients and 49 healthy volunteers (HV) were included in the study. The diagnosis of SLE was performed according to the 2019 EULAR – ACR classification criteria, the diagnosis of pSS - according to the 2016 EULAR – ACR criteria. Phenotyping of blood B cell subsets was done using flow cytometry. Total peripheral blood B cells were identified using CD19 expression, distinct B cell subsets were characterized by IgD, CD38 and CD27 expression. All of the statistical analysis of data was performed with STATISTICA Version 12.0 Inc. (USA).Results:We evaluated the percentages of circulating B-cell subsets using three major classification schemes based on the relative co-expression of either IgD/CD38 (so-called “Bm1-Bm5” classification), IgD/CD27 and CD38/CD27. A discriminant analysis was performed for all B cell classifications. Analysis of CD38 and CD27 co-expression demonstrated most significant separation between patients with SLE and pSS (fig. 1). Moreover, discriminant analysis carried out by using a forward stepwise model demonstrated that the top significance was documented while assessing the percentage of plasmoblasts (CD27hiCD38hi), resting memory B-cells (CD27dimCD38low), mature active B-cells (CD27dimCD38dim), naive mature B-cells (CD27dimCD38low), as well as counting the absolute numbers of transitional B-cells (CD27lowCD38hi), model percent correct was 78,6% (p <0,05, tab.1).Figure 1.Graphic distribution of SLE and pSS patients as well as HV analyzed by discriminant analysis.Conclusion:B cell subsets might provide a useful diagnostic tool for distinction SLE and pSS. More research needed to investigate clinical value of B-cell subsets in autoimmune rheumatic diseases.Table 1.Peripheral B-cell subset composition in SLE and SS patients vs. HV group assessed by discriminant analysis.ParameterF-testp-levelPlasmoblasts (CD27hiCD38hi), %7,93<0.001Resting memory B-cells (CD27dimCD38low), %13,72<0.001Transitional B-cells (CD27lowCD38hi)29,74<0.001Mature active B-cells (CD27dimCD38dim), %5,20<0.001Naive mature B-cells (CD27dimCD38low), %3,100.049Double negative (CD27lowCD38low), %1,980,14Resting memory B-cells (CD27dimCD38low)1,020,36Double negative (CD27lowCD38low)2,320,10Plasmoblasts (CD27hiCD38hi)1,020,36Naive mature B-cells (CD27dimCD38low)1,030,36Mature active B-cells (CD27dimCD38dim)1,020,36Transitional B-cells (CD27lowCD38hi), %1,030,36Disclosure of Interests:None declared

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Specific induction of double negative B cells during protective and pathogenic immune responses

10.1101/2020.09.08.285148 ◽

2020 ◽

Author(s):

Christoph Ruschil ◽

Gisela Gabernet ◽

Gildas Lepennetier ◽

Simon Heumos ◽

Miriam Kaminski ◽

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Keyword(s):

B Cells ◽

B Cell ◽

Cell Population ◽

Vaccine Antigen ◽

Double Negative ◽

Humoral Immune ◽

Follicular Maturation ◽

Inflammatory Conditions ◽

Tick Borne Encephalitis Virus ◽

B Cell Subsets

1AbstractDouble negative (DN) (CD19+CD20lowCD27−IgD−) B cells are expanded in patients with autoimmune and infectious diseases; however their role in the humoral immune response remains unclear. Using systematic flow cytometric analyses of peripheral blood B cell subsets, we observed an inflated DN B cell population in patients with variety of active inflammatory conditions: myasthenia gravis, Guillain-Barré syndrome, neuromyelitis optica spectrum disorder, meningitis/encephalitis, and rheumatic disorders. Furthermore, we were able to induce DN B cells in healthy subjects following vaccination against influenza and tick borne encephalitis virus. Transcriptome analysis revealed a gene expression profile in DN B cells that clustered with naïve B cells, memory B cells, and plasmablasts. Immunoglobulin VH transcriptome sequencing and analysis of recombinant antibodies revealed clonal expansion of DN B cells, that were targeted against the vaccine antigen. Our study suggests that DN B cells are expanded in multiple inflammatory neurologic diseases and represent an inducible B cell population that responds to antigenic stimulation, possibly through an extra-follicular maturation pathway.

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Marginating transitional B cells modulate neutrophils in the lung during inflammation and pneumonia

Journal of Experimental Medicine ◽

10.1084/jem.20210409 ◽

2021 ◽

Vol 218 (9) ◽

Author(s):

John Podstawka ◽

Sarthak Sinha ◽

Carlos H. Hiroki ◽

Nicole Sarden ◽

Elise Granton ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Regulatory Networks ◽

Vascular Inflammation ◽

Transitional B Cells ◽

Pulmonary Capillaries ◽

Life Threatening ◽

B Cell Subsets

Pulmonary innate immunity is required for host defense; however, excessive neutrophil inflammation can cause life-threatening acute lung injury. B lymphocytes can be regulatory, yet little is known about peripheral transitional IgM+ B cells in terms of regulatory properties. Using single-cell RNA sequencing, we discovered eight IgM+ B cell subsets with unique gene regulatory networks in the lung circulation dominated by transitional type 1 B and type 2 B (T2B) cells. Lung intravital confocal microscopy revealed that T2B cells marginate in the pulmonary capillaries via CD49e and require CXCL13 and CXCR5. During lung inflammation, marginated T2B cells dampened excessive neutrophil vascular inflammation via the specialized proresolving molecule lipoxin A4 (LXA4). Exogenous CXCL13 dampened excessive neutrophilic inflammation by increasing marginated B cells, and LXA4 recapitulated neutrophil regulation in B cell–deficient mice during inflammation and fungal pneumonia. Thus, the lung microvasculature is enriched in multiple IgM+ B cell subsets with marginating capillary T2B cells that dampen neutrophil responses.

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