Beyond autoantibodies: Biological roles of human autoreactive B cells in rheumatoid arthritis revealed by whole transcriptome profiling

AbstractAlthough the contribution of B-cell derived autoreactive antibodies to rheumatoid arthritis (RA) has been studied extensively, the autoantibody-independent roles of B cells in the progression of the disease is not well-defined. Here we present the first comprehensive transcriptome profile of human autoreactive B cells in an autoimmune disease by performing RNA-sequencing of citrulline-specific B cells from RA patients. In order to facilitate a comprehensive understanding of the profile of these citrulline-specific (RA-CCPPOS) B cells, we performed comparative analyses to both citrulline-negative (RA-CCPNEG) B cells from the same donors, and identified 431 differentially expressed genes (DEGs); and hemagglutinin-specific (HA) B cells from healthy individuals and identified 1658 DEGs. Three-way comparisons of these B cell populations demonstrated that RA-CCPPOS B cells, in comparison to the RA-CCPNEG B cells, demonstrate a potential role in protein citrullination and inflammation; RA-CCPPOS B cells in comparison to HA-specific B cells demonstrate RA-specific signatures like the expression of pro-inflammatory cytokines, chemokines, costimulatory molecules and B-cell activation cascades; and all B cells from RA patients demonstrated a significant impact of the multitude of TNF signaling pathways. Furthermore, transcription factor profiling suggested that cyclic AMP (cAMP) related pathways and downstream signaling molecules are selectively enriched in RA-CCPPOS cells in comparison to the other two B cell subsets. We advanced the understanding of the citrulline reactive B cells in RA pathophysiology by documenting and validating two novel observations in independent cohorts of patients: (1) the expression of IL15Rα is restricted to citrulline-specific cells within RA patients and the concentration of soluble IL15Rα is elevated in the sera of RA patients, (2) B cells from RA patients are capable of producing epidermal growth factor ligand, amphiregulin (AREG) which in turn has a direct impact on the mechanistic effectors of RA, osteoclasts and fibroblastlike synoviocytes (FLS). Overall, our comprehensive dataset identifies several existing FDA-approved drugs that can potentially be repurposed for RA and can serve as a foundation for studying the multi-faceted roles of B cells in other autoimmune diseases.

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PTIP chromatin regulator controls development and activation of B cell subsets to license humoral immunity in mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1707938114 ◽

2017 ◽

Vol 114 (44) ◽

pp. E9328-E9337 ◽

Cited By ~ 4

Author(s):

Dan Su ◽

Stijn Vanhee ◽

Rebeca Soria ◽

Elin Jaensson Gyllenbäck ◽

Linda M. Starnes ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Humoral Immunity ◽

Cell Activation ◽

Cell Receptor ◽

B Cell Receptor ◽

Transactivation Domain ◽

B Cell Activation ◽

Chromatin Regulator ◽

B Cell Subsets

B cell receptor signaling and downstream NF-κB activity are crucial for the maturation and functionality of all major B cell subsets, yet the molecular players in these signaling events are not fully understood. Here we use several genetically modified mouse models to demonstrate that expression of the multifunctional BRCT (BRCA1 C-terminal) domain-containing PTIP (Pax transactivation domain-interacting protein) chromatin regulator is controlled by B cell activation and potentiates steady-state and postimmune antibody production in vivo. By examining the effects of PTIP deficiency in mice at various ages during ontogeny, we demonstrate that PTIP promotes bone marrow B cell development as well as the neonatal establishment and subsequent long-term maintenance of self-reactive B-1 B cells. Furthermore, we find that PTIP is required for B cell receptor- and T:B interaction-induced proliferation, differentiation of follicular B cells during germinal center formation, and normal signaling through the classical NF-κB pathway. Together with the previously identified role for PTIP in promoting sterile transcription at the Igh locus, the present results establish PTIP as a licensing factor for humoral immunity that acts at several junctures of B lineage maturation and effector cell differentiation by controlling B cell activation.

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Synoviocytes-derived Interleukin 35 Potentiates B Cell Response in Patients with Osteoarthritis and Rheumatoid Arthritis

The Journal of Rheumatology ◽

10.3899/jrheum.161363 ◽

2017 ◽

Vol 45 (4) ◽

pp. 563-573 ◽

Cited By ~ 1

Author(s):

Ngar-Woon Kam ◽

Dehua Liu ◽

Zhe Cai ◽

Wah-Yan Mak ◽

Chun-Kwok Wong ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Flow Cytometry ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Synovial Fibroblasts ◽

B Cell Activation ◽

Qrt Pcr ◽

Tnf Α ◽

Factor Α

Objective.Elevated expression of interleukin 35 (IL-35) is associated with autoimmune disease, including rheumatoid arthritis (RA). The present study was undertaken to determine the functional interaction among IL-35, B cells, and stromal cells residing in the synovium of patients with RA and osteoarthritis (OA).Methods.IL-35 (EBI-3/p35) expression was investigated in RA and OA synovium using quantitative real-time PCR (qRT-PCR) and immunohistochemistry. IL-35 receptor (IL-35R) expression on B cells dissociated from synovium and periphery of patients with RA, OA, and healthy donor controls (HC) was determined by flow cytometry. The degree of B cells activation after IL-4 and/or IL-35 stimulation was measured by flow cytometry and qRT-PCR. Synovial fibroblasts (SF) purified from RA and OA synovium were cocultured with peripheral HC B cells in the presence/absence of tumor necrosis factor-α (TNF-α) and with/without anti-IL-35–blocking antibodies.Results.EBI-3/p35 transcripts were expressed in close proximity to B cells residing in RA and OA synovium. IL-35R subunits, gp130 and IL-27Rα, but not IL-12Rβ2, were expressed in B cells extracted from the synovium and periphery of patients with RA/OA. Notably, RA synovium expressed the highest level of IL-27Rα on their cell surface. IL-35 induced proliferation and IgG production in HC B cells. Cocultures of HC B cells with RASF, but not OASF, exhibited significantly elevated B cells activation. TNF-α–induced, RASF-dependent secretion of IgG in B cells is partly IL-35–dependent.Conclusion.To our knowledge, for the first time we demonstrated that synovial/peripheral B cells expressed IL-35R and were responsive to IL-35 stimulation. SF residing in RA synovium can be linked to B cell activation and maintenance in RA synovium through IL-35.

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B Cell Activation and Escape of Tolerance Checkpoints: Recent Insights from Studying Autoreactive B Cells

Cells ◽

10.3390/cells10051190 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1190

Author(s):

Carlo G. Bonasia ◽

Wayel H. Abdulahad ◽

Abraham Rutgers ◽

Peter Heeringa ◽

Nicolaas A. Bos

Keyword(s):

T Cells ◽

B Cells ◽

Autoimmune Diseases ◽

B Cell ◽

Cell Activation ◽

Therapeutic Strategies ◽

B Cell Activation ◽

Autoreactive B Cells ◽

Key Drivers

Autoreactive B cells are key drivers of pathogenic processes in autoimmune diseases by the production of autoantibodies, secretion of cytokines, and presentation of autoantigens to T cells. However, the mechanisms that underlie the development of autoreactive B cells are not well understood. Here, we review recent studies leveraging novel techniques to identify and characterize (auto)antigen-specific B cells. The insights gained from such studies pertaining to the mechanisms involved in the escape of tolerance checkpoints and the activation of autoreactive B cells are discussed. In addition, we briefly highlight potential therapeutic strategies to target and eliminate autoreactive B cells in autoimmune diseases.

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Intrathecal B-cell activation in LGI1 antibody encephalitis

Neurology Neuroimmunology & Neuroinflammation ◽

10.1212/nxi.0000000000000669 ◽

2020 ◽

Vol 7 (2) ◽

pp. e669 ◽

Cited By ~ 2

Author(s):

Klaus Lehmann-Horn ◽

Sarosh R. Irani ◽

Shengzhi Wang ◽

Arumugam Palanichamy ◽

Sarah Jahn ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Activation ◽

Mononuclear Cells ◽

Cell Activity ◽

Oligoclonal Bands ◽

B Cell Activation ◽

Cell Repertoire ◽

Antibody Titers ◽

B Cell Subsets

ObjectiveTo study intrathecal B-cell activity in leucine-rich, glioma-inactivated 1 (LGI1) antibody encephalitis. In patients with LGI1 antibodies, the lack of CSF lymphocytosis or oligoclonal bands and serum-predominant LGI1 antibodies suggests a peripherally initiated immune response. However, it is unknown whether B cells within the CNS contribute to the ongoing pathogenesis of LGI1 antibody encephalitis.MethodsPaired CSF and peripheral blood (PB) mononuclear cells were collected from 6 patients with LGI1 antibody encephalitis and 2 patients with other neurologic diseases. Deep B-cell immune repertoire sequencing was performed on immunoglobulin heavy chain transcripts from CSF B cells and sorted PB B-cell subsets. In addition, LGI1 antibody levels were determined in CSF and PB.ResultsSerum LGI1 antibody titers were on average 127-fold higher than CSF LGI1 antibody titers. Yet, deep B-cell repertoire analysis demonstrated a restricted CSF repertoire with frequent extensive clusters of clonally related B cells connected to mature PB B cells. These clusters showed intensive mutational activity of CSF B cells, providing strong evidence for an independent CNS-based antigen-driven response in patients with LGI1 antibody encephalitis but not in controls.ConclusionsOur results demonstrate that intrathecal immunoglobulin repertoire expansion is a feature of LGI1 antibody encephalitis and suggests a need for CNS-penetrant therapies.

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Btk levels set the threshold for B-cell activation and negative selection of autoreactive B cells in mice

Blood ◽

10.1182/blood-2011-12-397919 ◽

2012 ◽

Vol 119 (16) ◽

pp. 3744-3756 ◽

Cited By ~ 108

Author(s):

Laurens P. Kil ◽

Marjolein J. W. de Bruijn ◽

Menno van Nimwegen ◽

Odilia B. J. Corneth ◽

Jan Piet van Hamburg ◽

...

Keyword(s):

B Cells ◽

Transgenic Mice ◽

B Cell ◽

Cell Activation ◽

Systemic Autoimmune Disease ◽

B Cell Activation ◽

Autoantibody Production ◽

Autoreactive B Cells ◽

Autoimmune Pathology

Abstract On antigen binding by the B-cell receptor (BCR), B cells up-regulate protein expression of the key downstream signaling molecule Bruton tyrosine kinase (Btk), but the effects of Btk up-regulation on B-cell function are unknown. Here, we show that transgenic mice overexpressing Btk specifically in B cells spontaneously formed germinal centers and manifested increased plasma cell numbers, leading to antinuclear autoantibody production and systemic lupus erythematosus (SLE)–like autoimmune pathology affecting kidneys, lungs, and salivary glands. Autoimmunity was fully dependent on Btk kinase activity, because Btk inhibitor treatment (PCI-32765) could normalize B-cell activation and differentiation, and because autoantibodies were absent in Btk transgenic mice overexpressing a kinase inactive Btk mutant. B cells overexpressing wild-type Btk were selectively hyperresponsive to BCR stimulation and showed enhanced Ca2+ influx, nuclear factor (NF)–κB activation, resistance to Fas-mediated apoptosis, and defective elimination of selfreactive B cells in vivo. These findings unravel a crucial role for Btk in setting the threshold for B-cell activation and counterselection of autoreactive B cells, making Btk an attractive therapeutic target in systemic autoimmune disease such as SLE. The finding of in vivo pathology associated with Btk overexpression may have important implications for the development of gene therapy strategies for X-linked agammaglobulinemia, the immunodeficiency associated with mutations in BTK.

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Abatacept Reduces Levels of Switched Memory B Cells, Autoantibodies, and Immunoglobulins in Patients with Rheumatoid Arthritis

The Journal of Rheumatology ◽

10.3899/jrheum.130905 ◽

2014 ◽

Vol 41 (4) ◽

pp. 666-672 ◽

Cited By ~ 39

Author(s):

Mirko Scarsi ◽

Lucia Paolini ◽

Doris Ricotta ◽

Antonio Pedrini ◽

Silvia Piantoni ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Cell Activation ◽

Serum Levels ◽

Memory B Cells ◽

Cell Phenotype ◽

B Cell Activation ◽

Switch Memory

Objective.Abatacept (ABA) is a chimeric molecule, able to block the CD28-mediated costimulatory pathway. To evaluate the hypothesis that, through this mechanism of action, ABA may down-modulate the immune responses of B lymphocytes in rheumatoid arthritis (RA), we investigated the serum levels of immunoglobulins (Ig), free light chains (FLC), anticitrullinated protein antibodies (ACPA), and rheumatoid factor (RF), as well as the number of B lymphocytes differentiated into post-switch memory cells in patients treated with ABA.Methods.The serum levels of Ig, FLC, different ACPA, RF isotypes, and the B cell phenotype were longitudinally evaluated in 30 patients with RA treated with ABA.Results.At baseline, the proportion of total and post-switch memory B cells was lower in RA than in healthy individuals. After 6 months of ABA treatment we observed significant reductions of serum levels of IgG, IgA, and IgM, as well as FLC, with a normalization in many patients who had initially abnormal values. A significant reduction of the titers of IgG- and IgA-ACPA, as well as of IgM-, IgA-, and IgG-RF was also observed. A decrease of autoantibodies below the upper limits of normal values was found in 2 of 26 patients (8%) initially seropositive for IgG-ACPA, 1 of 14 (7%) for IgA-ACPA, 5 of 22 (23%) for IgM-RF, 7 of 22 (30%) for IgA-RF, and 5 of 16 (31%) for IgG-RF. After treatment, the proportion of circulating post-switch memory B cells was also further significantly decreased.Conclusion.ABA treatment in patients with RA can reduce signs of polyclonal B cell activation, inducing a trend toward normalization of serum levels of different classes of Ig and of FLC, decreasing titers of ACPA and RF, and percentages of post-switch memory B cells.

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Carrier-directed anti-hapten responses by b-cell subsets

Journal of Experimental Medicine ◽

10.1084/jem.146.1.1 ◽

1977 ◽

Vol 146 (1) ◽

pp. 1-10 ◽

Cited By ~ 37

Author(s):

GK Lewis ◽

JW Goodman

Keyword(s):

B Cells ◽

B Cell ◽

Cell Activation ◽

Burst Size ◽

Cell Subset ◽

B Cell Activation ◽

Cell Subpopulations ◽

Activation Pathways ◽

B Cell Subsets

The capacity of the trinitrophenyl (TNP) haptenic group, coupled to a series of chemically dissimilar carriers, to cross-stimulate putative T- dependent and T-independent murine B-cell subpepulations was determined by using an in vitro limiting dilution technique to generate primary IgM responses. It was found that TNP-Ficoll and TNP-dextran, two T- independent antigens with little or no polyclonal mitogenicity, stimulate the same population of anti-TNP precursors, which is distinct from the precursor population activated by TNP-bacterial lipopolysaccharide (LPS), a T-independent polyclonal mitogen, or TNP-horse erythrocytes (HRBC), a T-dependent antigen. On the other hand, TNP-LPS and TNP-HRBC activate the same precursor population, indicating that LPS can substitute for the T- cell signal in T-dependent B-cell responses, whereas nonmitogenic T- independent antigens cannot. However, the cumulative evidence from this and other laboratories strongly indicates that LPS and T-dependent antigens activate B cells by different mechanisms. Of particular interest, LPS is incapable of activating B cells responsive to weakly- or nonmitogenic T-independent antigens. Based on clonal burst size, T-dependent antigens are capable of inducing greater antigen-specific B-cell proliferation than T-independent antigens. However, TNP conjugates of Ficoll and dextran, which are relatively poor inducers of polyclonal B-cell activation, induced larger anti-TNP clones than did TNP-LPS, a strong polyclonal mitogen. The findings reinforce the evidence favoring existence of multiple B- cell subpopulations with distinctive activation pathways. They also strengthen the proposition that a given B-cell subset can be activated by more than one mechanism.

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Osteopontin and malaria: no direct effect on parasite growth, but correlation with P. falciparum-specific B cells and BAFF in a malaria endemic area

BMC Microbiology ◽

10.1186/s12866-021-02368-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Susanne E Mortazavi ◽

Allan Lugaajju ◽

Mark Kaddumukasa ◽

Muyideen Kolapo Tijani ◽

Fred Kironde ◽

...

Keyword(s):

Immune Response ◽

B Cells ◽

B Cell ◽

Direct Effect ◽

Cell Activation ◽

Cell Immune Response ◽

Natural Immunity ◽

B Cell Activation ◽

B Cell Subsets

Abstract Background The dysregulation of B cell activation is prevalent during naturally acquired immunity against malaria. Osteopontin (OPN), a protein produced by various cells including B cells, is a phosphorylated glycoprotein that participates in immune regulation and has been suggested to be involved in the immune response against malaria. Here we studied the longitudinal concentrations of OPN in infants and their mothers living in Uganda, and how OPN concentrations correlated with B cell subsets specific for P. falciparum and B cell activating factor (BAFF). We also investigated the direct effect of OPN on P. falciparum in vitro. Results The OPN concentration was higher in the infants compared to the mothers, and OPN concentration in infants decreased from birth until 9 months. OPN concentration in infants during 9 months were independent of OPN concentrations in corresponding mothers. OPN concentrations in infants were inversely correlated with total atypical memory B cells (MBCs) as well as P. falciparum-specific atypical MBCs. There was a positive correlation between OPN and BAFF concentrations in both mothers and infants. When OPN was added to P. falciparum cultured in vitro, parasitemia was unaffected regardless of OPN concentration. Conclusions The concentrations of OPN in infants were higher and independent of the OPN concentrations in corresponding mothers. In vitro, OPN does not have a direct effect on P. falciparum growth. Our correlation analysis results suggest that OPN could have a role in the B cell immune response and acquisition of natural immunity against malaria.

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CD21lo/−CD27−IgM− Double-Negative B Cells Accumulate in the Joints of Patients With Antinuclear Antibody-Positive Juvenile Idiopathic Arthritis

Frontiers in Pediatrics ◽

10.3389/fped.2021.635815 ◽

2021 ◽

Vol 9 ◽

Author(s):

Johannes Dirks ◽

Jonas Fischer ◽

Gabriele Haase ◽

Annette Holl-Wieden ◽

Christine Hofmann ◽

...

Keyword(s):

Juvenile Idiopathic Arthritis ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Cross Sectional Study ◽

Double Negative ◽

B Cell Differentiation ◽

B Cell Activation ◽

Cross Sectional ◽

B Cell Subsets

Juvenile idiopathic arthritis (JIA) encompasses a heterogeneous group of diseases. The appearance of antinuclear antibodies (ANAs) in almost half of the patients suggests B cell dysregulation as a distinct pathomechanism in these patients. Additionally, ANAs were considered potential biomarkers encompassing a clinically homogenous subgroup of JIA patients. However, in ANA+ JIA patients, the site of dysregulated B cell activation as well as the B cell subsets involved in this process is still unknown. Hence, in this cross-sectional study, we aimed in an explorative approach at characterizing potential divergences in B cell differentiation in ANA+ JIA patients by assessing the distribution of peripheral blood (PB) and synovial fluid (SF) B cell subpopulations using flow cytometry. The frequency of transitional as well as switched-memory B cells was higher in PB of JIA patients than in healthy controls. There were no differences in the distribution of B cell subsets between ANA- and ANA+ patients in PB. However, the composition of SF B cells was different between ANA- and ANA+ patients with increased frequencies of CD21lo/−CD27−IgM− “double negative” (DN) B cells in the latter. DN B cells might be a characteristic subset expanding in the joints of ANA+ JIA patients and are potentially involved in the antinuclear immune response in these patients. The results of our explorative study might foster further research dissecting the pathogenesis of ANA+ JIA patients.

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In vitro elimination of autoreactive B cells from rheumatoid arthritis patients by universal chimeric antigen receptor T cells

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-217844 ◽

2020 ◽

pp. annrheumdis-2020-217844

Author(s):

Bo Zhang ◽

Yan Wang ◽

Yeshuang Yuan ◽

Jiaqi Sun ◽

Lulu Liu ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

T Cells ◽

B Cells ◽

B Cell ◽

Autoreactive B Cells ◽

Peptide Epitopes ◽

Car T Cells ◽

Car T ◽

B Cell Subsets ◽

Citrullinated Peptide

ObjectivesAutoreactive B cells play a crucial role in the pathogenesis of rheumatoid arthritis (RA), and B cell-depleting therapies using an antibodies, such as rituximab, have been suggested to be effective in RA treatment. However, transient B cell depletion with rituximab is associated with significant safety challenges related to global suppression of the immune system and thus increases the risks of infection and cancer development. To address selective and persistent issues associated with RA therapy, we developed a customised therapeutic strategy employing universal antifluorescein isothiocyanate (FITC) chimeric antigen receptor T cells (CAR-T cells) combined with FITC-labelled antigenic peptide epitopes to eliminate autoreactive B cell subsets recognising these antigens in RA.MethodsFor a proof-of-concept study, four citrullinated peptide epitopes derived from citrullinated autoantigens, namely, citrullinated vimentin, citrullinated type II collagen, citrullinated fibrinogen and tenascin-C, and a cyclocitrulline peptide-1 were selected as ligands for targeting autoreactive B cells; Engineered T cells expressing a fixed anti-FITC CAR were constructed and applied as a universal CAR-T cell system to specifically eliminate these protein-specific autoreactive B cells via recognition of the aforementioned FITC-labelled autoantigenic peptide epitopes.ResultsWe demonstrated that anti-FITC CAR-T cells could be specifically redirected and kill hybridoma cells generated by immunisation with antigenic peptides, and autoreactive B cell subsets from RA patients via recognition of corresponding FITC-labelled citrullinated peptide epitopes. Additionally, the cytotoxicity of the CAR-T cells was dependent on the presence of the peptides and occurred in a dose-dependent manner.ConclusionsThe approach described here provides a direction for precise, customised approaches to treat RA and can likely be applied to other systemic autoimmune diseases.

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