Frequency of CD19+CD24hiCD38hi regulatory B cells is decreased in peripheral blood and synovial fluid of patients with juvenile idiopathic arthritis: a preliminary study

Children with extended oligoarticular and polyarticular juvenile idiopathic arthritis have alterations in B and T follicular cell subsets in peripheral blood and a cytokine profile sustaining B cell activation

OBJECTIVES

The main goal of this study was to characterise the frequency and phenotype of B, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells in peripheral blood and the cytokine environment present in circulation in children with extended oligoarticular juvenile idiopathic arthritis (extended oligo JIA) and polyarticular JIA (poly JIA) when compared with healthy controls, children with persistent oligoarticular JIA (persistent oligo JIA) and adult JIA patients.

METHODS

Blood samples were collected from 105 JIA patients (children and adults) and 50 age-matched healthy individuals. The frequency and phenotype of B, Tfh and Tfr cells were evaluated by flow cytometry. Serum levels of APRIL, BAFF, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-17A, IL-21, IL-22, IFN-γ, PD-1, PD-L1, sCD40L, CXCL13 and TNF were measured by multiplex bead-based immunoassay and/or ELISA in all groups included.

RESULTS

The frequency of B, Tfh and Tfr cells was similar between JIA patients and controls. Children with extended oligo JIA and poly JIA, but not persistent oligo JIA, had significantly lower frequencies of plasmablasts, regulatory T cells and higher levels of Th17-like Tfh cells in circulation when compared with controls. Furthermore, APRIL, BAFF, IL-6 and IL-17A serum levels were significantly higher in paediatric extended oligo JIA and poly JIA patients when compared with controls. These immunological alterations were not found in adult JIA patients in comparison to controls.

CONCLUSIONS

Our results suggest a potential role and/or activation profile of B and Th17-like Tfh cells in the pathogenesis of extended oligo JIA and poly JIA, but not persistent oligo JIA.

Regulatory B cells (Bregs) in Helicobacter pylori chronic infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is linked with a wide variety of diseases and was reported in more than half of the world's population. Chronic H. pylori infection and its final clinical outcome depend mainly on the bacterial virulence factors and its ability to manipulate and adapt to human immune responses. Bregs blood levels have been correlated with increased bacterial load and infection chronicity, especially Gram-negative bacterial infection. This study aimed to identify prevalence and virulence factors of chronic H. pylori infection among symptomatic Egyptian patients and to examine its possible correlation to levels of regulatory B cells (Bregs) in blood.

MATERIALS AND METHODS

Gastric biopsies and blood samples from each of 113 adult patients, who underwent upper endoscopy, were examined for the detection of H. pylori by culture and PCR methods. Conventional PCR was used to determine various virulent genes prevalence and association to clinical outcome. Flow cytometry was used to evaluate Bregs levels.

RESULTS

Helicobacter pylori prevalence was 49.1% (55/112). Regarding virulence genes incidence, flaA gene was detected in 73% (40/55), vir B11 in 56.4% (31/55), hopZ1 in 34.5% (19/55), hopZ2 in 89% (49/55), babA2 in 52.7% (29/55), dupA jhp917 in 61.8% (34/55), vacA m1/m2 in 70.9% (39/55), and vacA s1/s2 in 69% (38/55) strains. Bregs levels were significantly lower in H. pylori-infected patients (p = 0.013), while total leukocyte count (TLC) showed no significant differences.

CONCLUSION

Helicobacter pylori infection prevalence was almost 49%, and the infection was found to be related to inflammatory conditions as gastritis and ulcers rather than malignant transformations. Also, we found that CD24⁺ CD38⁺ B cells were downregulated in H. pylori-infected patients.

CD19+CD24highCD27+ B cell and interleukin 35 as potential biomarkers of disease activity in systemic lupus erythematosus patients

BACKGROUND

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that associates with aberrant activation of B lymphocytes and excessive autoantibodies. Interleukin 10 (IL-10)/interleukin 35 (IL-35) and IL-10/IL-35-producing regulatory B cells have been demonstrated to possess immunosuppressive functions during systemic lupus erythematosus. Here, we detected the proportion of CD19⁺CD24^highCD27⁺ B cells as well as IL-10 and IL-35 levels in peripheral blood of SLE patients and healthy individuals, and investigated their relations with clinical features of SLE.

METHODS

41 SLE patients and 25 healthy controls were recruited. The patients were divided into groups based on SLEDAI score, anti-dsDNA antibody, rash, nephritis and hematological disorder. Flow cytometry was used to detect the proportion of CD24^hiCD27⁺ B cells. ELISA was used to detect serum levels of IL-10 and IL-35.

RESULTS

Our results showed that the CD19⁺CD24^highCD27⁺ B population was decreased in active SLE patients, and anti-correlated with the disease activity. Of note, we found significant increase of IL-10 and decrease of IL-35 in SLE patients with disease activity score > 4, lupus nephritis or hematological disorders compared to those without related clinical features.

CONCLUSIONS

Reduced CD19⁺CD24^highCD27⁺ B cells expression may be involved in the pathogenesis of SLE. Moreover, we supposed that IL-35 instead of IL-10 played a crucial role in immune regulation during SLE disease.

Intracellular Levels of IL-10 and STAT3 in Patients with Chronic Lymphocytic Leukemia

Objective: Chronic Lymphocytic Leukemia (CLL) is characterized by the accumulation of CD5+CD19+ B cells in the bone marrow and peripheral blood. Recent studies indicated that expression of IL-10, AID and mir-155 which are regulated by STAT3 are increased in CLL patients. CD5+CD19+ regulator B (Breg) cells secrete IL-10 and suppress the immune system. While the CLL cells show similar immunophenotypic properties to Breg cells, they are also thought to be functionally similar. In this study, STAT3 and IL-10 levels of CLL patients were investigated. Methods: Peripheral blood samples obtained from patients (n:24) and healthy controls (n:14). Peripheral blood mononuclear cells were cultured for 48 hours in the presence and absence of CpG for IL-10 expression and cultured with and without PMA for STAT3 expression. IL-10 and STAT3 expression were analyzed with anti-CD5, anti-CD19, anti-CD38, anti-STAT3 and anti-IL-10 monoclonal antibodies by using flow cytometry. Results: Compared to healthy subjects, increased IL-10+, IL-10+CD19+, STAT3+CD19+ were obtained in lymphocyte population of patients. Increased IL-10 was showed CD19+ B cells of CLL patients. Our results showed that IL-10 levels had no significant difference between CD5+CD19+ cells, whereas STAT3 levels were found lower in patient compared to healthy controls. Conclusion: These results made us thought that the levels of IL-10 and STAT3 expression in CLL B cells is clearly different from normal B lymphocytes might have a role in the biology of CLL. It is believed that the presented data will contribute to the studies that scrutinize the similarity of CLL cells to Breg cells.

Defining Growing Pains: A Scoping Review

BACKGROUND AND OBJECTIVES

Up to one third of children may be diagnosed with growing pains, but considerable uncertainty surrounds how to make this diagnosis. The objective of this study was to detail the definitions of growing pains in the medical literature.

METHODS

Scoping review with 8 electronic databases and 6 diagnostic classification systems searched from their inception to January 2021. The study selection included peer-reviewed articles or theses referring to "growing pain(s)" or "growth pain(s)" in relation to children or adolescents. Data extraction was performed independently by 2 reviewers.

RESULTS

We included 145 studies and 2 diagnostic systems (ICD-10 and SNOMED). Definition characteristics were grouped into 8 categories: pain location, age of onset, pain pattern, pain trajectory, pain types and risk factors, relationship to activity, severity and functional impact, and physical examination and investigations. There was extremely poor consensus between studies as to the basis for a diagnosis of growing pains. The most consistent component was lower limb pain, which was mentioned in 50% of sources. Pain in the evening or night (48%), episodic or recurrent course (42%), normal physical assessment (35%), and bilateral pain (31%) were the only other components to be mentioned in more than 30% of articles. Notably, more than 80% of studies made no reference to age of onset in their definition, and 93% did not refer to growth. Limitations of this study are that the included studies were not specifically designed to define growing pains.

CONCLUSIONS

There is no clarity in the medical research literature regarding what defines growing pain. Clinicians should be wary of relying on the diagnosis to direct treatment decisions.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Interleukin-35 promotes Breg expansion and interleukin-10 production in CD19+ B cells in patients with ankylosing spondylitis

OBJECTIVE

IL-35 is a potent immunosuppressive and anti-inflammatory cytokine, consisting of a p35 subunit and an Epstein-Barr virus-induced gene 3 (EBI3) subunit, which suppresses CD4⁺ effector T cell proliferation and promotes regulatory T cell (Treg) expansion. However, the effects of IL-35 on regulatory B cells (Bregs) in ankylosing spondylitis (AS) have not been explored. The present study aimed (i) to measure serum IL-35 levels and the percentages of Bregs in the peripheral blood of patients with AS and (ii) to explore their relationships in the pathogenesis of AS.

METHODS

A total of 77 patients with AS (AS group), including 47 inactive AS and 30 active AS cases, and 59 healthy controls (HCs) were enrolled into this study. The serum levels of IL-35 and IL-10 were detected by ELISA, and the mRNA levels of p35 and EBI3 were measured by RT-qPCR. The percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs and IL-35 receptor (IL-12Rβ2, IL-27Rα and gp130), IL-10, p-STAT1, p-STAT3, and p-STAT4 in CD19⁺ B cells were detected by flow cytometry. The correlations between IL-35 levels and percentages of Bregs were analyzed by determining Pearson's correlation coefficient. The effect of IL-35 on Bregs was determined by mix-culture of recombinant (r) IL-35 with peripheral blood mononuclear cells (PBMCs).

RESULTS

The serum IL-35 and IL-10 levels, p35 and EBI3 mRNA levels, and the percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs were significantly lower in AS patients than those in HCs. In addition, the percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs in active AS patients were significantly lower than those in inactive AS patients. The serum IL-35 levels were positively correlated with the percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs in AS patients. IL-12Rβ2 and IL-27Rα, but not gp130 subunit, were expressed in CD19⁺ B cells in AS patients. RIL-35 could effectively promote CD19⁺CD24^hiCD38^hi Breg expansion and IL-10 production. Meanwhile, rIL-35 also promoted the expression of IL-12Rβ2 and IL-27Rα and the phosphorylation of STAT1 and STAT3 in CD19⁺ B cells.

CONCLUSION

These results demonstrated that reduced IL-35 production may be associated with Bregs defects in AS patients. RIL-35 induced the proliferation of CD19⁺CD24^hiCD38^hi Bregs and IL-10 production, suggesting that IL-35 may serve as a reference for further investigation to develop novel treatments for AS. Key Points • Our study investigated the effects of IL-35 on Bregs in AS patients. • We found the serum IL-35, IL-10 levels, and the percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs were significantly lower in AS patients. • The serum IL-35 levels were positively correlated with the percentages of CD19⁺CD24^hiCD38^hi and CD19⁺CD24^hiCD27⁺ Bregs in AS patients. • Recombinant IL-35 could effectively promote CD19⁺CD24^hiCD38^hi Breg expansion and IL-10 production.

Role of rare immune cells in common variable immunodeficiency

Common variable immunodeficiency disorder (CVID) is a heterogeneous disorder and the most common symptomatic antibody deficiency disease characterized with hypogammaglobulinemia and a broad range of clinical manifestations. Multiple genetic, epigenetic, and immunological defects are involved in the pathogenesis of CVID. These immunological defects include abnormalities in the number and/or function of B lymphocytes, T lymphocytes, and other rare immune cells. Although some immune cells have a relatively lower proportion among total immune subsets in the human body, they could have important roles in the pathogenesis of immunological disorders like CVID. To the best of our knowledge, this is the first review that described the role of rare immune cells in the pathogenesis and clinical presentations of CVID.

Hyaluronidase treatment of synovial fluid is required for accurate detection of inflammatory cells and soluble mediators

BACKGROUND

Synovial fluid (SF) is commonly used for diagnostic and research purposes, as it is believed to reflect the local inflammatory environment. Owing to its complex composition and especially the presence of hyaluronic acid, SF is usually viscous and non-homogeneous. In this study, we investigated the importance of homogenization of the total SF sample before subsequent analysis.

METHODS

SF was obtained from the knee of 29 arthritis patients (26 rheumatoid arthritis, 2 osteoarthritis, and 1 juvenile idiopathic arthritis patient) as part of standard clinical care. Synovial fluid was either treated with hyaluronidase as a whole or after aliquoting to determine whether the concentration of soluble mediators is evenly distributed in the viscous synovial fluid. Cytokine and IgG levels were measured by ELISA or Luminex and a total of seven fatty acid and oxylipin levels were determined using LC-MS/MS in all aliquots. For cell analysis, synovial fluid was first centrifuged and the pellet was separated from the fluid. The fluid was subsequently treated with hyaluronidase and centrifuged to isolate remaining cells. Cell numbers and phenotype were determined using flow cytometry.

RESULTS

In all patients, there was less variation in IgG, 17-HDHA, leukotriene B₄ (LTB₄), and prostaglandin E₂ (PGE₂) levels when homogenization was performed before aliquoting the SF sample. There was no difference in variation for cytokines, 15-HETE, and fatty acids arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Between 0.8 and 70% of immune cells (median 5%) remained in suspension and were missing in subsequent analyses when the cells were isolated from untreated SF. This percentage was higher for T and B cells: 7-85% (median 22%) and 7-88% (median 23 %), respectively.

CONCLUSIONS

Homogenization of the entire SF sample leads to less variability in IgG and oxylipin levels and prevents erroneous conclusions based on incomplete isolation of synovial fluid cells.

Levels and Clinical Significance of Regulatory B Cells and T Cells in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy, whose immunological mechanisms are still partially uncovered. Regulatory B cells (Bregs) and CD4+ regulatory T cells (Tregs) are subgroups of immunoregulatory cells involved in modulating autoimmunity, inflammation, and transplantation reactions. Herein, by studying the number and function of Breg and Treg cell subsets in patients with AML, we explored their potential role in the pathogenesis of AML. Newly diagnosed AML patients, AML patients in complete remission, and healthy controls were enrolled. Flow cytometry was used to detect percentages of Bregs and Tregs. ELISA was conducted to detect IL-10 and TGF-β in plasma. The mRNA levels of IL-10 and Foxp3 were measured with RT-qPCR. The relationship of Bregs and Tregs with the clinicopathological parameters was analyzed. There was a significant reduction in the frequencies of Bregs and an increase of Tregs in newly diagnosed AML patients compared with healthy controls. Meanwhile, patients in complete remission exhibited levels of Bregs and Tregs comparable to healthy controls. Furthermore, compared with healthy controls and AML patients in complete remission, newly diagnosed AML patients had increased plasma IL-10 but reduced TGF-β. IL-10 and Foxp3 mRNA levels were upregulated in the newly diagnosed AML patients. However, there were no significant differences in IL-10 and Foxp3 mRNA levels between patients in complete remission and healthy controls. Bregs and Tregs have abnormal distribution in AML patients, suggesting that they might play an important role in regulating immune responses in AML.

Innate Lymphocytes in Inflammatory Arthritis

Inflammatory arthritis (IA) refers to a group of chronic diseases, including rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), and other spondyloarthritis (SpA). IA is characterized by autoimmune-mediated joint inflammation and is associated with inflammatory cytokine networks. Innate lymphocytes, including innate-like lymphocytes (ILLs) expressing T or B cell receptors and innate lymphoid cells (ILCs), play important roles in the initiation of host immune responses against self-antigens and rapidly produce large amounts of cytokines upon stimulation. TNF (Tumor Necrosis Factor)-α, IFN (Interferon)-γ, Th2-related cytokines (IL-4, IL-9, IL-10, and IL-13), IL-17A, IL-22, and GM-CSF are involved in IA and are secreted by ILLs and ILCs. In this review, we focus on the current knowledge of ILL and ILC phenotypes, cytokine production and functions in IA. A better understanding of the roles of ILLs and ILCs in IA initiation and development will ultimately provide insights into developing effective strategies for the clinical treatment of IA patients.

HSP70, a Novel Regulatory Molecule in B Cell-Mediated Suppression of Autoimmune Diseases

B cells have recently emerged as playing regulatory role in autoimmune diseases. We have previously demonstrated that human peripheral blood CD19⁺CD24^hiCD27⁺ B cells have regulatory function both in healthy donors and in patients with autoimmune disease. However, the mechanism of this regulation is still not fully understood. In this study, microarrays were utilized to compare gene expression of CD19⁺CD24^hiCD27⁺ B cells (regulatory B cells, Bregs) with CD19⁺CD24^loCD27^- B cells (non-Bregs) in human peripheral blood. We found that heat shock protein 70 (HSP70) expression was significantly upregulated in Bregs. In vitro studies explored that HSP70 inhibition impaired the regulatory function of peripheral blood Bregs. In mouse models of autoimmune disease, using HSP70-deficient mice or HSP70 inhibitors, Bregs suppressed effector cells and rescued disease-associated phenotypes that were dependent on HSP70. Mechanistically, Bregs secreted HSP70, directly suppressing effector cells, such as T effect cells. These findings reveal that HSP70 is a novel factor that modulates Breg function and suggest that enhancing Breg-mediated production of HSP70 could be a viable therapy for autoimmune disease.

Novel biomarkers for early targeted and individualized treatment in Juvenile Idiopathic Arthritis

Background

The programmed cell death protein-1 (PD-1) and its ligands (PD-L 1 and 2) suppress immune responses, thus promoting self-tolerance. Among the immunomodulatory cells, acting through the PD-1 pathway, are the B-regulatory cells (Bregs). The role of the PD-1 pathway in Juvenile Idiopathic Arthritis (JIA) has not been adequately studied.

Aims of the study

To investigate the immunophenotypic profile of T- and B-cells and the activity of the PD-1 pathway in JIA patients. More specifically, we will examine the levels of: a) the soluble form of PD-1 (sPD-1), b) Bregs; and the expression levels of: c) PD-1 on CD4+ and CD8+ T-cells, d) PD-L1 on Bregs and CD19+ B-cells, in blood and synovial fluid samples, at various stages of the disease (onset, relapse, remission, on or off treatment). The above biomarkers will be investigated for correlation with JIA activity.

Methods

A case-control study of JIA patients (expected number: 60) and healthy controls (n: 20). Total expected number of samples: 100 of peripheral blood, 120 of serum (solely for soluble markers) and 60 of synovial fluid. The patients' demographic data and treatment will be recorded. JIA will be classified according to the ILAR and the recently proposed PReS/PRINTO criteria. JIA activity will be assessed using the JADAS-10 tool. The biomarkers will be determined using multiparametric-polychromatic flow cytometry (quintuple fluorescence protocol) and immunoenzymatic assay ELISA.

Anticipated benefits

Further elucidation of the immunophenotypic expression and variation of the abovementioned molecules and cells during active inflammation and remission in JIA. Thereby, the present study is expected to contribute to: a) the modern research and understanding of the confirmed immune dysfunction at the cellular level, which leads to the development of serious autoimmune diseases in childhood, such as JIA, and b) the search for biomarkers that could be targets of early "intelligent" treatment and thereby could support the implementation of precision-medicine. The early diagnosis and targeted treatment of JIA are crucial for the maintenance of normal physical functioning and the psychosocial balance of the still growing adolescent/child.

The role of B regulatory (B10) cells in inflammatory disorders and their potential as therapeutic targets

Over the past decade, studies have identified subset of B cells, which play suppressive functions in additions to the conventional functions of B cells: antigen processing and presentation, activation of T cells and antibody productions. Because of their regulatory function, they were named as B regulatory cells (Bregs). Bregs restrict the severity of autoimmune disorders in animal disease models such as experimental autoimmune myocarditis (EAM), experimental autoimmune encephalitis (EAE), and collagen-induced arthritis (CIA) but can contribute to the development of infection and cancer. In humans, the roles of B regulatory cells in autoimmune diseases have not been clearly established because of the inconsistent findings from many researchers. This is believed to arise from the speculated fact that Bregs lack specific marker, which can be used to identify and characterize them in human diseases. The CD19⁺CD24^hiCD38^hiCD1d^hiB cells have been associated with the regulatory function. Available evidences highlight the relevance of increasing IL-10-producing B cells in autoimmune diseases and the possibility of serving as new therapeutic targets in inflammatory disorders. This review empanels the functions of Bregs in autoimmune diseases in both human and animal models, and further evaluates the possibility of Bregs as therapeutic targets in inflammatory disorders. Consequently, this might help identify possible research gaps, which need to be clarified as researchers speculate the possibility of targeting some subsets of Bregs in the treatment of inflammatory disorders.

Low frequency of IL-10-producing B cells and high density of ILC2s contribute to the pathological process in Graves' disease, which may be related to elevated-TRAb levels

IL-10-producing B Cells (B10) is a functionally defined regulatory B-cell subset. It plays an important role in the control of inflammation and autoimmune diseases, although it is present at low numbers in peripheral blood. Graves' disease is an autoimmune disease characterized by the production of autoantibodies such as TRAb. ILC2s maintains Th2 polarization state by producing type-II cytokines. It is not clear whether the level of autoantibody is related to ILC2s and B10 cells in Graves' disease. In this study, we analyzed the frequencies of B10, Treg cells and ILC2s, as well as the expression of related cytokines in peripheral blood from patients with Graves' disease and evaluated the correlation between B10 cell numbers and autoantibodies level. Our data showed that the frequency of B10 or Treg cells was significantly decreased in peripheral blood mononuclear cells from Graves' disease patients, while the percentage of ILC2s cells was increased; the levels of cytokine IL-5, IL-13 and related transcription factor RORα were up-regulated. Autoantibodies analysis also showed that high level of TRAb was accompanied by low rates of B10 cells in patients, there was a negative correlation trend. In addition, the analytical data from mouse disease models also showed similar results. It indicates that B10 cells may affect the production of TRAb by negative regulation of Th2 cells, while ILC2s can promote the production of autoantibodies such as TRAb by maintaining the dominant response state of Th2 cells.

B Cells as a Therapeutic Target in Paediatric Rheumatic Disease

B cells carry out a central role in the pathogenesis of autoimmune disease. In addition to the production of autoantibodies, B cells can contribute to disease development by presenting autoantigens to autoreactive T cells and by secreting pro-inflammatory cytokines and chemokines which leads to the amplification of the inflammatory response. Targeting both the antibody-dependent and antibody-independent function of B cells in adult rheumatic disease has led to the advent of B cell targeted therapies in clinical practice. To date, whether B cell depletion could also be utilized for the treatment of pediatric disease is relatively under explored. In this review, we will discuss the role of B cells in the pathogenesis of the pediatric rheumatic diseases Juvenile Idiopathic Arthritis (JIA), Juvenile Systemic Lupus Erythematosus (JSLE) and Juvenile Dermatomyositis (JDM). We will also explore the rationale behind the use of B cell-targeted therapies in pediatric rheumatic disease by highlighting new case studies that points to their efficacy in JIA, JSLE, and JDM.