Regulatory B cells: New players in inflammatory and autoimmune rheumatic diseases

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Mesenchymal stem cell transplantation may be able to induce immunological tolerance in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a common, potentially fatal autoimmune disease involving a significant inflammatory response. SLE is characterised by failure of self-tolerance and activation of autoreactive lymphocytes, leading to persistent disease. Although current treatments achieve some improvement in patients, some SLE patients are refractory and others relapse after drug withdrawal. The toxicity of current drug regimens, with recurrent infections, together with ongoing inflammation, contribute significantly to the progressive decline in organ function. Therefore, the clinical management of SLE requires more effective and less toxic treatments, ideally inducing complete remission and self-tolerance. In this context, recently developed cell therapies based on mesenchymal stem cells (MSCs) represent a promising and safe strategy in SLE. MSCs inhibit the activation of B cells, prevent the differentiation of CD4⁺ T cells into autoreactive T cells, reprogram macrophages with anti-inflammatory effects and inhibit dendritic cells (DCs), limiting their activity as antigen-presenting cells. In addition, MSCs could induce antigen-specific tolerance by enhancing anergy processes in autoreactive cells - by inhibiting the maturation of antigen-presenting DCs, blocking the T cell receptor (TcR) pathway and secreting inhibitory molecules -, increasing apoptotic activity to eliminate them, and activating regulatory T cells (Tregs) to enhance their proliferation and induction of tolerogenic DCs. Thus, induction of self-tolerance leads to immune balance, keeping inflammation under control and reducing lupus flares.

Autoimmune liver disease and multiple sclerosis: state of the art and future perspectives

Clinical observations suggest that the prevalence of autoimmune diseases is changing over time. Both autoimmune liver diseases and multiple sclerosis have shown a significant increase in the last decades. Although the coexistence of autoimmune diseases within individuals and families is a common phenomenon, the extent to which liver disease and multiple sclerosis co-occur is not clear. Case reports and few studies have reported the possible coexistence of multiple sclerosis with thyroid diseases, inflammatory bowel disease, psoriasis, and rheumatoid arthritis. It is unknown whether there is a definite association between multiple sclerosis and autoimmune liver diseases. We reviewed the literature to summarize the available studies on the association between different autoimmune liver diseases (autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis) and treated or untreated multiple sclerosis.

Elevation of Metrnβ and Its Association with Disease Activity in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an auto-immune disease, the pathogenesis of which remains to be fully addressed. Metrnβ is a novel cytokine involved in the pathogenesis of inflammatory disease, but its regulatory roles in SLE are unclear. We aimed to comprehensively investigate the clinical value of Metrnβ in SLE. A massive elevation of circulating Metrnβ levels was observed in SLE, and patients with an active phase displayed higher Metrnβ concentrations than those with inactive phases. Additionally, we found that Metrnβ expression was positively correlated with clinical indicators of SLE. Longitudinal cytokine and chemokine profiles revealed a disturbed immune response in SLE, with high activity profiles displayed severe pathogenic inflammation, and a positive correlation of the serum Metrnβ with CXCL9, IL10, IL18 and IL1RA was observed as well. Moreover, Metrnβ expressions exhibited an inverse correlation with Treg and B10. Of note, a significant decrease of ILC2 was found in SLE, and there was a negative correlation of Metrnβ with ILC2 as well. Further ROC analysis showed that the area under the curve (AUC) for Metrnβ was 0.8250 (95% CI: 0.7379-0.9121), with a cutoff value of 1131 pg/mL to effectively distinguish SLE patients from healthy controls. Our study herein demonstrated for the first time that Metrnβ values were increased and were immunologically correlated with SLE activity, which could be utilized as an alternative biomarker for the early identification and predicting of the immuno-response of SLE.

Elevated circulating CD19+CD24hiCD38hi B cells display pro-inflammatory phenotype in idiopathic membranous nephropathy

CD19+CD24hiCD38hi regulatory B cells exert immunosuppressive functions by producing IL-10, but their role in idiopathic membranous nephropathy (IMN) remains elusive. Here, we investigated the frequency and functional changes of circulating CD19+CD24hiCD38hi B cells and evaluated the correlation of CD19+CD24hiCD38hi B cells with clinical features and T helper cell subsets in IMN patients. Compared with healthy controls (HCs), IMN patients showed an increased frequency of CD19+CD24hiCD38hi B cells, but a significant reduction in the percentage of CD19+CD24hiCD38hi B cells was observed 4 weeks after cyclophosphamide treatment. The frequency of CD19+CD24hiCD38hi B cells was positively correlated with the levels of 24h urinary protein, but negatively correlated with serum total protein and serum albumin, respectively. CD19+CD24hiCD38hi B cells in IMN patients displayed a skewed pro-inflammatory cytokine profile with a higher level of IL-6 and IL-12, but a lower concentration of IL-10 than their healthy counterparts. Accompanied by upregulation of Th2 and Th17 cells in IMN patients, the percentage of CD19+CD24hiCD38hi B cell subset was positively associated with Th17 cell frequency. In conclusion, CD19+CD24hiCD38hi B cells were expanded but functionally impaired in IMN patients. Their altered pro-inflammatory cytokine profile may contribute to the pathogenesis of IMN.

Anorexia Nervosa in Juvenile Systemic Lupus Erythematosus (SLE): A Causality Dilemma

Juvenile-onset systemic lupus erythematosus (jSLE) is an autoimmune disorder with multifaceted clinical findings in different organ systems. Neuropsychiatric manifestations affect more than half of SLE patients, and there is increasing evidence that anorexia nervosa (AN), a feeding and eating disorder (FED) characterized by significantly reduced energy intake, is among them. Herein, a review of the literature on the potential association between jSLE and AN was performed. Reported clinical cases were identified, and putative pathophysiological mechanisms were sought that could potentially explain the observed relationship between these two pathological entities. Four reports of isolated cases and a case series including seven patients were identified. In this limited patient pool, the diagnosis of AN preceded that of SLE in the majority of cases, whereas in all cases both entities were diagnosed within a time span of two years. Many explanations for the observed relationships have been proposed. AN has been associated with the stress of chronic disease diagnosis; on the other hand, the chronic inflammation associated with AN may contribute to the development/appearance of SLE. Adverse childhood experiences, concentrations of leptin, shared autoantibodies, and genetic traits appear to be important factors in this well-established interplay. In essence, it seems important to increase clinician awareness of the concomitant development of AN and SLE and invite further research on the subject.

Open challenges in the management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a rare autoimmune disease of the liver with many open questions as regards its etiopathogenesis, natural history and clinical management. The classical picture of AIH is chronic hepatitis with fluctuating elevation of serum transaminases and Immunoglobulin G levels, the presence of circulating autoantibodies and typical histological features. However, atypical presentations do occur and are not well captured by current diagnostic scores, with important consequences in terms of missed diagnoses and delayed treatments. AIH is treated with corticosteroids and immunosuppressive drugs but up to 40% of patients do not achieve full biochemical response and are at risk of progressing to cirrhosis and liver failure. Moreover, standard therapies are associated by significant side-effects which may impair the quality of life of patients living with AIH. However, advances in the understanding of the underlying immunology of AIH is raising the prospect of novel therapies and optimization of existing therapeutic approaches to reduce side-effect burdens and potentially restore immunological tolerance. In this review we outlined the clinical characteristics, etiopathogenesis and management of AIH and current challenges in the diagnosis and management of AIH and provided evidence underlying the evolution of diagnostic and clinical management protocols.

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.

Old known and possible new biomarkers of ANCA-associated vasculitis

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders involving severe, systemic, small-vessel vasculitis with short- and long term serious and life-threating complications. Despite the simplification of treatment, fundamental aspects concerning assessment of its efficacy and its adaptation to encountered complications or to the relapsing/remitting/subclinical disease course remain still unknown. The pathogenesis of AAV is complex and unique, and despite the progress achieved in the last years, much has not to be learnt. Foremost, there is still no accurate marker enabling us to monitoring disease and guide therapy. Therefore, the disease management relays often on clinical judgment and follows a" trial and error approach". In the recent years, an increasing number of new molecules s have been explored and used for this purpose including genomics, B- and T-cell subpopulations, complement system factors, cytokines, metabolomics, biospectroscopy and components of our microbiome. The aim of this review is to discuss both the role of known historical and clinically established biomarkers of AAV, as well as to highlight potential new ones, which could be used for timely diagnosis and monitoring of this devastating disease, with the goal to improve the effectiveness and ameliorate the complications of its demanding therapy.

Autoantibodies as Biomarker and Therapeutic Target in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare connective tissue disorder characterized by immune dysregulation evoking the pathophysiological triad of inflammation, fibrosis and vasculopathy. In SSc, several alterations in the B-cell compartment have been described, leading to polyclonal B-cell hyperreactivity, hypergammaglobulinemia and autoantibody production. Autoreactive B cells and autoantibodies promote and maintain pathologic mechanisms. In addition, autoantibodies in SSc are important biomarkers for predicting clinical phenotype and disease progression. Autoreactive B cells and autoantibodies represent potentially promising targets for therapeutic approaches including B-cell-targeting therapies, as well as strategies for unselective and selective removal of autoantibodies. In this review, we present mechanisms of the innate immune system leading to the generation of autoantibodies, alterations of the B-cell compartment in SSc, autoantibodies as biomarkers and autoantibody-mediated pathologies in SSc as well as potential therapeutic approaches to target these.

Efficacy of n-3 fatty acid supplementation on rheumatoid arthritis' disease activity indicators: a systematic review and meta-analysis of randomized placebo-controlled trials

Theoretical evidence and previous studies suggest that oralnutrient supplementation (ONS) with n-3 fatty acids for rheumatoid arthritis (RA) has the potential to lower disease activity indicators and non-steroidal anti-inflammatory drug (NSAID) uptake. A systematic search was conducted on five databases/registries from inception until May 23, 2021 with the aim to identify randomized placebo-controlled trials comparing n-3 supplements to placebo on disease-specific outcomes. A total of 23 studies matched the criteria (PROSPERO: CRD42019137041). Pooled analyses revealed that n-3 ONS provided a small effect in reducing pain [standardized mean difference (SMD): -0.16, 95% confidence intervals (CI): -0.40 to 0.09], and tender (SMD: -0.20, 95% CI: -0.46 to 0.05) and swollen joint count (SMD: -0.10, 95% CI: -0.28 to 0.07). In sensitivity analyses, there was a small effect in the reduction of NSAIDs intake (SMD: -0.22, 95% CI: -0.90 to 0.46), and c-reactive protein was reduced only by 0.21 mg/dL (95% CI: -0.75 to 0.33). Similar findings were observed regarding other objective/subjective outcomes. The certainty of the evidence was mostly of "very low/low" quality. Overall, n-3 ONS in RA might have a limited clinical benefit. Previous findings suggesting a reduction in NSAID intake may have been biased from the inadequate blinding of interventions.

Gender-Diverse Inclusion in Immunological Research: Benefits to Science and Health

The differences between male and female immune systems are an under-researched field, ripe for discovery. This is evidenced by the stark sex biases seen in autoimmunity and infectious disease. Both the sex hormones (oestrogen and testosterone), as well as the sex chromosomes have been demonstrated to impact immune responses, in multiple ways. Historical shortcomings in reporting basic and clinical scientific findings in a sex-disaggregated manner have led not only to limited discovery of disease aetiology, but to potential inaccuracies in the estimation of the effects of diseases or interventions on females and gender-diverse groups. Here we propose not only that research subjects should include both cis-gender men and cis-gender women, but also transgender and gender-diverse people alongside them. The known interaction between the hormonal milieu and the sex chromosomes is inseparable in cis-gender human research, without the confounders of puberty and age. By inclusion of those pursuing hormonal affirmation of their gender identity- the individual and interactive investigation of hormones and chromosomes is permitted. Not only does this allow for a fine-tuned dissection of these individual effects, but it allows for discovery that is both pertinent and relevant to a far wider portion of the population. There is an unmet need for detailed treatment follow-up of the transgender community- little is known of the potential benefits and risks of hormonal supplementation on the immune system, nor indeed on many other health and disease outcomes. Our research team has pioneered the inclusion of gender-diverse persons in our basic research in adolescent autoimmune rheumatic diseases. We review here the many avenues that remain unexplored, and suggest ways in which other groups and teams can broaden their horizons and invest in a future for medicine that is both fruitful and inclusive.

Regulatory B Cells in Systemic Sclerosis Isolated or Concomitant With Hashimoto Thyroiditis

Systemic sclerosis (SSc) is a systemic autoimmune disease in which gastrointestinal disorders represent a complication in up to 90% of patients. SSc may associate with thyroid autoimmune disorders, with Hashimoto’s thyroiditis (HT) being the more prevalent worldwide. Previous studies have examined the behavior of Th17 lymphocytes and Breg cells in patients with HT and concomitant autoimmune organ-specific disorders. These immune phenotypes seem to play a significant role in the pathogenesis of both these autoimmune processes, but their behavior when these two disorders coexist has not been described. We analyzed Th17 and Breg (CD24hiCD38hi) cell subsets in 50 subjects (45F/5M; median age = 49 years): 18 were healthy donors (HD), 20 had isolated HT, and 12 had SSc, seven of whom had both HT and SSc. Breg cells’ function was also evaluated by measuring their IL-10 production when stimulated by specific activators. An increased percentage of Th17 lymphocytes characterized HT patients as compared to both HD and the whole group of SSc patients (p = 0.0018). On the contrary, the percentage of unstimulated Breg cells in SSc patients was higher (p = 0.0260), either associated or not with HT, as compared to both HT patients and HD, which, instead, showed a similar percentage of Breg cells. Following a specific stimulation with CpG, the percentages of Breg cells were increased in the whole sample of SSc patients (p < 0.001) as well as in isolated SSc and in SSc+HT ones as compared to isolated HT. However, qualitative analysis, obtained through the detection of the IL-10-producing phenotype, revealed that the percentage of CpG-stimulated CD24hiCD38hi-IL10+cells was significantly decreased in SSc patients (p < 0.0001) with no difference between isolated SSc and SSc+HT patients. The IL-10-producing phenotype was instead slightly increased in HT patients as compared to HD (4.1% vs. 2.8%). The presence of SSc seems to be characterized by an enrichment of total Breg cells but by a reduced Breg IL-10-producing phenotype, representing functional Bregs. This last finding was entirely due to the presence of SSc independently from the association with HT. This behavior is different from the ones described about the association of HT with organ-specific autoimmune disorders.

A MZB Cell Activation Profile Present in the Lacrimal Glands of Sjögren's Syndrome-Susceptible C57BL/6.NOD-Aec1Aec2 Mice Defined by Global RNA Transcriptomic Analyses

The C57BL/6.NOD-Aec1Aec2 mouse has been extensively studied to define the underlying cellular and molecular basis for the onset and development of Sjögren's syndrome (SS), a human systemic autoimmune disease characterized clinically as the loss of normal lacrimal and salivary gland functions leading respectively to dry eye and dry mouth pathologies. While an overwhelming majority of SS studies in both humans and rodent models have long focused primarily on pathophysiological events and the potential role of T lymphocytes in these events, recent studies in our murine models have indicated that marginal zone B (MZB) lymphocytes are critical for both development and onset of SS disease. Although migration and function of MZB cells are difficult to study in vivo and in vitro, we have carried out ex vivo investigations that use temporal global RNA transcriptomic analyses to track early cellular and molecular events in these exocrine glands of C57BL/6.NOD-Aec1Aec2 mice. In the present report, genome-wide transcriptome analyses of lacrimal glands indicate that genes and gene-sets temporally upregulated during early onset of disease define the Notch2/NF-kβ14 and Type1 interferon signal transduction pathways, as well as identify chemokines, especially Cxcl13, and Rho-GTPases, including DOCK molecules, in the cellular migration of immune cells to the lacrimal glands. We discuss how the current results compare with our recently published salivary gland data obtained from similar studies carried out in our C57BL/6.NOD-Aec1Aec2 mice, pointing out both similarities and differences in the etiopathogeneses underlying the autoimmune response within the two glands. Overall, this study uses the power of transcriptomic analyses to identify temporal molecular bioprocesses activated during the preclinical covert pathogenic stage(s) of SS disease and how these findings may impact future intervention therapies as the disease within the two exocrine glands may not be identical.

The Forgotten Brother: The Innate-like B1 Cell in Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system (CNS), traditionally considered a chronic autoimmune attack against the insulating myelin sheaths around axons. However, the exact etiology has not been identified and is likely multi-factorial. Recently, evidence has been accumulating that implies that autoimmune processes underlying MS may, in fact, be triggered by pathological processes initiated within the CNS. This review focuses on a relatively unexplored immune cell-the "innate-like" B1 lymphocyte. The B1 cell is a primary-natural-antibody- and anti-inflammatory-cytokine-producing cell present in the healthy brain. It has been recently shown that its frequency and function may differ between MS patients and healthy controls, but its exact involvement in the MS pathogenic process remains obscure. In this review, we propose that this enigmatic cell may play a more prominent role in MS pathology than ever imagined. We aim to shed light on the human B1 cell in health and disease, and how dysregulation in its delicate homeostatic role could impact MS. Furthermore, novel therapeutic avenues to restore B1 cells' beneficial functions will be proposed.

Identification of Hub Biomarkers and Immune-Related Pathways Participating in the Progression of Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease that generally induces the progression of rapidly progressive glomerulonephritis (GN). The purpose of this study was to identify key biomarkers and immune-related pathways involved in the progression of ANCA-associated GN (ANCA-GN) and their relationship with immune cell infiltration.

Methods

Gene microarray data were downloaded from the Gene Expression Omnibus (GEO). Hub markers for ANCA-GN were mined based on differential expression analysis, weighted gene co-expression network analysis (WGCNA) and lasso regression, followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) of the differential genes. The infiltration levels of 28 immune cells in the expression profile and their relationship to hub gene markers were analysed using single-sample GSEA (ssGSEA). In addition, the accuracy of the hub markers in diagnosing ANCA-GN was subsequently evaluated using the receiver operating characteristic curve (ROC).

Results

A total of 651 differential genes were screened. Twelve co-expression modules were obtained via WGCNA; of which, one hub module (black module) had the highest correlation with ANCA-GN. A total of 66 intersecting genes were acquired by combining differential genes. Five hub genes were subsequently obtained by lasso analysis as potential biomarkers for ANCA-GN. The immune infiltration results revealed the most significant relationship among monocytes, CD4⁺ T cells and CD8⁺ T cells. ROC curve analysis demonstrated a prime diagnostic value of the five hub genes. According to the functional enrichment analysis of the differential genes, hub genes were mainly enhanced in immune- and inflammation-related pathways.

Conclusion

B cells and monocytes were closely associated with the pathogenesis of ANCA-GN. Hub genes (CYP3A5, SLC12A3, BGN, TAPBP and TMEM184B) may be involved in the progression of ANCA-GN through immune-related signal pathways.

Mechanistic insights into the role of B cells in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease epitomized by severe inflammation that induces tendon, cartilage, and bone damage over time. Although different types of cells undertake pathogenic functions in RA, the B cell's significant involvement has increasingly been known following the development of rheumatoid factor and it has been re-emphasized in recent years. Therefore, the rheumatoid factors and anti-cyclic citrullinated peptide antibodies are well-known indications of infection and clinical manifestations, and that they can precede the development of illness by several years. The emergence of rituximab a B cell reducing chimeric antidote in 1997 and 1998 transformed B-cell-targeted therapy for inflammatory disorder from a research hypothesis to a functional fact. Ever since, several autoantibody-related conditions were addressed, including the more intriguing indications of effectiveness seen in rheumatoid arthritis patients. Numerous types of B-cell-targeted compounds are currently being researched. From the beginning, one of the primary goals of B-cell therapy was to reinstate some kind of immune tolerance. While B cells have long been recognized as essential autoantibody producers, certain antibody-independent functions and usefulness as a key targeted therapy were not recognized until recently. The knowledge of B cells' diverse physical and pathogenic roles in autoimmune diseases is growing. As a result, the number of successful agents targeting the B cell complex is becoming more ubiquitous. Therefore, in this article, we explore fresh perspectives upon the roles of B cells in arthritis treatment, as well as new evidence regarding the effectiveness of B lymphocytes reduction and the therapeutic outcome of biological markers.

Exploring the Pathogenic Role and Therapeutic Implications of Interleukin 2 in Autoimmune Hepatitis

Interleukin 2 is essential for the expansion of regulatory T cells, and low-dose recombinant interleukin 2 has improved the clinical manifestations of diverse autoimmune diseases in preliminary studies. The goals of this review are to describe the actions of interleukin 2 and its receptor, present preliminary experiences with low-dose interleukin 2 in the treatment of diverse autoimmune diseases, and evaluate its potential as a therapeutic intervention in autoimmune hepatitis. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Interleukin 2 is critical for the thymic selection, peripheral expansion, induction, and survival of regulatory T cells, and it is also a growth factor for activated T cells and natural killer cells. Interleukin 2 activates the signal transducer and activator of transcription 5 after binding with its trimeric receptor on regulatory T cells. Immune suppressor activity is increased; anti-inflammatory interleukin 10 is released; pro-inflammatory interferon-gamma is inhibited; and activation-induced apoptosis of CD8⁺ T cells is upregulated. Preliminary experiences with cyclic injections of low-dose recombinant interleukin 2 in diverse autoimmune diseases have demonstrated increased numbers of circulating regulatory T cells, preserved regulatory function, improved clinical manifestations, and excellent tolerance. Similar improvements have been recognized in one of two patients with refractory autoimmune hepatitis. In conclusion, interferon 2 has biological actions that favor the immune suppressor functions of regulatory T cells, and low-dose regimens in preliminary studies encourage its rigorous investigation in autoimmune hepatitis.

Incorporating mucosal-associated invariant T cells into the pathogenesis of chronic liver disease

Mucosal-associated invariant T (MAIT) cells have been described in liver and non-liver diseases, and they have been ascribed antimicrobial, immune regulatory, protective, and pathogenic roles. The goals of this review are to describe their biological properties, indicate their involvement in chronic liver disease, and encourage investigations that clarify their actions and therapeutic implications. English abstracts were identified in PubMed by multiple search terms, and bibliographies were developed. MAIT cells are activated by restricted non-peptides of limited diversity and by multiple inflammatory cytokines. Diverse pro-inflammatory, anti-inflammatory, and immune regulatory cytokines are released; infected cells are eliminated; and memory cells emerge. Circulating MAIT cells are hyper-activated, immune exhausted, dysfunctional, and depleted in chronic liver disease. This phenotype lacks disease-specificity, and it does not predict the biological effects. MAIT cells have presumed protective actions in chronic viral hepatitis, alcoholic hepatitis, non-alcoholic fatty liver disease, primary sclerosing cholangitis, and decompensated cirrhosis. They have pathogenic and pro-fibrotic actions in autoimmune hepatitis and mixed actions in primary biliary cholangitis. Local factors in the hepatic microenvironment (cytokines, bile acids, gut-derived bacterial antigens, and metabolic by-products) may modulate their response in individual diseases. Investigational manipulations of function are warranted to establish an association with disease severity and outcome. In conclusion, MAIT cells constitute a disease-nonspecific, immune response to chronic liver inflammation and infection. Their pathological role has been deduced from their deficiencies during active liver disease, and future investigations must clarify this role, link it to outcome, and explore therapeutic interventions.

Early Covert Appearance of Marginal Zone B Cells in Salivary Glands of Sjögren's Syndrome-Susceptible Mice: Initiators of Subsequent Overt Clinical Disease

The C57BL/6.NOD-Aec1Aec2 mouse model has been extensively studied to define the underlying cellular and molecular bioprocesses critical in the onset of primary Sjögren’s Syndrome (pSS), a human systemic autoimmune disease characterized clinically as the loss of lacrimal and salivary gland functions leading to dry eye and dry mouth pathologies. This mouse model, together with several gene knockout mouse models of SS, has indicated that B lymphocytes, especially marginal zone B (MZB) cells, are necessary for development and onset of clinical manifestations despite the fact that destruction of the lacrimal and salivary gland cells involves a classical T cell-mediated autoimmune response. Because migrations and functions of MZB cells are difficult to study in vivo, we have carried out ex vivo investigations that use temporal global RNA transcriptomic analyses to profile autoimmunity as it develops within the salivary glands of C57BL/6.NOD-Aec1Aec2 mice. Temporal profiles indicate the appearance of Notch2-positive cells within the salivary glands of these SS-susceptible mice concomitant with the early-phase appearance of lymphocytic foci (LF). Data presented here identify cellular bioprocesses occurring during early immune cell migrations into the salivary glands and suggest MZB cells are recruited to the exocrine glands by the upregulated Cxcl13 chemokine where they recognize complement (C’)-decorated antigens via their sphingosine-1-phosphate (S1P) and B cell (BC) receptors. Based on known MZB cell behavior and mobility, we propose that MZB cells activated in the salivary glands migrate to splenic follicular zones to present antigens to follicular macrophages and dendritic cells that, in turn, promote a subsequent systemic cell-mediated and autoantibody-mediated autoimmune T cell response that targets exocrine gland cells and functions. Overall, this study uses the power of transcriptomic analyses to provide greater insight into several molecular events defining cellular bioprocesses underlying SS that can be modelled and more thoroughly studied at the cellular level.

Review article: experimental therapies in autoimmune hepatitis

BACKGROUND

Current therapeutic options for autoimmune hepatitis (AIH) are limited by adverse events associated with corticosteroids and thiopurines and the limited evidence base for second- and third-line treatment options. Furthermore, current treatment approaches require long-term exposure of patients to pharmacological agents. There have been significant advances in the understanding of the mechanisms underpinning autoimmunity and an expansion in the available therapeutic agents for suppressing autoimmune responses or potentially restoring self-tolerance.

AIM

To review the mechanisms and evidence for experimental therapies that are being actively explored in the management of AIH.

METHODS

We have reviewed the literature relating to a range of novel therapeutic immunomodulatory treatment strategies and drugs.

RESULTS

Drugs which block B cell-activating factor of the tumour necrosis factor family (BAFF) and tumour necrosis factor α are currently in clinical trials for the treatment of AIH. Experimental therapies and technologies to increase immune tolerance, such as pre-implantation factor and regulatory T cell therapies, are undergoing development for application in autoimmune disorders. There is also evidence for targeting inflammatory pathways to control other autoimmune conditions, such as blockade of IL1 and IL6 and Janus-associated kinase (JAK) inhibitors.

CONCLUSIONS

With the range of tools available to clinicians and patients increasing, it is likely that the therapeutic landscape of AIH will change over the coming years and treatment approaches offering lower corticosteroid use and aiming to restore immune self-tolerance should be sought.

Autoantibodies against specific nuclear antigens are present in psoriatic disease and are diminished by secukinumab

Anti-nuclear antibodies (ANA) are frequently detected in patients with psoriasis (Ps) and psoriatic arthritis (PsA), but their target autoantigens remain unknown. We assessed antibody (ab) reactivity against 23 known nuclear antigens in patients with Ps and PsA and assess the effects of secukinumab (anti-IL17A) treatment on ANA levels. A total of 201 patients, 101 with Ps and 100 with PsA, and 50 ANA-negative healthy controls (HCs) were tested for ANAs by a line immunoassay testing reactivity to 23 nuclear antigens. Ab reactivity to at least 1 antigen was found in 20.4% psoriatic disease patients (25.7% Ps and 15% PsA) compared to 8% HCs (p = ns), the most frequent being against dense fine speckled 70 (DFS70) (6.5%). In Ps and PsA patients with secukinumab-induced remission, anti-DFS70 and other antigen-specific autoantibodies were diminished over time. No decline was noted for IgG abs against antigens from pathogens such as cytomegalovirus, Epstein-Barr virus and Helicobacter pylori. Autoantibody decrease was associated with significant reduction of plasmablasts, follicular B and follicular T cells. In conclusion, one third of antigen-specific ANA patients with psoriatic disease recognize DFS70. Secukinumab decreases nuclear antigen autoreactivity, plasmablasts, follicular B and follicular T cells, highlighting a new mechanism of its action.

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.

Astilbin combined with lipopolysaccharide induces IL-10-producing regulatory B cells via the STAT3 signalling pathway

OBJECTIVES

Astilbin exerts immunoregulatory activities and plays anti-inflammatory effects in inflammation-associated diseases. IL-10-producing B cells are the major subset of regulatory B cells (Bregs) and inhibit inflammation and autoimmune diseases. This study aimed to analyse the inducing effect of astilbin on Bregs and investigate the involved molecular mechanisms.

METHODS

The frequencies and activities of IL-10-producing Bregs were observed using the co-treatment of astilbin and lipopolysaccharide (LPS) ex vivo. The protective effect of astilbin/LPS-induced Bregs on dextran sulphate sodium (DSS)-induced colitis was confirmed in vivo. The molecular signalling events of Breg induction were checked via Western blot. CD40^-/- and toll-like receptor (TLR) 4^-/- B cells were treated with astilbin/LPS to determine the modulatory role of CD40 or TLR4 on astilbin/LPS-induced Bregs.

RESULTS

Although astilbin alone could not affect Bregs, the co-treatment of astilbin and LPS remarkably induced CD19⁺ CD1d^hi and CD19⁺ TIM-1⁺ cells which produced IL-10 ex vivo. Colonic CD19⁺ CD1d^hi and CD19⁺ TIM-1⁺ cells were also increased in astilbin-treated mice with DSS-induced colitis. The adoptive transfer of CD19⁺ TIM-1⁺ cells pre-induced by astilbin/LPS directly suppressed the progression of DSS-induced colitis. Combined astilbin and LPS stimulated the STAT3 activation of CD19⁺ TIM-1⁺ cells but had no effects on SOCS3, AKT, NF-κB, Erk, JNK nor P38. Inhibiting the STAT3 phosphorylation of CD19⁺ TIM-1⁺ cells abolished Breg induction by astilbin/LPS. Furthermore, Breg induction was weakened in CD40^-/- B cells with the decrease in STAT3 activation, but had disappeared in TLR4^-/- B cells with no STAT3 activation, thereby confirming the indispensable role of TLR4 signalling in the induction of IL-10-producing Bregs.

CONCLUSIONS

This study reports the new immunoregulatory role of astilbin for promoting IL-10-producing B cells and suggests the possible use of astilbin in the therapy of inflammatory diseases.

Activation of immunosuppressive network in the aging process

Chronic low-grade inflammation has a key role in the aging process, a state called inflammaging. It is known that the chronic inflammatory condition generates counteracting immunosuppressive state in many diseases. Inflammaging is also associated with an immune deficiency; generally termed as immunosenescence, although it is not known whether it represents the senescence of immune cells or the active remodeling of immune system. Evidence has accumulated since the 1970's indicating that immunosenescence might be caused by an increased activity of immunosuppressive cells rather than cellular senescence. Immune cells display remarkable plasticity; many of these cells can express both proinflammatory and immunosuppressive phenotypes in a context-dependent manner. The immunosuppressive network involves the regulatory subtypes of T (Treg) and B (Breg) cells as well as regulatory phenotypes of macrophages (Mreg), dendritic (DCreg), natural killer (NKreg), and type II natural killer T (NKT) cells. The immunosuppressive network also includes monocytic (M-MDSC) and polymorphonuclear (PMN-MDSC) myeloid-derived suppressor cells which are immature myeloid cells induced by inflammatory mediators. This co-operative network is stimulated in chronic inflammatory conditions preventing excessive inflammatory responses but at the same time they exert harmful effects on the immune system and tissue homeostasis. Recent studies have revealed that the aging process is associated with the activation of immunosuppressive network, especially the functions of MDSCs, Tregs, and Mregs are increased. I will briefly review the properties of the regulatory phenotypes of immune cells and examine in detail the evidences for an activation of immunosuppressive network with aging.

First case of laboratory-confirmed severe fever with thrombocytopenia syndrome disease revealed the risk of SFTSV infection in Xinjiang, China

The Xinjiang Uygur Autonomous Region locating in Northwest of China was not considered the epidemic area of severe fever with thrombocytopenia syndrome (SFTS). Here we report the first laboratory-confirmed SFTS case that a female patient had tick bite in Xinjiang and illness onset after returning to Hainan Province. Laboratory tests identified SFTS virus (SFTSV) infection, and the virus was isolated from the patient’s serum sample. Furthermore, SFTSV prevalence among tick groups was identified, and IgM response to SFTSV from febrile patients was identified. The findings suggested that there have been risks of SFTSV infection due to exposure to ticks in Xinjiang.

Mini Review: New Treatments in Psoriatic Arthritis. Focus on the IL-23/17 Axis

Psoriasis, an inflammatory skin disease, and psoriatic arthritis (PsA), an inflammatory arthritis, share clinical, genetic, and pathogenic factors and may be summed as one disease, the psoriatic disease. Interleukin (IL)-17 plays a major role in the development of both psoriasis and PsA. IL-23 is important in the proliferation and maintenance of IL-17, and therefore, cytokines of the IL-23/IL-17 axis attracted much interest as therapeutic targets in psoriasis and PsA. Therapeutic agents targeting the IL-23/IL-17 axis have been proven to be very effective in psoriasis and PsA, some are already in the therapeutic armamentarium and others are in the development. Some agents, target IL-23 and others IL-17 and include anti-IL-12/IL-23 p40 (ustekinumab, briankizumab), anti-IL-23p19 (guselkumab, tildrakizumab, risankizumab, brazikumab, mirikizumab), anti-IL-17A (secukinumab, ixekizumab), dual anti-IL-17A and anti-IL-17F (bimekizumab), or anti-IL-17 receptor (brodalumab) monoclonal antibodies. Janus tyrosine kinase(JAK) inhibitors also directly affect IL-23 and, thus, IL-17. After the first-generation pan-JAK inhibitors have been shown efficacy (tofacitinib, baricitinib), new-generation selective JAK inhibitors (filgotinib, upadacitinib) are under investigation in psoriasis and PsA.

B Cell Responses: Cell Interaction Dynamics and Decisions

B cells and the antibodies they produce have a deeply penetrating influence on human physiology. Here, we review current understanding of how B cell responses are initiated; the different paths to generate short- and long-lived plasma cells, germinal center cells, and memory cells; and how each path impacts antibody diversity, selectivity, and affinity. We discuss how basic research is informing efforts to generate vaccines that induce broadly neutralizing antibodies against viral pathogens, revealing the special features associated with allergen-reactive IgE responses and uncovering the antibody-independent mechanisms by which B cells contribute to health and disease.