Disturbed B cell subpopulations and increased plasma cells in myasthenia gravis patients

2013 ◽  
Vol 264 (1-2) ◽  
pp. 114-119 ◽  
Author(s):  
Siegfried Kohler ◽  
Thomas Oskar Philipp Keil ◽  
Marc Swierzy ◽  
Sarah Hoffmann ◽  
Hanne Schaffert ◽  
...  
Keyword(s):  
Myasthenia Gravis ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Subpopulations

scholarly journals Hyperproliferation of B Cells Specific for a Weakly Immunogenic PorA in a Meningococcal Vaccine Model

2008 ◽  
Vol 15 (10) ◽  
pp. 1598-1605 ◽  
Author(s):  
Thomas A. Luijkx ◽  
Jacqueline A. M. van Gaans-van den Brink ◽  
Harry H. van Dijken ◽  
Germie P. J. M. van den Dobbelsteen ◽  
Cécile A. C. M. van Els
Keyword(s):  
B Cells ◽  
B Cell ◽  
Bactericidal Activity ◽  
Plasma Cells ◽  
Affinity Maturation ◽  
Memory B Cells ◽  
Vaccine Antigen ◽  
Cell Subpopulation ◽  
Cell Subpopulations ◽  
Group B

ABSTRACT Highly homologous meningococcal porin A (PorA) proteins induce protective humoral immunity against Neisseria meningitidis group B infection but with large and consistent differences in the levels of serum bactericidal activity achieved. We investigated whether a poor PorA-specific serological outcome is associated with a limited size of the specific B-cell subpopulation involved. The numbers of PorA-specific splenic plasma cells, bone marrow (BM) plasma cells, and splenic memory B cells were compared between mice that received priming and boosting with the weakly immunogenic PorA (P1.7-2,4) protein and those that received priming and boosting with the highly immunogenic PorA (P1.5-1,2-2) protein. Immunoglobulin G (IgG) titers (except at day 42), bactericidal activity, and the avidity of IgG produced against P1.7-2,4 were significantly lower at all time points after priming and boosting than against P1.5-1,2-2. These differences, however, were not associated with a lack of P1.7-2,4-specific plasma cells. Instead, priming with both of the PorAs resulted in the initial expansion of comparable numbers of splenic and BM plasma cells. Moreover, P1.7-2,4-specific BM plasma cells, but not P1.5-1,2-2-specific plasma cells, expanded significantly further after boosting. Likewise, after a relative delay during the priming phase, the splenic P1.7-2,4-specific memory B cells largely outnumbered those specific for P1.5-1,2-2, upon boosting. These trends were observed with different vaccine formulations of the porins. Our results show for the first time that B-cell subpopulations involved in a successfully maturated antibody response against a clinically relevant vaccine antigen are maintained at smaller population sizes than those associated with poor affinity maturation. This bears consequences for the interpretation of immunological memory data in clinical vaccine trials.

scholarly journals Different B cell subpopulations show distinct patterns in their IgH repertoire metrics

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Marie Ghraichy ◽  
Valentin von Niederhäusern ◽  
Aleksandr Kovaltsuk ◽  
Jacob D Galson ◽  
Charlotte M Deane ◽  
...  
Keyword(s):  
B Cell ◽  
In Silico ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Bioinformatic Analysis ◽  
Cell Repertoire ◽  
Humoral Immune ◽  
B Cell Repertoire ◽  
Cell Subpopulations ◽  
The Individual

Several human B-cell subpopulations are recognized in the peripheral blood, which play distinct roles in the humoral immune response. These cells undergo developmental and maturational changes involving VDJ recombination, somatic hypermutation and class switch recombination, altogether shaping their immunoglobulin heavy chain (IgH) repertoire. Here, we sequenced the IgH repertoire of naïve, marginal zone, switched and plasma cells from 10 healthy adults along with matched unsorted and in silico separated CD19+ bulk B cells. Using advanced bioinformatic analysis and machine learning, we show that sorted B cell subpopulations are characterised by distinct repertoire characteristics on both the individual sequence and the repertoire level. Sorted subpopulations shared similar repertoire characteristics with their corresponding in silico separated subsets. Furthermore, certain IgH repertoire characteristics correlated with the position of the constant region on the IgH locus. Overall, this study provides unprecedented insight over mechanisms of B cell repertoire control in peripherally circulating B cell subpopulations.

Differential Expression and Non-Redundant Functions of NF-κB Transcription Factor Subunits in Germinal Center (GC) B Cell Subpopulations

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 216-216 ◽  
Author(s):  
Nicole Heise ◽  
Nilushi De Silva ◽  
Amanda Carette ◽  
Giorgia Simonetti ◽  
Govind Bhagat ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Differential Expression ◽  
Plasma Cell ◽  
Germinal Center ◽  
Plasma Cells ◽  
Nuclear Translocation ◽  
Cell Subpopulations

Abstract Abstract 216 The majority of B cell-derived neoplasms, including Hodgkin and Non-Hodgkin lymphoma and multiple myeloma (MM), arise from antigen-specific B cells that have undergone the germinal center (GC) reaction of T-dependent immune responses. Recent work has demonstrated that GC-derived tumors frequently harbor genetic mutations in nuclear factor-κB (NF-κB) signaling pathway components, resulting in the constitutive activation of NF-κB signaling, thus identifying NF-κB as a critical player in GC-lymphomagenesis. Moreover, there is evidence for a preferential activation of particular NF-κB transcription factor subunits in tumor subtypes. Despite extensive knowledge about the biology of NF-κB, its potential function in the physiology and development of GC B cells, the presumptive tumor precursor cells, is largely unresolved. The NF-κB signaling cascade comprises 5 different subunits, which occur as homo- and heterodimers and can be activated via two different routes, the canonical (classical) and the alternative (non-canonical/classical) NF-κB pathways. RELA, c-REL and p105/p50 represent the subunits of the canonical, while RELB and p100/p52 comprise those of the alternative pathway. It is known that there is no active NF-κB signaling in tonsillar GC centroblasts. Conversely, NF-κB activation was shown to occur in a subset of GC centrocytes. In this study, we demonstrate that each of the 5 NF-κB subunits exhibit nuclear translocation in centrocytes. Surprisingly, we observed that centrocytes expressing the plasma cell master regulator BLIMP1 showed strong immunofluorescence (IF) staining for the alternative NF-κB subunit p100/p52 and weak expression of the canonical subunits p105/p50 and c-REL compared to surrounding lymphocytes. Plasma cells localized in the tonsillar subepithelium showed the same pattern of expression. This observed differential expression of alternative vs. canonical NF-κB subunits in plasma cells and B cells, respectively, is supported by gene expression profiling data of human B cell subpopulations. Moreover, we observed that a mouse lymphoma cell line (M12) shows activation of the alternative NF-κB pathway upon induction of plasma cell differentiation. Also, Western and IF analysis of MM vs. diffuse large B cell lymphoma (DLBCL) cell lines revealed high protein levels and nuclear translocation of both p52 and RELB and low levels and cytosolic localization of c-REL in MM cell lines, while the opposite pattern was observed in the analyzed DLBCL lines. In summary, the elevated protein expression and presumed activity of the alternative over the canonical NF-κB pathway in plasma cells and their precursors suggests that activation of the alternative NF-κB pathway in centrocytes may contribute to plasma cell development and/or physiology. To elucidate the in vivo function of individual NF-κB transcription factor subunits, we started by determining the extent to which deletion of c-REL specifically in GC B cells affects the biology and differentiation of GC and post-GC B cells. We generated and then crossed a conditional loxP-flanked rel (c-REL) allele to mice that express the Cre-recombinase in GC B cells instructed to undergo class switch recombination (Cγ1-Cre mice). Following immunization with a T-dependent antigen, PNA+CD95+ GC B cell numbers were markedly reduced in immunized relfl/flCγ1-Cre mice compared to rel+/+Cγ1-Cre control mice. In addition, immunohistochemical analysis of spleen sections for BCL6 and IgG1 showed significantly smaller GCs, and a strong reduction in the numbers of GC-derived IgG1-secreting plasma cells, in relfl/flCγ1-Cre mice compared to controls. Consistent with these findings, we observed that relfl/flCγ1-Cre mice showed dramatically reduced numbers of nitrophenyl (NP) hapten-specific cells 14 days after immunization with NP-KLH compared to the control mice. Taken together, these findings suggest that c-REL may be required for the maintenance of GC B cells or for their selection into the post-GC compartment. Of note, the results demonstrate that deletion of a single NF-κB subunit in GC B cells can have drastic effects, suggesting a lack of general redundancy of the canonical subunits during the GC reaction. These findings imply that c-REL activation needs to be tightly controlled during GC B cell development, and raise the possibility that other NF-κB subunits may also exert unique functions in GC B cell differentiation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Genome-Wide Histone Acetylation Profiling in Chronic Lymphocytic Leukemia Reveals a Distinctive Signature in Stereotyped Subset #8

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1241-1241
Author(s):  
Maria Tsagiopoulou ◽  
Vicente Chapaprieta ◽  
Nuria Russiñol ◽  
Fotis Psomopoulos ◽  
Nikos Papakonstantinou ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Research Funding ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Memory B Cells ◽  
Site Analysis ◽  
Total Variability ◽  
Cell Subpopulations ◽  
Chromatin Acetylation

In CLL, subsets of patients carrying stereotyped B cell receptors (BcR) share similar biological and clinical features independently of IGHV gene somatic hypermutation status. Although the chromatin landscape of CLL as a whole has been recently characterized, it remains largely unexplored in stereotyped cases. Here, we analyzed the active chromatin regulatory landscape of 3 major CLL stereotyped subsets associated with clinical aggressiveness. We performed chromatin-immunoprecipitation followed by sequencing (ChIP-Seq) with an antibody for the H3K27ac histone mark in sorted CLL cells from 19 cases, including clinically aggressive subsets #1 (clan I genes/IGKV(D)1-39, IG-unmutated CLL (U-CLL)(n=3)], #2 [IGHV3-21/IGLV3-21, IG-mutated CLL (M-CLL)(n=3)] and #8 [IGHV4-39/IGKV1(D)-39, U-CLL(n=3)] which we compared to non-stereotyped CLL cases [5 M-CLL|5 U-CLL]. In addition, a series of 15 normal B cell samples from different stages of B-cell differentiation were analyzed [naive B cells from peripheral blood (n=3), tonsillar naive B cells (n=3), germinal centre (GC) B cells (n=3), memory B cells (n=3), tonsillar plasma cells (n=3)]. Initial unsupervised principal component analysis (PCA) disclosed a distinct chromatin acetylation pattern in CLL, regardless of stereotypy status, versus normal B cells. CLL as a whole was found to be closer to naive and memory B cells rather than GC B cells and plasma cells. Detailed analysis of individual principal components (PC) revealed that PC4, which accounts for 5% of the total variability, segregated subset #8 cases and GC B cells from other CLLs and normal B cell subpopulations. Although PC4 accounts for only a small part of the total variability (5%), this suggests that subset #8 cases may share some chromatin features with proliferating GC B cells, in line with the fact that subset #8 BcR are IgG-switched. We also investigated whether stereotyped CLLs have different chromatin acetylation features compared to non-stereotyped CLLs matched by IGHV somatic hypermutation status and identified 878 Differential Regions (DR) in subset #8 vs. U-CLL, 84 DR in subset #1 vs. U-CLL and 66 DR in #2 compared vs. M-CLL. As subset #8 cases seemed to have the most distinct profile, we further characterized the detected regions. The 435 and 443 regions gaining and losing activation, respectively, mostly targeted promoters (29.5%) and regulatory elements located in introns (31%) and distal intergenic regions (21.8%). Hierarchical clustering based on the 878 DRs enabled the clear discrimination of subset #8 cases from U-CLL and normal B cells; however, it is worth noting that for several of these 878 DRs the acetylation patterns were shared between subset #8 and normal B cell subpopulations rather than subset #8 and U-CLL. Of note, 11/435 regions gaining activity on subset #8 were found within the gene encoding for the EBF1 transcription factor (TF); additional regions were associated with genes significant to CLL pathogenesis, e.g. TCF4 and E2F1. Moreover, 3 DRs losing activity in subset #8 were located within the CTLA4 gene and 2 DRs within the IL21R gene, which we have recently reported as hypermethylated and not expressed in subset #8. Next, we performed TF binding site analysis by MEME/AME suit, separately for regions gaining or losing activity, and identified significant enrichment (adj-p<0.001) on TFs such as AP-1, FOX, GATA, IRF. The regions losing activity in subset #8 showed a higher number of enriched TFs versus those gaining activity (165 vs 93 TFs), particularly displaying enrichment for many HOX family members . However, a cluster of TFs with enrichment on TF binding site analysis, such as FOXO1, FOXP1, MEF2D, PRDM1, RUNX1, RXRA, STAT6, were also located within the 878 DRs discriminating subset #8 from either U-CLL or normal B cell subpopulations. Taken together, subset #8 cases have a distinct chromatin acetylation signature which includes both loss and gain of active elements, shared features with proliferating GC B cells, and specific changes in chromatin activity of several genes and TFs relevant to B cell/CLL biology. These findings further underscore the concept that BcR stereotypy defines subsets of patients with consistent biological profile, while they may also be relevant to the particular clinical behavior of subset #8, known to be associated with the highest risk of Richter's transformation amongst all CLL. Disclosures Stamatopoulos: Abbvie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

scholarly journals Different B cell subpopulations show distinct patterns in their IgH repertoire metrics

2021 ◽  
Author(s):  
Marie Ghraichy ◽  
Valentin von Niederhäusern ◽  
Aleksandr Kovaltsuk ◽  
Jacob Daniel Galson ◽  
Charlotte M Deane ◽  
...  
Keyword(s):  
B Cell ◽  
In Silico ◽  
Plasma Cells ◽  
Somatic Hypermutation ◽  
Bioinformatic Analysis ◽  
Cell Repertoire ◽  
Humoral Immune ◽  
B Cell Repertoire ◽  
Cell Subpopulations ◽  
The Individual

Background: Several human B-cell subpopulations are recognized in the peripheral blood, which play distinct roles in the humoral immune response. These cells undergo developmental and maturational changes involving VDJ recombination, somatic hypermutation and class switch recombination, altogether shaping their immunoglobulin heavy chain (IgH) repertoire. Methods: Here, we sequenced the IgH repertoire of naïve, marginal zone, switched and plasma cells from 10 healthy adults along with matched unsorted and in silico separated CD19+ bulk B cells. We used advanced bioinformatic analysis and machine learning to thoroughly examine and compare these repertoires. Results: We show that sorted B cell subpopulations are characterised by distinct repertoire characteristics on both the individual sequence and the repertoire level. Sorted subpopulations shared similar repertoire characteristics with their corresponding in silico separated subsets. Furthermore, certain IgH repertoire characteristics correlated with the position of the constant region on the IgH locus. Conclusion: Overall, this study provides unprecedented insight over mechanisms of B cell repertoire control in peripherally circulating B cell subpopulations.

scholarly journals Serological Immunoglobulin-Free Light Chain Profile in Myasthenia Gravis Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Umberto Basile ◽  
Mariapaola Marino ◽  
Cecilia Napodano ◽  
Krizia Pocino ◽  
Paolo Emilio Alboini ◽  
...  
Keyword(s):  
Myasthenia Gravis ◽  
Disease Activity ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
Plasma Cells ◽  
Cell Activity ◽  
B Cell Activation ◽  
Heavy Chains ◽  
Autoimmune Conditions

Background. Serological levels of free immunoglobulin light chains (FLCs), produced in excess of heavy chains during synthesis of immunoglobulins by plasma cells, can be considered a direct marker of B cell activity in different systemic inflammatory-autoimmune conditions and may represent a useful predictor of rituximab (RTX) therapeutic efficacy, as reported for rheumatoid arthritis and systemic lupus erythematosus. Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction with antibodies (abs) targeting the acetylcholine receptor (AChR) or the muscle-specific tyrosine kinase (MuSK), inducing muscle weakness and excessive fatigability. As MG course may be remarkably variable, we evaluated the possible use of FLCs as biomarkers of disease activity. Subjects and Methods. We assessed FLC levels in 34 sera from 17 AChR-MG and from 13 MuSK-MG patients, in comparison with 20 sera from patients with systemic autoimmune rheumatic diseases and 18 from healthy blood donors, along with titers of specific auto-abs and IgG subclass distribution. Results. We found a statistically significant increase in free κ chains in both AChR- and MuSK-MG patients, while free λ chain levels were increased only in AChR-MG. We also observed a significant reduction of both free κ and λ chains in 1/4 MuSK-MG patients along with specific abs titer, two months after RTX treatment. Conclusions. From our data, FLCs appear to be a sensitive marker of B cell activation in MG. Further investigations are necessary to exploit their potential as reliable biomarkers of disease activity.

scholarly journals Gene expression derived from alternative promoters improves prognostic stratification in multiple myeloma

Leukemia ◽  
2021 ◽  
Author(s):  
Luis V. Valcárcel ◽  
Ane Amundarain ◽  
Marta Kulis ◽  
Stella Charalampopoulou ◽  
Ari Melnick ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cell ◽  
Plasma Cells ◽  
Genetic Alterations ◽  
Cell Subpopulation ◽  
Alternative Promoters ◽  
Bone Marrow Plasma ◽  
Prognostic Stratification ◽  
Specific Alternative ◽  
Cell Subpopulations

AbstractClinical and genetic risk factors are currently used in multiple myeloma (MM) to stratify patients and to design specific therapies. However, these systems do not capture the heterogeneity of the disease supporting the development of new prognostic factors. In this study, we identified active promoters and alternative active promoters in 6 different B cell subpopulations, including bone-marrow plasma cells, and 32 MM patient samples, using RNA-seq data. We find that expression initiated at both regular and alternative promoters was specific of each B cell subpopulation or MM plasma cells, showing a remarkable level of consistency with chromatin-based promoter definition. Interestingly, using 595 MM patient samples from the CoMMpass dataset, we observed that the expression derived from some alternative promoters was associated with lower progression-free and overall survival in MM patients independently of genetic alterations. Altogether, our results define cancer-specific alternative active promoters as new transcriptomic features that can provide a new avenue for prognostic stratification possibilities in patients with MM.

scholarly journals Characterization of the DNA Methylome during Human B-Cell Differentiation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4346-4346
Author(s):  
Marta Kulis ◽  
Simon Heath ◽  
Giancarlo Castellano ◽  
Renée Beekman ◽  
Angelika Merkel ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Differentiation ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Maturation ◽  
B Cell Differentiation ◽  
Dna Methylome ◽  
B Cell Maturation ◽  
Cell Subpopulations ◽  
Human B Cell

Abstract Introduction: Modulation of the DNA methylation landscape during cell differentiation is a well-established phenomenon. The B-cell lineage represents a paradigmatic cellular model to study the dynamic epigenome during cell development and specification because major B-cell maturation stages are well defined and display differential phenotypic and gene expression features. Furthermore, different B-cell subpopulations show different proliferation abilities, microenvironmental influences and life spans, providing a window of opportunity to study the epigenome in the context of multiple processes. Methods: We performed whole-genome bisulfite sequencing (WGBS), high-density methylation microarrays and gene expression profiling of ten purified human B-cell subpopulations spanning the entire differentiation program, ranging from uncommitted progenitors to terminally-differentiated plasma cells. Results: The results of both WGBS and methylation microarrays indicate that B-cell ontogenesis involves an extensive and gradual reconfiguration of the DNA methylome. We uncovered that non-CpG methylation at CpApC trinucleotides is present in progenitor cells and disappears upon B-cell commitment independently of CpG demethylation. CpG methylation, in contrast, changed extensively during the entire B-cell maturation program, with one quarter of all measured CpGs showing dynamic methylation. B-cell enhancers suffered more extensive methylation changes than promoter regions, especially in the early differentiation steps up to the germinal center B-cell (gcBC) stage, and their demethylation seemed to be mediated by binding of lineage-specific transcription factors. Enhancers with dynamic methylation were related to genes involved in a large B-cell network that showed high gene expression variability throughout differentiation. In highly proliferative gcBCs, we observed a shift of dynamic methylation from regulatory towards non-functional elements; gcBCs start to undergo global demethylation of late-replicating heterochromatic regions and methylation of polycomb-repressed regions. This signature becomes particularly extensive in long-lived memory B cells and plasma cells, indicating that these changes start in highly proliferative cells and then accumulate in non-proliferative cells with extended lifespan. Conclusion: Our epigenomic analysis of the B-cell differentiation program extends our knowledge on how the DNA methylome is modulated during cell specification and maturation and offers a resource for researchers in the field, both at global and single gene levels. Disclosures No relevant conflicts of interest to declare.

scholarly journals Thymus-derived B cell clones persist in the circulation after thymectomy in myasthenia gravis

2020 ◽  
Vol 117 (48) ◽  
pp. 30649-30660 ◽  
Author(s):  
Ruoyi Jiang ◽  
Kenneth B. Hoehn ◽  
Casey S. Lee ◽  
Minh C. Pham ◽  
Robert J. Homer ◽  
...  
Keyword(s):  
B Cells ◽  
Myasthenia Gravis ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Repertoire ◽  
B Cell Repertoire ◽  
Cell Clones ◽  
Autoantibody Titer ◽  
Repertoire Sequencing ◽  
Symptom Measures

Myasthenia gravis (MG) is a neuromuscular, autoimmune disease caused by autoantibodies that target postsynaptic proteins, primarily the acetylcholine receptor (AChR) and inhibit signaling at the neuromuscular junction. The majority of patients under 50 y with AChR autoantibody MG have thymic lymphofollicular hyperplasia. The MG thymus is a reservoir of plasma cells that secrete disease-causing AChR autoantibodies and although thymectomy improves clinical scores, many patients fail to achieve complete stable remission without additional immunosuppressive treatments. We speculate that thymus-associated B cells and plasma cells persist in the circulation after thymectomy and that their persistence could explain incomplete responses to resection. We studied patients enrolled in a randomized clinical trial and used complementary modalities of B cell repertoire sequencing to characterize the thymus B cell repertoire and identify B cell clones that resided in the thymus and circulation before and 12 mo after thymectomy. Thymus-associated B cell clones were detected in the circulation by both mRNA-based and genomic DNA-based sequencing. These antigen-experienced B cells persisted in the circulation after thymectomy. Many circulating thymus-associated B cell clones were inferred to have originated and initially matured in the thymus before emigration from the thymus to the circulation. The persistence of thymus-associated B cells correlated with less favorable changes in clinical symptom measures, steroid dose required to manage symptoms, and marginal changes in AChR autoantibody titer. This investigation indicates that the diminished clinical response to thymectomy is related to persistent circulating thymus-associated B cell clones.

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