Elevated Th17 cells are accompanied by FoxP3+ Treg cells decrease in patients with lupus nephritis

Efficacy, safety and the lymphocyte subsets changes of low-dose IL-2 in patients with systemic lupus erythematosus: A systematic review and meta-analysis

INTRODUCTION

Existing therapies of systemic lupus erythematosus (SLE) are efficacious only in certain patients. Developing new treatment methods is urgent. This meta-analysis aimed to evaluate the efficacy and safety of low-dose IL-2 (LD-IL-2).

METHODS

According to published data from PubMed, Web of Science, Embase, ClinicalTrials.gov, MEDLINE, MEDLINE, Web of Knowledge, Cochrane Library, and FDA.gov, eight trials were included.

RESULTS

After the LD-IL-2 treatment, 54.8% of patients had distinct clinical remission. The SRI-4 response rates were 0.819 (95% confidence interval [CI]: 0.745-0.894), and the SELENA-SLEDAI scores were significantly decreased (SMD = -2.109, 95% CI: [-3.271, -0.947], p < .001). Besides, the proportions of CD4+ T (SMD = 0.614, 95% CI: [0.250, 0.979], p = .001) and Treg cells (SMD = 1.096, 95% CI: [0.544, 1.649], p < .001) were increased dramatically after LD-IL-2 treatment, while there were no statistical differences in the proportions of CD8+ T cells, Th1 cells, Th2 cells, and Th17 cells (p > .05). Besides, the proportions of Th17 (SMD = 1.121, 95% CI: [0.709, 1.533], p < .001) and Treg (SMD = 0.655, 95% CI: [0.273, 1.038], p = .001) were significantly increased after receiving subcutaneously 0.5 million IU of LD-IL-2 treatment per day for 5 days, but there were no statistical differences in the proportions of Treg after receiving 1 million IU every other day subcutaneously of LD-IL-2 treatment. Injection site reaction and fever were common side effects of IL-2, which occurred in 33.1% and 14.4% of patients. No serious adverse events were reported.

CONCLUSION

LD-IL-2 was promising and well-tolerated in treating SLE, which could promote Treg's proliferation and functional recovery. Injecting 0.5 million IU of IL-2 daily can better induce the differentiation of Treg cells and maintain immune homeostasis than injecting 1 million IU every other day.

Salt Behind the Scenes of Systemic Lupus Erythematosus and Rheumatoid Arthritis

PURPOSE OF REVIEW

Sodium is vital for human health. High salt intake is a global health problem and is associated with cardiovascular morbidity and mortality. Recent evidence suggests that both innate and adaptive immune systems are affected by sodium. In general, excess salt intake drives immune cells toward a pro-inflammatory phenotype. The incidence of autoimmune diseases, including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), is steadily increasing. As excess salt induces a pro-inflammatory state, increased salt intake may have impacts on autoimmune diseases. The relationship between salt intake and autoimmune diseases is most widely studied in patients with SLE or RA. This review aimed to summarize the relationship between salt intake and SLE and RA.

RECENT FINDINGS

Most, but not all, of these studies showed that high salt intake might promote SLE by M1 macrophage shift, increase in Th17/Treg cell ratio, activation of dendritic and follicular helper T cells, and increased secretion of pro-inflammatory cytokines. In RA, apart from driving immune cells toward a pro-inflammatory state, high salt intake also influences cellular signaling pathways, including receptor activator of nuclear factor κB ligand (RANKL), Rho GTPases, and MAPK (mitogen-activated protein kinase). There is now sufficient evidence that excess salt intake may be related to the development and progression of SLE and RA, although there are still knowledge gaps. More studies are warranted to further highlight the relationship between excess salt intake, SLE, and RA. Salt intake may affect cell types and pro-inflammatory cytokines and signaling pathways associated with the development and progression of systemic lupus erythematosus and rheumatoid arthritis. Bcl-6 B-cell lymphoma, 6 Erk extracellular signal-regulated kinases, IFN-γ interferon-gamma, JNK c-Jun N-terminal kinase, IL-4 interleukin 4, IL-6 interleukin 6, MAPK mitogen-activated protein kinase, STAT signal transducer and activator of transcription, Tnf-α tumor necrosis factor, Treg T regulatory cell.

Association of regulatory T cells with renal outcomes in patients with proliferative lupus nephritis

BACKGROUND

Despite progress in the diagnosis and treatment of proliferative lupus nephritis (PLN), the prognosis remains unfavorable. Previous investigations have suggested that the deficiency of regulatory T cells (Tregs) is involved in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). But the prognostic value of Tregs in PLN remains controversial. This study aimed to investigate the association of Tregs with renal outcomes in patients with PLN.

METHODS

The baseline and follow-up data of patients with biopsy-proven PLN were collected in this study. All patients were divided into two groups according to whether the renal endpoint event occurred. Clinicopathologic features and therapeutic responses were compared between the two groups. Cox regression analyses curve fitting and threshold effect analysis were implemented to investigate the relationship between Tregs level and the long-term renal outcomes. The renal endpoint was defined as end-stage kidney disease (ESKD) or doubling the SCr value.

RESULTS

A total of 405 PLN patients were included. After a follow-up of 71.53 (53.13-97.47) months, 42 (10.4%) patients reached the renal endpoint. The Treg cell counts (16/μL) in the renal endpoint group were significantly decreased than that in the non-renal endpoint group (p < 0.001). Univariate and multivariate Cox regression analyses showed that the high level of Tregs was an independent protective factor for the long-term renal prognosis of PLN. Smooth curve fitting of the generalized additive mixed model analysis indicated that the risk of renal endpoint first decreased with Tregs and then slightly increased along with Treg cell levels. The segmented linear model revealed that when Treg cell counts <46/μL, the risk of renal endpoint decreased by 6.8% for every 1 μL increase in Treg levels (p = 0.0029).

CONCLUSION

Treg cell counts are closely related to the long-term renal outcomes of patients with PLN, and increasing Treg cell levels may play an important role in improving the prognosis of the kidney, but there may be a turning point (i.e., threshold effect) at the Treg cell counts that leads to directional changes in the renal outcomes.

Cytokines in Systemic Lupus Erythematosus-Focus on TNF-α and IL-17

Systemic lupus erythematosus (SLE) is an autoimmune disorder known for its complex pathogenesis, in which cytokines play an essential role. It seems that the modulation of these cytokines may impact disease progression, being considered potential biomarkers. Thus, TNF (tumor necrosis factor)-α and IL (interleukin)-17 are molecules of great interest in SLE. TNF-α plays a dual role in SLE, with both immunosuppressive and proinflammatory functions. The role of IL-17 is clearly described in the pathogenesis of SLE, having a close association with IL-23 in stimulating the inflammatory response and consecutive tissue destruction. It appears that patients with elevated levels of these cytokines are associated with high disease activity expressed by the SLE disease activity index (SLEDAI) score, although some studies do not confirm this association. However, TNF-α and IL-17 are found in increased titers in lupus patients compared to the general population. Whether inhibition of these cytokines would lead to effective treatment is under discussion. In the case of anti-TNF-α therapies in SLE, the possibility of ATIL (anti-TNF-induced lupus) is a serious concern that limits their use. The use of anti-IL-17 therapies in SLE is a promising option, but not yet approved. Future studies of these cytokines in large cohorts will provide valuable information for the management of SLE.

The role of thyroid hormone in the renal immune microenvironment

Thyroid hormones are essential for proper kidney growth and development. The kidney is not only the organ of thyroid hormone metabolism but also the target organ of thyroid hormone. Kidney disease is a common type of kidney damage, mainly including different types of acute kidney injury, chronic kidney disease, diabetic nephropathy, lupus nephritis, and renal cell carcinoma. The kidney is often damaged by an immune response directed against its antigens or a systemic immune response. A variety of immune cells in the innate and adaptive immune systems, including neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes, is essential for maintaining immune homeostasis and preventing autoimmune kidney disease. Recent studies have found that thyroid hormone plays an indispensable role in the immune microenvironment of various kidney diseases. Thyroid hormones regulate the activity of neutrophils, and dendritic cells express triiodothyronine receptors. Compared to hypothyroidism, hyperthyroidism has a greater effect on neutrophils. Furthermore, in adaptive immune systems, thyroid hormone may activate T lymphocytes through several underlying mechanisms, such as mediating NF-κB, protein kinase C signalling pathways, and β-adrenergic receptors, leading to increased T lymphocyte activation. The present review discusses the effects of thyroid hormone metabolism regulation in the immune microenvironment on the function of various immune cells, especially neutrophils, macrophages, dendritic cells, T lymphocytes, and B lymphocytes. Although there are not enough data at this stage to conclude the clinical relevance of these findings, thyroid hormone metabolism may influence autoimmune kidney disease by regulating the renal immune microenvironment.

Autoantibodies in Neuropsychiatric Systemic Lupus Erythematosus (NPSLE): Can They Be Used as Biomarkers for the Differential Diagnosis of This Disease?

Systemic lupus erythematosus is a complex immunological disease where both environmental factors and genetic predisposition lead to the dysregulation of important immune mechanisms. Eventually, the combination of these factors leads to the production of self-reactive antibodies that can target any organ or tissue of the human body. Autoantibodies can form immune complexes responsible for both the organ damage and the most severe complications. Involvement of the central nervous system defines a subcategory of the disease, generally known with the denomination of neuropsychiatric systemic lupus erythematosus. Neuropsychiatric symptoms can range from relatively mild manifestations, such as headache, to more severe complications, such as psychosis. The evaluation of the presence of the autoantibodies in the serum of these patients is the most helpful diagnostic tool for the assessment of the disease. The scientific progresses achieved in the last decades helped researchers and physicians to discover some of autoepitopes targeted by the autoantibodies, although the majority of them have not been identified yet. Additionally, the central nervous system is full of epitopes that cannot be found elsewhere in the human body, for this reason, autoantibodies that selectively target these epitopes might be used for the differential diagnosis between patients with and without the neuropsychiatric symptoms. In this review, the most relevant data is reported with regard to mechanisms implicated in the production of autoantibodies and the most important autoantibodies found among patients with systemic lupus erythematosus with and without the neuropsychiatric manifestations.

Disturbance in Serum Levels of IL-17 and TGF-β1 and in Gene Expression of ROR-γt and FOX-P3 Is Associated with Pathogenicity of Systematic Lupus Erythematosus

To investigate the disturbance in serum levels of interleukin-17 (IL-17) and transforming growth factor-beta1 (TGF-β1) and gene expression of retinoic acid-related orphan receptor-gamma t (ROR-γt) and forkhead box-P3 (FOX-P3) in patients with systemic lupus erythematosus (SLE) and to study their association with disease pathogenicity and activity. Newly diagnosed active patients with SLE (n=88) and healthy volunteers (n=70) were included. Serum IL-17 and TGF-β1 were measured using enzyme-linked immunosorbent assay. Gene-expression profiles of ROR-γt and FOX-P3 were screened using real-time polymerase chain reaction. The IL-17/TGF-β1 and ROR-γt/FOX-P3 levels were also calculated. The mean age of the patients was 30.96±8.25 years; they were 82 women and 6 men. Of the patients, 11.4% manifested mild disease while 88.6% had severe disease. The serum level of TGF-β1 was significantly lower (70.2±34.9 vs. 200.23±124.77 pg/ml), while both IL-17 (614.7±317.5 vs. 279.76±110.65 pg/ml) and IL-17/TGF-β1 (18.5±30.1 vs. 1.66±0.9) levels were significantly higher, in patients than in controls (p&lt;0.0001). The gene-expression level of FOX-P3 (0.6±0.8 vs. 13.68±39.35) was reported to be lower, while ROR-γt (3.9±3.5 vs. 1.99±2.09) and ROR-γt/FOX-P3 (18.6±21.1 vs. 7.63±17.19) levels were significantly higher, in patients than in controls (p&lt;0.0001). Disturbance in serum levels of IL-17 and TGF-β1 in T helper-17 and T-regulatory cells proliferation was highlighted through an imbalance in the gene expression of FOX-P3 and ROR-γt, as both are signature genes for the two cell types, respectively. These findings underscore the critical role of IL-17 and TGF-β1 in SLE development, rendering them potential targets for developing novel immunotherapeutic strategies.

YY1 alleviates lupus nephritis-induced renal injury by reducing the Th17/Treg cell ratio via the IFN-γ/Fra2 axis

Lupus nephritis (LN) is associated with extensive injury and nephron loss in the afflicted kidney. Evidence has revealed the involvement of dysregulated Yin Yang 1 (YY1), a reported inflammatory modulator, in LN-induced kidney injury, and our microarray profile identified downregulated YY1 expression. Therefore, this study explored the functional relevance and mechanism of YY1 in LN-induced kidney injury. LN was modeled in mice by intraperitoneal injection of pristane, and Jurkat cells (CD41 human T lymphocytes) were activated with TNF-α to mimic the inflammatory environment found in LN. The expression patterns of YY1 and bioinformatics predictions of the downstream factor IFN-γ were confirmed in renal tissues from the mice with LN using qRT-PCR and Western blot analyses. The contents of proinflammatory cytokines in mouse serum samples and cell supernatants were determined using enzyme-linked immunosorbent assays (ELISAs). Ectopic expression and depletion approaches were subsequently used in vitro and in vivo to examine the effects of the YY1/IFN-γ/Fra2/PARP-1/FOXO1 axis on TNF-α-induced inflammation and LN-induced kidney injury. The results showed downregulated expression of YY1 and FOXO1 in the kidney tissues of the mice with LN. Increased proinflammatory factor production was observed in the mice with LN and TNF-α-treated Jurkat cell supernatant, accompanied by increased cell apoptosis and a high ratio of Th17/Treg cells, and these effects were reversed by YY1 restoration. YY1 was further shown to inhibit IFN-γ expression and thereby downregulate Fra2 expression. Fra2 depletion then inhibited PARP-1 expression and promoted FOXO1 expression to suppress cell apoptosis and the release of inflammatory factors. Collectively, our findings revealed that YY1 may alleviate LN-induced renal injury via the IFN-γ/Fra2/PARP-1/FOXO1 axis.

New insights for regulatory T cell in lupus nephritis

Lupus nephritis (LN) is a complicated autoimmune disease marked by out-of-balance of immunological reactivity and immune tolerance. With the advance of immunotherapy in human disease, regulatory T (Treg) cells serve a crucial function in immune tolerance regulation and are characterized with suppression function as one of the most important research hotspots for autoimmunity diseases. In recent years, Treg cells have shown the robust potential for treatment to autoimmunity diseases like type I diabetic mellitus and rheumatoid arthritis. However, Treg cell therapy is poorly understood for LN patients. This review aims to summarize new insights for Treg-targeting techniques in LN patients. The current data regarding the biology features of Treg cells in LN patients is discussed. The propotion of Treg cells in LN patients have contradictory results regarding the use of different molecular markers. Forkhead box protein 3 (FOXP3) are hallmarks for control function of Treg cells. Treg cells can directly or indirectly target T cells and B cells by playing supressive role. The molecular targets for Treg cells in LN patients includes gene variants, miRNAs, and inflammatory related factors. Based on the current knowledge of Treg cell biology, several therapeutic strategies could be used to treat LN: cell transplantation, low dose IL-2 treatment, drugs target the balance of Treg and type 17 T helper (Th17) cells, and Chinese medicine.

Th17 and Th1 cells in systemic lupus erythematosus with focus on lupus nephritis

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by T cells imbalance. Indeed, a correlation between levels of Th17 cells and disease activity has been reported. Our work aimed to study the functional association of subpopulations of Th cells and SLE with (lupus nephritis, LN) or without (lupus erythematosus, LE) renal involvement in Tunisian patients through the detection of intracellular cytokines and surface marker expression. The IL23R and RORC mRNA expression levels were evaluated. The level of Th17 and Th1 cells was higher in LE and LN patients compared to healthy controls (HC) (p = 0.007 and p = 0.018, respectively), while Th1/17 cells were increased only in LN patients compared to HC (p = 0.011). However, no significant difference was described in the mRNA expression levels of RORC and IL-23R between SLE and HC. Our findings suggest that the Th1/Th17 differentiation mechanisms are altered in SLE and that this imbalance should have an important influence on the development and severity of the disease.

Increased frequency of activated regulatory T cells in patients with lupus nephritis

BACKGROUND AND OBJECTIVE

Lupus nephritis (LN) is one of the common manifestations of SLE, which affects the quality of life of patients. Abnormality in the adaptive immune response, such as T cell response, plays the main role in the pathogenesis of SLE and LN. In this study, we aimed to evaluate the role of different subpopulations of regulatory T cells (Tregs) and effector T cells (Teff) in patients with LN and compare them with SLE patients.

MATERIALS AND METHODS

A total of 48 participants were enrolled in this study and divided into three groups: (i) patients with SLE; (ii) patients with LN; and (iii) healthy controls (HCs) subjects. The frequencies of CD4⁺ CD25⁺⁺ CD45RA^- Foxp3^hi activated Tregs (aTregs), CD4⁺ CD25⁺ CD45RA⁺ Foxp3^lo resting Tregs (rTregs), CD4⁺ CD25⁺ CD45RA^- Foxp3^lo non-Tregs, CD4⁺ CD25⁺ Foxp3^- Teff, and Tregs were analyzed in all subjects using flow cytometer.

RESULTS

LN patients had a considerable increased frequency of aTregs and Tregs compared with SLE patients (standardized mean difference [SMD] 0.50; 95% CI [-0.26, 1.25]; p > 0.05 and SMD 0.60; 95% CI [-0.16, 1.36]; p > 0.05, respectively). Patients with LN had a considerable increased frequency of Teff compared with SLE patients (SMD 0.49; 95% CI [-0.26, 1.24]; p > 0.05). However, the increased ratio of Tregs/Teff was observed in patients with LN compared with SLE patients (SMD -0.25; 95% CI [-0.97, 0.48]; p > 0.05).

CONCLUSION

Patients with LN showed immunoregulatory properties, in which both aTregs and Tregs had increased frequencies.

Involvement of IL-33 in the Pathophysiology of Systemic Lupus Erythematosus: Review

IL-33 is a newly discovered cytokine displaying pleiotropic localizations and functions. More specifically, it also functions as an alarmin, following its release from cells undergoing cell death or necrosis, to alert the innate immune system. The role of IL-33 has been underlined in several inflammatory and autoimmune diseases including systemic lupus erythematosus (SLE). The expressions of IL-33 as well as its receptor, ST2, are significantly upregulated in SLE patients and in patients with lupus nephritis. This review discusses the involvement of IL-33 in the pathology of SLE.

The relation of CD4+CD25+Foxp3+ regulatory T cells concentration with disease activity and damage index in systemic lupus erythematosus

Introduction

Regulatory T cells (Treg) deficits, both quantitative and qualitative, are known to be possible triggers for the development of autoimmune disorders by causing T and B cells dysfunction. The contribution of Treg deficiency in the etiology of systemic lupus erythematosus (SLE) is still being debated. The aim of the present study is to evaluate the percentage of circulating CD4+CD25+Foxp3+ Treg cells in a cohort of Egyptian SLE patients and to correlate this value with the activity and damage index of these patients.

Methods

50 female patients with SLE together with an equal number of age- and sex-matched healthy controls were enrolled in the study. Flow cytometric determination of peripheral Treg cells was carried out for all participants by detecting the percentage of CD4+CD25+Foxp3+ cells to compare cases with the control group. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K), while disease damage was assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI). Both indices were correlated with the percentage of CD4+CD25+Foxp3 T regulatory cells.

Results

CD4+CD25+Foxp3+ Treg cells percentage was significantly decreased in patients with SLE as compared to healthy controls. On correlating CD4+CD25+Foxp3+ Treg percentage with SLEDAI-2K, a significantly negative correlation was found. Also, there was a negative significant correlation between CD4+CD25+Foxp3+ Treg cells percentage and SLICC/ACR DI. On correlating SLEDAI-2K with damage index (SLICC/ACR DI), we found highly significant positive correlation.

Conclusion

Our study showed impaired production of CD4+CD25+Foxp3+ Tregs in SLE patients, which can play a reciprocal role with some cytokines to affect the activity of the disease and organ damage. CD4+CD25+Foxp3+ Tregs cells should be the target to determine the clinical effectiveness of new therapy to modulate Tregs besides the traditional treatments.

Th17/Regulatory T cells ratio evolution: A prospective study in a group of healthy pregnant women

During pregnancy, the maternal immune system is challenged to tolerate a semi-allogenic fetus. A shift toward a tolerogenic profile is essential to ensure a healthy fetal and placental development. One of the most important mechanisms involved in the maternal immune tolerance towards the fetal antigens is expressed in the activity of the regulatory T (Treg) and Th17 cells. The behavior and equilibrium of these two T lymphocyte populations were rarely studied in normal healthy pregnancies through the beginning of gestation to the postpartum period. We conducted a prospective longitudinal observational study where peripheral blood lymphocyte subsets were analyzed in each trimester of pregnancy and postpartum period in a group of healthy pregnant women. Our study observed a consistent reduction in peripheric Treg cell count through all pregnancy while the Th17 cell count remained stable. The Th17/Treg ratio increases significantly throughout pregnancy to the postpartum period. These changes could be justified by the migration of the immunotolerant Treg cells to the maternal decidua and lead to the establishment of a systemic pro-inflammatory profile by the end of pregnancy. This data could explain why systemic syndromes like preeclampsia develop in susceptible women during the second half of pregnancy or why many autoimmune disorders flourish in the first weeks postpartum.

Low-Dose Interleukin-2 as an Alternative Therapy for Refractory Lupus Nephritis

INTRODUCTION

Low-dose interleukin-2 (IL-2) selectively restores disturbances of regulatory T cells (Treg) and conventional T cells, resulting in the induction of remission in patients with systemic lupus erythematosus. However, to date no research has been carried out on the efficacy of low-dose IL-2 in the treatment of refractory lupus nephritis (LN). The aim of the study reported here was to investigate the renal response to low-dose IL-2 in patients with refractory LN.

METHODS

The study population comprised ten patients with refractory LN who failed to achieve complete response or who had relapsed while being treated with at least two conventional immunosuppressive agents. One treatment cycle consisted of IL-2 at a dose of 1 million IU administered subcutaneously every other day for 2 weeks followed by a 2-week break. All patients received three cycles of IL-2 and were then followed up for another 12 weeks without any increase in the dose of previous immunosuppressive agents and steroids.

RESULTS

Of the ten patients enrolled in the study, seven (70%) achieved ≥ 50% improvement in proteinuria at 12 weeks after initiating treatment with IL-2. Median proteinuria was significantly reduced by 50.3% at week 12, from 1.83 (interquartile range [IQR] 1.23-3.21)  g/24 h at baseline to 0.91 (IQR 0.52-1.60)  g/24 h at 12 weeks (P = 0.005). This was accompanied by a 71% reduction in urine erythrocytes, from 64/µl (IQR 24-102/µl) at baseline to 18/µl (IQR 2-20/µl) at 12 weeks (P = 0.018). Anti-dsDNA was decreased from 27.9 (IQR 7.6-40.28) IU/ml at baseline to 14.1 (IQR 7.3-20.12) IU/ml (P = 0.021) at week 12, while complements C3 and C4 were slightly increased (P = 0.445, P = 0.241, respectively). A significant expansion of Treg cells, from 9.3% at baseline to 16.6% at 12 weeks, was also found (P < 0.05). No serious adverse events occurred during the treatment period.

CONCLUSIONS

Low-dose IL-2 therapy may have a promising role in the treatment of refractory LN as an alternative and safe therapeutic approach. It may be used as multi-target combination therapy in clinical practice.

Low Dose of IL-2 Normalizes Hypertension and Mitochondrial Function in the RUPP Rat Model of Placental Ischemia

IL-2 is a cytokine released from CD4+T cells with dual actions and can either potentiate the inflammatory response or quell a chronic inflammatory response depending on its circulating concentration. IL-2 is elevated in many chronic inflammatory conditions and is increased during preeclampsia (PE). PE is characterized by new-onset hypertension during pregnancy and organ dysfunction and increasing evidence indicates that proinflammatory cytokines cause hypertension and mitochondrial (mt) dysfunction during pregnancy. The reduced uterine perfusion pressure (RUPP) model of placental ischemia is a rat model of PE that we commonly use in our laboratory and we have previously shown that low doses of recombinant IL-2 can decrease blood pressure in RUPP rats. The objective of this study was to determine the effects of a low dose of recombinant IL-2 on multi-organ mt dysfunction in the RUPP rat model of PE. We tested our hypothesis by infusing recombinant IL-2 (0.05 ng/mL) into RUPP rats on GD14 and examined mean arterial pressure (MAP), renal, placental and endothelial cell mt function compared to control RUPP. MAP was elevated in RUPP rats (n = 6) compared to controls (n = 5) (122 ± 5 vs. 102 ± 3 mmHg, p < 0.05), but was reduced by administration of LD recombinant IL-2 (107 ± 1 vs. 122 ± 5 mmHg, n = 9, p < 0.05). Renal, placental and endothelial mt ROS were significantly increased in RUPP rats compared to RUPP+ IL-2 and controls. Placental and renal respiration rates were reduced in RUPP rats compared to control rats but were normalized with IL-2 administration to RUPPs. These data indicate that low-dose IL-2 normalized multi-organ mt function and hypertension in response to placental ischemia.

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.

The Th17/IL-17 Axis and Kidney Diseases, With Focus on Lupus Nephritis

Systemic lupus erythematosus (SLE) is a disease characterized by dysregulation and hyperreactivity of the immune response at various levels, including hyperactivation of effector cell subtypes, autoantibodies production, immune complex formation, and deposition in tissues. The consequences of hyperreactivity to the self are systemic and local inflammation and tissue damage in multiple organs. Lupus nephritis (LN) is one of the most worrying manifestations of SLE, and most patients have this involvement at some point in the course of the disease. Among the effector cells involved, the Th17, a subtype of T helper cells (CD4+), has shown significant hyperactivation and participates in kidney damage and many other organs. Th17 cells have IL-17A and IL-17F as main cytokines with receptors expressed in most renal cells, being involved in the activation of many proinflammatory and profibrotic pathways. The Th17/IL-17 axis promotes and maintains repetitive tissue damage and maladaptive repair; leading to fibrosis, loss of organ architecture and function. In the podocytes, the Th17/IL-17 axis effects include changes of the cytoskeleton with increased motility, decreased expression of health proteins, increased oxidative stress, and activation of the inflammasome and caspases resulting in podocytes apoptosis. In renal tubular epithelial cells, the Th17/IL-17 axis promotes the activation of profibrotic pathways such as increased TGF-β expression and epithelial-mesenchymal transition (EMT) with consequent increase of extracellular matrix proteins. In addition, the IL-17 promotes a proinflammatory environment by stimulating the synthesis of inflammatory cytokines by intrinsic renal cells and immune cells, and the synthesis of growth factors and chemokines, which together result in granulopoiesis/myelopoiesis, and further recruitment of immune cells to the kidney. The purpose of this work is to present the prognostic and immunopathologic role of the Th17/IL-17 axis in Kidney diseases, with a special focus on LN, including its exploration as a potential immunotherapeutic target in this complication.

Post-translational modifications in T cells in systemic erythematosus lupus

Systemic erythematosus lupus (SLE) is a classic autoimmune disease characterized by multiple autoantibodies and immune-mediated tissue damage. The aetiology of this disease is still unclear. A new drug, belimumab, which acts against the B-lymphocyte stimulator (BLyS), can effectively improve the condition of SLE patients, but it cannot resolve all SLE symptoms. The discovery of novel, precise therapeutic targets is urgently needed. It is well known that abnormal T-cell function is one of the most crucial factors contributing to the pathogenesis of SLE. Protein post-translational modifications (PTMs), including phosphorylation, glycosylation, acetylation, methylation, ubiquitination and SUMOylation have been emphasized for their roles in activating protein activity, maintaining structural stability, regulating protein-protein interactions and mediating signalling pathways, in addition to other biological functions. Summarizing the latest data in this area, this review focuses on the potential roles of diverse PTMs in regulating T-cell function and signalling pathways in SLE pathogenesis, with the goal of identifying new targets for SLE therapy.

Paeoniflorin ameliorates murine lupus nephritis by increasing CD4+Foxp3+ Treg cells via enhancing mTNFα-TNFR2 pathway

Treg cells are essential for re-establishing self-tolerance in lupus. However, given that direct Treg therapies may be inadequate to control autoimmunity and inflammation, a strategy of inducing or expanding endogenous Treg cells in vivo may be a good option. Macrophages are main tissue-infiltrating cells and play a role in promoting Treg differentiation while paeoniflorin (PF), a monoterpene glycoside, exhibits anti-inflammatory and immunoregulatory effects. Here, we studied the effects of PF on CD4⁺FoxP3⁺ Treg frequency and the potential mechanisms involving M2 macrophages. We demonstrated that PF ameliorated lupus nephritis in lupus-prone B6/gld mice by reducing urinary protein, serum creatinine and anti-dsDNA levels, diminishing renal cellular infiltration, improving renal immunopathology and downregulating renal gene and protein expressions of key cytokines, including IFN-γ, IL-6, IL-12 and IL-23. PF also lowered the percentage of CD44^highCD62L^low effector T cells while augmenting CD4⁺FoxP3⁺ Treg frequency in B6/gld mice. Importantly, PF increased TNFR2 expression on CD4⁺FoxP3⁺ Tregs, but not CD4⁺FoxP3^- T cells, in vivo and in vitro. Furthermore, we found that CD206⁺ subset of F4/80⁺CD11b⁺ macrophages expressed a higher level of mTNF-α than their CD206^- counterparts while PF increased mTNF-α expression on CD206⁺ macrophages in vitro and in vivo. In vitro studies showed that mTNF-α⁺ M2 macrophages were more potent in inducing Treg differentiation and proliferation than their mTNF-α^- counterparts, whereas the effects of mTNF-α⁺ M2 macrophages were largely reversed by separation of M2 macrophages using a transwell or TNFR2-blocking Ab in the culture. Finally, PF also promoted in vitro Treg generation induced by M2 macrophages. Thus, we demonstrated that mTNFα-TNFR2 interaction is a new mechanism responsible for Treg differentiation mediated by M2 macrophages. We provided the first evidence that PF may be used to treat lupus nephritis.

Effect of astragaloside on diaphragm cell apoptosis in chronic obstructive pulmonary disease

PURPOSE

This study aimed to discuss the effects and relative mechanisms of astragaloside (AST) on diaphragm cell apoptosis in mice with chronic obstructive pulmonary disease (COPD).

MATERIALS AND METHODS

The mouse models of COPD were established by passive smoking. The pathological changes in lung and diaphragm tissues were observed by hematoxylin and eosin staining and evaluating the number of apoptotic cells of the diaphragm via a terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The relative protein expression levels of AKT, p-AKT, caspase-3, and caspase-9 were measured through immunohistochemistry and Western blot assay.

RESULTS

In comparison with the normal control mice, the pathological change and number of apoptotic cells deteriorated in the lung and diaphragm tissues of COPD model mice. With AST supplement, the pathological change and the number of apoptotic cells significantly improved (p < .05). With AKT inhibitor intervention, the effects of AST treatment disappeared. p-AKT, caspase-3, and caspase-9 protein expression was stimulated in the model group but was depressed in the AST-treated groups.

CONCLUSION

Our in vivo study revealed that AST improved COPD-induced diaphragm apoptosis by regulating and depressing AKT activities.

Interleukin-35 regulates the balance of Th17 and Treg responses during the pathogenesis of connective tissue diseases

Interleukin (IL)-35 belongs to the IL-12 cytokine family and is a heterodimer of the p35 and Epstein-Barr virus-induced gene 3 (EBI3) subunits. Functionally, IL-35 can promote the proliferation and activation of regulatory T cells (Tregs) and suppress the function of T helper 17 (Th17) cells and other inflammatory cells to inhibit immune responses. In recent years, an abnormal IL-35 expression causing a Th17/Treg imbalance has been associated with the development and progression of several connective tissue diseases (CTDs), such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), and primary Sjögren's syndrome (pSS). Here, we review the role of IL-35 in regulating the balance of Th17/Treg responses in different types of CTDs and provide new insights into the role of IL-35 in these diseases.

B Cell Subsets and Cellular Signatures and Disease Relapse in Lupus Nephritis

Introduction

Renal relapses adversely affect the long-term outcomes of patients with lupus nephritis (LN), but the pathogenic mechanisms remain elusive. B cell signatures of miR-148a, BACH1, BACH2, and PAX5 expression are relevant to the regulation of B lymphocyte homeostasis. It is unknown whether B cell signature is related to the relapse of LN.

Methods

We compared B lymphocyte subsets and cellular signatures during disease quiescence between LN patients with multiple relapses (MR, ≥3 LN relapses within 36 months) and those with no relapse (NR). Also, circulating B lymphocytes were isolated from treatment-naïve patients with active LN and treated with antagomir-148a in vitro to investigate the relationship between miR-148a, BACH1, BACH2, and PAX5.

Results

MR patients (n = 19), when compared with NR (n = 14), showed significantly lower percentage of circulating naïve B cells and higher memory B cell-to-naïve B cell ratio. MR patients also showed higher miR-148a levels in sera and B cells, and lower BACH1, BACH2, and PAX5 expression in naïve and memory B cells. Antagomir-148a upregulated BACH1, BACH2, and PAX5 expression, and reduced B cell proliferation upon stimulation, in naïve and memory B cells isolated from treatment-naïve active LN patients.

Conclusion

Altered B cell subsets and cellular signatures of miR-148a, BACH1, BACH2, and PAX5 may be associated with distinct patient phenotypes related to the risk of LN relapse.

Metformin enhances the immunomodulatory potential of adipose-derived mesenchymal stem cells through STAT1 in an animal model of lupus

OBJECTIVES

Mesenchymal stem cells (MSCs) are considered potential therapeutic agents for treating autoimmune disease because of their immunomodulatory capacities and anti-inflammatory effects. However, several studies have shown that there is no consistency in the effectiveness of the MSCs to treat autoimmune disease, including SLE. In this study, we investigated whether metformin could enhance the immunoregulatory function of MSCs, what mechanism is relevant, and whether metformin-treated MSCs could be effective in an animal lupus model.

METHODS

Adipose-derived (Ad)-MSCs were cultured for 72 h in the presence of metformin. Immunoregulatory factors expression was analysed by real-time PCR and ELISA. MRL/lpr mice weekly injected intravenously with 1 × 106 Ad-MSCs or metformin-treated Ad-MSCs for 8 weeks. 16-week-old mice were sacrificed and proteinuria, anti-dsDNA IgG antibody, glomerulonephritis, immune complex, cellular subset were analysed in each group.

RESULTS

Metformin enhanced the immunomodulatory functions of Ad-MSCs including IDO, IL-10 and TGF-β. Metformin upregulated the expression of p-AMPK, p-STAT1 and inhibited the expression of p-STAT3, p-mTOR in Ad-MSCs. STAT1 inhibition by siRNA strongly diminished IDO, IL-10, TGF-β in metformin-treated Ad-MSCs. As a result, metformin promoted the immunoregulatory effect of Ad-MSCs by enhancing STAT1 expression, which was dependent on the AMPK/mTOR pathway. Administration of metformin-treated Ad-MSCs resulted in significant disease activity improvement including inflammatory phenotype, glomerulonephritis, proteinuria and anti-dsDNA IgG antibody production in MRL/lpr mice. Moreover, metformin-treated Ad-MSCs inhibited CD4-CD8- T-cell expansion and Th17/Treg cell ratio.

CONCLUSION

Metformin optimized the immunoregulatory properties of Ad-MSCs and may be a novel therapeutic agent for the treatment of lupus.

Regulating the Polarization of Macrophages: A Promising Approach to Vascular Dermatosis

Macrophages, a kind of innate immune cells, derive from monocytes in circulation and play a crucial role in the innate and adaptive immunity. Under the stimulation of the signals from local microenvironment, macrophages generally tend to differentiate into two main functional phenotypes depending on their high plasticity and heterogeneity, namely, classically activated macrophage (M1) and alternatively activated macrophage (M2). This phenomenon is often called macrophage polarization. In pathological conditions, chronic persistent inflammation could induce an aberrant response of macrophage and cause a shift in their phenotypes. Moreover, this shift would result in the alteration of macrophage polarization in some vascular dermatoses; e.g., an increase in proinflammatory M1 emerges from Behcet's disease (BD), psoriasis, and systemic lupus erythematosus (SLE), whereas an enhancement in anti-inflammatory M2 appears in infantile hemangioma (IH). Individual polarized phenotypes and their complicated cytokine networks may crucially mediate in the pathological processes of some vascular diseases (vascular dermatosis in particular) by activation of T cell subsets (such as Th1, Th2, Th17, and Treg cells), deterioration of oxidative stress damage, and induction of angiogenesis, but the specific mechanism remains ambiguous. Therefore, in this review, we discuss the possible role of macrophage polarization in the pathological processes of vascular skin diseases. In addition, it is proposed that regulation of macrophage polarization may become a potential strategy for controlling these disorders.

Correlation of the levels of DNA-binding inhibitor Id3 and regulatory T cells with SLE disease severity

E proteins, a subset of basic helix-loop-helix (bHLH) proteins, are transcription activators and their functions are inhibited by DNA-binding inhibitor (Id) 1-4. Studies have shown that Treg levels are decreased in Id3 knockout mice. Mice over-expressing Id1 in CD4 T cells possessed a greater number of regulatory T cells (Treg) and exhibited attenuated experimental autoimmune encephalomyelitis (EAE). The significance of Id proteins in human systemic lupus erythematosus (SLE) remains unclear. In this study, we systematically analyzed Id transcription in naïve, memory CD4 cells and regulatory T cells in peripheral blood mononuclear cells (PBMCs) in patients with active or inactive SLE. In parallel, Treg subsets in PBMCs were analyzed using different strategies. Id expression levels were correlated with Treg numbers as well as clinical indicators. We found that Id genes expressed in human peripheral CD4 cells were mainly Id2 and Id3. Id3 levels were significantly elevated in CD4⁺CD25^hi T cells of patients with active SLE. Likewise, Id3 levels were positively correlated with increased CD4⁺FoxP3⁺ and CD4⁺Helios⁺FoxP3⁺ Treg cells in these patients. Id3 levels were found to be positively correlated with erythrocyte sedimentation rate (ESR), lupus anticoagulant (LAC), ribosomal antibody and SLE Disease Activity Index (SLEDAI) in patients with active SLE. Mice overexpressing Id1 in CD4⁺ T cells possessed significantly higher Treg levels in spleen and lower autoantibody concentrations in serum. Our results suggest that during the pathogenesis of SLE, up-regulation of Id3 can promote Treg differentiation to play an inhibitory effect on autoimmune responses.

Interleukin-2 Deficiency Associated with Renal Impairment in Systemic Lupus Erythematosus

Impaired interleukin-2 (IL-2) production was reported in systemic lupus erythematosus (SLE). The aim of this study was to investigate the clinical relevance of serum IL-2 and therapeutic effects of recombinant IL-2 (rIL-2) in SLE, especially in lupus nephritis (LN). Decreased serum IL-2 was found in patients with active LN (P = 0.014) and correlated with 24-h urine protein excretion (r = -0.281, P = 0.026). Compared with LN patients with decreased levels of serum IL-2, patients with increased levels had better remission rate (P = 0.041). Furthermore, patients with exogenous low-dose IL-2 supplement demonstrated better improved nephritis and higher remission rate (55.56%, P = 0.058) than those with conventional therapy. In addition, the percentages of regulator T (Treg) cells expanded in LN patients with low-dose recombinant human IL-2 treatment (P = 0.007), especially in LN patients achieving remission (P = 0.010). IL-2 deficiency is associated with renal impairment that can be improved by exogenous IL-2 supplement.

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.

Immunomodulatory receptors are differentially expressed in B and T cell subsets relevant to autoimmune disease

Inhibitory cell-surface receptors on lymphocytes, often called immune checkpoints, are powerful targets for cancer therapy. Despite their direct involvement in autoimmune pathology, they are currently not exploited therapeutically for autoimmune diseases. Understanding the expression pattern of these receptors in health and disease is essential for targeted drug design. Here, we designed three 23-colour flow cytometry panels for peripheral-blood T cells, including 15 lineage-defining markers and 21 immunomodulatory cell-surface receptors, and a 22-marker panel for B cells. Blood samples from healthy individuals, multiple sclerosis (MS), and lupus (SLE) patients were included in the study. Several receptors show differential expression on regulatory T cells (Treg) compared to T helper (Th) 1 and Th17 cells, and functional relevance of this difference could be shown for BTLA and CD5. Unbiased multiparametric analysis revealed a subset of activated CD8⁺ T cells and a subset of unswitched memory B cells that are diminished in MS and SLE, respectively.

Low Tregs: A targetable risk factor for life-threatening cardiovascular complications after major noncardiac surgery

Discussion on Tregs that have anti-inflammatory and anti-atherogenic properties as an ideal therapeutic target to reduce fatal cardiovascular deaths following major noncardiac surgery.

Vasoactive intestinal peptide ameliorates renal injury in a pristane-induced lupus mouse model by modulating Th17/Treg balance

Background

Lupus nephritis (LN) is an inflammation of the kidneys and is a major cause of mortality in systemic lupus erythaematosus (SLE) patients. In addition, Th17/Treg balance is one of the most important factors that can promote the development of LN. It has been reported that vasoactive intestinal peptide (VIP) is associated with the downregulation of both inflammatory and autoimmune diseases through regulating T lymphocyte balance. Therefore, the aim of this study was to determine the role of VIP in modulating Th17/Treg balance in LN.

Methods

LN was induced in BALB/c female mice by injection pristane. After 3 months, mice were randomly divided into four groups: control, VIP + control, LN and VIP + LN. Autoantibody levels were tested by ELISA. The distribution of Th17/Treg cells in vivo and in vitro was detected by FC. Renal tissues were examined by PASM and DIF for pathology and Foxp3⁺CD3⁺. The mRNA and protein expression levels of pro- and anti-inflammatory cytokines were detected by qRT-PCR and western blotting.

Results

VIP can improve renal injury by regulating Th17/Treg imbalance in LN mice. Proteinuria, renal function defects and autoantibodies were significantly decreased, and Th17/Treg cell balance was restored in VIP compared with LN mice. In addition, VIP improved renal lesions by promoting the expression of Foxp3⁺CD3⁺ in renal tissue. Furthermore, VIP downregulated the mRNA and protein expression of IL-17, IL-6 and upregulated Foxp3, IL-10 expression.

Conclusions

VIP reduced LN proteinuria and renal function defects and restored the Th17/Treg cell balance. Furthermore, VIP also downregulated autoantibody and inflammatory cytokine expression and upregulated Foxp3 and IL-10 expression.

Low dose of IL-2 combined with rapamycin restores and maintains the long-term balance of Th17/Treg cells in refractory SLE patients

BACKGROUND

The development of Systemic lupus erythematosus (SLE) has been associated with the balance of Th17 and Treg cells. IL-2 and rapamycin can influence the populations of both Th17 and Treg cells. However, it is unclear whether low dose of IL-2 and rapamycin can relieve the symptoms of SLE patients and what is the mechanisms. In this study, we aim to analyze the effect of low dose of IL-2 plus rapamycin on the number of Tregs, Th17 cells and the ratio of Th17/Treg cells, as well as to evaluate its therapeutic efficacy in refractory SLE patients.

RESULT

Fifty refractory SLE patients and 70 healthy controls were enrolled and followed up for 24 weeks. We found that compared with HC, the refractory SLE patients had a lower number of Tregs, a similar number of Th17 cells, but an increased ratio of Th17/Treg. After the treatment, the number of Tregs of the patients at 12th and 24th week was significantly increased. While the number of Th17 cells was unchanged, the ratio of Th17/Treg was significantly decreased at both 6 weeks and 24 weeks. After 6, 12 and 24 weeks of treatment, the SLEDAI score was significantly reduced. The prednison dosage at 6th,12th and 24th week post treatment was significantly decreased.

CONCLUSION

Our results support that the reduction of Tregs and the imbalance of Th17/Treg cells were correlated with the occurrence and development of refractory SLE. Low dose of IL-2 combined with rapamycin was able to restore the number of Tregs and the balance of Th17/Treg cells. As a result, this approach was able to induce immune tolerance and promote disease remission, allowing for the reduction in prednisone dosage.

TRIAL REGISTRATION

ChiCTR-IPR-16009451 Registration date: 2016/10/16.

Human Memory Th17 Cell Populations Change Into Anti-inflammatory Cells With Regulatory Capacity Upon Exposure to Active Vitamin D

Autoimmune diseases are characterized by an aberrantly activated immune system, resulting in tissue damage and functional disability in patients. An important therapeutic goal is to restore the deregulated immunological balance between pro- and anti-inflammatory T cells. This imbalance is illustrated by elevated levels and activity of memory Th17 cell populations, such as Th17, Th1/Th17, and Th17.1 cells, in various autoimmune diseases. These cells are characterized by the chemokine receptor CCR6, RORC expression and production of IL-17A, IFNγ, and TNFα. Using rheumatoid arthritis (RA) as a model of autoimmune disease, we here demonstrate that pro-inflammatory memory CCR6+ Th cells can switch into anti-inflammatory cells with regulatory capacity using the active vitamin D metabolite 1,25(OH)₂D₃. Memory CCR6+ Th cells, excluding Tregs, were sorted from healthy controls or treatment-naïve patients with early rheumatoid arthritis (RA) and cultured with or without 1,25(OH)₂D₃. Treatment with 1,25(OH)₂D₃ inhibited pro-inflammatory cytokines such as IL-17A, IL-17F, IL-22 and IFNγ in memory CCR6+ Th cells from both healthy controls and RA patients. This was accompanied by induction of anti-inflammatory factors, including IL-10 and CTLA4. Interestingly, these formerly pathogenic cells suppressed proliferation of autologous CD3+ T cells similar to classical Tregs. Importantly, the modulated memory cells still migrated toward inflammatory milieus in vitro, modeled by RA synovial fluid, and retained their suppressive capacity in this environment. These data show the potential to reset the pathogenic profile of human memory Th cells into non-pathogenic cells with regulatory capacity.

Daurinol Attenuates Autoimmune Arthritis via Stabilization of Nrp1-PTEN-Foxp3 Signaling in Regulatory T Cells

Optimizing Treg function and improving Treg stability are attractive treatment strategies for treating autoimmune rheumatoid arthritis (RA). However, the limited number of circulating Tregs and questions about the functional stability of in vitro-expanded Tregs are potential limitations of Treg-based cell therapy. The aim of this study was to analyze the regulatory effect of daurinol, a catalytic inhibitor of topoisomerase IIα, on Th cell differentiation and to evaluate their therapeutic potential in a preclinical experimental model of RA. We investigated the effect of daurinol on T cell differentiation by flow cytometry. Foxp3 stability and methylation were analyzed by suppression assays and bisulfite pyrosequencing. Daurinol was treated in the collagen-induced arthritis (CIA) model, and the effects in vivo were determined. We found that daurinol can promote Treg differentiation and reciprocally inhibit Th17 differentiation. This Treg-inducing property of daurinol was associated with decreased activity of Akt-mTOR and reciprocally increased activity of neuropilin-1 (Nrp1)-PTEN. Daurinol treatment inhibited aerobic glycolysis in Th17 conditions, indicating the metabolic changes by daurinol. We found that the daurinol increase the Treg stability was achieved by Foxp3 hypomethylation. In vivo daurinol treatment in CIA mice reduced the clinical arthritis severity and histological inflammation. The Treg population frequency increased and the Th17 cells decreased in the spleens of arthritis mice treated with daurinol. These results showed the anti-arthritic and immunoregulating properties of daurinol is achieved by increased differentiation and stabilization of Tregs. Our study provides first evidence for daurinol as a treatment for RA.

Altered Homeostasis of Regulatory T Lymphocytes and Differential Regulation of STAT1/STAT5 in CD4+ T Lymphocytes in Childhood-onset Systemic Lupus Erythematosus

OBJECTIVE

Childhood-onset systemic lupus erythematosus (cSLE) is usually a more severe and aggressive disease than adult-onset SLE (aSLE), but cellular and subcellular reasons for these differences are not well understood. The present study analyzed Th subsets, STAT1/STAT5 signaling response, and cytokine profiles of cSLE.

METHODS

FOXP3+ regulatory (Treg) and effector Th subsets, expression and phosphorylation of STAT1/STAT5 in Th, and cytokine profiles were measured in the peripheral blood of patients with cSLE and healthy controls (HC), using flow cytometry and immunoassay on a biochip.

RESULTS

Significant correlation between expression of the activation marker HLA-DR and decreased Th counts, an increase in the percentage of FOXP3+ Th, and a decrease in the activated Treg (aTreg) subset among them were found in cSLE. In contrast to our previous findings in aSLE, no significant differences in percentages and a significant decrease in the numbers of the naive-resting Treg (rTreg) subset compared to HC were found. The percentages of CD25- cells, possibly reflecting interleukin 2 depletion, were significantly increased in cSLE aTreg, but not in the rTreg subset. Consistent with the results of our previous studies in aSLE, increased expression of STAT1, along with significant correlation between decreased Th counts and their increased basal phosphorylation of STAT5, were also found in cSLE.

CONCLUSION

Our results suggest that the key difference in Treg homeostasis between cSLE and aSLE is in the rTreg subset. However, perturbed aTreg homeostasis, increased levels of STAT1 protein, and homeostatic STAT5 signaling appear to be intrinsic characteristics of the disease, present in cSLE and aSLE alike.

Serum and urine interleukin-17A levels as biomarkers of disease activity in systemic lupus erythematosus

OBJECTIVES

This study examined the correlations of both serum and urine interleukin-17A (IL-17A) levels with disease activity in systemic lupus erythematosus (SLE). This study was also aimed at determining their sensitivity and specificity as biomarkers of disease activity in SLE.

METHODS

A cross-sectional study was performed involving SLE patients (n = 120 patients) from Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Serum and urinary IL-17A levels were determined by immunoassay while disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2K) and British Isles Lupus Assessment Group's 2004 index (BILAG 2004) scores. The correlations between serum and urinary IL-17A levels with total SLEDAI-2K and BILAG 2004 scores were determined using bivariate correlation analyses. Receiver operating characteristic curves were calculated to determine their sensitivity and specificity as disease activity biomarkers.

RESULTS

Both serum and urinary IL-17A levels correlated with total scores of BILAG 2004, BILAG renal, BILAG mucocutaneous, and SLEDAI-2K (P < 0.05). Urine IL-17A levels correlated positively with urine protein : creatinine index while serum IL-17 level correlated with the BILAG hematology score (all P < 0.05). The area under curve of serum IL-17A and urine IL-17A with BILAG and SLEDAI scores were low (<0.75).

CONCLUSION

Despite positive correlations between serum and urine IL-17A with SLE disease activity, both were neither sensitive nor specific as biomarkers to predict active disease. Hence, IL-17 measurement has no role in SLE disease activity assessments and future studies are needed to search for other reliable activity biomarkers.

Treg cells in autoimmunity: from identification to Treg-based therapies

Regulatory (Treg) cells are key regulators of inflammation and important for immune tolerance and homeostasis. A major progress has been made in the identification and classification of Treg cells. Due to technological advances, we have gained deep insights in the epigenetic regulation of Treg cells. The use of fate reporter mice allowed addressing the functional consequences of loss of Foxp3 expression. Depending on the environment Treg cells gain effector functions upon loss of Foxp3 expression. However, the traditional view that Treg cells become necessarily pathogenic by gaining effector functions was challenged by recent findings and supports the notion of Treg cell lineage plasticity. Treg cell stability is also a major issue for Treg cell therapies. Clinical trials are designed to use polyclonal Treg cells as therapeutic tools. Here, we summarize the role of Treg cells in selected autoimmune diseases and recent advances in the field of Treg targeted therapies.

Glomerular Proteomic Profiles in the NZB/W F1 Hybrid Mouse Model of Lupus Nephritis

Background

Lupus nephritis is one of the most serious complications of systemic lupus erythematosus (SLE) and is associated with patient mortality. This study aimed to investigate the proteomic profiles of the glomerulus in the NZB/W F1 hybrid mouse model of mild and severe lupus nephritis using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS).

Material/Methods

Female NZB/WF1 mice (n=60) at 28 weeks of age were divided into the mild proteinuria group (+1), the moderate proteinuria group (+2), and the severe proteinuria group (+3) using paper strip urine testing, and then later divided into a mild (≤1+) and severe (≥3+) proteinuria group to allow comparison of upregulation and down-regulation of proteins between the two groups. Renal glomeruli were isolated following renal perfusion with magnetic beads. Protein expression was determined by Western blot, immunohistochemistry, 2D-DIGE, and MALDI-TOF-MS.

Results

A total of 56 differentially expressed proteins were identified from 133 protein spots, of which 18 were upregulated and 23 were down-regulated between groups 1 and 2. Expression of the proteins Ras-related GTP-binding protein B (RRAGB), serine/threonine-protein kinase 1 (SMG1), angiopoietin 2 (ANGP2), methylmalonate semialdehyde (MMSA), and ATP beta chain (ATPB) were identified by Western blot and SMG1, ANGP2, and MMSA were identified by immunohistochemistry.

Conclusions

In a mouse model of lupus nephritis, expression of SMG1, MMSA, and ATPB were down-regulated, and RRAGB and ANGP2 were upregulated.

Osteopontin and interleukin-17A genes polymorphisms in Egyptian systemic lupus erythematosus patients: A relation to disease activity and severity

Osteopontin (OPN) is involved in the regulation of the immune response and is accused in the pathogenesis of several autoimmune diseases including systemic lupus erythematosus (SLE). An obvious link between OPN and T cells, particularly T helper 17 cells is reported, where OPN produced by dendritic cells supports interleukin-17 (IL-17) expression, contributing to pathology of autoimmune disorders. The aim of the study was to investigate the association of genotypes and alleles frequencies of OPN 9250 (rs1126616) and IL-17A 197 (rs2275913) genes polymorphisms with their serum levels, susceptibility, disease activity and severity in Egyptian SLE patients. A total of 80 SLE patients and 80 healthy subjects were enrolled. The PCR-RFLP technique was used to detect OPN 9250 C/T and IL-17A 197 G/A genes polymorphisms. Serum OPN and IL- 17 levels were measured by the enzyme-linked immunosorbent assay. OPN TT genotype and T allele were significantly detected in SLE patients more than controls (P = 0.003, P < 0.001 respectively). IL-17A AA genotype showed non-significant higher frequency in SLE patients than in their controls (P = 0.07). While only the A allele of IL-17A polymorphism was significantly elevated in patients (P = 0.048). There was statistical significant association between OPN CT and TT genotypes and both renal and mucocutaneous manifestations. Also IL-17A AG and AA genotypes was significantly associated with renal, mucocutaneous in addition to the hematological manifestations. Serum OPN levels were significantly increased with TT genotype while serum IL-17 levels were significantly increased with AA genotype. Disease activity and severity scores were significantly elevated with both OPN TT and IL-17A AA genotypes. In conclusion, OPN 9250 C/T and IL-17A 197 G/A genes polymorphisms and their serum levels seemed to have a role in pathogenesis of SLE.

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.

Fisetin inhibits pristine-induced systemic lupus erythematosus in a murine model through CXCLs regulation

Systemic lupus erythematosus (SLE) is associated with an increased risk of vascular complications. Lupus nephritis is a major manifestation of SLE in the clinic. Lupus nephritis is elevated by T helper type 17 (Th17) cells, the major pro‑inflammatory T‑cell subset, leading to autoimmunity modulation. Therapeutic treatments targeting leukocyte recruitment may be useful in attenuating vascular complications linked to SLE progression. 3,7,3',4'‑Tetrahydroxyflavone (fisetin) is a flavonol and a member of the flavonoid polyphenols. It is present in various fruits and vegetables, including persimmons, apples, kiwis, grapes, onions, strawberries and cucumbers. In the present study, the effects of fisetin against SLE induced by pristane (PRI) were evaluated in mice. Fisetin was indicated to reduce PRI‑induced anti‑double stranded DNA, anti‑ small nuclear ribonucleoprotein and the ratio of albumin to creatinine in urine. In addition, the chemokine (C‑X‑C motif) ligand (CXCL) signaling pathway was activated for PRI treatment, which was reversed by fisetin administration by reducing CXCL‑1 and 2, chemokine (C‑C motif) ligand 3, as well as CXC receptor 2 expression. In addition, the induction of inflammatory cytokines, including interleukin (IL)‑6, tumor necrosis factor‑α, IL‑1β, as well as the chemokine interferon‑γ, by PRI were downregulated by fisetin treatment in mice. Furthermore, Th17 cells and their associated cytokines were highly induced by PRI treatment, which was inhibited by fisetin administration. The present results indicated that fisetin may be an effective management for SLE by targeting the CXCL signaling pathway and regulating Th17 differentiation during lupus nephritis development.

Facilitated expansion of Th17 cells in lupus nephritis patients

The objective of this study was to investigate the mechanisms of T helper type 17 (Th17) expansion in lupus nephritis (LN) patients, and to determine whether or not it is associated with impaired function of regulatory T cells (T_reg ). Major effector subsets of peripheral blood CD4⁺ T cells were assessed by flow cytometry in 33 LN patients with different activity of the disease and 19 healthy controls. The percentage of circulating Th17 cells was increased in LN (median = 1·2% of CD4⁺ compared to 0·6% in the control group, P < 0·01), while T_reg cells remained unchanged (12·3 versus 12·1% in controls), resulting in a significantly lower T_reg /Th17 ratio. Th17 expansion in the patient group was not related to LN activity, renal histology or blood and urine inflammatory biomarkers, but has been associated with a higher cumulative dose of cyclophosphamide. T_reg cells in LN displayed mainly effector memory phenotype and expressed higher levels of transforming growth factor (TGF)-β; however, their suppressant activity in lymphocyte proliferation assay was diminished compared to controls (~fourfold, P < 0·05). Co-culture of T_reg and conventional CD4⁺ T cells resulted in marked suppression of the Th1 subset in both of the groups studied, but also in a potent expansion of Th17 cells, which in LN was twofold higher, as in controls (P < 0·05). In conclusion, our results demonstrate that Th17 expansion in LN is not increased during disease exacerbation, but is related to chronic immunosuppressive therapy. This immune signature is probably linked to the abnormal function of T_reg cells, which were less suppressive in LN patients and even facilitated differentiation of Th17 cells.

IL-17 and limits of success

Interleukin-17 (IL-17) is a potent proinflammatory cytokine that protects a host against fungal and extracellular bacterial infections. On the other hand, excessive or dysregulated production of IL-17 underlines susceptibility to autoimmune disease. Consequently, blocking IL-17 has become an effective strategy for modulating several autoimmune diseases, including multiple sclerosis (MS), psoriasis, and rheumatoid arthritis (RA). Notably, however, IL-17 blockade remains ineffective or even pathogenic against important autoimmune diseases such as inflammatory bowel disease (IBD). Furthermore, the efficacy of IL-17 blockade against other autoimmune diseases, including type 1 diabetes (T1D) is currently unknown and waiting results of ongoing clinical trials. Coming years will determine whether the efficacy of IL-17 blockade is limited to certain autoimmune diseases or can be expanded to other autoimmune diseases. These efforts include new clinical trials aimed at testing second-generation agents with the goal of increasing the efficiency, spectrum, and ameliorating side effects of IL-17 blockade. Here we briefly review the roles of IL-17 in the pathogenesis of selected autoimmune diseases and provide updates on ongoing and recently completed trials of IL-17 based immunotherapies.

Belimumab restores Treg/Th17 balance in patients with refractory systemic lupus erythematosus

Belimumab, a specific inhibitor of the soluble B lymphocyte stimulator (BlyS), is the first biological drug approved by the United States Food and Drug Administration for the treatment of patients with active systemic lupus erythematosus (SLE) refractory to standard therapy. Given that an imbalance between regulatory T cells (Treg) and interleukin (IL)-17A-secreting T cells (Th17) has been reported in various autoimmune disorders, we assessed the frequency of both Treg and Th17 peripheral blood populations before and after belimumab administration in 20 patients with active SLE refractory to standard therapy. After six months of treatment, the mean SELENA-SLEDAI score as well as the mean anti-double-stranded DNA antibody titers were significantly decreased. In addition, we observed a significant increase in Treg percentages and a parallel, significant decrease in Th17 percentages, accompanied by significantly reduced serum levels of IL-21. In vitro studies showed that Treg purified from belimumab-treated patients were fully functional and displayed a suppressor function similar to that of Treg purified from healthy donors. Belimumab can restore Treg/Th17 balance in SLE patients with uncontrolled disease activity, and this results in decreased flare rate and reduced glucocorticoid dosage.

The Proportion of Regulatory T Cells in Patients with Systemic Lupus Erythematosus: A Meta-Analysis

Background

Accumulating evidence indicates that a deficiency in or dysfunction of regulatory T cells (Tregs) is involved in the pathogenesis of systemic lupus erythematosus (SLE). As different markers have been used to identify Tregs, recent studies on the proportions of Tregs in SLE patients have generated controversial results. To clarify the status of Tregs in such patients, we determined the proportions of Tregs present during development of the disease, with special consideration of controversial cellular markers.

Methods

We identified studies reporting the proportions of Tregs in SLE patients by searching relevant databases through March 2018. Using the PRISMA guidelines, we performed a random effects meta-analysis of the frequencies of Tregs defined in different ways. Inconsistency was evaluated using the I-squared index (I²), and publication bias was assessed by examining funnel plot asymmetry using the Begger and Egger tests.

Results

Forty-four studies involving 2779 participants were included in the meta-analysis. No significant difference in the proportions of Tregs was evident between 1772 patients and 1007 controls [−0.191, (−0.552, 0.362), p = 0.613, I² = 95.7%]. We next conducted subanalyses based on individual definitions of Tregs. When the Treg definition included “FOXP3-positive” cells, the proportions did not differ between SLE patients and controls [−0.042, (−0.548, 0.632), p = 0.889, I² = 96.6%]; this was the case when Tregs were defined as either “CD25^low/−FOXP3⁺” or “CD25^high/+FOXP3⁺” cells. SLE patients had lower proportions of Tregs that were “single CD25-positive” [−1.428, (−1.982, −0.873), p < 0.001, I² = 93.4%] and “CD127-negative” [−1.093, (−2.002, −0.183), p = 0.018, I² = 92.6%] compared to controls. Tregs defined as “CD25^bright,” “CD25^bright/highCD127^low/−,” and “CD25^highCD127^low/−FOXP3⁺” did not differ in proportion between SLE patients and controls.

Conclusions

The Treg proportions varied by the cellular identification method used. The proportions of Tregs that were accurately identified and functionally validated fell among patients with SLE. Stricter definitions of Tregs are necessary when evaluating the status of such patients.

In vivo study: Th1-Th17 reduction in pristane-induced systemic lupus erythematosus mice after treatment with tolerogenic Lactobacillus probiotics

Uncontrolled inflammation in systemic lupus erythematosus (SLE) could cause dysfunction in multiple organs. T helper 17 (Th17) cells are a main branch of inflammatory responses in the pathogenesis of SLE, and by producing interleukin 17 (IL-17), represent a major functional tool in the progression of inflammation. Animal models provide a special field for better studies of the pathogenesis of diseases. Tolergenic probiotics could decrease inflammation in autoimmune diseases by modulating the immune system and maintaining homeostasis. The aim of this project was to evaluate the effects of Lactobacillus rhamnosus and Lactobacillus delbrueckii on Th17 cells and their related mediators in a pristane-induced BALB/c mice model of SLE. The mice were divided into pretreatment groups, which received probiotics or prednisolone at Day 0, and treatment groups, which received probiotics and prednisolone 2 months after injection. The presence of antinuclear antibody (ANA), anti-double-stranded DNA (anti-dsDNA), and anti-ribonucleoprotein (anti-RNP) and lipogranuloma was evaluated; also, the population of Th1-Th17 cells as well as interferon γ (IFN-γ), IL-17, and IL-10 levels, and the expression of RAR-related orphan related receptor gamma (RORγt) and IL-17 were determined. We observed that probiotics and prednisolone could delay SLE in pretreatment and treatment mice groups, with a reduction in ANA, anti-dsDNA, anti-RNP, and mass of lipogranuloma. Probiotics and prednisolone decreased the population of Th1-Th17 cells and reduced IFN-γ and IL-17 as inflammatory cytokines in the pretreatment and treatment groups in comparison with SLE-induced mice. Our results indicated that, due to their anti-inflammatory properties and reduction of Th17, Th1, and cytotoxic T lymphocyte (CTL) cells, the use of these probiotics could probably represent a new tool for the better management of SLE.

Regulatory T Cells Compensation Failure Cause the Dysregulation of Immune Response in Pristane Induced Lupus Mice Model

Introduction

Regulatory T cells' (Tregs') role remains unclear in the pathogenesis of systemic lupus erythematosus (SLE). This study was aimed at monitoring the percentage of Tregs within 32 weeks and monitoring its relationship with the percentage of other T helper (Th) cell subsets and the levels of autoantibodies and pro-inflammatory cytokines in a murine SLE model induced by pristane.

Methods

Forty-eight female BALB/c mice were divided into a healthy control (HC) and a pristine-induced (PI) group. SLE was induced by a single 0.5 cc pristane intraperitoneal injection. Six from each group were sacrificed every eight weeks until 32 weeks post-pristane injection. Treg, Th1, Th2 and Th17 percentages from the spleen were measured using flowcytometry. ANA, IL-6 and IFN-α levels were measured from serum using ELISA.

Results

The Treg percentage from the PI group increased significantly at 16 weeks compared to the HC group, while Th1, Th2 and Th17 percentages decreased. Tregs in the PI group began to reduce from the 24th to 32nd weeks, followed by an elevation of the Th1, Th2 and Th17 percentages. Tregs were negatively correlated with Th1 and Th2. Tregs in the PI group had a negative correlation with ANA and IFN-α levels from serum, whereas Tregs had a positive correlation with IL-6 levels.

Conclusion

The compensation of Tregs observed at 16 weeks after pristane injection failed, marked by a decreasing number of Tregs, followed by an increase of Th subsets, pro-inflammatory cytokines and autoantibodies. This compensatory failure of Tregs could be affected by pro-inflammatory cytokines, such as IFN-α and IL-6.

Regulatory T cells in acute and chronic kidney diseases

Foxp3-expressing CD4+ regulatory T cells (Tregs) make up one subset of the helper T cells (Th) and are one of the major mechanisms of peripheral tolerance. Tregs prevent abnormal activation of the immune system throughout the lifespan, thus protecting from autoimmune and inflammatory diseases. Recent studies have elucidated the role of Tregs beyond autoimmunity. Tregs play important functions in controlling not only innate and adaptive immune cell activation, but also regulate nonimmune cell function during insults and injury. Inflammation contributes to a multitude of acute and chronic diseases affecting the kidneys. This review examines the role of Tregs in pathogenesis of renal inflammatory diseases and explores the approaches for enhancing Tregs for prevention and therapy of renal inflammation.