AB0039 The Frequency of Acpa-Specific B Cells in the Circulating Memory B Cell Pool of Patients with Rheumatoid Arthritis: Table 1.

Objective.The efficacy of B cell depletion in the treatment of patients with rheumatoid arthritis (RA) has revitalized interest in the pathogenic role(s) of B cells in RA. We evaluated the distribution of synovial B lineage cells and their correlation with histologic disease activity and joint destruction in RA.Methods.Synovial tissue samples were obtained by closed-needle biopsy from 69 Chinese patients with active RA, from 14 patients with osteoarthritis (OA), and from 15 with orthopedic arthropathies (OrthA) as disease controls. Serial tissue sections were stained immunohistochemically for CD79a (pro-B cell to plasma cell), CD20 (B cells), CD38 (plasma cells), CD21 (follicular dendritic cells), CD68 (macrophages), CD3 (T cells), and CD34 (endothelial cells). Densities of positive-staining cells were determined and correlated with histologic disease activity (Krenn 3-component synovitis score) and radiographic joint destruction (Sharp score).Results.Mean sublining CD79a-positive cell density was significantly higher in RA than in OA (p <0.001) or OrthA (p = 0.003). Receiver operating characteristic curve analysis showed that CD79a-positive cell density differentiated RA well from OA [area under the curve (AUC) = 0.79] or OrthA (AUC = 0.75). Spearman’s rank order correlation showed significant correlations between sublining CD79a-positive cell density and the synovitis score (r = 0.714, p < 0.001), total Sharp score (r = 0.490, p < 0.001), and the erosion subscore (r = 0.545, p < 0.001), as well as the joint space narrowing subscore (r = 0.468, p = 0.001) in RA.Conclusion.Synovial CD79a-positive B cells may be a helpful biomarker for histologic disease activity in RA and may be involved in the pathogenesis of joint destruction in RA.

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POS1223 RAS GUANYL RELEASING PROTEIN 1 (RASGRP1) IN PERIPHERAL B CELLS LINKS RA TO COVID-19

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2809 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 895.2-895

Author(s):

S. Hannawi ◽

F. Alqutami ◽

M. Y. Hachim

Keyword(s):

Rheumatoid Arthritis ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Plasma Cells ◽

Immune Cell ◽

In Silico Analysis ◽

Differentially Expressed ◽

Transcriptional Enhancer ◽

Activated T Cells

Background:Changes in the B cell subpopulations is a hallmark of the antiviral response against SARS-CoV-2 and is associated with COVID-19 severity (1). Recently our group showed common derangement observed in rheumatoid arthritis (RA) and COVID-19 (2). In RA, synovium attracts potentially autoreactive—B cells and plasma cells that play a central role in RA pathogenesis (3). We were interested to know the similarity in B cell’s transcriptomic changes specific to RA and COVID-19.Objectives:Identify similar upregulated genes in synovium and B cells in RA and at the same time are differentially expressed in B cells infected with SARS-CoV-2 or from COVID-19 patients.Methods:RNAseq dataset (GSE89408) of (218) samples isolated from joint synovial biopsies from subjects with and without rheumatoid arthritis were retrieved from GEO online database. Differentially expressed genes (DRGs) specific to RA were identified after exclusion of those upregulated in Osteoarthritis or other joint condition samples in the same dataset. The RA specific genes were intersected with DEGs between B cells from healthy versus RA as extracted from (GSE110999) dataset. The shortlisted genes specifically upregulated in B cells of RA were identified and were explored in B cells COVID-19 transcriptome datasets using (https://metascape.org/COVID).Results:60 genes were found to be specifically upregulated in RA synovium and B cells and are changed in B cells infected with SARS-CoV-2 or from COVID-19 patients, Figure (1-A). Those genes were involved in interferon signaling, antiviral and immune cell activation. RASGRP1 was common between B cells of RA and COVID-19 and might play a role in the pathogenesis of both, Figure (1-B). RASGRP1 controls ERK/MAPK kinase cascade needed in B-/T-cell differentiation and development. It is vital to protect against viral infection and the autoimmune associated proliferation of activated T-cells like RA (4). We checked its level in another dataset (GSE152641) of the whole blood RNASeq of 62 COVID-19 patients and 24 healthy controls. RASGRP1 was significantly down in COVID-19 compared to healthy control, Figure (1-C).Conclusion:SARS-CoV-2 impair B and T’s cells’ immune response through its action on RASGRP1 and that can be a novel mechanistic explanation of how the virus decreases immune cells and impair the B cell’s humoral immunity.References:[1]Sosa-Hernández VA, Torres-Ruíz J, Cervantes-Díaz R, Romero-Ramírez S, Páez-Franco JC, Meza-Sánchez DE, et al. B Cell Subsets as Severity-Associated Signatures in COVID-19 Patients. Frontiers in Immunology. 2020;11(3244).[2]Hachim MY, Hachim IY, Naeem KB, Hannawi H, Al Salmi I, Hannawi S. C-C chemokine receptor type 5 links COVID-19, rheumatoid arthritis, and Hydroxychloroquine: in silico analysis. Translational Medicine Communications. 2020;5(1):14.[3]Doorenspleet ME, Klarenbeek PL, de Hair MJ, van Schaik BD, Esveldt RE, van Kampen AH, et al. Rheumatoid arthritis synovial tissue harbours dominant B-cell and plasma-cell clones associated with autoreactivity. Ann Rheum Dis. 2014;73(4):756-62.[4]Molineros JE, Singh B, Terao C, Okada Y, Kaplan J, McDaniel B, et al. Mechanistic Characterization of RASGRP1 Variants Identifies an hnRNP-K-Regulated Transcriptional Enhancer Contributing to SLE Susceptibility. Frontiers in Immunology. 2019;10(1066).Disclosure of Interests:None declared

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Population kinetics of rat peripheral B cells.

Journal of Experimental Medicine ◽

10.1084/jem.167.3.805 ◽

1988 ◽

Vol 167 (3) ◽

pp. 805-816 ◽

Cited By ~ 50

Author(s):

D Gray

Keyword(s):

Bone Marrow ◽

B Cells ◽

B Cell ◽

Population Kinetics ◽

Tissue Sections ◽

Cell Pool ◽

Cell Life ◽

Dividing Cells ◽

Kinetics Of ◽

Selective Effects

Currently available estimates of B cell life span vary from 4 d to 6 wk. The discrepancy may have arisen out of the selective effects of stress and drug cytotoxicity on short-lived populations. In this report, bromodeoxyuridine (BUdR), a drug that incorporates into the DNA of dividing cells, has been fed to rats in their drinking water, eliminating stressful injection procedures. Labeled cells in the recirculating B cell pool are identified in tissue sections using an mAb to BUdR. BUdR is shown to have no cytostatic effects at the dose used. Over a 5-d period of infusion, only 20% of the peripheral recirculating pool incorporate label (approximately 4% per day); labeling over various periods indicates that the peripheral B cell pool turns over in approximately 4 wk. To distinguish between turnover due to incorporation of new B cells into the peripheral pool and division of antigen-activated B cells rats underwent two consecutive periods of labeling, first with [3H]thymidine for 5 d and then with BUdR for a further 5 d. Virgin B cells newly derived from dividing precursors in the bone marrow do not continue to proliferate in the periphery, while activated cells undergo several rounds of division during both labeling periods. The results indicate that 3-4% of the peripheral pool is replaced by new B cells each day, while 0.3-0.6% become part of activated clones every day. Assuming that the peripheral pool of the rat contains 10(9) B cells, then 3-4 X 10(7) new B cells become stably incorporated per day. This represents approximately 10% of the putative output of the bone marrow.

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Mast cells in early rheumatoid arthritis associate with disease severity and support B cell autoantibody production

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2018-213418 ◽

2018 ◽

Vol 77 (12) ◽

pp. 1773-1781 ◽

Cited By ~ 20

Author(s):

Felice Rivellese ◽

Daniele Mauro ◽

Alessandra Nerviani ◽

Sara Pagani ◽

Liliane Fossati-Jimack ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

B Cells ◽

Mast Cells ◽

Disease Activity ◽

B Cell ◽

Synovial Tissue ◽

Autoantibody Production ◽

Early Ra ◽

Treatment Naïve

ObjectivesMast cells (MCs) are involved in the pathogenesis of rheumatoid arthritis (RA). However, their contribution remains controversial. To establish their role in RA, we analysed their presence in the synovium of treatment-naïve patients with early RA and their association and functional relationship with histological features of synovitis.MethodsSynovial tissue was obtained by ultrasound-guided biopsy from treatment-naïve patients with early RA (n=99). Immune cells (CD3/CD20/CD138/CD68) and their relationship with CD117+MCs in synovial tissue were analysed by immunohistochemistry (IHC) and immunofluorescence (IF). The functional involvement of MCs in ectopic lymphoid structures (ELS) was investigated in vitro, by coculturing MCs with naïve B cells and anticitrullinated protein antibodies (ACPA)-producing B cell clones, and in vivo in interleukin-27 receptor alpha (IL27ra)-deficient and control mice during antigen-induced arthritis (AIA).ResultsHigh synovial MC counts are associated with local and systemic inflammation, autoantibody positivity and high disease activity. IHC/IF showed that MCs reside at the outer border of lymphoid aggregates. Furthermore, human MCs promote the activation and differentiation of naïve B cells and induce the production of ACPA, mainly via contact-dependent interactions. In AIA, synovial MC numbers increase in IL27ra deficient mice, in association with ELS and worse disease activity.ConclusionsSynovial MCs identify early RA patients with a severe clinical form of synovitis characterised by the presence of ELS.

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Potential anti-EBV effects associated with elevated interleukin-21 levels: a case report

BMC Infectious Diseases ◽

10.1186/s12879-020-05609-z ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Kristian Assing ◽

Christian Nielsen ◽

Marianne Jakobsen ◽

Charlotte B. Andersen ◽

Kristin Skogstrand ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Plasma Cell ◽

Germinal Center ◽

Plasma Cells ◽

Cell Formation ◽

Memory B Cells ◽

Memory B Cell

Abstract Background Germinal center derived memory B cells and plasma cells constitute, in health and during EBV reactivation, the largest functional EBV reservoir. Hence, by reducing germinal center derived formation of memory B cells and plasma cells, EBV loads may be reduced. Animal and in-vitro models have shown that IL-21 can support memory B and plasma cell formation and thereby potentially contribute to EBV persistence. However, IL-21 also displays anti-viral effects, as mice models have shown that CD4+ T cell produced IL-21 is critical for the differentiation, function and survival of anti-viral CD8+ T cells able to contain chronic virus infections. Case presentation We present immunological work-up (flow-cytometry, ELISA and genetics) related to a patient suffering from a condition resembling B cell chronic active EBV infection, albeit with moderately elevated EBV copy numbers. No mutations in genes associated with EBV disease, common variable immunodeficiency or pertaining to the IL-21 signaling pathway (including hypermorphic IL-21 mutations) were found. Increased (> 5-fold increase 7 days post-vaccination) CD4+ T cell produced (p < 0.01) and extracellular IL-21 levels characterized our patient and coexisted with: CD8+ lymphopenia, B lymphopenia, hypogammaglobulinemia, compromised memory B cell differentiation, absent induction of B-cell lymphoma 6 protein (Bcl-6) dependent peripheral follicular helper T cells (pTFH, p = 0.01), reduced frequencies of peripheral CD4+ Bcl-6+ T cells (p = 0.05), compromised plasmablast differentiation (reduced protein vaccine responses (p < 0.001) as well as reduced Treg frequencies. Supporting IL-21 mediated suppression of pTFH formation, pTFH and CD4+ IL-21+ frequencies were strongly inversely correlated, prior to and after vaccination, in the patient and in controls, Spearman’s rho: − 0.86, p < 0.001. Conclusions To the best of our knowledge, this is the first report of elevated CD4+ IL-21+ T cell frequencies in human EBV disease. IL-21 overproduction may, apart from driving T cell mediated anti-EBV responses, disrupt germinal center derived memory B cell and plasma cell formation, and thereby contribute to EBV disease control.

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Requirement for memory B-cell activation in protection from heterologous influenza virus reinfection

International Immunology ◽

10.1093/intimm/dxz049 ◽

2019 ◽

Vol 31 (12) ◽

pp. 771-779 ◽

Cited By ~ 8

Author(s):

Sarah Leach ◽

Ryo Shinnakasu ◽

Yu Adachi ◽

Masatoshi Momota ◽

Chieko Makino-Okamura ◽

...

Keyword(s):

Influenza Virus ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Influenza Infection ◽

Memory B Cells ◽

B Cell Activation ◽

Memory B Cell

Memory B cells protect against heterologous influenza infection

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Complexity of the human memory B-cell compartment is determined by the versatility of clonal diversification in germinal centers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1511270112 ◽

2015 ◽

Vol 112 (38) ◽

pp. E5281-E5289 ◽

Cited By ~ 29

Author(s):

Bettina Budeus ◽

Stefanie Schweigle de Reynoso ◽

Martina Przekopowitz ◽

Daniel Hoffmann ◽

Marc Seifert ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Clone ◽

Human Memory ◽

Memory B Cells ◽

Sequencing Analysis ◽

Cell Compartment ◽

Memory B Cell ◽

Cell Clones ◽

B Cell Subsets

Our knowledge about the clonal composition and intraclonal diversity of the human memory B-cell compartment and the relationship between memory B-cell subsets is still limited, although these are central issues for our understanding of adaptive immunity. We performed a deep sequencing analysis of rearranged immunoglobulin (Ig) heavy chain genes from biological replicates, covering more than 100,000 memory B lymphocytes from two healthy adults. We reveal a highly similar B-cell receptor repertoire among the four main human IgM+ and IgG+ memory B-cell subsets. Strikingly, in both donors, 45% of sequences could be assigned to expanded clones, demonstrating that the human memory B-cell compartment is characterized by many, often very large, B-cell clones. Twenty percent of the clones consisted of class switched and IgM+(IgD+) members, a feature that correlated significantly with clone size. Hence, we provide strong evidence that the vast majority of Ig mutated B cells—including IgM+IgD+CD27+ B cells—are post-germinal center (GC) memory B cells. Clone members showed high intraclonal sequence diversity and high intraclonal versatility in Ig class and IgG subclass composition, with particular patterns of memory B-cell clone generation in GC reactions. In conclusion, GC produce amazingly large, complex, and diverse memory B-cell clones, equipping the human immune system with a versatile and highly diverse compartment of IgM+(IgD+) and class-switched memory B cells.

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