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Precise regulation of B cell differentiation is essential for an effective adaptive immune response. Here, we show that B cell development in mice with B cell-specific Maf deletion is unaffected, but marginal zone B cells, germinal centre B cells, and plasmablasts are significantly more frequent in the spleen of naive Maf-deficient mice compared to wild type controls. In the context of a T cell-dependent immunization, Maf deletion causes increased proliferation of germinal centre B cells and extrafollicular plasmablasts. This is accompanied by higher production of antigen-specific IgG1 antibodies with minimal modification of early memory B cells, but a reduction in plasma cell numbers. Single-cell RNA sequencing shows upregulation of genes associated with DNA replication and cell cycle progression, confirming the role of Maf in cell proliferation. Subsequent pathway analysis reveals that Maf influences cellular metabolism, transporter activity, and mitochondrial proteins, which have been implicated in controlling the germinal centre reaction. In summary, our findings demonstrate that Maf acts intrinsically in B cells as a negative regulator of late B cell differentiation, plasmablast proliferation and germinal centre B cell formation. Maf is a transcription factor regulating pivotal biological processes in multiple immune cells, but its B-cell-intrinsic role is not fully known. Here authors show that genomic deletion of Maf in the B cell lineage does not disturb the sequence of developmental stages, however, removes an important inhibitory step to restrict the early steps of germinal centre B cell and extrafollicular plasmablast population expansion. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) are two autoimmune diseases characterised by the production of pathogenic autoreactive antibodies. Their aetiology is poorly understood. Nevertheless, they have been shown to involve several factors, such as infections and epigenetic mechanisms. They also likely involve a physiological process known as glycosylation. Both SLE T cell markers and pSS-associated autoantibodies exhibit abnormal glycosylation. Such dysregulation suggests that defective glycosylation may also occur in B cells, thereby modifying their behaviour and reactivity. This study aimed to investigate B cell subset glycosylation in SLE, pSS and healthy donors and to extend the glycan profile to serum proteins and immunoglobulins. We used optimised lectin-based tests to demonstrate specific glycosylation profiles on B cell subsets that were specifically altered in both diseases. Compared to the healthy donor B cells, the SLE B cells exhibited hypofucosylation, whereas only the pSS B cells exhibited hyposialylation. Additionally, the SLE B lymphocytes had more galactose linked to N-acetylglucosamine or N-acetylgalactosamine (Gal-GlcNAc/Gal-GalNAc) residues on their cell surface markers. Interestingly, some similar alterations were observed in serum proteins, including immunoglobulins. These findings indicate that any perturbation of the natural glycosylation process in B cells could result in the development of pathogenic autoantibodies. The B cell glycoprofile can be established as a preferred biomarker for characterising pathologies and adapted therapeutics can be used for patients if there is a correlation between the extent of these alterations and the severity of the autoimmune diseases. [ABSTRACT FROM AUTHOR]

Regulatory B cells (Bregs) have been highlighted in very different pathology settings including autoimmune diseases, allergy, graft rejection, and cancer. Improving tools for the characterization of Bregs has become the main objective especially in humans. Transitional, mature B cells and plasma cells can differentiate into IL-10 producing Bregs in both mice and humans, suggesting that Bregs are not derived from unique precursors but may arise from different competent progenitors at unrestricted development stages. Moreover, in addition to IL-10 production, regulatory B cells used a broad range of suppressing mechanisms to modulate the immune response. Although Bregs have been consistently described in the literature, only a few reports described the molecular aspects that control the acquisition of the regulatory function. In this manuscript, we detailed the latest reports describing the control of IL-10, TGFβ, and GZMB production in different Breg subsets at the molecular level. We focused on the understanding of the role of the transcription factors STAT3 and c-MAF in controlling IL-10 production in murine and human B cells and how these factors may represent an important crossroad of several key drivers of the Breg response. Finally, we provided original data supporting the evidence that MAF is expressed in human IL-10- producing plasmablast and could be induced in vitro following different stimulation cocktails. At steady state, we reported that MAF is expressed in specific human B-cell tonsillar subsets including the IgD+ CD27+ unswitched population, germinal center cells and plasmablast. [ABSTRACT FROM AUTHOR]

Objective: The effector T cell and B cell cytokine networks have been implicated in the pathogenesis of systemic autoimmune diseases, but the association of these cytokine networks with the heterogeneity of clinical manifestations and immune profiles has not been carefully examined. This study was undertaken to examine whether cytokine profiles can delineate distinct groups of patients in 4 systemic autoimmune diseases (systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, and systemic sclerosis). Methods: A total of 179 patients and 48 healthy volunteers were enrolled in the multicenter cross‐sectional PRECISE Systemic Autoimmune Diseases (PRECISESADS) study. Multi‐low‐dimensional omics data (cytokines, autoantibodies, circulating immune cells) were examined. Coculture experiments were performed to test the impact of the cytokine microenvironment on T cell/B cell cross‐talk. Results: A proinflammatory cytokine profile defined by high levels of CXCL10, interleukin‐6 (IL‐6), IL‐2, and tumor necrosis factor characterized a distinct group of patients in the 4 systemic autoimmune diseases. In each disease, this proinflammatory cluster was associated with a specific circulating immune cell signature, more severe disease, and higher levels of autoantibodies, suggesting an uncontrolled proinflammatory Th1 immune response. We observed in vitro that B cells reinforce Th1 differentiation and naive T cell proliferation, leading to the induction of type 1 effector B cells and IgG production. This process was associated with an increase in CXCL10, IL‐6, IL‐2, and interferon‐γ production. Conclusion: This composite analysis brings new insights into human B cell functional heterogeneity based on T cell/B cell cross‐talk, and proposes a better stratification of patients with systemic autoimmune diseases, suggesting that combined biomarkers would be of great value for the design of personalized treatments. [ABSTRACT FROM AUTHOR]

Biological abnormalities associated with B lymphocytes are a hallmark of patients with primary Sjögren's syndrome. Those patients present abnormal distribution of B lymphocytes in peripheral blood and B cells in exocrine glands. B cells produce auto‐antibodies, cytokines and present antigens but can also suppressive functions. In this review, we will summarize current knowledge on B cells in primary Sjögren's syndrome patients, demonstrate their critical role in the immunopathology of the disease and describe the past and current trials targeting B cells. [ABSTRACT FROM AUTHOR]

Objective: To look for abnormalities in circulating B-cell subsets in patients with rheumatic symptoms of Whipple’s disease (WD). Method: Consecutive patients seen between 2010 and 2016 for suspected inflammatory joint disease were identified retrospectively. Results of standardized immunological and serological tests and of peripheral-blood B-cell and T-cell subset analysis by flow cytometry were collected. Patients with criteria suggesting WD underwent PCR testing for Tropheryma whipplei, and those with diagnosis of WD (cases) were compared to those without diagnosis (controls). We used ROC curve analysis to evaluate the diagnostic value of flow cytometry findings for WD. Results: Among 2917 patients seen for suspected inflammatory joint disease, 121 had suspected WD, including 9 (9/121, 7.4%) confirmed WD. Proportions of T cells and NK cells were similar between suspected and confirmed WD, whereas cases had a lower proportion of circulating memory B cells (IgD-CD38low, 18.0%±9.7% vs. 26.0%±14.2%, P = 0.041) and higher ratio of activated B cells over memory B cells (4.4±2.0 vs. 2.9±2.2, P = 0.023). Among peripheral-blood B-cells, the proportion of IgD+CD27- naive B cells was higher (66.2%±18.2% vs. 54.6%±18.4%, P = 0.047) and that of IgD-CD27+ switched memory B cells lower (13.3%±5.7% vs. 21.4%±11.9%, P = 0.023), in cases vs. controls. The criterion with the best diagnostic performance was a proportion of IgD+CD27- naive B cells above 70.5%, which had 73% sensitivity and 80% specificity. Conclusion: Our study provides data on peripheral-blood B-cell disturbances that may have implications for the diagnosis and pathogenetic understanding of WD. [ABSTRACT FROM AUTHOR]

Objectives To develop a method to detect and phenotype circulating proteinase 3 (PR3)-specific B-cells in patients with PR3-ANCA associated vasculitis (AAV). Methods Recombinant human PR3 (rPR3) was tagged with FITC or biotin, and its binding characteristics were studied by flow cytometry using three hybridoma cell lines secreting antibodies (Ab) against human PR3, mouse PR3 (no cross-reactivity with human PR3), and human neutrophil elastase. We measured the proportion of PR3-specific B-cells and studied their surface phenotype in patients with PR3-AAV and healthy controls (HC). Results Labeled rPR3 efficiently and specifically bound to hybridoma cells producing anti-human-PR3-Ab but not anti-mouse-PR3-Ab or anti-human-elastase-Ab. The proportion of rPR3-stained B cells was higher in patients with PR3-AAV compared to HCs: median (IQR) 1.11% (0.81–2.43) vs 0.45% (0.26–0.62) respectively, p < 0.001. There was a trend towards a higher proportion of PR3-specific B cells among patients with active disease compared to patients in remission: 2.91% (1.18–6.52) vs 0.99% (0.72–1.58), p = 0.09. In HCs, the proportion of PR3-specific B cells was highest among the transitional B-cell subset, and decreased with the maturation of B cells. Conversely, in patients, the proportion of PR3-specific B cells progressively increased with the maturation of B cells (median 1.90% of naïve B cells, 2.30% of unswitched memory B cells, 2.37% of switched memory B cells, and 3.68% of plasmablasts). Conclusions Circulating PR3-specific B cells can be detected in HC and patients with PR3-AAV. Their progressive enrichment during B-cell maturation suggests that they are actively selected and escape peripheral tolerance checkpoints in patients. [ABSTRACT FROM AUTHOR]

Objectives. The aim was to study lymphocyte subsets and circulating cytokines at diagnosis of PMR and after tocilizumab monotherapy. Methods. Eighteen untreated patients with PMR were included in a prospective study and received 3-monthly tocilizumab infusions without glucocorticoids. Lymphocyte subset distribution was assessed by flow cytometry and serum cytokines were assayed by a 34-cytokine array and ELISA, at baseline and during follow-up. Baseline data were also compared with age- and sex-matched controls. Results. At baseline, total lymphocytes, T-cell subsets and NK cell counts were similar in patients and controls, but patients had significantly lower B-cell counts attributable to lower transitional, naïve and post-switch memory B-cell subsets. Circulating B-cell counts were positively correlated with the PMR activity score (PMR-AS) in untreated active patients at baseline, but subsequently increased to normal values while disease activity was controlled after tocilizumab therapy. Among serum cytokines, IL-6 showed the largest concentration difference between patients and controls, and the serum IL-6 concentration was correlated with baseline PMR-AS. The effects of tocilizumab on serum IL-6 concentration were heterogeneous, and the patients whose serum IL-6 decreased after tocilizumab therapy exhibited a significant increase in circulating B-cell counts. Conclusion. In patients with PMR, B-cell lymphopenia and abnormal B-cell subset distribution are associated with disease activity and IL-6 concentration, and both are corrected by the IL-6 antagonist tocilizumab. KEYWORDS: B cells; cytokines; interleukin-6; polymyalgia rheumatica; tocilizumab [ABSTRACT FROM AUTHOR]

Purpose: To determine whether the severity of salivary-gland involvement, assessed using salivary gland ultrasonography [SGUS], histological focus score, or the unstimulated whole salivary flow [UWSF], was associated with the response to rituximab in patients with primary Sjögren’s syndrome [pSS]. Materials and Methods: Among the 120 patients with pSS enrolled in the randomised TEARS trial of rituximab versus placebo, 35 underwent either centralised minor salivary-gland biopsy or SGUS at inclusion. The echostructure of each parotid and submandibular gland was graded on a scale of 0 to 4. Histologic minor salivary gland involvement was assessed by the focus score. Among rituximab-treated patients with available data (n = 14), half met the Sjögren’s Syndrome Responder Index [SSRI]-30 definition of a response at week 24. Results: The SGUS score correlated positively to the focus score [r = 0.61] and negatively to the UWSF [r = -0.68]. The focus score was not correlated to the UWSF. The median total SGUS grade at inclusion was 9 [6-11] in responders versus 16 [11-16] in non-responders [p = 0.04]. The proportion of SSRI-30 responders was 0% among patients with SGUS grade 4 and 88% among those with SGUS grade ≤3. Low baseline SGUS scores were associated with sicca-related outcomes improvement, but not with fatigue or biological improvement. Median baseline focus score was 0.3 [0.0–1.3] in the responders versus 4.0 [2.7–5.3] in the non-responders [p = 0.02]. Baseline UWSF was not associated with the response rate. Conclusion: In patients with pSS, the highest SGUS grade or a high histological focus score is associated with absence of a response to a single rituximab course after 6 months. Further studies, including more patients and different treatment strategies, are required to confirm the clinical utility of these potential biomarkers in pSS. [ABSTRACT FROM AUTHOR]

Objectives To determine whether B-cell markers (blood and minor salivary gland [SG] B-cell depletion [BCD], autoantibodies, B-cell-activating factor [BAFF]) are associated with clinical response to rituximab in patients with primary Sjögren's syndrome (pSS). Methods 45 patients with pSS were included: in group I, 14 received low-dose rituximab (two 375-mg/m 2 infusions) in an open-labelled study; in group II, 17 received full-dose rituximab (two 1000-mg infusions) and 14 received a placebo in a randomized, controlled study. The proportion of SG B cells was assessed using pixel-based software analyses of digitized double-immunostained (CD3/CD20) whole SGs. Response was defined at week-24 according to the Sjögren's Syndrome Responder Index (SSRI)-30. Results Response rate was 50% in both groups of rituximab-treated patients. Duration of blood BCD was similar in both groups despite the difference in rituximab dosage, and was highly correlated with residual serum-rituximab levels at week-16. SG B-cell dynamics mirrored blood B-cell levels, with a drastic decrease in SG B-cells at week-12 (group I), but an increase in ∼50% of patients in group II by week-24, in whom blood B cells had already returned. Duration of BCD was not associated with the clinical response, but responders had lower baseline proportions of SG B cells. Baseline serum BAFF level was correlated with the proportion of SG B-cells and other B-cell-activation markers, and was associated with the clinical response with higher levels in non-responders. Conclusions In pSS, half of the patients display an intense BAFF-driven B-cell activation and do not respond to a single course of rituximab. [ABSTRACT FROM AUTHOR]

Aim Rheumatoid arthritis ( RA) and periodontitis present many similar features. The benefits of anti-B lymphocyte therapy (rituximab) on reducing tissue resorption in RA prompted us to assess its potential efficacy on the periodontal status of patients with RA treated with rituximab. Materials and Methods Periodontal status was assessed in 21 subjects with RA, divided into two groups: Group I consisted in 11 subjects assessed before their first infusion of rituximab and again 6 months later. Five of them were also assessed for up to 4 years after their first rituximab infusion. The 10 subjects in group II had received more than two courses of two rituximab infusions at the time of periodontal assessment. Results Pocket depth and attachment loss were significantly decreased 6 months after treatment with rituximab in group I. The periodontal status of the five subjects from group I followed for up to 48 months after rituximab treatment was improved irrespective of the clinical parameter observed. Patients from group II had a better periodontal status than patients from group I before treatment with rituximab. Conclusions Anti-B lymphocyte therapy could be beneficial to improve periodontitis suggesting a major role of B cells in this disease. [ABSTRACT FROM AUTHOR]

Abstract: Primary Sjögren''s syndrome (pSS) is a chronic autoimmune systemic disease, characterized by a lymphoplasmocytic infiltration and a progressive destruction of salivary and lachrymal glands, leading to ocular and mouth dryness. T cells were originally considered to play the initiating role in the autoimmune process, while B cells were restricted to autoantibody production. However, recent years have seen growing evidence that the roles of B cells in pSS pathophysiology are multiple, and that these cells may actually play a central role in the development of the disease. B cells are over-stimulated and produce excessive amounts of immunoglobulins and various autoantibodies. Peripheral blood and salivary-gland B-cell subset distribution is altered, leading to the constitution of ectopic germinal centers where auto-reactive clones may escape tolerance checkpoints. B cells control T-cell activation by different means: B effector cells guide Th1 or Th2 differentiation, whereas regulatory B cells inhibit T-cell proliferation. Several B-cell specific cytokines, such as BAFF or Flt-3L, are instrumental in the occurrence of B-cell dysfunction. Chronic and excessive stimulation of B cells may lead to the development of lymphoma in pSS patients. Autoantibodies and blood B-cell subset analysis are major contributors of a clinical diagnosis of pSS. These considerations led to the development of B-cell depletion therapies for the management of pSS. Rituximab, a monoclonal antibody to CD20, is the best studied biologics in pSS, but other treatments hold promise, targeting for example CD22 or BAFF. Thus, during the last 20 years, the understanding of the multifaceted roles of B cells in pSS has revolutionized the management of this complex disease. [Copyright &y& Elsevier]

The potential predictive value of tumor bulk, genetic, and immunological variants in patients with low-grade non-Hodgkin's lymphoma to respond to treatment with rituximab (RTX) monotherapy was evaluated. Thus, the value of assessing the effect of 18-fluoro-desoxy- d-glucose (FDG) uptake on PET scan, polymorphisms in Fc gamma receptor (FcγR) IIIa-158, FcγRIIa-131, and C1qA-276 genes in predicting the response to treatment were evaluated in 50 low-grade non-Hodgkin's lymphoma patients. The influence of RTX pharmacokinetics, plasma levels of the B cell-activating factor (BAFF), and human antichimeric antibodies was also investigated. The therapeutic response was evaluated 10 weeks after treatment using revised Cheson's criteria. Lower maximal standardized uptake values (SUV) at baseline were predictive of complete response. FcγRIIIa-158 polymorphism was also associated with complete response to RTX confirming previous findings, whereas polymorphisms in the FcγRIIa-131 and C1qA-276 genes were not. Lower blood levels of RTX were observed in males, but the effectiveness of RTX in males and females was the same. BAFF was not detectable in plasma before or after treatment, and no patients developed human antichimeric antibodies. Low-grade non-Hodgkin's lymphoma patients with a low SUV at baseline and an FcγRIIIa-158 V/V genotype generally had a complete response to RTX. [ABSTRACT FROM AUTHOR]

The article discusses a pilot study which aimed to evaluate whether the levels of total B cells and of the different B-cell subsets could be an important determinant of abatacept efficacy. Included in the study were 22 patients who started abatacept for rheumatoid arthritis (RA) in Brest rheumatology department between Januar 2006 and April 2014. It suggests an association between the clinical efficacy of abatacept in RA patients with high B-cell and especially memory B-cell counts at baseline.

Major target antigens of ANCA-associated vasculitis (AAV) are myeloperoxidase (MPO) and proteinase 3 (PR3). High-affinity MPO- and PR3-ANCA immunoglobulins are produced by antigen-experienced, class-switched autoreactive B cells. To prevent autoreactivity, B cells are subjected to several self-tolerance checkpoints, from the early immature stages in the bone marrow (BM), collectively called "central tolerance", to late mature stages, collectively called "peripheral tolerance"; the latter was recently elucidated for autoreactive PR3+ B cells. Here we investigated central tolerance controlling immature PR3+B cells in the BM before their migration into the periphery as transitional B cells. We applied an established flow cytometry-based method using labeled recombinant PR3 (rPR3) to identify the PR3+B cells to compare the phenotype of PR3+B cells in paired samples of BM mononuclear cells (BMMC) and peripheral blood mononuclear cells (PBMC) of non-vasculitis controls (No-AAV), and PBMC of patients with PR3-ANCA-associated vasculitis (PR3-AAV). We observed that the proportion of PR3+B cells within BMMC was higher (median [IQR]; 1.98 % [1.77–2.75]) than within PBMC of No-AAV (0.9 % [0.63–1.44], p < 0.01 by paired comparison) and similar to their proportion within PBMC of patients with PR3-AAV (1.82 % [1.66–3.21]; p > 0.05). Within CD24++CD38++ B cells, the subset of B cell migrating from BM to the periphery, BMMC contained a greater proportion of PR3+B cells as compared to PBMC in No-AAV (3.35 % [1.99–4.92] versus 1.23 % [0.62–1.55], p < 0.01), showing different surface markers of maturation (i.e. higher proportion of CD27−CD10+ and lower expression of CD21, IgD, IgM). Importantly, we observed a significant decline of the PR3+ fraction from the immature subset (IgD−IgM+; 2.80 % [1.23–4.02]) to the early transitional subset (IgD+IgM+; 1.76 % [0.96–2.68], p < 0.01) in BMMC, while no significant reduction was observed between the early transitional of BMMC and the transitional compartment of PBMC in No-AAV (1.26 % [0.62–1.56], p > 0.05). In conclusion, to prevent PR3-related autoimmunity, autoreactive PR3+B cells pass a stringent selection in the BM, and their removal by central tolerance checkpoint activity occurs mainly between T1-like/immature to T2-like/early transitional B cells of BMMC. [Display omitted] • The proportion of proteinase 3 (PR3+) B cells within bone marrow mononuclear cells (BMMC) is higher than within peripheral blood MC (PBMC) of non-vasculitis controls (No-AAV), and similar to that one within PBMC of PR3-ANCA associated-vasculitis patients (PR3-AAV). • Within CD24++CD38++B cells, BMMC contains the greatest proportion of PR3+ B cells as compared to PBMC in No-AAV. • There is a significant decline of the PR3+ fraction from immature subset to early transitional subset within BMMC, representing the tolerance checkpoint contributing the most to PR3+ B cell removal in No-AAV. [ABSTRACT FROM AUTHOR]

While the involvement of IL-7/IL-7R axis in pSS has been described in relation to T cells, little is known about the contribution of this pathway in relationship with other immune cells, and its implication in autoimmunity. Using high-content multiomics data, we aimed at characterizing IL-7R expressing cells and the involvement of IL-7/IL-7R pathway in pSS pathophysiology. An IL-7 signature established using RNA-sequencing of human PBMCs incubated with IL-7 was applied to 304 pSS patients, and on RNA-Seq datasets from tissue biopsies. High-content immunophenotyping using flow and imaging mass cytometry was developed to characterize peripheral and in situ IL-7R expression. We identified a blood 4-gene IL-7 module (IKZF4 , KIAA0040 , PGAP1 and SOS1) associated with anti-SSA/Ro positiveness in patients as well as disease activity, and a tissue 5-gene IL-7 module (IL7R, PCED1B, TNFSF8, ADAM19, MYBL1) associated with infiltration severity. We confirmed expression of IL-7R on T cells subsets, and further observed upregulation of IL-7R on double-negative (DN) B cells, and especially DN2 B cells. IL-7R expression was increased in pSS compared to sicca patients with variations seen according to the degree of infiltration. When expressed, IL-7R was mainly found on epithelial cells, CD4+ and CD8+ T cells, switched memory B cells, DN B cells and M1 macrophages. This exhaustive characterization of the IL-7/IL-7R pathway in pSS pathophysiology established that two IL-7 gene modules discriminate pSS patients with a high IL-7 axis involvement. Their use could guide the implementation of an anti-IL-7R targeted therapy in a precision medicine approach. [Display omitted] • High-content multi-omics approach on primary Sjögren's syndrome molecular datasets. • 2 gene modules highlight IL-7 axis involvement and association with disease severity. • Upregulation of IL-7R expression on double negative B cells and innate immune cells. • Relevance of an anti-IL-7R therapy in targeting T and B-cell mediated autoimmunity. • IL-7 modules as easy-to-use markers for clinical practice to guide patient selection. [ABSTRACT FROM AUTHOR]

The conventional classification of mature B cells overlooks the diversity within IgD+ CD27− naïve B cells. Here, to identify distinct mature naïve B cells, we categorized CD45RBMEM55- B cells (NA RB-) and CD45RBMEM55+ B cells (NA RB+) and explore their function and localization in circulation and tissues under physiological and pathological conditions. NA RB+ B cells, found in secondary lymphoid organs, differentiate into plasmablasts and secrete IgM. In Sjögren's disease, their numbers decrease, and they show over-activation and abnormal migration, suggesting an adaptive disease response. NA RB+ B cells also appear in inflamed salivary glands, indicating involvement in local immune responses. These findings highlight the distinct roles of NA RB+ B cells in health and Sjögren's disease. [Display omitted] •.IgD+ CD45RBMEM55+ (NA RB+) and IgD+ CD45RBMEM55- B cells are phenotypically, transcriptionally, and functionally distinct. • NA RB+ B cells normally circulate between lymphoid organs but are recruited to inflamed salivary glands in Sjögren's Disease. • In Sjögren's Disease, NA RB+ B cells show an activated phenotype, altered migration, and are near ectopic lymphoid structures. [ABSTRACT FROM AUTHOR]

Abstract: One way for intravenous Ig (IVIg) to affect responses of the B cells might be to operate through their TLR7 and TLR9. We confirm the ability of TLR agonists to induce CD25 expression in B cells. For this to occur, sialylated Fc-gamma of IgG included in the IVIg preparation are required. As a result, IVIg suppresses TLR-induced production of the proinflammatory IL-6, but not that of the anti-inflammatory IL-10. That is, IVIg mimics the effects of the MyD88 inhibitor. Finally, as we previously showed that IVIg induces CD22 to recruit the inhibitory SHP-1, we established that this enzyme was also involved in IVIg-induced inhibition of TLR9 signaling. This is the first report to demonstrate such a mechanism underlying the negative impact of IVIg on B lymphocytes. [Copyright &y& Elsevier]

To link changes in the B-cell transcriptome from systemic lupus erythematosus (SLE) patients with those in their macroenvironment, including cellular and fluidic components. Analysis was performed on 363 patients and 508 controls, encompassing transcriptomics, metabolomics, and clinical data. B-cell and whole-blood transcriptomes were analysed using DESeq and GSEA. Plasma and urine metabolomics peak changes were quantified and annotated using Ceu Mass Mediator database. Common sources of variation were identified using MOFA integration analysis. Cellular macroenvironment was enriched in cytokines, stress responses, lipidic synthesis/mobility pathways and nucleotide degradation. B cells shared these pathways, except nucleotide degradation diverted to nucleotide salvage pathway, and distinct glycosylation, LPA receptors and Schlafen proteins. B cells showed metabolic changes shared with their macroenvironment and unique changes directly or indirectly induced by IFN-α signalling. This study underscores the importance of understanding the interplay between B cells and their macroenvironment in SLE pathology. • Nucleotide salvage pathway is specifically activated in SLE B cells. • Schlafen proteins and LPAR6 were specifically upregulated in SLE B cells. • Changes in B-cell glycosylation enzymes suggests a cell-specific role in SLE. • This is the first application of MOFA integration method in autoimmune diseases. [ABSTRACT FROM AUTHOR]

Abstract: Sjögren''s syndrome (SS) is an autoimmune exocrinopathy characterized by an epithelium injury with dense lymphocytic infiltrates, mainly composed of activated T and B cells. Present at the interface of genetic and environmental risk factors, DNA methylation is suspected to play a key role in SS. To clarify this point, global DNA methylation was tested within salivary gland epithelial cells (SGEC), peripheral T cells and B cells from SS patients. Global DNA methylation was reduced in SGEC from SS patients, while no difference was observed in T and B cells. SGEC demethylation in SS patients was associated with a 7-fold decrease in DNA methyl transferase (DNMT) 1 and a 2-fold increase in Gadd45-alpha expression. The other DNA methylation/demethylation partners, tested by real time PCR (DNMT3a/b, PCNA, UHRF1, MBD2, and MBD4), were not different. Interestingly, SGEC demethylation may be attributed in part to the infiltrating B cells as suspected in patients treated with anti-CD20 antibodies to deplete B cells. Such hypothesis was confirmed using co-culture experiments with human salivary gland cells and B cells. Furthermore, B cell-mediated DNA demethylation could be ascribed to an alteration of the PKC delta/ERK/DNMT1 pathway. As a consequence, part of the SGEC dysfunction in SS may be linked to epigenetic modifications, thus opening new therapeutic perspectives in SS. [Copyright &y& Elsevier]

To investigate serum IL-6 (sIL-6) levels during active disease, complete remission (CR), and relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and to explore the association of changes in sIL-6 with clinical outcomes. sIL-6 levels were measured at baseline and longitudinally over 18 months, in 78 patients with AAV enrolled in a randomized controlled trial comparing treatment with either rituximab (RTX) or cyclophosphamide (CYC)/azathioprine (AZA). Outcome variables included baseline clinical features, ANCA specificity, disease activity (active disease versus CR), time to relapse events, B cell repopulation, and ANCA titer increases. At baseline, sIL6 levels were detectable in 81% of patients; 73% (n = 57) of subjects were proteinase 3 (PR3)-ANCA positive, sIL-6 levels were higher in subjects with PR3-ANCAs and positively correlated with their levels (r s = 0.36, p < 0.01), but not with levels of myeloperoxidase (MPO)-ANCA (r s = −0.17, p = 0.47). Higher baseline sIL-6 levels were associated with PR3-ANCA positivity, fever, pulmonary nodules/cavities, conductive deafness, and absence of urinary red blood cell casts (p < 0.05). Baseline sIL6 levels did not predict CR at month 6 (p = 0.71), and the median sIL-6 level declined from baseline with induction therapy, regardless of CR achievement. An increase in sIL-6 during CR was a predictor for subsequent severe relapse in RTX-treated patients (hazard ratio (HR):7.24, p = 0.01), but not in CYC/AZA-treated patients (HR:0.62, p = 0.50). In contrast, a sIL-6 increase did not predict B cell repopulation or ANCA titer increase in either treatment arm (p > 0.05). At baseline, sIL-6 concentrations correlate with PR3-ANCA titers and are associated with specific clinical manifestations of AAV. Baseline sIL6 concentrations do not predict CR at 6 months, but the increase in sIL-6 concentrations during CR is associated with subsequent severe relapse among RTX-treated patients. Further investigation into the mechanistic role of IL6 in AAV might lead to identifying this pathway as a potential therapeutic target in this disease. Image 1 • IL-6 levels are increased at onset and decline with therapy in ANCA-associated vasculitis. • High IL-6 levels are associated with granulomatous manifestations and correlate with PR3-ANCA titers. • Increases in IL6 levels during complete remission are portend severe relapses in rituximab-treated patients. [ABSTRACT FROM AUTHOR]