IgE Inhibits Toll-like Receptor 7- and Toll-like Receptor 9-Mediated Expression of Interferon-α by Plasmacytoid Dendritic Cells in Patients With Systemic Lupus Erythematosus

The influence and therapeutic effect of microbiota in systemic lupus erythematosus

Systemic erythematosus lupus (SLE) is an autoimmune disease involving multiple organs that poses a serious risk to the health and life of patients. A growing number of studies have shown that commensals from different parts of the body and exogenous pathogens are involved in SLE progression, causing barrier disruption and immune dysregulation through multiple mechanisms. However, they sometimes alleviate the symptoms of SLE. Many factors, such as genetic susceptibility, metabolism, impaired barriers, food, and sex hormones, are involved in SLE, and the microbiota drives the development of SLE either by depending on or interacting with these factors. Among these, the crosstalk between genetic susceptibility, metabolism, and microbiota is a hot topic of research and is expected to lay the groundwork for the amelioration of the mechanism, diagnosis, and treatment of SLE. Furthermore, the microbiota has great potential for the treatment of SLE. Ideally, personalised therapeutic approaches should be developed in combination with more specific diagnostic methods. Herein, we provide a comprehensive overview of the role and mechanism of microbiota in lupus of the intestine, oral cavity, skin, and kidney, as well as the therapeutic potential of the microbiota.

Anti-dsDNA IgE induces IL-4 production from basophils, potentially involved in B-cell differentiation in systemic lupus erythematosus

OBJECTIVES

Recently, the involvement of basophils and IgE-type autoantibodies in the pathogenesis of SLE has been elucidated using mouse models; however, few studies have been conducted in humans. In this study, the role of basophils and anti-double-stranded DNA (dsDNA) IgE in SLE was examined using human samples.

METHODS

The correlation between disease activity and serum levels of anti-dsDNA IgE in SLE was evaluated using enzyme-linked immunosorbent assay. Cytokines produced by IgE-stimulated basophils from healthy subjects were assessed using RNA sequences. The interaction of basophils and B cells to promote B cell differentiation was investigated using a co-culture system. The ability of basophils from patients with SLE with anti-dsDNA IgE to create cytokines that may be involved in B cell differentiation in response to dsDNA was examined using real-time PCR.

RESULTS

Anti-dsDNA IgE levels in the serum of patients with SLE correlated with disease activity. Healthy donor basophils produced IL-3, IL-4 and TGF-β1 after anti-IgE stimulation. Co-culture of B cells with anti-IgE-stimulated basophils increased plasmablasts which were cancelled by neutralizing IL-4. After encountering the antigen, basophils released IL-4 more quickly than follicular helper T cells. Basophils isolated from patients with anti-dsDNA IgE promoted IL-4 expression by adding dsDNA.

CONCLUSIONS

These results suggest that basophils contribute to the pathogenesis of SLE by promoting B cell differentiation via dsDNA-specific IgE in patients similar to the process described in mouse models.

High serum immunoglobulin D levels in systemic lupus erythematosus: more to be found?

INTRODUCTION

Many studies have shown that serum immunoglobulin D (IgD) is usually increased in autoimmune diseases. The potential role of IgD in systemic lupus erythematosus (SLE) is still unclear. Our study aimed to compare the serum IgD levels of SLE with different population and to evaluate the relationship between serum IgD and SLE.

METHODS

Fifty SLE patients, 40 non-SLE chronic kidney disease (CKD) patients, and 50 healthy volunteers were enrolled in this study. Serum IgD levels were analyzed by ELISA assay and compared between groups. The correlation of serum IgD and SLE disease were evaluated. The ability of serum IgD to predict SLE was analyzed by graphing receiver operating characteristic curves.

RESULTS

Serum IgD levels were significantly higher in SLE patients compared to non-SLE CKD and healthy controls (7436.1 ± 5862.1 vs. 4517.8 ± 5255.2 vs. 4180.4 ± 4881 ng/mL, p = 0.01, p = 0.002, respectively), and in patients with high SLE Disease Activity Index (SLEDAI) scores compared with those with low scores (8572.9 ± 5968.7 vs. 5020.4 ± 4972.5 ng/mL, p = 0.044). High level of inflammatory cytokines and decreased circulating basophil counts were found in SLE patients (p < 0.05). No correlations was identified between serum IgD levels and SLEDAI scores (p > 0.05). Serum IgD was noninferior to IgG or IgE in discriminating SLE with an area under the curve of 0.672 (95% CI, 0.59-0.75).

CONCLUSIONS

Serum IgD levels are significantly elevated in SLE patients with high SLEDAI scores. Simultaneous occurrence of increased inflammatory cytokines and decreased basophil counts highlights the potential role of IgD-targets interaction in SLE pathogenesis. Key points • Total serum IgD levels were elevated in SLE patients. • High IgD levels were significantly higher in SLE patients with high SLEDAI scores. • The ability of serum IgD was equivalent to IgG or IgE in discriminating SLE from CKD and healthy adult.

Self-reactive IgE and anti-IgE therapy in autoimmune diseases

Growing evidence indicates the pathogenic role of autoreactive IgE in autoimmune diseases. Incidence of autoimmune and allergic diseases in the industrialized countries is consistently icreasing, thus leading to concerted efforts to comprehend the regulation of IgE-mediated mechanisms. The first reports of a presence of IgE autoantibodies in patients with autoimmune diseases have been published a long time ago, and it is now recognized that self-reactive IgE can mediate inflammatory response in bullous pemhigoid, systemic lupus erythematosus, chronic urticaria, and atopic dermatitis. The advances in understanding the pathomechanisms of these disorders brought to a successful use of anti-IgE strategies in their management. The present review discusses the current state of knowledge on the IgE-mediated autoimmunity and anti-IgE treatment, and pave the way for further exploration of the subject.

Regulatory T cells and immunoglobulin E: A new therapeutic link for autoimmunity?

Autoimmune diseases have a prevalence of approximately 7 to 9% and are classified as either organ-specific diseases, including type I diabetes, multiple sclerosis, inflammatory bowel disease and myasthenia gravis, or systemic diseases, including systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome. While many advancements have been made in understanding of the mechanisms of autoimmune disease, including the nature of self-tolerance and its breakdown, there remain unmet needs in terms of effective and highly targeted treatments. T regulatory cells (Tregs) are key mediators of peripheral tolerance and are implicated in many autoimmune diseases, either as a result of reduced numbers or altered function. Tregs may be broadly divided into those generated in the thymus (tTregs) and those generated in the periphery (pTregs). Tregs target many different immune cell subsets and tissues to suppress excessive inflammation and to support tissue repair and homeostasis: there is a fine balance between Treg cell stability and the plasticity that is required to adjust Tregs' regulatory purposes to particular immune responses. The central role of immunoglobulin E (IgE) in allergic disease is well recognized, and it is becoming increasingly apparent that this immunoglobulin also has a wider role encompassing other diseases including autoimmune disease. Anti-IgE treatment restores the capacity of plasmacytoid dendritic cells (pDCs) impaired by IgE- high-affinity IgE receptor (FcεR1) cross-linking to induce Tregs in vitro in atopic patients. The finding that anti-IgE therapy restores Treg cell homeostasis, and that this mechanism is associated with clinical improvement in asthma and chronic spontaneous urticaria suggests that anti-IgE therapy may also have a potential role in the treatment of autoimmune diseases in which Tregs are involved.

Inverse association between autoimmunity and elevated IgE among childhood vitiligo

BACKGROUND

Multiple factors contribute to the pathogenesis of childhood vitiligo. The characteristics in a different population under modified environmental factors need further reevaluation. The present study aimed to reevaluate the clinical and laboratory features in consequent children vitiligo patients.

MATERIALS AND METHODS

We retrospectively reviewed consequent children vitiligo patients who visited Children's Hospital of Fudan University (National Children's Medical Center of China). The prevalence rate of thyroid dysfunction, circulating autoantibodies, serum IgE, and associated factors were analyzed.

RESULTS

A total of 244 consequent vitiligo patients were included, of which 20 children had personal autoimmune history. Two hundred and nineteen of the 244 patients took a thyroid function test, and the abnormal rate was only 3.7% (8/219). The elevated IgE rate was 31.7% (52/157), the antinuclear antibody (ANA) positive rate was 9.8% (12/123), and the extractable nuclear antigens (ENA) positive rate was 4.4% (4/91), respectively. The elevated IgE was significantly associated with atopic disease history and male gender. Of note, personal autoimmune history showed a significant inverse association with elevated IgE.

CONCLUSIONS

Thyroid dysfunction rate was low among the consequent children vitiligo patients. Personal autoimmune history was inversely associated with elevated IgE. Various clinical characteristics and pathogenesis might contribute to different long-term outcomes of vitiligo.

Fc receptors gone wrong: A comprehensive review of their roles in autoimmune and inflammatory diseases

Systemic autoimmune and inflammatory diseases have a complex and only partially known pathophysiology with various abnormalities involving all the components of the immune system. Among these components, antibodies, and especially autoantibodies are key elements contributing to autoimmunity. The interaction of antibody fragment crystallisable (Fc) and several distinct receptors, namely Fc receptors (FcRs), have gained much attention during the recent years, with possible major therapeutic perspectives for the future. The aim of this review is to comprehensively describe the known roles for FcRs (activating and inhibitory FcγRs, neonatal FcR [FcRn], FcαRI, FcεRs, Ro52/tripartite motif containing 21 [Ro52/TRIM21], FcδR, and the novel Fc receptor-like [FcRL] family) in systemic autoimmune and inflammatory disorders, namely rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus, systemic sclerosis, idiopathic inflammatory myopathies, mixed connective tissue disease, Crohn's disease, ulcerative colitis, immunoglobulin (Ig) A vasculitis, Behçet's disease, Kawasaki disease, IgG4-related disease, immune thrombocytopenia, autoimmune hemolytic anemia, antiphospholipid syndrome and heparin-induced thrombocytopenia.

IgE in the Pathogenesis of SLE: From Pathogenic Role to Therapeutic Target

Systemic lupus erythematosus (SLE) is a multifactorial chronic autoimmune disease, marked by the presence of autoantibodies to nuclear antigens belonging to different isotype classes. For several years, IgE antibodies have been incriminated in the development of allergic diseases and parasitic infections and different anti-IgE therapies have been developed to encounter the pathogenic role of IgE in these pathologies. Recently, multiple studies showed the presence of elevated total IgE levels and demonstrated a pathogenic role of autoreactive IgE in SLE. This review aims to summarize the findings incriminating IgE and autoreactive IgE in the pathophysiology of SLE, to describe their functional outcomes on their targeted cells as well as to discuss different IgE-related therapeutic modalities that emerged and that may be beneficial for SLE patient care.

Toll-like Receptors as Potential Therapeutic Targets in Kidney Diseases

Toll-like Receptors (TLRs) are members of pattern recognition receptors and serve a pivotal role in host immunity. TLRs response to pathogen-associated molecular patterns encoded by pathogens or damage-associated molecular patterns released by dying cells, initiating an inflammatory cascade, where both beneficial and detrimental effects can be exerted. Accumulated evidence has revealed that TLRs are closely associated with various kidney diseases but their roles are still not well understood. This review updated evidence on the roles of TLRs in the pathogenesis of kidney diseases including urinary tract infection, glomerulonephritis, acute kidney injury, transplant allograft dysfunction and chronic kidney diseases.

IgE-Mediated Immune Response and Antibody-Mediated Rejection

BACKGROUND AND OBJECTIVES

Active antibody-mediated rejection is the main cause of kidney transplant loss, sharing with SLE the alloimmune response and the systemic activation of the IFN-α pathway. IgE-mediated immune response plays a key role in the development of SLE nephritis and is associated with IFN-α secretion. The aim of our study was to investigate IgE-mediated immune response in antibody-mediated rejection.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a cross-sectional study of 56 biopsy-proven antibody-mediated rejection study participants, 80 recipients with normal graft function/histology (control), 16 study participants with interstitial fibrosis/tubular atrophy, and six participants with SLE. We evaluated graft IgE deposition, tryptase (a mast cell marker), and CD203 (a specific marker of activated basophils) by immunofluorescence/confocal microscopy. In addition, we measured serum concentration of human myxovirus resistance protein 1, an IFN-α-induced protein, and anti-HLA IgE.

RESULTS

We observed a significantly higher IgE deposition in tubules and glomeruli in antibody-mediated rejection (1766±79 pixels) and SLE (1495±43 pixels) compared with interstitial fibrosis/tubular atrophy (582±122 pixels) and control (253±50 pixels). Patients with antibody-mediated rejection, but not control patients and patients with interstitial fibrosis/tubular atrophy, presented circulating anti-HLA IgE antibodies, although with a low mean fluorescence intensity. In addition, immunofluorescence revealed the presence of both mast cells and activated basophils in antibody-mediated rejection but not in control and interstitial fibrosis/tubular atrophy. The concentration of circulating basophils was significantly higher in antibody-mediated rejection compared with control and interstitial fibrosis/tubular atrophy. MxA serum levels were significantly higher in antibody-mediated rejection compared with control and correlated with the extent of IgE deposition.

CONCLUSIONS

Our data suggest that IgE deposition and the subsequent recruitment of basophils and mast cells within the kidney transplant might play a role in antibody-mediated rejection.

Type I Interferons in Autoimmune Disease

Type I interferons, which make up the first cytokine family to be described and are the essential mediators of antivirus host defense, have emerged as central elements in the immunopathology of systemic autoimmune diseases, with systemic lupus erythematosus as the prototype. Lessons from investigation of interferon regulation following virus infection can be applied to lupus, with the conclusion that sustained production of type I interferon shifts nearly all components of the immune system toward pathologic functions that result in tissue damage and disease. We review recent data, mainly from studies of patients with systemic lupus erythematosus, that provide new insights into the mechanisms of induction and the immunologic consequences of chronic activation of the type I interferon pathway. Current concepts implicate endogenous nucleic acids, driving both cytosolic sensors and endosomal Toll-like receptors, in interferon pathway activation and suggest targets for development of novel therapeutics that may restore the immune system to health.

Toll-like receptors in lupus nephritis

The pathogenesis of systemic autoimmune diseases such as systemic lupus erythematosus (SLE) is based on the loss of self-tolerance against ubiquitous autoantigens involving all mechanisms of adaptive immunity. However, data accumulating over the last decade imply an important role also for numerous elements of innate immunity, namely the Toll-like receptors in the pathogenesis of SLE. Here we discuss their role in the most common organ complication of SLE, i.e. lupus nephritis. We summarize experimental and clinical data on the expression and functional contribution of the Toll-like receptors in immune complex glomerulonephritis, and intrarenal inflammation. Based on these discoveries Toll-like receptors are evolving as therapeutic targets for the treatment of SLE and lupus nephritis.

IgE in lupus pathogenesis: Friends or foes?

Systemic lupus erythematosus (SLE) is a complex autoimmune disease involving multiple immunological pathways. Recently, several studies have suggested an implication of Immunoglobulin E (IgE) in the pathophysiology of SLE. In the Lyn^-/- and FcγIIB^-/-.Yaa lupus mouse models, autoreactive IgE activate basophils, and promote a Th2 environment with, subsequently, production of autoantibodies by plasma cells. Autoreactive IgE has been also shown to play a role in the activation of human plasmacytoid dendritic cells (pDCs), in synergy with IgG, which results in an increase of interferon-alpha (IFN-α) production. In contrast, a protective effect of total non-autoreactive IgE has also been suggested, through a decreased ability of FcεRI-triggered pDCs to secrete IFN-α. This review summarizes in a comprehensive manner the emerging recent literature in the field, and propose new concepts to reconcile the observations.

Toll-like receptor-9 is involved in the development of B cell stimulating factor-induced systemic lupus erythematosus

The objective of the present study was to investigate the role of Toll-like receptor (TLR)-9 in B lymphocyte stimulating factor (BLyS)-induced systemic lupus erythematosus (SLE) in mice. The anti-double stranded (ds)DNA antibody titer, levels of complement proteins (C3 and C4), interleukin (IL)-10 and the disease activity [assessed by the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level] were measured. A total of 21 transgenic female mice (aged 8-10 weeks and weighing 30-40 g) expressing the Epstein-Barr virus membrane antigen, BLLF1, were studied. Mice were randomly divided into the control, the BLyS inhibition and the TLR-9 inhibition groups, with 7 mice in each group. Mice in the blank control group received intraperitoneal injections of normal saline, mice in the BLyS inhibition group received intraperitoneal injections of anti-BR3 monoclonal antibody (5,000 ng/day) and mice in the TLR-9 inhibition group received intraperitoneal injections of anti-human TLR-9 antibody (250 ng/day). The treatment regimens continued for 10 days, followed by the collection of peripheral venous blood. The relative levels of TLR-9 mRNA were measured by reverse transcription-quantitative polymerase chain reaction. Furthermore, the BLyS protein concentration and IL-10 levels were measured by ELISA. TLR-9 mRNA, BLyS, IL-10, anti-dsDNA antibody titer, C3, C4, ESR and CRP levels of the blank control group were significantly higher than those of the other two groups (P<0.05). The differences in comparison of these indexes between the BLyS inhibition and TLR-9 inhibition groups were not statistically significant (P>0.05), with the exception of TLR-9 mRNA and BLyS. In conclusion, the TLR-9 signaling pathway may be important for BLyS-induced SLE, and regulation of the inflammatory immune level.

Interferon α2 and interferon γ induce the degranulation independent production of VEGF-A and IL-1 receptor antagonist and other mediators from human mast cells

Background

Mast cells are resident immune effector cells, often studied in the context of allergic disease. Found in substantial numbers at sites of potential infection they are increased at sites of angiogenesis and can be pivotal for the sensing and clearance of a variety of pathogens. Interferons (IFNs) are cytokines that are critical for host defence against intracellular pathogens. Increased levels of IFNs are observed during viral infection and in autoimmune diseases. IFNs are also widely used therapeutically and have been examined in the therapy of severe asthma.

Objective

To define the selective human mast cell cytokine and chemokine response following activation with type I or type II IFN's.

Methods

The ability of both IFNα2 and IFNγ to induce cytokine production by human cord blood‐derived mast cells was examined in vitro. Cytokine and chemokine production at 6 and 24 h was assessed by multiplex protein analysis. Degranulation was assessed by β‐hexosaminidase release. Mast cells were also treated with reovirus or respiratory syncytial virus and their production of CXCL10, IL‐1 receptor antagonist (IL‐1Ra), and vascular endothelial growth factor (VEGF) examined after 24 h.

Results

In addition to increased expression of classical IFN response genes, such as CXCL10, small but significant increases in CCL5 and IL‐17 production were observed following IFN activation. Notably, human mast cells produced both VEGF and IL‐1Ra in a dose dependent manner. These responses occurred in the absence of mast cell degranulation by a mechanism consistent with classical IFN signaling. Both reovirus and respiratory syncytial virus infection of mast cells, were also associated with IFN‐dependent IL‐1Ra expression.

Conclusion and Clinical Relevance

Our findings demonstrate that IFNs have profound impact on cytokine and chemokine expression by human mast cells, alone or in the context of viral infection. Mast cell VEGF and IL‐1Ra responses to IFNs could impact the regulation of local inflammatory responses and subsequent tissue remodeling.

Disease-Associated Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs), also called natural interferon (IFN)-producing cells, represent a specialized cell type within the innate immune system. pDCs are specialized in sensing viral RNA and DNA by toll-like receptor-7 and -9 and have the ability to rapidly produce massive amounts of type 1 IFNs upon viral encounter. After producing type 1 IFNs, pDCs differentiate into professional antigen-presenting cells, which are capable of stimulating T cells of the adaptive immune system. Chronic activation of human pDCs by self-DNA or mitochondrial DNA contributes to the pathogenesis of systemic lupus erythematosis and IFN-related autoimmune diseases. Under steady-state conditions, pDCs play an important role in immune tolerance. In many types of human cancers, recruitment of pDCs to the tumor microenvironment contributes to the induction of immune tolerance. Here, we provide a systemic review of recent progress in studies on the role of pDCs in human diseases, including cancers and autoimmune/inflammatory diseases.