Interleukin 17 acts in synergy with B cell-activating factor to influence B cell biology and the pathophysiology of systemic lupus erythematosus

Immune and non-immune mediators in the fibrosis pathogenesis of salivary gland in Sjögren's syndrome

Sjögren's syndrome (SS) or Sjögren's disease (SjD) is a systemic autoimmune disease clinically manifested as sicca symptoms. This disease primarily impacts the functionality of exocrine glands, specifically the lacrimal and salivary glands (SG). SG fibrosis, an irreversible morphological change, is a severe consequence that occurs in the later stages of the disease due to sustained inflammation. However, the mechanism underlying SG fibrosis in SS remains under-investigated. Glandular fibrosis may arise from chronic sialadenitis, in which the interactions between infiltrating lymphocytes and epithelial cells potentially contributes to fibrotic pathogenesis. Thus, both immune and non-immune cells are closely involved in this process, while their interplays are not fully understood. The molecular mechanism of tissue fibrosis is partly associated with an imbalance of immune responses, in which the transforming growth factor-beta (TGF-β)-dependent epithelial-mesenchymal transition (EMT) and extracellular matrix remodeling are recently investigated. In addition, viral infection has been implicated in the pathogenesis of SS. Viral-specific innate immune response could exacerbate the autoimmune progression, resulting in overt inflammation in SG. Notably, post-COVID patients exhibit typical SS symptoms and severe inflammatory sialadenitis, which are positively correlated with SG damage. In this review, we discuss the immune and non-immune risk factors in SG fibrosis and summarize the evidence to understand the mechanisms upon autoimmune progression in SS.

Role of Interleukin-17 in Predicting Activity of Rheumatoid Arthritis and Systemic Lupus Erythematosus

Background

Although high serum levels of interleukin (IL)-17 and its producing cells have been found in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in earlier research, it is still unclear how these findings relate to disease activity.

Objectives

This study examines the link between serum levels of IL-17 and the activity of both RA and SLE.

Design

This pilot case-control study included 100 patients with RA, 100 with SLE, and 100 healthy controls.

Methods

The Disease Activity Score-28 (DAS28) scores assessed the activity of RA, whereas the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores assessed SLE activity. All participants' data were compared and correlated.

Results

Serum levels of IL-17 were significantly higher in RA and SLE patients compared with the controls (P < .001) and showed significantly positive correlations (P < .001) with rheumatoid factor titer, anti-cyclic citrullinated peptide (anti-CCP) and DAS28 score among the RA patients. Although among SLE patients, they were significantly positively correlated (P < .001) with anti-double-stranded DNA (anti-ds DNA) levels and the SLEDAI-2K scores, the best cut-off value of IL-17 for predicting moderate and high disease activity was > 175 pg/mL among RA patients and > 95 pg/mL among SLE patients.

Conclusions

There is a significant correlation between RA and SLE activity and serum levels of IL-17. This discovery emphasizes IL-17 as a potential therapeutic target.

Prevalence of antiphospholipid autoantibodies associated with biologics treatment for psoriasis

Psoriasis is a chronic inflammatory disease that sometimes necessitates therapeutic intervention with biologics. Autoantibody production during treatment with tumor necrosis factor (TNF) inhibitors is a recognized phenomenon, however, the production of autoantibodies associated with antiphospholipid syndrome (APS) has not been comprehensively evaluated in patients with psoriasis. This study was conducted to assess the prevalence of APS-associated autoantibodies in patients with psoriasis treated with different biologics and to investigate the potential associations between autoantibody production and clinical or serological parameters. Patients with psoriasis undergoing biologics treatments were enrolled in this study, and were categorized based on the type of biologics administered, TNF, interleukin (IL)-17, or IL-23 inhibitors. Clinical and serological data were collected and analyzed in conjunction with data on APS autoantibodies. TNF inhibitors were associated with a higher frequency of APS autoantibodies compared to IL-17 and IL-23 inhibitors. Notably, the presence of APS autoantibodies correlated with concurrent arthritis and higher disease severity at treatment initiation in patients treated with TNF inhibitors. Elevated Psoriasis Area and Severity Index scores and anti-nuclear antibody titers higher than × 320 were predictors of APS autoantibody production. Despite the higher autoantibody rates, clinical symptoms of APS were absent in these patients. This study provides the first comprehensive evidence of an increased frequency of APS autoantibodies associated with TNF inhibitor treatment in patients with psoriasis. The observed association between APS autoantibody positivity and TNF inhibitor treatment or clinical parameters suggests a potential immunomodulatory interplay between autoimmunity and inflammation in the pathogenesis of psoriasis.

Molecular consideration relevant to the mechanism of the comorbidity between psoriasis and systemic lupus erythematosus (Review)

Systemic lupus erythematosus (SLE), a common autoimmune disease with a global incidence and newly diagnosed population estimated at 5.14 (range, 1.4-15.13) per 100,000 person-years and 0.40 million people annually, respectively, affects multiple tissues and organs; for example, skin, blood system, heart and kidneys. Accumulating data has also demonstrated that psoriasis (PS) can be a systemic inflammatory disease, which can affect organs other than the skin and occur alongside other autoimmune diseases, such as inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis and SLE. The current explanations for the possible comorbidity of PS and SLE include: i) The two diseases share susceptible gene loci; ii) they share a common IL-23/T helper 17 (Th17) axis inflammatory pathway; and iii) the immunopathogenesis of the two conditions is a consequence of the interactions between IL-17 cytokines with effector Th17 cells, T regulatory cells, as well as B cells. In addition, the therapeutic efficacy of IL-17 or TNF-α inhibitors has been demonstrated in PS, and has also become evident in SLE. However, the mechanisms have not been investigated. To the best of our knowledge, there remains a lack of substantial studies on the correlation between PS and SLE. In the present review, the literature, with regards to the epidemiology, genetic predisposition, inflammatory mechanisms and treatment of the patients with both PS and SLE, has been reviewed. Further investigations into the molecular pathogenic mechanism may provide drug targets that could benefit the patients with concomitant PS and SLE.

New-age vaccine adjuvants, their development, and future perspective

In the present scenario, immunization is of utmost importance as it keeps us safe and protects us from infectious agents. Despite the great success in the field of vaccinology, there is a need to not only develop safe and ideal vaccines to fight deadly infections but also improve the quality of existing vaccines in terms of partial or inconsistent protection. Generally, subunit vaccines are known to be safe in nature, but they are mostly found to be incapable of generating the optimum immune response. Hence, there is a great possibility of improving the potential of a vaccine in formulation with novel adjuvants, which can effectively impart superior immunity. The vaccine(s) in formulation with novel adjuvants may also be helpful in fighting pathogens of high antigenic diversity. However, due to the limitations of safety and toxicity, very few human-compatible adjuvants have been approved. In this review, we mainly focus on the need for new and improved vaccines; the definition of and the need for adjuvants; the characteristics and mechanisms of human-compatible adjuvants; the current status of vaccine adjuvants, mucosal vaccine adjuvants, and adjuvants in clinical development; and future directions.

Decreased SUV39H1 at the promoter region leads to increased CREMα and accelerates autoimmune response in CD4+ T cells from patients with systemic lupus erythematosus

BACKGROUND

Overproduction of cAMP-responsive element modulator α (CREMα) in total T cells from patients with systemic lupus erythematosus (SLE) can inhibit IL-2 and increase IL-17A. These ultimately promote progression of SLE. This study aims to investigate the expression of CREMα in SLE CD4⁺ T cells and find out the mechanisms for the regulation of CREMα in SLE CD4⁺ T cells.

RESULTS

CREMα mRNA was overexpressed in CD4⁺ T cells from SLE patients. The levels of histone H3 lysine 9 trimethylation (H3K9me3) and suppressor of variation 3-9 homolog 1 (SUV39H1) at the CREMα promoter of SLE CD4⁺ T cells were markedly decreased. Down-regulating SUV39H1 in normal CD4⁺ T cells elevated the levels of CREMα, IL-17A, and histone H3 lysine 4 trimethylation (H3K4me3) in the CREMα promoter region, and lowered IL-2, H3K9me3, DNA methylation, and DNA methyltransferase 3a (DNMT3a) enrichments within the CREMα promoter, while no sharp change in SET domain containing 1 (Set1) at the CREMα promoter. Up-regulating SUV39H1 in SLE CD4⁺ T cells had the opposite effects. The DNA methylation and DNMT3a levels were obviously reduced, and H3K4me3 enrichment was greatly increased at the CREMα promoter of CD4⁺ T cells from SLE patients. The Set1 binding in the CREMα promoter region upgraded significantly, and knocking down Set1 in SLE CD4⁺ T cells alleviated the H3K4me3 enrichment within this region, suppressed CREMα and IL-17A productions, and promoted the levels of IL-2, CREMα promoter DNA methylation, and DNMT3a. But there were no obviously alterations in H3K9me3 and SUV39H1 amounts in the region after transfection.

CONCLUSIONS

Decreased SUV39H1 in the CREMα promoter region of CD4⁺ T cells from SLE patients contributes to under-expression of H3K9me3 at this region. In the meantime, the Set1 binding at the CREMα promoter of SLE CD4⁺ T cells is up-regulated. As a result, DNMT3a and DNA methylation levels alleviate, and H3K4me3 binding increases. All these lead to overproduction of CREMα. Thus, the secretion of IL-2 down-regulates and the concentration of IL-17A up-regulates, ultimately promoting SLE.

Norcantharidin ameliorates the development of murine lupus via inhibiting the generation of IL-17 producing cells

Systemic lupus erythematosus (SLE) is a devastating autoimmune disorder associated with severe organ damage. The abnormality of T cell apoptosis is considered as an important pathogenetic mechanism of SLE. Norcantharidin (NCTD), a derivative of Cantharidin, is an efficacious anti-cancer drug by inhibiting cell proliferation and inducing cell apoptosis. Besides, NCTD has also been proved to protect the function of kidneys, while damaged renal function is the most important predictor of morbidity and mortality in SLE. All these suggest the potential effects of NCTD in SLE treatment. In this study we investigated whether NCTD exerted therapeutic effects in a mouse SLE model. Lupus prone female MRL/lpr mice were treated with NCTD (1, 2 mg·kg^-1·d^-1, ip) for 8 weeks. We showed that NCTD administration significantly decreased mortality rate, diminished the expression of anti-dsDNA IgG antibody, a diagnostic marker for SLE, as well as restored renal structure and function in MRL/lpr mice. Moreover, NCTD administration dose-dependently inhibited lymphoproliferation and T cell accumulation in the spleens of MRL/lpr mice. We further revealed that NCTD specifically inhibited DN T cell proliferation and Th17 cell differentiation both via blocking activation of signal transducer and activator of transcription 3 (STAT3) signaling pathway. On the other hand, NCTD did not affect T cell apoptosis in MRL/lpr mice. Taken together, our data suggest that NCTD may be as a promising therapeutic drug through targeting T cells for the treatment of SLE.

Innate stimulation of B cells ex vivo enhances antibody secretion and identifies tumour-reactive antibodies from cancer patients

Human B cells and their expressed antibodies are crucial in conferring immune protection. Identifying pathogen-specific antibodies following infection is possible due to enhanced humoral immunity against well-described molecules on the pathogen surface. However, screening for cancer-reactive antibodies remains challenging since target antigens are often not identified a priori and the frequency of circulating B cells recognizing cancer cells is likely very low. We investigated whether combined ex vivo culture of human B cells with three innate stimuli, interleukin-17 (IL-17), B-cell activation factor (BAFF), and the toll-like receptor 9 (TLR-9) agonist DNA motif CpG ODN 2006 (CpG), each known to activate B cells through different signalling pathways, promote cell activation, proliferation, and antibody production. Combined IL-17+BAFF+CpG prolonged B-cell survival and increased proliferation compared with single stimuli. IL-17+BAFF+CpG triggered higher IgG secretion, likely by activating differentiated, memory and class-switched CD19⁺CD20⁺CD27⁺IgD^- B cells. Regardless of anti-FOLR antibody seropositive status, IL-17+BAFF+CpG combined with a monovalent tumour-associated antigen (folate receptor alpha [FOLR]) led to secreted antibodies recognizing the antigen and the antigen-expressing IGROV1 cancer cells. In a seropositive individual, FOLR stimulation favoured class-switched memory B-cell precursors (CD27^-CD38^-IgD^-), class-switched memory B cells and anti-FOLR antibody production, while IL-17+BAFF+CpG combined with FOLR, promoted class-switched memory B-cell precursors and antibody-secreting (CD138+IgD-) plasma cells. Furthermore, IL-17+BAFF+CpG stimulation of peripheral blood B cells from patients with melanoma revealed tumour cell-reactive antibodies in culture supernatants. These findings suggest that innate signals stimulate B-cell survival and antibody production and may help identify low-frequency antigen-reactive humoral responses.

Interleukin-17 levels in gingival crevicular fluid of aggressive periodontitis and chronic periodontitis patients

Context

Interleukin-17 (IL-17) plays an important function in initiation, progression of any inflammatory condition. It is a pro-inflammatory cytokine and considered to be founding member. Periodontitis being an inflammatory condition of periodontium, IL-17 does have a potential role in periodontitis. The current research has shown positive correlation between the IL-17 and severity of periodontitis. Therefore, this research study aimed to evaluate the levels of IL-17 in aggressive periodontitis (AgP), chronic periodontitis (CP), and "healthy gingival sites."

Materials and Methods

A total of 45 selected subjects (90 samples) were equally divided into three different groups. Group 1 (Healthy gingiva on clinical examination): Subjects with healthy gingiva and no evidence of periodontal attachment level (PAL), probing pocket depth (PPD) <3 mm papillary bleeding index (PBI) <1. Group 2 (AgP): Subjects having age <35 years with at least six permanent teeth apart from the incisors and first molars with PPD and PAL ≥5 mm. Group 3 (CP): It consist of subjects with clinical features of inflammation of gingiva with minimum six teeth in each jaw, with PPD ≥4 mm, PAL ≥4 mm. IL-17 levels were analyzed by using Gingival crevicular fluid (GCF). It was collected from the sulcus of first maxillary molar sites for quantitative analysis.

Results

GCF IL-17 levels in AgP were found to be 1.12 ± 0.29, 1.96 ± 1.71 in CP and 0.64 ± 0.23 in healthy gingival sites. Clinical parameters such as (1) plaque index (Turesky et al., modification of Quigley-Hein), (2) PPD, (3) PBI were higher (significantly) in periodontitis group as compared to healthy gingiva. Positive correlation was found to be significant between levels of IL-17 with PAL and PPD in AgP however in cases of CP, positive correlation of IL-17 levels was found only with PAL but not PPD.

Conclusion

Our study shows that the IL-17 levels were comparatively higher in GCF of AgP, CP in comparison to healthy gingiva, but the GCF IL-17 levels were higher in CP as compared to AgP.

Association of genetic polymorphisms in IL-23R and IL-17A with the susceptibility to IgA nephropathy in a Chinese Han population

IgA Nephropathy (IgAN) is one of the most common causes of chronic kidney damage worldwide. Identifying new genetic factors associated with IgAN risk is of invaluable importance. To explore the association between polymorphisms of IL-23R and IL-17A and the susceptibility of IgAN, 164 IgAN patients and 192 healthy controls were genotyped for five SNPs in a Chinese Han population. A comparative analysis between genotype distributions, clinical indexes and pathological grades in the IgAN patients was also performed. The GG genotype and a G allele of rs7517847 were associated with a decreased IgAN risk (OR: 0.545; 95% CI: 0.299-0.993; p = 0.046; OR: 0.730; 95% CI: 0.541-0.984; p = 0.039) compared to the TT genotype and T allele respectively. Furthermore, the AA genotype of rs2275913 appeared to reduce the IgAN risk (OR: 0.405; 95% CI: 0.209-0.786; p = 0.007) compared to the GG genotype. Consistently, individuals harboring an AA genotype had a lower IgAN risk (OR: 0.380; 95% CI: 0.211-0.686; p = 0.001) under the recessive model. Our study demonstrated for the first time the significant associations of rs7517847 in IL-23R and rs2275913 in IL-17A with the risk of IgAN in Chinese Han.

Association Between a History of Nontyphoidal Salmonella and the Risk of Systemic Lupus Erythematosus: A Population-Based, Case-Control Study

Objective

We investigated the correlation between nontyphoidal Salmonella (NTS) infection and systemic lupus erythematosus (SLE) risk.

Methods

This case-control study comprised 6,517 patients with newly diagnosed SLE between 2006 and 2013. Patients without SLE were randomly selected as the control group and were matched at a case-control ratio of 1:20 by age, sex, and index year. All study individuals were traced from the index date back to their NTS exposure, other relevant covariates, or to the beginning of year 2000. Conditional logistic regression analysis was used to analyze the risk of SLE with adjusted odds ratios (aORs) and 95% confidence intervals (CIs) between the NTS and control groups.

Results

The mean age was 37.8 years in the case and control groups. Females accounted for 85.5%. The aOR of having NTS infection were significantly increased in SLE relative to controls (aOR, 9.20; 95% CI, 4.51-18.78) in 1:20 sex-age matching analysis and (aOR, 7.47; 95% CI=2.08-26.82) in propensity score matching analysis. Subgroup analysis indicated that the SLE risk was high among those who dwelled in rural areas; had rheumatoid arthritis, multiple sclerosis, or Sjogren’s syndrome; and developed intensive and severe NTS infection during admission.

Conclusions

Exposure to NTS infection is associated with the development of subsequent SLE in Taiwanese individuals. Severe NTS infection and other autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, or Sjogren’s syndrome also contributed to the risk of developing SLE.

The Microbiota in Systemic Lupus Erythematosus: An Update on the Potential Function of Probiotics

Systemic lupus erythematosus (SLE) is a kind of chronic diffuse connective tissue illness characterized by multisystem and multiorgan involvement, repeated recurrence and remission, and the presence of a large pool of autoantibodies in the body. Although the exact cause of SLE is not thoroughly revealed, accumulating evidence has manifested that intake of probiotics alters the composition of the gut microbiome, regulating the immunomodulatory and inflammatory response, which may be linked to the disease pathogenesis. Particularly, documented experiments demonstrated that SLE patients have remarkable changes in gut microbiota compared to healthy controls, indicating that the alteration of microbiota may be implicated in different phases of SLE. In this review, the alteration of microbiota in the development of SLE is summarized, and the mechanism of intestinal microbiota on the progression of immune and inflammatory responses in SLE is also discussed. Due to limited reports on the effects of probiotics supplementation in SLE patients, we emphasize advancements made in the last few years on the function and mechanisms of probiotics in the development of SLE animal models. Besides, we follow through literature to survey whether probiotics supplements can be an adjuvant therapy for comprehensive treatment of SLE. Research has indicated that intake of probiotics alters the composition of the gut microbiome, contributing to prevent the progression of SLE. Adjustment of the gut microbiome through probiotics supplementation seems to alleviate SLE symptoms and their cardiovascular and renal complications in animal models, marking this treatment as a potentially novel approach.

A Variant of sNASP Exacerbates Lymphocyte Subset Disorder and Nephritis in a Spontaneous Lupus Model Sle1.Yaa Mouse

A variant of somatic nuclear autoantigenic sperm protein (sNASP) was identified from the murine lupus susceptibility locus Sle2c1 by whole exome sequencing (WES). Previous studies have shown that mutant sNASP could synergize with the Fas^lpr mutation in exacerbating autoimmunity and aggravating end-organ inflammation. In the current study, the sNASP mutation was introduced into Sle1.Yaa mice to detect whether it has a synergistic effect with Sle1 or Yaa loci. As expected, compared with Sle1.Yaa mice, Sle1.Yaa.ΔsNASP mice showed enlarged lymph nodes, aggravated renal inflammation, and shortened survival time. The proportions of CD3⁺ T cells, activated CD19⁺CD86⁺ B cells, Th1 cells in the spleen and lymph nodes, and Th17 cells in lymph nodes in Sle1.Yaa.ΔsNASP mice were increased compared to those in Sle1.Yaa mice. The levels of IFN-γ and TNF-α in the serum of Sle1.Yaa.ΔsNASP mice were higher than those of Sle1.Yaa mice. The above results show that mutant sNASP can interact with different lupus susceptibility genes and promote the disease process of systemic lupus erythematosus.

SPaRTAN, a computational framework for linking cell-surface receptors to transcriptional regulators

The identity and functions of specialized cell types are dependent on the complex interplay between signaling and transcriptional networks. Recently single-cell technologies have been developed that enable simultaneous quantitative analysis of cell-surface receptor expression with transcriptional states. To date, these datasets have not been used to systematically develop cell-context-specific maps of the interface between signaling and transcriptional regulators orchestrating cellular identity and function. We present SPaRTAN (Single-cell Proteomic and RNA based Transcription factor Activity Network), a computational method to link cell-surface receptors to transcription factors (TFs) by exploiting cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) datasets with cis-regulatory information. SPaRTAN is applied to immune cell types in the blood to predict the coupling of signaling receptors with cell context-specific TFs. Selected predictions are validated by prior knowledge and flow cytometry analyses. SPaRTAN is then used to predict the signaling coupled TF states of tumor infiltrating CD8+ T cells in malignant peritoneal and pleural mesotheliomas. SPaRTAN enhances the utility of CITE-seq datasets to uncover TF and cell-surface receptor relationships in diverse cellular states.

The role of IL-17 rs2275913, IL-17RC rs708567 and TGFB1 rs1800469 SNPs and IL-17A serum levels in patients with lupus nephritis

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease and polymorphisms in the cytokine genes and their receptors are thought to influence its development. The aim of this case-control study was to investigate the association of the IL-17A rs2275913, IL-17RC rs708567 and TGFB1 rs1800469 polymorphisms with SLE, its clinical manifestations and the polymorphisms influence on the IL-17A serum levels. Altogether 59 SLE patients with lupus nephritis and 95 healthy controls were genotyped by TaqMan assay. Serum levels were determined by Human IL-17A Platinum ELISA kit. From the studied polymorphisms, only TGFB1 T allele was found to be associated with SLE. Within the patient group, IL-17A GG genotype and TGFB1 -509T allele showed an association with the neurological disease and IL-17RC CC genotype appeared to be associated with lupus arthritis. The IL17A serum levels in the SLE and control groups (7.24 pg/ml and 5.76 pg/ml, respectively) did not show any statistical difference. A weak correlation between IL17A levels and SLEDAI-2K was observed. Our results indicate that IL-17A rs2275913, IL-17RCrs708567 and TGFB1 rs1800469 polymorphisms might play a role in the susceptibility and the clinical manifestations of SLE and IL-17A serum levels should be monitored in the course of the disease. The identification of subsets of SLE with an IL-17-driven disease could improve the therapeutic approach leading to more precise personalized treatment.

Transcriptome landscape of double negative T cells by single-cell RNA sequencing

CD4 and CD8 coreceptor double negative TCRαβ⁺ T (DNT) cells are increasingly being recognized for their critical and diverse roles in the immune system. However, their molecular and functional signatures remain poorly understood and controversial. Moreover, the majority of studies are descriptive because of the relative low frequency of cells and non-standardized definition of this lineage. In this study, we performed single-cell RNA sequencing on 28,835 single immune cells isolated from mixed splenocytes of male C57BL/6 mice using strict fluorescence-activated cell sorting. The data was replicated in a subsequent study. Our analysis revealed five transcriptionally distinct naïve DNT cell clusters, which expressed unique sets of genes and primarily performed T helper, cytotoxic and innate immune functions. Anti-CD3/CD28 activation enhanced their T helper and cytotoxic functions. Moreover, in comparison with CD4⁺, CD8⁺ T cells and NK cells, Ikzf2 was highly expressed by both naïve and activated cytotoxic DNT cells. In conclusion, we provide a map of the heterogeneity in naïve and active DNT cells, addresses the controversy about DNT cells, and provides potential transcription signatures of DNT cells. The landscape approach herein will eventually become more feasible through newer high throughput methods and will enable clustering data to be fed into a systems analysis approach. Thus the approach should become the "backdrop" of similar studies in the myriad murine models of autoimmunity, potentially highlighting the importance of DNT cells and other minor lineage of cells in immune homeostasis. The clear characterization of functional DNT subsets into helper DNT, cytotoxic DNT and innate DNT will help to better understand the intrinsic roles of different functional DNT subsets in the development and progression of autoimmune diseases and transplant rejection, and thereby may facilitate diagnosis and therapy.

NK1.1- natural killer T cells upregulate interleukin-17 expression in experimental lupus nephritis

Interleukin (IL)-17-secreting invariant natural killer T (NKT) cells are involved in several inflammatory diseases. However, their role in lupus nephritis (LN) has not been fully characterized. Samples from patients with LN or glomerulonephritis and healthy controls were obtained, and elevated IL-17+ NKT cell numbers and IL-17 expression were observed in blood cells and kidneys, respectively, in patients with LN. Comparison of a mouse model of experimental autoimmune LN with the parental strain (NKT-deficient B6.CD1d-/- mice) revealed improved proteinuria, disease severity, and histopathology and decreased levels of chemokine (C-X-C motif) ligand 16 and T cell receptor-α variable 14 expression. Spleens and kidneys of B6.CD1d-/- mice also showed downregulation of inflammatory markers and IL-17. In coculture with renal mesangial and NKT cells, inflammatory markers and IL-17 were upregulated following α-galactosylceramide treatment and downregulated after treatment with IL-17-blocking antibodies. This was most prominent with killer cell lectin-like receptor subfamily B member 1 C (NK1.1)- NKT cells. Thus, IL-17 is upregulated in LN. Activation of NKT cells regulates IL-17-related immune responses systemically and in the kidneys, primarily via NK1.1- NKT cells. IL-17-secreting NK1.1- NKT cells could serve as diagnostic and therapeutic targets for LN.NEW & NOTEWORTHY This study makes a significant contribution to the literature because our results indicate that IL-17 is upregulated in lupus nephritis and that natural killer T (NKT) cells are involved in its pathogenesis. Activation of NKT cells regulates IL-17-related immune responses, both systemically and in the kidney, and this mainly involves NK1.1- NKT cells. Furthermore, IL-17-secreting NK1.1- NKT cells could serve as a diagnostic and therapeutic target for lupus nephritis.

The Potential of Harnessing IL-2-Mediated Immunosuppression to Prevent Pathogenic B Cell Responses

Immunosuppressive drugs can partially control Antibody (Ab)-dependent pathology. However, these therapeutic regimens must be maintained for the patient's lifetime, which is often associated with severe side effects. As research advances, our understanding of the cellular and molecular mechanisms underlying the development and maintenance of auto-reactive B cell responses has significantly advanced. As a result, novel immunotherapies aimed to restore immune tolerance and prevent disease progression in autoimmune patients are underway. In this regard, encouraging results from clinical and preclinical studies demonstrate that subcutaneous administration of low-doses of recombinant Interleukin-2 (r-IL2) has potent immunosuppressive effects in patients with autoimmune pathologies. Although the exact mechanism by which IL-2 induces immunosuppression remains unclear, the clinical benefits of the current IL-2-based immunotherapies are attributed to its effect on bolstering T regulatory (Treg) cells, which are known to suppress overactive immune responses. In addition to Tregs, however, rIL-2 also directly prevent the T follicular helper cells (Tfh), T helper 17 cells (Th17), and Double Negative (DN) T cell responses, which play critical roles in the development of autoimmune disorders and have the ability to help pathogenic B cells. Here we discuss the broader effects of rIL-2 immunotherapy and the potential of combining rIL-2 with other cytokine-based therapies to more efficiently target Tfh cells, Th17, and DN T cells and subsequently inhibit auto-antibody (ab) production in autoimmune patients.

Expanding mechanistic insights into the pathogenesis of idiopathic CD4+ T cell lymphocytopenia

Idiopathic CD4+ T cell lymphocytopenia (ICL) is a heterogeneous syndrome presenting with persistent CD4+ T cell lymphopenia of unknown origin, and opportunistic infections in some patients. The underlying pathogenesis and appropriate management remain understudied. In this issue of the JCI, Perez-Diez and Wong et al. assessed the prevalence of autoantibodies from the sera of 51 adult ICL patients (out of a cohort of 72). Some patients showed high levels of IgG and IgM autoantibodies against numerous autoantigens, and some autoantibodies were specific for lymphocytes. The researchers implicate these autoantibodies as a possible pathogenic mechanism responsible for the reduction in circulating CD4+ T cells. This study goes beyond defining a mechanism in a complex, poorly defined disease; it also brings a renewed focus on ICL that will likely result in improved diagnostic evaluation and treatment.

CD4 derived double negative T cells prevent the development and progression of nonalcoholic steatohepatitis

Hepatic inflammation is the driving force for the development and progression of NASH. Treatment targeting inflammation is believed to be beneficial. In this study, adoptive transfer of CD4+ T cells converted double negative T cells (cDNT) protects mice from diet-induced liver fat accumulation, lobular inflammation and focal necrosis. cDNT selectively suppress liver-infiltrating Th17 cells and proinflammatory M1 macrophages. IL-10 secreted by M2 macrophages decreases the survival and function of cDNT to protect M2 macrophages from cDNT-mediated lysis. NKG2A, a cell inhibitory molecule, contributes to IL-10 induced apoptosis and dampened suppressive function of cDNT. In conclusion, ex vivo-generated cDNT exert potent protection in diet induced obesity, type 2 diabetes and NASH. The improvement of outcome is due to the inhibition on liver inflammatory cells. This study supports the concept and the feasibility of potentially utilizing this autologous immune cell-based therapy for the treatment of NASH.

Calcineurin and Systemic Lupus Erythematosus: The Rationale for Using Calcineurin Inhibitors in the Treatment of Lupus Nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a broad spectrum of clinical presentations that can affect almost all organ systems. Lupus nephritis (LN) is a severe complication that affects approximately half of the systemic erythematosus lupus (SLE) patients, which significantly increases the morbidity and the mortality risk. LN is characterized by the accumulation of immune complexes, ultimately leading to renal failure. Aberrant activation of T cells plays a critical role in the pathogenesis of both SLE and LN and is involved in the production of inflammatory cytokines, the recruitment of inflammatory cells to the affected tissues and the co-stimulation of B cells. Calcineurin is a serine-threonine phosphatase that, as a consequence of the T cell hyperactivation, induces the production of inflammatory mediators. Moreover, calcineurin is also involved in the alterations of the podocyte phenotype, which contribute to proteinuria and kidney damage observed in LN patients. Therefore, calcineurin inhibitors have been postulated as a potential treatment strategy in LN, since they reduce T cell activation and promote podocyte cytoskeleton stabilization, both being key aspects in the development of LN. Here, we review the role of calcineurin in SLE and the latest findings about calcineurin inhibitors and their mechanisms of action in the treatment of LN.

Blocking IL-17: A Promising Strategy in the Treatment of Systemic Rheumatic Diseases

Systemic rheumatic diseases are a heterogeneous group of autoimmune disorders that affect the connective tissue, characterized by the involvement of multiple organs, leading to disability, organ failure and premature mortality. Despite the advances in recent years, the therapeutic options for these diseases are still limited and some patients do not respond to the current treatments. Interleukin-17 (IL-17) is a cytokine essential in the defense against extracellular bacteria and fungi. Disruption of IL-17 homeostasis has been associated with the development and progression of rheumatic diseases, and the approval of different biological therapies targeting IL-17 for the treatment of psoriatic arthritis (PsA) and ankylosing spondylitis (AS) has highlighted the key role of this cytokine. IL-17 has been also implicated in the pathogenesis of systemic rheumatic diseases, including systemic lupus erythematosus (SLE), Sjögren's syndrome (SS) and systemic sclerosis (SSc). The aim of this review is to summarize and discuss the most recent findings about the pathogenic role of IL-17 in systemic rheumatic and its potential use as a therapeutic option.

Sacroiliitis in Systemic Lupus Erythematosus Revisited

Objectives

This study aims to investigate the prevalence of inflammatory back pain (IBP) and sacroiliitis in a systemic lupus erythematosus (SLE) population as well as the association between IBP and the frequency of human leukocyte antigen B27 (HLA-B27).

Patients and methods

The study included 281 SLE patients (16 males, 265 females; mean age 39.9±11.9 years; range, 20 to 69 years) and 100 healthy controls (HCs) (2 males, 98 females; mean age 41.2±10.1 years; range, 19 to 64 years). Participants were administered a five-item Assessment of SpondyloArthritis international Society-IBP questionnaire. Patients and controls with IBP underwent detailed clinical and laboratory examinations to detect sacroiliitis. Radiographic evaluations were performed by a blinded rheumatologist and radiologist. Interobserver reliability was assessed with Cohen's kappa test.

Results

According to the questionnaire, IBP was present in 46 SLE patients (46/281; 16.3%) whereas none of the HC had IBP (p<0.001). In radiological assessment, 22 SLE patients (7.8%) had sacroiliitis detected by conventional X-ray and/or magnetic resonance imaging. Only one SLE patient with sacroiliitis had HLA-B27.

Conclusion

Our study showed that IBP is increased in SLE patients and IBP in SLE is not associated with HLA-B27.

Dysregulation of T Follicular Helper Cells in Lupus

Although multiple and overlapping mechanisms are ultimately responsible for the immunopathology observed in patients with systemic lupus erythematosus, autoreactive Abs secreted by autoreactive plasma cells (PCs) are considered to play a critical role in disease progression and immunopathology. Given that PCs derive from the germinal centers (GC), long-term dysregulated GC reactions are often associated with the development of spontaneous autoantibody responses and immunopathology in systemic lupus erythematosus patients. In this review, we summarize the emerging evidence concerning the roles of T follicular helper cells in regulating pathogenic GC and autoreactive PC responses in lupus.

Clinicopathological factors for tubulointerstitial injury in lupus nephritis

OBJECTIVE

To investigate the incidence of tubulointerstitial injury in lupus nephritis (LN) and to examine clinicopathological factors that could indicate the presence of tubulointerstitial injury.

METHODS

This study included 98 patients with LN. Clinical data and the pathological results of the initial renal biopsy were collected.

RESULTS

The frequency of each tubulointerstitial injury parameter was over 50%, except for the interstitial edema, in the 98 patients investigated in this study. The most frequently detected tubulointerstitial injury parameter was tubular atrophy in this study. Neutrophil infiltration/karyorrhexis, wire loop lesion, and arteriosclerosis were observed frequently in patients with tubulointerstitial injuries. High serum creatinine and blood urea nitrogen (BUN) were observed more frequently in patients with tubulointerstitial injuries except tubular degeneration. The multivariable regression analysis showed a relationship between neutrophil infiltration/karyorrhexis and interstitial fibrosis/tubular degeneration, a relationship between wire loop lesion and tubulointerstitial inflammation/edema, and a relationship between arteriosclerosis and tubulointerstitial injuries (except interstitial edema). Patients with tubular degeneration had lower D-Dimer levels compared with those without. Patients with interstitial fibrosis had higher blood leukocyte counts than those without. The rate of low response to therapy was 13% among those without tubulointerstitial inflammation, but 35% in those with interstitial inflammation (P = 0.03).

CONCLUSION

Acute and chronic renal tubulointerstitial lesions are often found along with glomerular and vascular lesions. Immune and vascular factors are probably involved in tubulointerstitial injuries. Tubulointerstitial inflammation may be the initiator of chronic renal injury and may predict response to therapy.Key Points•To provide a theoretical basis for tubulointerstitial injury in LN.

Elevated Circulating Interleukin-17 Levels in Patients with Systemic Lupus Erythematosus: A Meta-analysis

BACKGROUND

Previous studies concerning the circulating interleukin-17 (IL-17) in systemic lupus erythematosus (SLE) were contradictory.

AIMS

To further precisely investigate circulating IL-17 in SLE and evaluate its influential factors by meta-analysis.

METHODS

EMBASE, PubMed and Cochrane Library were comprehensively searched to obtain studies on circulating IL-17 in SLE patients by November 22, 2018. The results were illustrated by pooled standard mean difference (SMD) with corresponding 95% confidence interval (CI) using random-effects model as there was significant heterogeneity, which was estimated using Cochran Q and I² statistics. Subgroup analyses and sensitivity analyses were also conducted.

RESULTS

Overall, 1872 articles were reviewed and 20 studies involving 1067 subjects with SLE and 721 healthy controls (HCs) were enrolled in the final analysis according to inclusion criteria. Compared with HCs, circulating IL-17 levels in SLE patients were elevated (SMD: 1.183, 95% CI: 0.763-1.603; P < .001). Moreover, in comparison to HCs, European and Asian SLE patients, age <30 years, disease duration ≥5 years, NOS scores <7 and using ELISA showed increased circulating IL-17 status, whereas no significant change was observed in other subgroups. There was no significant publication bias. Sensitivity analyses demonstrated that the results of our meta-analysis were robust.

CONCLUSIONS

SLE patients have higher circulating IL-17 levels, which is influenced by ethnic, age and disease duration, literature quality and measurements.

Interleukin-17 and lupus: enough to be a target? For which patients?

The involvement of the interleukin (IL)-17 axis in many inflammatory and autoimmune diseases is now well established, and this has led to the development of successful targeted therapies. Its role in systemic lupus erythematosus (SLE) is less described, since SLE is characterized by the impairment of many other immune actors. However, results from animal models and patients strongly suggest that IL-17 and its producing cells are involved in SLE pathogenesis. Circulating levels of IL-17 are increased in lupus, and tissue staining shows the presence of IL-17-producing cells in organ lesions. Through different mechanisms, the IL-17 axis promotes autoantibody production, immune complex deposition, complement activation and then tissue damage. There are also many interactions with other immune and non-immune actors, which account for the broad spectrum of clinical manifestations and disease heterogeneity. SLE treatment faces challenges with many disappointing trials and persistent unmet needs. The identification of subsets of SLE patients with an IL-17-driven disease now constitutes the key priority before starting trials. More preclinical studies are needed to improve the selection of the right patients able to respond and tolerate the many inhibitors that are already available.

The connection between the Th17 cell related cytokines and cancer stem cells in cancer: Novel therapeutic targets

Cancer Stem Cells (CSCs) are the subpopulation of cells present in the different types of cancers with capabilities of self-renewal, differentiation, and tumorigenicity when transplanted into an animal host. The research work on the CSC has been providing a promising approach for the improvement of cancer therapies in the future. The CSCs have a close connection with the cytokines related with the T helper 17 (Th17) cell and other factors present in the tumor microenvironment, and these play a pivotal role in tumor progression and metastasis. The properties of CSCs are well defined in various type of tumor which is mainly developed by chemically and spontaneously in murine cancer model but in human defined primarily on acute myeloid leukemia, glioma, and breast cancer. The role of Th1, Th2, Natural Killer cells are well described in the cancer biology, but the Th17 cells are the subset which is recently exploited, and lots of research are going on. In this Review, we summarize current findings of the characteristics and functions of the Th17 cell and its signature cytokines in different cancers and their interconnections with cancer stem cells and with their markers. We have also discussed the functional properties of CSCs and how the CSCs markers can be distinguished from normal stem cells markers. We have also talked about the strategies that are efficiently targeting of CSCs and Th17 cells in different cancers.

Th17/Treg Ratio and Disease Activity in Systemic Lupus Erythematosus

Background:

Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterized by T-cells imbalance. There are ongoing controversies about the role of specific T-helper cell subsets and their cytokines. The study aimed to confirm the disturbance of Th17/Treg ratio in SLE patients.

Methods:

Subjects were SLE patients who met the American College of Rheumatology 1997 criteria. Disease activity assessment was measured by SLAM index. Th17 and Treg level was measured by flow cytometry. Th17 level was evaluated as CD4⁺L17 whilst Treg as CD4⁺Foxp3⁺. Final result is stated as Th17/Treg ratio.

Results:

Thirty female subjects with active SLE had mean SLAM Score of 29.3±3.88, C3 level 25.2 (6-59.5), C4 level 15.25 (5-54.3), ESR 62.1±37.85, CRP 30.16±59.45, and anti-dsDNA 155.32±186.10. Higher Th17 level was found in SLE patients compared to healthy subjects (30.09 pg/ml vs 13.01pg/ml; 12.60% vs 0.91%). However, it did not correlate to disease activity (p>0.05; r=-0.28). Regarding Treg level, there was no significant difference between active SLE and healthy subjects (12.85 vs 11.05 pg/ml; 9.57% vs 2.05%). Treg level negatively correlated to SLE disease activity (p<0.01; r=-0.73). Th17/Treg ratio was 3.28±2.22% and it positively correlated to SLE disease activity (p<0.01; r=0.78).

Conclusion:

Th17/Treg ratio is positively correlated with disease activity. Th17 level is elevated but not correlated with disease activity. Decrease of Treg level is not significant though correlated with disease activity in SLE patients.

Functional and phenotypic heterogeneity of Th17 cells in health and disease

BACKGROUND

Th17 cells have nonredundant roles in maintaining immunity, particularly at mucosal surfaces. These roles are achieved principally through the production of cytokines and the recruitment of other immune cells to maintain the integrity of mucosal barriers and prevent the dissemination of microorganisms. Th17 cells are heterogeneous and exhibit a considerable degree of plasticity. This allows these cells to respond to changing environmental challenges. However, Th17 cells also play pro-inflammatory roles in chronic autoimmune diseases. The trigger(s) that initiate these Th17 responses in chronic autoimmune diseases remain unclear.

DESIGN

In this report, we provide an overview of studies involving animal models, patient data, genome wide association studies and clinical trials targeting IL-17 for treatment of patients to gain a better understanding of the pathogenic roles of Th17 cells play in a range of autoimmune diseases.

RESULTS

The report sheds light on likely triggers that initiate or perpetuate Th17 responses that promote chronic inflammation and autoimmunity. The divergent effects of tumour necrosis factor alpha blockade on Th17 cells in patients, is explored. Furthermore, we highlight the role of Th17 cells in inducing autoreactive B cells, leading to autoantibody production. Pathogenic bacterial species can change Th17 cell phenotype and responses. These findings provide insights into how Th17 cells could be induced to promoting autoimmune disease pathogenesis.

CONCLUSION

This article provides an overview of the distinct roles Th17 cells play in maintaining immunity at mucosal surfaces and in skin mucosa and how their functional flexibility could be linked with chronic inflammation in autoimmune rheumatic diseases.

MicroRNA‑146a inhibits the inflammatory responses induced by interleukin‑17A during the infection of Helicobacter pylori

Helicobacter pylori (H. pylori) infection is the major cause of chronic active gastritis and peptic ulcer disease. Upregulation of IL‑17A is associated with H. pylori infection in the gastric mucosa; however, the factors involved in the regulation of interleukin (IL)‑17A‑induced inflammatory responses in H. pylori‑associated gastritis remain unknown. MicroRNAs (miRNAs) serve as key post‑transcriptional regulators of gene expression and are associated with the H. pylori infection. The present study aimed to analyze the effects of IL‑17A on the expression of miR‑146a upon infection with H. pylori, as well as to identify the possible impact of miR‑146a dysregulation on the inflammatory response in vivo and in vitro. Reverse transcription‑quantitative polymerase chain reaction analysis was used to determine the expression levels of miR‑146a in gastric epithelial cells upon IL‑17A stimulation. The effects of miR‑146a mimics on IL‑17A‑induced inflammatory responses in SGC‑7901 cells were evaluated. The effects of miR‑146a mimics on the expression levels of IL‑1 receptor‑associated kinase 1 (IRAK1) and tumor necrosis factor receptor‑associated factor 6 (TRAF6) upon IL‑17A treatment were analyzed, and the IL‑17A‑stimulated inflammation following the silencing of IRAK1 and TRAF6 was observed. In addition, the correlation between miR‑146a and IL‑17A in human gastric mucosa with H. pylori was examined. The results indicated that IL‑17A‑induced miR‑146a may regulate the inflammatory response during the infection of H. pylori in a nuclear factor‑κB‑dependent manner. Furthermore, the expression of miR‑146a and IL‑17A are positively correlated in human gastric mucosa infected with H. pylori. These data suggested that miR‑146a may serve as a biomarker or therapeutic target in gastritis therapy.

Decreased levels of regulatory B cells in patients with acute pancreatitis: association with the severity of the disease

Early stratification of the severity of acute pancreatitis (AP) is clinically important. Regulatory B cells have been found to be associated with disease activity of autoimmune diseases. However, the role of Regulatory B cells in AP remains unknown. We investigate the dynamic longitudinal changes in circulating IL-10-producing B cells (B10) and memory CD19+CD24hiCD27hi cells in patients with AP to evaluate their prediction utility for AP severity. B10, CD19+CD24hiCD27hi cells, inflammatory markers and cytokines were detected in patients with AP immediately after admission to the hospital (day 1), then on the third and seventh days. We observed decreases in lymphocytes, CD19+, B10, CD19+CD24hiCD27hi cells and lower mean fluorescence intensity (MFI) of CD80 and CD86 on B10 or CD19+CD24hiCD27hi cells in patients with AP, especially in those with severe acute pancreatitis (SAP). CD19+CD24hiCD27hi cells from patients with AP suppressed the cytokine productions of CD4+ T cells and CD14+ monocytes, but had impaired ability to induce regulatory T cells response. B10 and CD19+CD24hiCD27hi cells significantly increased in patients with mild acute pancreatitis (MAP) from day 1 to day 7, whereas these indexes remained stable in patients with SAP. B10 or CD19+CD24hiCD27hi cells were negatively correlated with the severity index (APACHE II score), inflammatory markers (C-reactive protein, CD64 index), and cytokines (IL-6, IL-17, TNF-α). Furthermore, receiver operating characteristic (ROC) curve analysis revealed that B10 and CD19+CD24hiCD27hi cells could predict the development of SAP. Thus, the detection of B10 and CD19+CD24hiCD27hi cells may be a practical way to improve the early assessment of AP severity.

Mechanisms and functions of IL-17 signaling in renal autoimmune diseases

Immune-mediated glomerular diseases (glomerulonephritis) encompass a heterogeneous collection of diseases that cause inflammation within the glomerulus and other renal compartments with significant morbidity and mortality. In general, CD4⁺ T cells orchestrate the immune response and play a unique role in autoimmune and chronic inflammatory diseases. In particular, the characterization of a distinct, IL-17 cytokines producing CD4⁺ T cell subset named T_H17 cells has significantly advanced the current understanding of the pathogenic mechanisms of organ-specific immunity. Our group and others have shown that the recruitment of T_H17 cells to the inflamed kidney drives renal tissue injury in experimental and possibly human crescentic glomerulonephritis (GN), but much remains to be understood about the biological functions, regulation, and signaling pathways of the T_H17/IL-17 axis leading to organ damage. Here we review our current knowledge about the mechanisms and functions of IL-17 signaling in renal autoimmune diseases, with a special focus on experimental and human crescentic GN.

New Cytokines in the Pathogenesis of Atopic Dermatitis-New Therapeutic Targets

Atopic dermatitis (AD) is a recurrent, chronic, and inflammatory skin disease, which processes with severe itchiness. It often coexists with different atopic diseases. The number of people suffering from AD is relatively high. Epidemiological research demonstrates that 15–30% of children and 2–10% adults suffer from AD. The disease has significant negative social and economic impacts, substantially decreasing the quality of life of the patients and their families. Thanks to enormous progress in science and technology, it becomes possible to recognise complex genetic, immunological, and environmental factors and epidermal barrier defects that play a role in the pathogenesis of AD. We hope that the new insight on cytokines in AD will lead to new, individualised therapy and will open different therapeutic possibilities. In this article, we will focus on the cytokines, interleukin (IL)-17, IL-19, IL-33, and TSLP (thymic stromal lymphopoietin), which play a significant role in AD pathogenesis and may become the targets for future biologic therapies in AD. It is believed that the new era of biological drugs in AD will give a chance for patients to receive more successful treatment.

Therapeutic effect of human amniotic epithelial cells in murine models of Hashimoto's thyroiditis and Systemic lupus erythematosus

BACKGROUND AIMS

The chronic inflammation of autoimmune diseases develops repetitive localized destruction or systemic disorders, represented by Hashimoto's thyroiditis (HT) and Systemic lupus erythematosus (SLE) respectively. Currently, there are no efficient ways to treat these autoimmune diseases. Therefore, it is critically important to explore new therapeutic strategies. The aim of this study was to investigate the therapeutic efficacy of human amniotic epithelial cells (hAECs) in murine models of HT and SLE.

METHODS

Experimental autoimmune thyroiditis (EAT) was induced in female CBA/J mice by immunization with porcine thyroglobulin (pTg). hAECs were intravenously administered at different time points during the disease course. MRL-Fas^lpr mice, a strain with spontaneously occurring SLE, were intravenously administered hAECs when their sera were positive for both anti-nuclear antibodies (ANAs) and anti-double-stranded DNA (anti-dsDNA) antibodies. Two weeks after the last cell transplantation, blood and tissue samples were collected for histological examination and immune system analysis.

RESULTS

hAECs prevented lymphocytes infiltration into the thyroid and improved the damage of thyroid follicular in EAT mice. Correspondingly, hAECs administration reduced anti-thyroglobulin antibodies (TGAb), anti-thyroid peroxidase antibodies (TPOAb) and thyroid stimulating hormone (TSH) levels. SLE mice injected with hAECs appeared negative for ANAs and anti-dsDNA antibodies and showed reduced immunoglobulin profiles. Mechanically, hAECs modulated the immune cells balance in EAT and SLE mice, by downregulating the ratios of Th17/Treg cells in both EAT and SLE mice and upregulating the proportion of B10 cells in EAT mice. This was confirmed by in vitro assay, in which hAECs inhibited the activation of EAT mice-derived splenocytes. Moreover, hAECs improved the cytokine environment in both EAT and SLE mice, by suppressing the levels of IL-17A and IFN-γ and enhancing TGF-β.

CONCLUSION

These results demonstrated the immunoregulatory effect of hAECs for inflammation inhibition and injury recovery in HT and SLE murine models. The current study may provide a novel therapeutic strategy for these autoimmune diseases in clinic.

The Mucosal Vaccine Adjuvant LT(R192G/L211A) or dmLT

Perhaps the best-studied mucosal adjuvants are the bacterially derived ADP-ribosylating enterotoxins. This adjuvant family includes heat-labile enterotoxin of Escherichia coli (LT), cholera toxin (CT), and mutants or subunits of LT and CT. These proteins promote a multifaceted antigen-specific response, including inflammatory Th1, Th2, Th17, cytotoxic T lymphocytes (CTLs), and antibodies. However, more uniquely among adjuvant classes, they induce antigen-specific IgA antibodies and long-lasting memory to coadministered antigens when delivered mucosally or even parenterally. The purpose of this minireview is to describe the general properties, history and creation, preclinical studies, clinical studies, mechanisms of action, and considerations for use of the most promising enterotoxin-based adjuvant to date, LT(R192G/L211A) or dmLT. This review is timely due to completed, ongoing, and planned clinical investigations of dmLT in multiple vaccine formulations by government, nonprofit, and industry groups in the United States and abroad.

Genome-wide association study meta-analysis identifies five new loci for systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a common systemic autoimmune disease with a complex genetic inheritance. Genome-wide association studies (GWAS) have significantly increased the number of significant loci associated with SLE risk. To date, however, established loci account for less than 30% of the disease heritability and additional risk variants have yet to be identified. Here we performed a GWAS followed by a meta-analysis to identify new genome-wide significant loci for SLE.

METHODS

We genotyped a cohort of 907 patients with SLE (cases) and 1524 healthy controls from Spain and performed imputation using the 1000 Genomes reference data. We tested for association using logistic regression with correction for the principal components of variation. Meta-analysis of the association results was subsequently performed on 7,110,321 variants using genetic data from a large cohort of 4036 patients with SLE and 6959 controls of Northern European ancestry. Genetic association was also tested at the pathway level after removing the effect of known risk loci using PASCAL software.

RESULTS

We identified five new loci associated with SLE at the genome-wide level of significance (p < 5 × 10^- 8): GRB2, SMYD3, ST8SIA4, LAT2 and ARHGAP27. Pathway analysis revealed several biological processes significantly associated with SLE risk: B cell receptor signaling (p = 5.28 × 10^- 6), CTLA4 co-stimulation during T cell activation (p = 3.06 × 10^- 5), interleukin-4 signaling (p = 3.97 × 10^- 5) and cell surface interactions at the vascular wall (p = 4.63 × 10^- 5).

CONCLUSIONS

Our results identify five novel loci for SLE susceptibility, and biologic pathways associated via multiple low-effect-size loci.

Administration of activated lymphocyte-derived DNA accelerates and aggravates lupus nephritis in B6/lpr mice: a new approach to modify a lupus murine model

B6/lpr mouse strain is a well-known systemic lupus erythematosus murine model characterized by uncontrolled lymphoproliferation and autoantibody production. However, it displays a delayed and mild development of lupus nephritis (LN), which is not conducive to the research of the pathogenesis and therapeutic strategies of this condition. Our previous study demonstrated that activated lymphocyte-derived DNA (ALD-DNA) could induce high urine protein levels and severe glomerulonephritis (GN) in BALB/c mice. In the present study, we tried to remedy delayed urine protein production and mild GN in B6/lpr mice via ALD-DNA immunization. We found that urine protein levels were enhanced significantly in B6/lpr mice 4 weeks after ALD-DNA immunization compared with those in unactivated lymphocyte-derived (UnALD)-DNA- and phosphate-buffered saline (PBS)-treated controls. Moreover, more serious GN and glomerular immune complex were observed in ALD-DNA-immunized B6/lpr mice. We further explored the mechanism, and found that ALD-DNA immunization promoted T helper type 17 (Th17) cell enrichment remarkably, which enhanced the proportion of autoantibody-secreting plasma cells and promoted the production of anti-dsDNA autoantibodies, leading to accelerated and aggravated LN. Our data demonstrated that ALD-DNA immunization could remedy delayed urine protein production and mild GN in B6/lpr mouse, which makes it more suitable for studies on the pathogenesis of and therapeutic strategies against LN.

PKCδ-Mediated Nox2 Activation Promotes Fluid-Phase Pinocytosis of Antigens by Immature Dendritic Cells

Aims

Macropinocytosis is a major endocytic pathway by which dendritic cells (DCs) internalize antigens in the periphery. Despite the importance of DCs in the initiation and control of adaptive immune responses, the signaling mechanisms mediating DC macropinocytosis of antigens remain largely unknown. The goal of the present study was to investigate whether protein kinase C (PKC) is involved in stimulation of DC macropinocytosis and, if so, to identify the specific PKC isoform(s) and downstream signaling mechanisms involved.

Methods

Various cellular, molecular and immunological techniques, pharmacological approaches and genetic knockout mice were utilized to investigate the signaling mechanisms mediating DC macropinocytosis.

Results

Confocal laser scanning microscopy confirmed that DCs internalize fluorescent antigens (ovalbumin) using macropinocytosis. Pharmacological blockade of classical and novel PKC isoforms using calphostin C abolished both phorbol ester- and hepatocyte growth factor-induced antigen macropinocytosis in DCs. The qRT-PCR experiments identified PKCδ as the dominant PKC isoform in DCs. Genetic studies demonstrated the functional role of PKCδ in DC macropinocytosis of antigens, their subsequent maturation, and secretion of various T-cell stimulatory cytokines, including IL-1α, TNF-α and IFN-β. Additional mechanistic studies identified NADPH oxidase 2 (Nox2) and intracellular superoxide anion as important players in DC macropinocytosis of antigens downstream of PKCδ activation.

Conclusion

The findings of the present study demonstrate a novel mechanism by which PKCδ activation via stimulation of Nox2 activity and downstream redox signaling promotes DC macropinocytosis of antigens. PKCδ/Nox2-mediated antigen macropinocytosis stimulates maturation of DCs and secretion of T-cell stimulatory cytokines. These findings may contribute to a better understanding of the regulatory mechanisms in DC macropinocytosis and downstream regulation of T-cell-mediated responses.

Peripheral B-Cell Subset Distribution in Primary Antiphospholipid Syndrome

Background: B-cell differentiation and B-cell tolerance checkpoints may be different in antiphospholipid syndrome (APS) from systemic lupus erythematosus (SLE) and can help to understand differences between them. Our aim was to define alterations of B-cell subsets in patients with primary APS (pAPS) and to compare them with SLE patients and healthy controls (HC). Methods: Cross-sectional study including three study groups: 37 patients with pAPS, 11 SLE patients, and 21 age- and gender-matched HC. We determined the frequencies of different B-cell subsets in peripheral blood naïve and memory compartments. In addition, we measured serum B cell-activating factor (BAFF) levels and circulating pro-inflammatory cytokines, such as IL-6, by commercial ELISA and CBA, respectively. Results: Patients with pAPS showed a lower percentage of immature and naïve B cells than patients with SLE (p = 0.013 and p = 0.010, respectively) and a higher percentage of non-switched memory B cells than patients with SLE (p = 0.001). No differences either in the percentage of switched memory cells or plasma cells were found among the different groups. Serum BAFF levels were higher in SLE patients than in healthy controls and pAPS patients (p = 0.001 and p = 0.017, respectively). A significant increase in the serum BAFF levels was also observed in pAPS patients compared to HC (p = 0.047). Circulating IL-6 levels were higher in SLE and pAPS patients than HC (p = 0.036 and p = 0.048, respectively). A positive correlation was found between serum BAFF and IL-6 levels in patients with SLE but not in pAPS (p = 0.011). Conclusions: Our characterization of peripheral blood B-cell phenotypes in pAPS demonstrates different frequencies of circulating B cells at different stages of differentiation. These differences in the naïve B-cell repertoire could explain the higher number and variety of autoantibodies in SLE patients in comparison to pAPS patients, especially in those with obstetric complications.

Gut Microbiota in Human Systemic Lupus Erythematosus and a Mouse Model of Lupus

Gut microbiota dysbiosis has been observed in a number of autoimmune diseases. However, the role of the gut microbiota in systemic lupus erythematosus (SLE), a prototypical autoimmune disease characterized by persistent inflammation in multiple organs of the body, remains elusive. Here we report the dynamics of the gut microbiota in a murine lupus model, NZB/W F1, as well as intestinal dysbiosis in a small group of SLE patients with active disease. The composition of the gut microbiota changed markedly before and after the onset of lupus disease in NZB/W F1 mice, with greater diversity and increased representation of several bacterial species as lupus progressed from the predisease stage to the diseased stage. However, we did not control for age and the cage effect. Using dexamethasone as an intervention to treat SLE-like signs, we also found that a greater abundance of a group of lactobacilli (for which a species assignment could not be made) in the gut microbiota might be correlated with more severe disease in NZB/W F1 mice. Results of the human study suggest that, compared to control subjects without immune-mediated diseases, SLE patients with active lupus disease possessed an altered gut microbiota that differed in several particular bacterial species (within the genera Odoribacter and Blautia and an unnamed genus in the family Rikenellaceae) and was less diverse, with increased representation of Gram-negative bacteria. The Firmicutes/Bacteroidetes ratios did not differ between the SLE microbiota and the non-SLE microbiota in our human cohort.IMPORTANCE SLE is a complex autoimmune disease with no known cure. Dysbiosis of the gut microbiota has been reported for both mice and humans with SLE. In this emerging field, however, more studies are required to delineate the roles of the gut microbiota in different lupus-prone mouse models and people with diverse manifestations of SLE. Here, we report changes in the gut microbiota in NZB/W F1 lupus-prone mice and a group of SLE patients with active disease.

IL-6/STAT3 pathway induced deficiency of RFX1 contributes to Th17-dependent autoimmune diseases via epigenetic regulation

Epigenetic modifications affect the differentiation of T cell subsets and the pathogenesis of autoimmune diseases, but many mechanisms of epigenetic regulation of T cell differentiation are unclear. Here we show reduced expression of the transcription factor RFX1 in CD4⁺ T cells from patients with systemic lupus erythematosus, which leads to IL-17A overexpression through increased histone H3 acetylation and decreased DNA methylation and H3K9 tri-methylation. Conditional deletion of Rfx1 in mice exacerbates experimental autoimmune encephalomyelitis and pristane-induced lupus-like syndrome and increases induction of Th17 cells. In vitro, Rfx1 deficiency increases the differentiation of naive CD4⁺ T cells into Th17 cells, but this effect can be reversed by forced expression of Rfx1. Importantly, RFX1 functions downstream of STAT3 and phosphorylated STAT3 can inhibit RFX1 expression, highlighting a non-canonical pathway that regulates differentiation of Th17 cells. Collectively, our findings identify a unique role for RFX1 in Th17-related autoimmune diseases.

Th17 cells are a common pathogenic effector cell in autoimmune inflammatory diseases. Here the authors show that the transcription factor RFX1 limits Th17 differentiation and is protective against the pathogenesis of Th17-driven autoimmune diseases.

CD19+ Tim-1+ B cells are decreased and negatively correlated with disease severity in Myasthenia Gravis patients

T cell immunoglobulin mucin domain-1(Tim-1) was recently identified to be critical and essential for optimal regulatory B cells function in maintaining immune tolerance. We aimed to measure the expression levels of Tim-1 on B cells from patients with Myasthenia Gravis (MG) and to investigate whether the expression of Tim-1 is associated with pathogenesis of MG. A total of 34 patients with MG (18 generalized MG (GMG) and 16 ocular MG (OMG) and 24 healthy donors were recruited in this study. The quantitative myasthenia gravis score (QMGS) was used to evaluate the clinical severity. Real-time PCR and flow cytometry were used to measure the levels of Tim-1 expressed on peripheral B cells. Peripheral CD138+ plasma cells were assayed by flow cytometry. Serum Th17-related cytokines (IL-6, IL-1β and IL-17) and anti-AChR antibody (Ab) titers were tested by enzyme-linked immunosorbent assay (ELISA). Our data demonstrated that the mRNA and protein expression levels of B cell Tim-1 in both the GMG and OMG groups were significantly lower than those in healthy controls, with lower expression in GMG than in OMG. Tim-1 expression on B cells from OMG/GMG was negatively correlated with clinical severity, plasma cells frequency, serum Th17-related cytokines and anti-AChR Ab levels. Our results indicated that aberrant expression of Tim-1 exists on B cells and may contribute to the Th17 polarization and antibody-secreting plasma cells differentiation in MG patients.

Curcumin: A natural modulator of immune cells in systemic lupus erythematosus

Curcumin is a polyphenol natural product isolated from turmeric, interacting with different cellular and molecular targets and, consequently, showing a wide range of pharmacological effects. Recent preclinical and clinical trials have revealed immunomodulatory properties of curcumin that arise from its effects on immune cells and mediators involved in the immune response, such as various T-lymphocyte subsets and dendritic cells, as well as different inflammatory cytokines. Systemic lupus erythematosus (SLE) is an inflammatory, chronic autoimmune-mediated disease characterized by the presence of autoantibodies, deposition of immune complexes in various organs, recruitment of autoreactive and inflammatory T cells, and excessive levels of plasma proinflammatory cytokines. The function and numbers of dendritic cells and T cell subsets, such as T helper 1 (Th1), Th17, and regulatory T cells have been found to be significantly altered in SLE. In the present report, we reviewed the results of in vitro, experimental (pre-clinical), and clinical studies pertaining to the modulatory effects that curcumin produces on the function and numbers of dendritic cells and T cell subsets, as well as relevant cytokines that participate in SLE.