CD4(+)CD25 (+) regulatory T cells in human lupus erythematosus

Dysregulated balance in Th17/Treg axis of Pristane-induced lupus mouse model, are mesenchymal stem cells therapeutic?

BACKGROUND

Despite advances in general and targeted immunosuppressive therapies, limiting all mainstay treatment options in refractory systemic lupus erythematosus (SLE) cases has necessitated the development of new therapeutic strategies. Mesenchymal stem cells (MSCs) have recently emerged with unique properties, including a solid propensity to reduce inflammation, exert immunomodulatory effects, and repair injured tissues.

METHODS

An animal model of acquired SLE mice was induced via intraperitoneal immunization with Pristane and affirmed by measuring specific biomarkers. Bone marrow (BM) MSCs were isolated from healthy BALB/c mice and cultured in vitro, then were identified and confirmed by flow cytometry and cytodifferentiation. Systemic MSCs transplantation was performed and then several parameters were analyzed and compared, including specific cytokines (IL-17, IL-4, IFN-ɣ, TGF-β) at the serum level, the percentage of Th cell subsets (Treg/Th17, Th1/Th2) in splenocytes, and also the relief of lupus nephritis, respectively by enzyme-linked immunosorbent assay (ELISA), flow cytometry analysis and by hematoxylin & eosin staining and also immunofluorescence assessment. Experiments were carried out with different initiation treatment time points (early and late stages of disease). Analysis of variance (ANOVA) followed by post hoc Tukey's test was used for multiple comparisons.

RESULTS

The rate of proteinuria, anti-double-stranded deoxyribonucleic acid (anti-dsDNA) antibodies, and serum creatinine levels decreased with BM-MSCs transplantation. These results were associated with attenuated lupus renal pathology in terms of reducing IgG and C3 deposition and lymphocyte infiltration. Our findings suggested that TGF-β (associated with lupus microenvironment) can contribute to MSC-based immunotherapy by modulating the population of TCD4⁺ cell subsets. Obtained results indicated that MSCs-based cytotherapy could negatively affect the progression of induced SLE by recovering the function of Treg cells, suppressing Th1, Th2, and Th17 lymphocyte function, and downregulating their pro-inflammatory cytokines.

CONCLUSION

MSC-based immunotherapy showed a delayed effect on the progression of acquired SLE in a lupus microenvironment-dependent manner. Allogenic MSCs transplantation revealed the ability to re-establish the balance of Th17/Treg, Th1/Th2 and restore the plasma cytokines network in a pattern dependent on disease conditions. The conflicting results of early versus advanced therapy suggest that MSCs may produce different effects depending on when they are administered and their activation status.

Lupus nephritis with corticosteroid responsiveness: molecular changes of CD46-mediated type 1 regulatory T cells

BACKGROUND

The engagement of the complement regulatory proteins CD46 and CD3 in human CD4+ T cells induces the type 1 regulatory T cells (Tr1) and interleukin-10 (IL-10) secretion. This study aimed to elucidate the molecular changes of Tr1 cells through CD46 cytoplasmic Cyt1 tail in lupus nephritis (LN) respond to intravenous methylprednisolone (ivMP) therapy.

METHODS

We enrolled 40 pediatric patients with LN and 30 healthy controls. Clinical characteristics and peripheral blood mononuclear cells were collected before and 3 days after the administration of ivMP. Kidney specimens were taken from five LN and five minimal-change nephrotic syndrome patients.

RESULTS

We found that defective CD46-mediated T-helper type 1 contraction (IL-10 switching) is present in active LN patients. The ivMP therapy enhanced LN remission, restored the production of IL-10, increased the CD46-Cyt1/Cyt2 ratio, AKT, and cAMP-responsive element-binding protein phosphorylation, and induced migration with the expression of chemokine receptor molecules CCR4, CCR6, and CCR7 of CD3/CD46-activated Tr1 cells.

CONCLUSIONS

Pharmacologic interventions that alter the patterns of CD46-Cyt1/Cyt2 expression and the secretion of IL-10 by CD3/CD46-activated Tr1 cells can be used in patients with active LN.

IMPACT

In patients with LN, ivMP was associated with increased IL-10 production and increased CD46-Cyt1/Cyt2 ratio and AKT phosphorylation by Tr1 cells, with enhanced potential to migration in response to CCL17. These results suggest that expression levels of CD46 isoforms Cyt1 and Cyt2 in CD4 + CD46 +  Tr1 cells differ in patients with active LN but can be corrected by corticosteroid treatment. Enhancing the expression of functional CD4 + CD46 +  Tr1 cells may be a useful therapeutic approach for LN.

Upregulation of Cytotoxic T-cells in pediatric patients with Gaucher disease

Cytotoxic (CD8) T-cells and natural killer (NK) cells have a significant immune function role. The ongoing stimulation of immunity and the excessive release of proinflammatory cytokines observed in pediatric patients with Gaucher disease (GD) can affect immune cells. Few studies have looked at the proportion of cytotoxic CD8 T-cells and their subsets in children with GD. A prospective case-control study was performed involving twenty pediatric patients with type 1 GD and twenty healthy age-matched controls. All patients received regular enzyme replacement therapy (ERT) for at least 6 months before the study. Complete blood count and flow cytometric analyses of CD8 T, Tc1, Tc2, NK, and NK T-cells were performed. GD patients showed significantly increased of CD8 T, Tc1 and significantly decreased NK cells frequencies when compared to healthy controls. However, no significant difference in Tc2 and NK T-cells was found between the studied groups. GD patients on regular ERT have increased CD8+ T-cell frequencies, predominantly Tc1, together with a reduction in NK cells than in healthy controls. These crucial immunological changes may contribute to some extent to the pathogenesis and the progression of GD.

Targeting the balance of T helper cell responses by curcumin in inflammatory and autoimmune states

CD4⁺ T helper (Th) cells are a crucial player in host defense but under certain conditions can contribute to the pathogenesis of inflammatory and autoimmune diseases. Beside the Th1/Th2 subset, several additional Th subsets have been identified, each with a distinctive transcription factor, functional properties, signature cytokine profile, and possible role in the pathophysiology of diseases. These newer Th subsets include Th17, regulatory Th cells (Tregs), and more recently, Th9, Th22, and follicular T helper cells. Interestingly, imbalance of Th subsets contributes to the immunopathology of several disease states. Therefore, targeting the imbalance of Th subsets and their signature cytokine profiles by a safe, effective and inexpensive nutraceutical agent such as curcumin could be helpful to treat autoimmune and inflammatory diseases. In this study different Th subsets and how the imbalance of these subsets could promote pathology of several diseases has been reviewed. Furthermore, the role of curcumin in this process will be discussed and the impact of targeting Th subsets by curcumin.

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.

From autoinflammation to autoimmunity: old and recent findings

Autoimmune diseases and autoinflammatory diseases have a number of similar etiopathogenetic and clinical characteristics, including genetic predisposition and recurrent systemic inflammatory flares. The first phase of ADs involves innate immunity: by means of TLRs, autoantigen presentation, B and T cell recruitment and autoantibody synthesis. The second phase involves adaptive immunity, a self-sustaining process in which immune complexes containing nucleic acids and autoantibodies activate self-directed inflammation. The link between autoimmunity and autoinflammation is IL-1ß, which is crucial in connecting the innate immune response due to NLR activation and the adaptive immune responses of T and B cells. In conclusion, although ADs are still considered adaptive immunity-mediated disorders, there is increasing evidence that innate immunity and inflammasomes are also involved. The aim of this review is to highlight the link between the innate and adaptive immune mechanisms involved in autoimmune diseases.

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.

Analysis of FOXP3+ regulatory T cell subpopulations in peripheral blood and tissue of patients with systemic lupus erythematosus

Regulatory T cells (Tregs) are critical mediators of immune tolerance, yet their involvement in the autoimmune disease systemic lupus erythematosus (SLE) is incompletely understood. We analyzed CD4⁺ T cell subpopulations with Treg-related phenotypes and their association with disease activity in peripheral blood (PB) and tissues of patients with SLE. In detail, we quantified subpopulations regarding CD25, FOXP3, CD62L, CCR6, CD27, CD45RA, and CD45RO expression in PB from 31 patients with SLE divided into two disease activity groups and 32 healthy controls using flow cytometry. CD4⁺ and FOXP3⁺ T cells in skin and kidney biopsies of patients with SLE were quantified by immunohistochemistry. CD4⁺CD25^+/++FOXP3⁺ and CD4⁺CD25⁺CD45RA^-/CD45RO⁺ T cell frequencies were significantly higher in PB from patients with active compared to inactive SLE. The fraction of CD4⁺CD25⁺⁺FOXP3⁺ Tregs and CD4⁺CD25⁺CD45RA⁺/CD45RO^- naïve Tregs was not significantly different between these groups. CD4⁺CD25⁺⁺ Tregs from active SLE patients comprised significantly less CD27⁺ cells and more CCR6⁺ cells compared to patients with inactive SLE. The percentage of CD4⁺FOXP3⁺ T cells among inflammatory infiltrates in skin and kidney biopsies of SLE patients was not different from other inflammatory skin/kidney diseases. In conclusion, although CD4⁺FOXP3⁺ T cell frequencies in the inflamed tissues of SLE patients were comparable to other inflammatory diseases, distinct T cell subpopulations appeared misbalanced in PB of patients with active SLE. Here, cells phenotypically resembling activated T cells, but not Tregs, were increased compared to patients with inactive SLE. Within Tregs of patients with active SLE, markers related to Treg function and homing were altered.

T regulatory cells and other lymphocyte subsets in patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease, and is associated with autoantibodies to the hemidesmosomal BP autoantigens BPAG1 and BPAG2.

AIM

We aimed to investigate the significance of T regulatory cells and other lymphocyte subsets in patients with BP.

METHODS

In total, 31 inpatients with BP were treated with systemic prednisolone in a tapered dose regimen, while 28 healthy individuals matched for age and sex served as the healthy control (HC) group., Blood samples were taken at baseline and after treatment, and levels of inducer/helper and suppressor/cytotoxic T lymphocytes, B lymphocytes, natural killer cells, CD4+CD25++CD127- cells were assessed by flow cytometry, while CD4, CD8, and FOXP3 positivity were assessed by immunohistochemistry, and FOXP3 mRNA was assessed by reverse transcription (RT)-PCR.

RESULTS

Flow cytometry showed that numbers of CD8+ and CD4+CD25++CD127- cells were significantly increased, while the number of CD4+ cells and the CD4/CD8 ratio were significantly decreased at baseline and after therapy in patients with BP compared with HCs. Immunohistology revealed that CD4+, CD8+ and FOXP3+ cells were significantly increased at baseline and post-treatment in patients with BP compared with HCs. FOXP3 mRNA levels were significantly increased in the blood of patients with BP compared with HCs.

CONCLUSION

These results indicate that increased numbers of CD8+, CD4+CD25++CD127- cells and FOXP3+ cells may play a pathogenetic role during the course of BP.

NKG2D+CD4+ T Cells Kill Regulatory T Cells in a NKG2D-NKG2D Ligand- Dependent Manner in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) features a decreased pool of CD4⁺CD25⁺Foxp3⁺ T regulatory (Treg) cells. We had previously observed NKG2D⁺CD4⁺ T cell expansion in contrast to a decreased pool of Treg cells in SLE patients, but whether NKG2D⁺CD4⁺ T cells contribute to the decreased Treg cells remains unclear. In the present study, we found that the NKG2D⁺CD4⁺ T cells efficiently killed NKG2D ligand (NKG2DL)⁺ Treg cells in vitro, whereby the surviving Treg cells in SLE patients showed no detectable expression of NKG2DLs. It was further found that MRL/lpr lupus mice have significantly increased percentage of NKG2D⁺CD4⁺ T cells and obvious decreased percentage of Treg cells, as compared with wild-type mice. Adoptively transferred NKG2DL⁺ Treg cells were found to be efficiently killed in MRL/lpr lupus mice, with NKG2D neutralization remarkably attenuating this killing. Anti-NKG2D or anti-interferon-alpha receptor (IFNAR) antibodies treatment in MRL/lpr mice restored Treg cells numbers and markedly ameliorated the lupus disease. These results suggest that NKG2D⁺CD4⁺ T cells are involved in the pathogenesis of SLE by killing Treg cells in a NKG2D-NKG2DL-dependent manner. Targeting the NKG2D-NKG2DL interaction might be a potential therapeutic strategy by which Treg cells can be protected from cytolysis in SLE patients.

Advances in the treatment of cutaneous lupus erythematosus

Lupus erythematosus (LE) is a multifactorial autoimmune disease with clinical manifestations of differing severity which may present with skin manifestations as primary sign of the disease (cutaneous lupus erythematosus, CLE) or as part of a disease spectrum (systemic lupus erythematosus, SLE). To date, no drugs are approved specifically for the treatment of CLE and only single agents have been applied in randomized controlled trials. Therefore, topical and systemic agents are used "off-label", primarily based on open-label studies, case series, retrospective analyses, and expert opinions. In contrast, several agents, such as hydroxychloroquine, chloroquine, cyclophosphamide, azathioprine, and belimumab, are approved for the treatment of SLE. Recent approaches in the understanding of the molecular pathogenesis of LE enabled the development of further new agents, which target molecules such as interleukin 6 (IL-6) and interferon (IFN). Only single trials, however, applied these new agents in patients with cutaneous involvement of the disease and/or included endpoints which evaluated the efficacy of these agents on skin manifestations. This article provides an updated review on new and recent approaches in the treatment of CLE.

Molecular and Cellular Characterization of Human CD8 T Suppressor Cells

Bidirectional interactions between dendritic cells and Ag-experienced T cells initiate either a tolerogenic or immunogenic pathway. The outcome of these interactions is of crucial importance in malignancy, transplantation, and autoimmune diseases. Blockade of costimulation results in the induction of T helper cell anergy and subsequent differentiation of antigen-specific CD8⁺ T suppressor/regulatory cells (Ts). Ts, primed in the presence of inhibitory signals, exert their inhibitory function in an antigen-specific manner, a feature with tremendous clinical potential. In transplantation or autoimmunity, antigen-specific Ts can enforce tolerance to auto- or allo-antigens, while otherwise leaving the immune response to pathogens uninhibited. Alternatively, blockade of inhibitory receptors results in the generation of cytolytic CD8⁺ T cells, which is vital toward defense against tumors and viral diseases. Because CD8⁺ T cells are MHC Class I restricted, they are able to recognize HLA-bound antigenic peptides presented not only by APC but also on parenchymal cells, thus eliciting or suppressing auto- or allo-immune reactions.

Current and Emerging Therapies for Lupus Nephritis

The introduction of corticosteroids and later, cyclophosphamide dramatically improved survival in patients with proliferative lupus nephritis, and combined administration of these agents became the standard-of-care treatment for this disease. However, treatment failures were still common and the rate of progression to ESRD remained unacceptably high. Additionally, treatment was associated with significant morbidity. Therefore, as patient survival improved, the goals for advancing lupus nephritis treatment shifted to identifying therapies that could improve long-term renal outcomes and minimize treatment-related toxicity. Unfortunately, progress has been slow and the current approaches to the management of lupus nephritis continue to rely on high-dose corticosteroids plus a broad-spectrum immunosuppressive agent. Over the past decade, an improved understanding of lupus nephritis pathogenesis fueled several clinical trials of novel drugs, but none have been found to be superior to the combination of a cytotoxic agent and corticosteroids. Despite these trial failures, efforts to translate mechanistic advances into new treatment approaches continue. In this review, we discuss current therapeutic strategies for lupus nephritis, briefly review recent advances in understanding the pathogenesis of this disease, and describe emerging approaches developed on the basis of these advances that promise to improve upon the standard-of-care lupus nephritis treatments.

Therapeutic Apheresis in Hematologic, Autoimmune and Dermatologic Diseases With Immunologic Origin

The process of curing a patient by removing his illness by extracting blood is a very old one. Many years ago, phlebotomy was practiced to cure illness. Now, this old process, placed on a rational basis with therapeutic apheresis (TA), is being followed in clinical practice. Therapeutic plasma exchange (TPE) with hollow fiber modules has been used in different severe diseases for more than 40 years. Based on many years of experience with the extracorporeal circulation in end-stage renal disease, the authors herein give an overview of TA in immunological diseases, especially in hematologic, autoimmune and dermatologic diseases. Updated information on immunology and molecular biology of different immunological diseases is discussed in relation to the rationale for apheresis therapy and its place in combination with other modern therapies. With the introduction of novel and effective biologic agents, TA is indicated only in severe cases, such as in rapid progression despite immunosuppressive therapy and/or biologic agents. In mild forms of autoimmune disease, treatment with immunosuppressive therapies and/or biologic agents seems to be sufficient. The prognosis of autoimmune diseases with varying organ manifestations has improved in recent years, due in part to very aggressive therapy schemes. For the immunological diseases that can be treated with TA, the guidelines of the German Working Group of Clinical Nephrology and of the Apheresis Applications Committee of the American Society for Apheresis are cited. TA has been shown to effectively remove the autoantibodies from blood and lead to rapid clinical improvement.

Pregnancy Associated with Systemic Lupus Erythematosus: Immune Tolerance in Pregnancy and Its Deficiency in Systemic Lupus Erythematosus--An Immunological Dilemma

Pregnancy is a physiological condition that requires immune tolerance to the product of conception. Systemic lupus erythematosus (SLE) is a disease with well-represented immune mechanisms that disturb immune tolerance. The association of pregnancy with systemic lupus erythematosus creates a particular immune environment in which the immune tolerance specific of pregnancy is required to coexist with alterations of the immune system caused by SLE. The main role is played by T regulatory (Treg) cells, which attempt to regulate and adapt the immune system of the mother to the new conditions of pregnancy. Other components of the immune system also participate to maintain maternal-fetal immune tolerance. If the immune system of pregnant women with SLE is not able to maintain maternal immune tolerance to the fetus, pregnancy complications (miscarriage, fetal hypotrophy, and preterm birth) or maternal complications (preeclampsia or activation of SLE, especially in conditions of lupus nephritis) may occur. In certain situations this can be responsible for neonatal lupus. At the same time, it must be noted that during pregnancy, the immune system is able to achieve immune tolerance while maintaining the anti-infectious immune capacity of the mother. Immunological monitoring of pregnancy during SLE, as well as of the mother's disease, is required. It is important to understand immune tolerance to grafts in transplant pathology.

Associations of rs4810485 and rs1883832 polymorphisms of CD40 gene with susceptibility and clinical findings of Behçet's disease

There are evidences that besides geographic tendency, interactions between genetic and environmental factors play an essential role in the pathogenesis of Behçet's disease (BD). In this study, we have evaluated the associations between rs4810485 and rs1883832 single nucleotide polymorphism (SNP)s of CD40 gene with the susceptibility and clinical findings of BD. Two hundred and eighty-five patients with BD and 225 age-matched healthy controls were enrolled in this study. The clinical findings of patients were noted. The distributions of genotypes, alleles, combined genotypes and haplotypes of these two SNPs in BD patients were compared with those in healthy controls. In further evaluation, we evaluated the patients with and without any of clinical findings with regarding to distribution of genotypes and alleles of these two SNPs. There was no significant difference concerning frequencies of genotypes, alleles, combined genotypes and haplotypes of rs4810485 and rs1883832 between patients and controls (p > 0.05 for all). Frequency of GT genotype of CD40 rs4810485 polymorphism was found to be significantly higher in patients with skin lesions (p < 0.05, OR 1.65, 95 % CI 1.02-2.64). Also, we have found significantly higher frequencies of CC genotype and C allele of CD40 rs1883832 polymorphism in patients with genital ulcers (p < 0.05 for both, OR 2.30, 95 % CI 1.07-4.94 and OR 1.78, 95 % CI 1.06-2.97, respectively). However, these significances were disappeared after Bonferroni correction. We suggest that differences in the expression levels of CD40 because of different genotypes of these two SNPs may take part in the development of skin lesions or genital ulcers in patients with BD.

Pathogenesis and potential therapeutic targets in systemic lupus erythematosus: from bench to bedside

Systemic lupus erythematosus (SLE) is considered an autoimmune disease with multiorgan involvement. Many advances have been made during the last decade regarding inflammatory pathways, genetic and epigenetic alterations, adaptive and innate immune system mechanisms specifically involved in SLE pathogenesis. Apoptosis has been proposed as an important player in SLE pathogenesis more than a decade ago. However, only recently new key apoptotic pathways have been investigated and the link between apoptotic debris containing autoantigens, innate immunity and ongoing inflammation has been further elucidated. Better understanding of cellular mechanisms and involved cytokines contributed to the development of new biological drugs specifically addressed for SLE therapy.

Class I and II histone deacetylase inhibition by ITF2357 reduces SLE pathogenesis in vivo

We sought to determine if a specific class I and II HDAC inhibitor (ITF2357) was able to decrease disease in lupus-prone NZB/W mice through regulation of T cell profiles. From 22 to 38 weeks-of-age, NZB/W and non-lupus NZW mice were treated with ITF2357 (5 mg/kg or 10 mg/kg), or vehicle control. Body weight and proteinuria were measured every 2 weeks, while sera anti-dsDNA and cytokine levels were measured every 4 weeks. Kidney disease was determined by sera IgG levels, immune complex deposition, and renal pathology. T lymphocyte profiles were assessed using flow cytometric analyses. Our results showed that NZB/W mice treated with the 10 mg/kgof ITF2357 had decreased renal disease and inflammatory cytokines in the sera. Treatment with ITF2357 decreased the Th17 phenotype while increasing the percentage of Tregs as well as Foxp3 acetylation. These results suggest that specific HDAC inhibition may decrease disease by altering T cell differentiation and acetylation.

Peripheral CD4+ cell prevalence and pleuropulmonary manifestations in systemic lupus erythematosus patients

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease involving several organs, including the lungs. Previous results confirmed changes of peripheral T cell subsets in lupus patients; however no data are available about their possible relationship with pulmonary involvement.

OBJECTIVE

To determine pulmonary manifestations and potential relationship in changes of peripheral CD4+ T cell subsets.

METHODS

Patients with SLE (N = 28) were enrolled in complex pulmonary examination. Patients were divided into groups with pleuropulmonary manifestations (SLEpulm N = 13 age: 44.9 ± 3.3 years, female: male = 11:2) or without (SLEc N = 15 age: 27.2 ± 3.7 years, female: male = 12:3). Peripheral blood was taken for T helper (Th)1, Th2, Th17, CD4+CD25hi+ and regulatory T (Treg: CD4+CD25hi+ CD127-) cell analysis from SLE patients and healthy volunteers (controls, N = 40).

RESULTS

SLEpulm patients were older, had more pulmonary symptoms and significantly decreased pO2 as compared to SLEc group. Ventilatory disorder was present in 92% of SLEpulm patients, with significantly decreased lung volumes, signs of airway involvement and decrease in DLco. Significant increase in Th1/Th2, while decrease in Th17/Treg ratios was present in all SLE compared to controls. In SLEpulm CD4+CD25hi+ subset without changes in Treg number was significantly increased as compared to SLEc and this subgroup of T cell showed significant positive correlation with dynamic lung function parameters and DLco (p < 0.05).

CONCLUSION

In lupus patients pleuropulmonary manifestations are prevalent and lung function and blood gas measurements should be regularly performed in the daily clinical assessment. Significant increase of activated CD4+CD25hi+ T cells, but not Treg is associated with decreased lung function parameters in SLEpulm patients.

Lupus nephritis: the evolving role of novel therapeutics

Immune complex accumulation in the kidney is the hallmark of lupus nephritis and triggers a series of events that result in kidney inflammation and injury. Cytotoxic agents and corticosteroids are standard of care for lupus nephritis treatment, but are associated with considerable morbidity and suboptimal outcomes. Recently, there has been interest in using novel biologic agents and small molecules to treat lupus nephritis. These therapies can be broadly categorized as anti-inflammatory (laquinamod, anti-tumor necrosis factor-like weak inducer of apotosis, anti-C5, and retinoids), antiautoimmunity (anti-CD20, anti-interferon α, and costimulatory blockers), or both (anti-interleukin 6 and proteasome inhibitors). Recent lupus nephritis clinical trials applied biologics or small molecules of any category to induction treatment, seeking short-term end points of complete renal response. These trials in general have not succeeded. When lupus nephritis comes to clinical attention during the inflammatory stage of the disease, the autoimmune stage leading to kidney inflammation will have been active for some time. The optimal approach for using novel therapies may be to initially target kidney inflammation to preserve renal parenchyma, followed by suppression of autoimmunity. In this review, we discuss novel lupus nephritis therapies and how they fit into a combinatorial treatment strategy based on the pathogenic stage.

Therapeutic apheresis in autoimmune diseases

Systemic autoimmune diseases based on an immune pathogenesis produce autoantibodies and circulating immune complexes, which cause inflammation in the tissues of various organs. In most cases, these diseases have a bad prognosis without treatment. Therapeutic apheresis in combination with immunosuppressive therapies has led to a steady increase in survival rates over the last 35 years. Here we provide an overview of the most important pathogenic aspects indicating that therapeutic apheresis can be a supportive therapy in some systemic autoimmune diseases, such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, and inflammatory eye disease. With the introduction of novel and effective biologic agents, therapeutic apheresis is indicated only in severe cases, such as in rapid progression despite immunosuppressive therapy and/or biologic agents, and in patients with renal involvement, acute generalized vasculitis, thrombocytopenia, leucopenia, pulmonary, cardiac, or cerebral involvement. In mild forms of autoimmune disease, treatment with immunosuppressive therapies and/or biologic agents seems to be sufficient. The prognosis of autoimmune diseases with varying organ manifestations has improved considerably in recent years, due in part to very aggressive therapy schemes.

Serum and lymphocytic neurotrophins profiles in systemic lupus erythematosus: a case-control study

BACKGROUND

Neurotrophins play a central role in the development and maintenance of the nervous system. However, neurotrophins can also modulate B and T cell proliferation and activation, especially via autocrine loops. We hypothesized that both serum and lymphocytic neurotrophin levels may be deregulated in systemic Lupus erythematosus (SLE) and may reflect clinical symptoms of the disease.

METHODS

Neurotrophins in the serum (ELISA tests) and lymphocytes (flow cytometry) were measured in 26 SLE patients and 26 control subjects. Th1 (interferon-γ) and Th2 (IL-10) profiles and serum concentration of BAFF were assessed by ELISA in the SLE and control subjects.

FINDINGS

We have demonstrated that both NGF and BDNF serum levels are higher in SLE patients than healthy controls (p=0.003 and p<0.001), independently of Th1 or Th2 profiles. Enhanced serum NT-3 levels (p=0.003) were only found in severe lupus flares (i.e. SLEDAI ≥ 10) and significantly correlated with complement activation (decreased CH 50, Γ=-0.28, p=0.03). Furthermore, there was a negative correlation between serum NGF levels and the number of circulating T regulatory cells (Γ=0.48, p=0.01). In circulating B cells, production of both NGF and BDNF was greater in SLE patients than in healthy controls. In particular, the number of NGF-secreting B cells correlated with decreased complement levels (p=0.05). One month after SLE flare treatment, BDNF levels decreased; in contrast, NGF and NT-3 levels remained unchanged.

CONCLUSION

This study demonstrates that serum and B cell levels of both NGF and BDNF are increased in SLE, suggesting that the neurotrophin production pathway is deregulated in this disease. These results must be confirmed in a larger study with naive SLE patients, in order to avoid the potential confounding influence of prior immune-modulating treatments on neurotrophin levels.

Glucocorticoids suppress T cell function by up-regulating microRNA-98

OBJECTIVE

To identify microRNAs (miRNAs) in human T cells that can explain known antiinflammatory properties of steroids.

METHODS

Activated human CD4+ T cells from healthy donors were exposed to 1 μM methylprednisolone (MP) in vitro and then subjected to miRNA and messenger RNA microarray analyses. Changes in expression profiles were recorded. Using quantitative polymerase chain reaction (qPCR), flow cytometry, and enzyme-linked immunosorbent assay (ELISA), we confirmed the suppression of predicted targets, and through miRNA transfection experiments, we could suggest mechanistic links.

RESULTS

We identified numerous steroid-responsive genes and miRNAs-many known and some novel-including multiple previously unknown proinflammatory genes suppressed by MP. Further studies using qPCR, flow cytometry, and ELISA demonstrated that methylprednisolone increased the expression of miRNA-98 (miR-98) and suppressed the levels of predicted targets, including interleukin-13 and 3 tumor necrosis factor receptors (TNFRs): Fas, FasL, and TNFR superfamily member 1B. Forced expression of miR-98 in T cells resulted in suppression of the same targets.

CONCLUSION

The findings of this study demonstrate a link between miR-98 expression and the effects of MP and provide evidence suggesting that MP acts through miR-98 to inhibit specific proinflammatory targets. Identification of this antiinflammatory mechanism of glucocorticoids is important, since it may pave the way toward the elusive goal of dissociating adverse effects from therapeutic effects.

FOXP3⁺ T regulatory cell modifications in inflammatory bowel disease patients treated with anti-TNFα agents

Treg modulation has been hypothesized as one of the mechanisms by which antitumor necrosis factor α (TNFα) agents exert their action in rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). However, data in IBD are still conflicting. We evaluated CD4⁺CD25⁺FOXP3⁺ (Tregs) by flow cytometry in peripheral blood from 32 adult IBD patient before (T0) and after the induction of anti-TNFα therapy (T1). Eight healthy controls (HCs) were included. We also evaluated the number of FOXP3⁺ cells in the lamina propria (LP) in biopsies taken in a subset of patients and controls. Treg frequencies were significantly increased in peripheral blood from our patients after anti-TNFα therapy compared to T0. T1 but not T0 levels were higher than HC. The increase was detectable only in clinical responders to the treatment. A negative correlation was found among delta Treg levels and the age of patients or disease duration and with the activity score of Crohn's disease (CD). No significant differences were found in LP FOXP3⁺ cells. Our data suggest the possibility that in IBD patients the treatment with anti-TNFα may affect Treg percentages and that Treg modifications may correlate with clinical response, but differently in early versus late disease.

TLR5 signaling enhances the proliferation of human allogeneic CD40-activated B cell induced CD4hiCD25+ regulatory T cells

Although diverse functions of different toll-like receptors (TLR) on human natural regulatory T cells have been demonstrated recently, the role of TLR-related signals on human induced regulatory T cells remain elusive. Previously our group developed an ex vivo high-efficient system in generating human alloantigen-specific CD4^hiCD25⁺ regulatory T cells from naïve CD4⁺CD25⁻ T cells using allogeneic CD40-activated B cells as stimulators. In this study, we investigated the role of TLR5-related signals on the generation and function of these novel CD4^hiCD25⁺ regulatory T cells. It was found that induced CD4^hiCD25⁺ regulatory T cells expressed an up-regulated level of TLR5 compared to their precursors. The blockade of TLR5 using anti-TLR5 antibodies during the co-culture decreased CD4^hiCD25⁺ regulatory T cells proliferation by induction of S phase arrest. The S phase arrest was associated with reduced ERK1/2 phosphorylation. However, TLR5 blockade did not decrease the CTLA-4, GITR and FOXP3 expressions, and the suppressive function of CD4^hiCD25⁺ regulatory T cells. In conclusion, we discovered a novel function of TLR5-related signaling in enhancing the proliferation of CD4^hiCD25⁺ regulatory T cells by promoting S phase progress but not involved in the suppressive function of human CD40-activated B cell-induced CD4^hiCD25⁺ regulatory T cells, suggesting a novel role of TLR5-related signals in the generation of induced regulatory T cells.

Decreased levels of circulating CD4+CD25+Foxp3+ regulatory T cells in patients with primary antiphospholipid syndrome

INTRODUCTION

CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cell dysfunction has been documented in various autoimmune disorders, but not in antiphospholipid syndrome (APS) so far.

METHODS

In this cross-sectional study, we aim to investigate CD4(+)CD25(+)Foxp3(+) Treg cells, CD3(+)CD19(-) T cells and CD3(-)CD19(+) B cells in patients with primary APS and healthy controls. Cell subtypes were immunophenotyped using specific monoclonal antibodies (anti-CD3 CY5, anti-CD4 FITC, anti-CD25, anti-Foxp3, anti-CD19 PE) and flow cytometry.

RESULTS

Twenty patients with APS and 20 age- and sex-matched controls were studied. The percentage of total lymphocytes, activated Th cells (CD4+CD25+), Treg cells and CD3(-)CD19(+) B cells were found significantly lower in APS patients as compared to controls (all p < 0.05).

CONCLUSION

A dysfunction in CD4(+)CD25(+)Foxp3(+) Treg cells may represent one of the mechanisms leading to autoimmunity in APS patients. The decreased number of CD3(-)CD19(+) B cells of APS patients warrants further elucidation.

The NZM2410-derived lupus susceptibility locus Sle2c1 increases Th17 polarization and induces nephritis in fas-deficient mice

OBJECTIVE

Sle2 is a lupus susceptibility locus that has been linked to glomerulonephritis in the NZM2410 mouse. By itself, Sle2 does not induce any autoimmune pathology but results in the accumulation of B-1a cells. This study was designed to assess the contribution of Sle2 to the pathogenesis of autoimmunity.

METHODS

Sle2 or its subcongenic intervals (Sle2a, Sle2b, and Sle2c1) were bred to Fas-deficient B6.lpr mice. Lymphoid phenotypes, which were focused on T cells, were assessed by flow cytometry, and histopathologic changes were compared between cohorts of B6.Sle2.lpr congenic mice and B6.lpr mice of ages up to 6 months.

RESULTS

Sle2 synergized with lpr, resulting in a greatly accelerated lymphadenopathy that largely targeted T cells and mapped to the Sle2c1 locus. This locus has been identified as the main contributor to B-1a cell expansion. Further analyses showed that Sle2c1 expression skewed the differentiation and polarization of Fas-deficient T cells, with a reduction of the CD4+CD25+FoxP3+ regulatory T cell subset and an expansion of the Th17 cells. This was associated with a high number of T cell infiltrates that promoted severe nephritis and dermatitis in the B6.Sle2c1.lpr mice.

CONCLUSION

These results show that Sle2c1 contributes to lupus pathogenesis by affecting T cell differentiation in combination with other susceptibility loci, such as lpr. The significance of the cosegregation of this phenotype and B-1a cell expansion in Sle2c1-expressing mice in relation to the pathogenesis of lupus is discussed.

Molecular characterization of circulating plasma cells in patients with active systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a generalized autoimmune disease characterized by abnormal B cell activation and the occurrence of increased frequencies of circulating plasma cells (PC). The molecular characteristics and nature of circulating PC and B cells in SLE have not been completely characterized. Microarray analysis of gene expression was used to characterize circulating PC in subjects with active SLE. Flow cytometry was used to sort PC and comparator B cell populations from active SLE blood, normal blood and normal tonsil. The gene expression profiles of the sorted B cell populations were then compared.

SLE PC exhibited a similar gene expression signature as tonsil PC. The differences in gene expression between SLE PC and normal tonsil PC and tonsil plasmablasts (PB) suggest a mature Ig secreting cell phenotype in the former population. Despite this, SLE PC differed in expression of about half the genes from previously published gene expression profiles of normal bone marrow PC, indicating that these cells had not achieved a fully mature status. Abnormal expression of several genes, including CXCR4 and S1P₁, suggests a mechanism for the persistence of SLE PC in the circulation. All SLE B cell populations revealed an interferon (IFN) gene signature previously only reported in unseparated SLE peripheral blood mononuclear cells. These data indicate that SLE PC are a unique population of Ig secreting cells with a gene expression profile indicative of a mature, but not fully differentiated phenotype.

Subpopulations of regulatory T cells in rheumatoid arthritis, systemic lupus erythematosus, and Behcet's disease

Recently, subpopulations of regulatory T (Treg) cells, resting Treg (rTreg) and activated Treg (aTreg), have been discovered. The authors investigated the relationship between the change of Treg, aTreg and rTreg and autoimmune diseases. Treg cells and those subpopulations were analyzed by using the human regulatory T cell staining kit and CD45RA surface marker for 42 rheumatoid arthritis (RA), 13 systemic lupus sclerosis (SLE), 7 Behcet's disease (BD), and 22 healthy controls. The proportion of Treg cells was significantly lower in RA (3.8% ± 1.0%) (P < 0.001) and BD (3.3% ± 0.5%) (P < 0.01) compared to healthy controls (5.0% ± 1.3%). The proportion of aTreg cells was also significantly lower in RA (0.4% ± 0.2%) (P = 0.008) and BD (0.3% ± 0.1%) (P = 0.013) compared to healthy controls (0.6% ± 0.3%). The rTreg cells showed no significant differences. The ratio of aTreg to rTreg was lower in RA patients (0.4% ± 0.2%) than that in healthy controls (0.7% ± 0.4%) (P = 0.002). This study suggests that the decrement of aTreg not rTreg cells contributes the decrement of total Treg cells in peripheral blood of RA and BD autoimmune diseases. Detailed analysis of Treg subpopulations would be more informative than total Treg cells in investigating mechanism of autoimmune disease.

Increased expression of regulatory T cells and down-regulatory molecules in lepromatous leprosy

T regulatory cells (Tregs) play an important role in the mechanism of host's failure to control pathogen dissemination in severe forms of different chronic granulomatous diseases, but their role in leprosy has not yet been elucidated; 28 newly diagnosed patients (16 patients with lepromatous leprosy and 12 patients with tuberculoid leprosy) and 6 healthy Mycobacterium leprae-exposed individuals (contacts) were studied. Tregs were quantified by flow cytometry (CD4+ CD25+ Foxp3+) in peripheral blood mononuclear cells stimulated in vitro with a M. leprae antigenic preparation and phytohemagglutinin as well as in skin lesions by immunohistochemistry. The lymphoproliferative (LPR), interleukin-10 (IL-10), and interferon-γ (IFN-γ) responses of the in vitro-stimulated peripheral blood mononuclear cells and the in situ expression of IL-10, transforming growth factor-β (TGF-β), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) were also determined. We show that M. leprae antigens induced significantly lower LPR but significantly higher Treg numbers in lepromatous than tuberculoid patients and contacts. Mitogen-induced LPR and Treg frequencies were not significantly different among the three groups. Tregs were also more frequent in situ in lepromatous patients, and this finding was paralleled by increased expression of the antiinflammatory molecules IL-10 and CTLA-4 but not TGF-β. In lepromatous patients, Tregs were intermingled with vacuolized hystiocyte infiltrates all over the lesion, whereas in tuberculoid patients, Tregs were rare. Our results suggest that Tregs are present in increased numbers, and they may have a pathogenic role in leprosy patients harboring uncontrolled bacillary multiplication but not in those individuals capable of limiting M. leprae growth.

The consequences of UV-induced immunosuppression for human health

Exposure to UV radiation can cause suppression of specific immune responses. The pathways leading to the down-regulation are complex, starting from the absorption of UV photons by chromophores in the skin and ending with local and systemic changes in immune mediators, the generation of T and B regulatory cells and inhibition of effector and memory T cell activation. The consequences for human health are thought to be both beneficial and adverse. The former are illustrated by protection against polymorphic light eruption, and possible protection against T cell-mediated autoimmune diseases and asthma. The latter are illustrated by skin cancer, cutaneous lupus erythematosus and infectious diseases including vaccination. Many outstanding questions remain in this rapidly developing and controversial area, not least what advice to give the general public regarding their sun exposure. While considerable advances have been made in the development of strategies that preserve the health benefits of sunlight exposure and decrease its detrimental effects, further research is required before optimal levels of protection are achieved.

Regulatory T cells control the Th1 immune response in murine crescentic glomerulonephritis

Crescentic glomerulonephritis is mediated by inappropriate humoral and cellular immune responses toward self-antigens that may result from defects in central and peripheral tolerance. Evidence now suggests that regulatory T cells (Tregs) may be of pathophysiological importance in proliferative and crescentic forms of glomerulonephritis. To analyze the role of endogenous Tregs in a T cell-dependent glomerulonephritis model of nephrotoxic nephritis, we used ‘depletion of regulatory T cell' (DEREG) mice that express the diphtheria toxin receptor under control of the FoxP3 (forkhead box P3) gene promoter. Toxin injection into these mice efficiently depleted renal and splenic FoxP3⁺ Treg cells as determined by fluorescent-activated cell sorting (FACS) and immunohistochemical analyses. Treg depletion exacerbated systemic and renal interferon-γ (IFNγ) expression and increased recruitment of IFNγ-producing Th1 cells into the kidney without an effect on the Th17 immune response. The enhanced Th1 response, following Treg cell depletion, was associated with an aggravated course of glomerulonephritis as measured by glomerular crescent formation. Thus, our results establish the functional importance of endogenous Tregs in the control of a significantly enhanced systemic and renal Th1 immune response in experimental glomerulonephritis.

The ageing immune system and its clinical implications

Ageing is associated with multiple changes in many different components of the immune system. A healthy immune system exists in a state of balance between efficient effector responses against pathogens and tolerance to self antigens. This balance is changed with age; functions such as antigen recognition, phagocytosis, antigen presentation, chemotaxis, cytokine secretion and killing ability are all compromised. Aberrant cellular responses lead to an altered cytokine network with increases in inflammatory cytokines and decreases in anti-inflammatory cytokines leading to a pro-inflammatory state. Consequently older patients require extra care in diagnosis of infections as symptoms may be perturbed, resulting in unusual presentations of common conditions. The defects in immunity due to immunosenescence also mean that older patients require more care and screening than other patients in the same disease cohort. Though it is generally understood by clinicians that older patients are more at risk from multiple infections, the wider clinical effects of immunosenescence are less understood. The immune system is involved in several neurodegenerative conditions and the inflammatory conditions of immunosenescence may be a key factor in pathogenesis. Similarly, there is reason to believe that immunosenescence might be a key factor explaining the increased incidence of cancer in older age. With increasing understanding of the immune system's involvement in many of these pathological processes, and the contribution that immunosenescence makes to these, more efficient vaccines and novel therapies may be developed to prevent/treat these conditions.

Pathogenesis of cutaneous lupus erythematosus: common and different features in distinct subsets

The term 'cutaneous lupus erythematosus' (CLE) comprises several related autoimmune skin disorders, defined as 'specific' skin manifestations of lupus erythematosus (LE). The spectrum of clinical presentation of CLE is wide, reaching from mild erythema to disseminated scarring skin lesions. There is increasing knowledge concerning the pathogenesis of LE skin lesions and it has been shown that a complex network of cutaneous cytokines, chemokines and adhesion molecules orchestrate and promote tissue injury observed in LE skin lesions. However, a complete understanding of the diverse pathophysiological mechanisms in the different CLE subsets does not exist. Here we review the main pathological features described in CLE patients against the background of the clinical diversity of different CLE subtypes.

Natural regulatory T cells in autoimmunity

The suppressive/immunomodulatory function of CD4(+)CD25(+)FOXP3(+) regulatory T (Treg) cells is crucial for the maintenance of immune homeostasis, which helps to prevent autoimmunity and reduce the inflammation induced by pathogens and environmental insults. This review summarizes the current knowledge on the types and mechanisms of action of Treg cells and their role in the immune tolerance to self-antigens, with a particular focus on naturally occurring Treg cells.