T regulatory cells are markers of disease activity in multiple sclerosis patients

Extracellular Purine Metabolism-Potential Target in Multiple Sclerosis

The purinergic signaling system comprises a complex network of extracellular purines and purine-metabolizing ectoenzymes, nucleotide and nucleoside receptors, ATP release channels, and nucleoside transporters. Because of its immunomodulatory function, this system is critically involved in the pathogenesis of multiple sclerosis (MS) and its best-characterized animal model, experimental autoimmune encephalomyelitis (EAE). MS is a chronic neuroinflammatory demyelinating and neurodegenerative disease with autoimmune etiology and great heterogeneity, mostly affecting young adults and leading to permanent disability. In MS/EAE, alterations were detected in almost all components of the purinergic signaling system in both peripheral immune cells and central nervous system (CNS) glial cells, which play an important role in the pathogenesis of the disease. A decrease in extracellular ATP levels and an increase in its downstream metabolites, particularly adenosine and inosine, were frequently observed at MS, indicating a shift in metabolism toward an anti-inflammatory environment. Accordingly, upregulation of the major ectonucleotidase tandem CD39/CD73 was detected in the blood cells and CNS of relapsing-remitting MS patients. Based on the postulated role of A2A receptors in the transition from acute to chronic neuroinflammation, the association of variants of the adenosine deaminase gene with the severity of MS, and the beneficial effects of inosine treatment in EAE, the adenosinergic system emerged as a promising target in neuroinflammation. More recently, several publications have identified ADP-dependent P2Y12 receptors and the major extracellular ADP producing enzyme nucleoside triphosphate diphosphohydrolase 2 (NTPDase2) as novel potential targets in MS.

Treated and Untreated Primary Progressive Multiple Sclerosis: Walkthrough Immunological Changes of Monocytes and T Regulatory Cells

The objective of this study was to investigate regulatory T cells (Tregs) and monocytes; specifically, the expression of CTLA-4 (CD152) and FOXP3+ in CD4+CD25+ Tregs and the expression of CD40+ and CD192+ monocyte subpopulations in subjects with primary progressive multiple sclerosis (PPMS). Immunological analysis was conducted on peripheral blood samples collected from the 28 PPMS subjects (15 treated with ocrelizumab and 13 untreated PPMS subjects) and 10 healthy control subjects (HCs). The blood samples were incubated with antihuman CD14, CD16, CD40, and CD192 antibodies for monocytes and antihuman CD4, CD25, FOXP3, and CTLA-4 antibodies for lymphocytes. The study results showed that in comparison to HCs both ocrelizumab treated (N = 15) and untreated (N = 13) PPMS subjects had significantly increased percentages of CTLA-4+ and FOXP3+ in CD4+CD25+ Tregs. Further, ocrelizumab treated PPMS subjects, compared to the untreated ones, had significantly decreased percentages of CD192+ and CD40+ nonclassical monocytes. Increased percentages of CTLA-4+ and FOXP3+ in CD4+CD25+ Tregs in both ocrelizumab treated and untreated PPMS subjects indicates the suppressive (inhibitory) role of Tregs in abnormal immune responses in PPMS subjects. Decreased percentages of CD40+ and CD192+ non-classical CD14+CD16++ monocytes for treated compared to untreated PPMS subjects suggests a possible role for ocrelizumab in dampening CNS inflammation.

MicroRNAs are dysregulated in peripheral blood mononuclear cells in multiple sclerosis and correlate with T cell mediators

T cell mediators and microRNAs are involved in the pathogenesis of multiple sclerosis (MS), but their interaction largely remains undetermined. We investigated by RT-qPCR the dysregulation of microRNAs in peripheral blood mononuclear cells of MS patients versus healthy controls, according to radiological disease activity or treatment. Several microRNAs correlated positively/negatively with IL21/FOXP3 mRNA expression, but not with serum neurofilament light chain levels. Cytokine expression is conceivably balanced by several regulators, whereas microRNAs possibly target upstream transcription factors rather than directly cytokine mRNAs. Functional studies are needed to investigate their interaction, notably for the predicted targeting of FOXP3 by miR-34c-5p.

The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by the destruction of the myelin sheath of the neuronal axon in the central nervous system. Many risk factors, including environmental, epigenetic, genetic, and lifestyle factors, are responsible for the development of MS. It has long been thought that only adaptive immune cells, especially autoreactive T cells, are responsible for the pathophysiology; however, recent evidence has indicated that innate immune cells are also highly involved in disease initiation and progression. Here, we compile the available data regarding the role immune cells play in MS, drawn from both human and animal research. While T and B lymphocytes, chiefly enhance MS pathology, regulatory T cells (Tregs) may serve a more protective role, as can B cells, depending on context and location. Cells chiefly involved in innate immunity, including macrophages, microglia, astrocytes, dendritic cells, natural killer (NK) cells, eosinophils, and mast cells, play varied roles. In addition, there is evidence regarding the involvement of innate-like immune cells, such as γδ T cells, NKT cells, MAIT cells, and innate-like B cells as crucial contributors to MS pathophysiology. It is unclear which of these cell subsets are involved in the onset or progression of disease or in protective mechanisms due to their plastic nature, which can change their properties and functions depending on microenvironmental exposure and the response of neural networks in damage control. This highlights the need for a multipronged approach, combining stringently designed clinical data with carefully controlled in vitro and in vivo research findings, to identify the underlying mechanisms so that more effective therapeutics can be developed.

Immunoregulatory Effects of the Active Form of Vitamin D (Calcitriol), Individually and in Combination with Curcumin, on Peripheral Blood Mononuclear Cells (PBMCs) of Multiple Sclerosis (MS) Patients

OBJECTIVES

Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease affecting the central nervous system. Immune cell subsets, notably T helper (Th) 17 and Th1, exert important roles in MS pathogenesis. Whereas, Treg cells modulate the disease process. Calcitriol, the active form of vitamin D, and curcumin, a bioactive compound derived from turmeric, play immunomodulatory effects relevant to autoimmune disorders, including MS. The objective of this study is to investigate the effects of calcitriol and Curcumin on Peripheral blood mononuclear cells (PBMCs) of individuals with MS.

METHODS

PBMCs from twenty MS patients were isolated, cultured, and exposed to 0.004 μg/mL of calcitriol and 10 μg/mL of curcumin. The cells underwent treatment with singular or combined doses of these components to assess potential cumulative or synergistic immunomodulatory effects. Following treatment, the expression levels of genes and the cellular population of Treg, Th1 and Th17 were evaluated using Real-time PCR and flow cytometry.

RESULTS

Treatment with curcumin and calcitriol led to a significant reduction in the expression levels of inflammatory cytokines and transcription factors related to Th1 and Th17 cells, including IFN-γ, T-bet, IL-17, and RORC. Furthermore, the frequency of these cells decreased following treatment. Additionally, curcumin and calcitriol treatment resulted in a significant upregulation of the FOXP3 gene expression and an increase in the frequency of Treg cells.

CONCLUSION

This study demonstrates that curcumin and calcitriol can effectively modulate the inflammatory processes intrinsic to MS by mitigating the expression of inflammatory cytokines by Th1 and Th17 cells while concurrently enhancing the regulatory role of Treg cells. Moreover, the combined treatment of curcumin and calcitriol did not yield superior outcomes compared to single-dosing strategies.

rs3761548 (C/A) and rs5902434 (del/ATT) polymorphisms of Foxp3 gene in Iranian patients with migraine

Background

Migraine is a neurovascular disorder; several studies have demonstrated the immune system plays a key role in migraine pathogenesis. The aim of this study was to investigate the association between FOXP3 gene polymorphism and susceptibility to migraine.

Methods

In a case–control study, 55 whole blood samples of patients with migraine and 80 healthy samples were collected. After DNA extraction, genotyping of the rs5902434 (del/ATT) and rs3761548 (C/A) FOXP3 was performed using sequence-specific primers method (PCR-SSP).

Results

The results of this study showed that there were statistically significant differences between patient and control group in genotype frequencies of rs3761548. In addition, the frequency of heterozygous genotype AC at rs3761548 in patients was found to be significantly higher than controls. We also found no significant differences between cases and controls were found in the allelic and genotype distribution of the rs5902434 (del/ATT) polymorphism. None of the rs5902434 (del/ATT) genotypes showed any significant association with the migraine.

Conclusions

According to finding of our study, polymorphism rs3761548 in FOXP3 gene were associated with susceptibility to migraine. Further studies with larger sample sizes and different populations in other parts of the world are needed to investigate relationship between this polymorphism on migraine susceptibility.

The impact of the gut microbiome on extra-intestinal autoimmune diseases

The prevalence of autoimmune diseases (ADs) worldwide has rapidly increased over the past few decades. Thus, in addition to the classical risk factors for ADs, such as genetic polymorphisms, infections and smoking, environmental triggers have been considered. Recent sequencing-based approaches have revealed that patients with extra-intestinal ADs, such as multiple sclerosis, rheumatoid arthritis, type 1 diabetes and systemic lupus erythematosus, have distinct gut microbiota compositions compared to healthy controls. Faecal microbiota transplantation or inoculation with specific microbes in animal models of ADs support the hypothesis that alterations of gut microbiota influence autoimmune responses and disease outcome. Here, we describe the compositional and functional changes in the gut microbiota in patients with extra-intestinal AD and discuss how the gut microbiota affects immunity. Moreover, we examine how the gut microbiota might be modulated in patients with ADs as a potential preventive or therapeutic approach.

Expression of T cell-related lncRNAs in multiple sclerosis

Long non-coding RNAs (lncRNAs) have been demonstrated to in the pathophysiology of multiple sclerosis (MS). In order to appraise the role of T cell-related lncRNAs in this disorder, we assessed expressions of NEST, RMRP, TH2-LCR, MAFTRR and FLICR in MS patients and healthy individuals. We detected significant difference in the expression of RMRP and FLICR between cases and controls. There were substantial correlations between expressions of NEST, RMRP, TH2-LCR, MAFTRR and FLICR lncRNAs among patients, but not controls. The strongest correlations were found between RMRP and TH2-LCR, and between MAFTRR and RMRP with correlation coefficients of 0.69 and 0.59, respectively. ROC curve analysis revealed appropriate power of FLICR in differentiating between MS patients and healthy controls (AUC value = 0.84). Expression of NEST lncRNA was positively correlated with disease duration in MS patients, but negatively correlated with age at onset. In brief, we reported dysregulation of two T cell-related lncRNAs in MS patients and proposed FLICR as a putative marker for this disorder.

microRNA-92a promotes CNS autoimmunity by modulating the regulatory and inflammatory T cell balance

A disequilibrium between immunosuppressive Tregs and inflammatory IL-17-producing Th17 cells is a hallmark of autoimmune diseases, including multiple sclerosis (MS). However, the molecular mechanisms underlying the Treg and Th17 imbalance in CNS autoimmunity remain largely unclear. Identifying the factors that drive this imbalance is of high clinical interest. Here, we report a major disease-promoting role for microRNA-92a (miR-92a) in CNS autoimmunity. miR-92a was elevated in experimental autoimmune encephalomyelitis (EAE), and its loss attenuated EAE. Mechanistically, miR-92a mediated EAE susceptibility in a T cell-intrinsic manner by restricting Treg induction and suppressive capacity, while supporting Th17 responses, by directly repressing the transcription factor Foxo1. Although miR-92a did not directly alter Th1 differentiation, it appeared to indirectly promote Th1 cells by inhibiting Treg responses. Correspondingly, miR-92a inhibitor therapy ameliorated EAE by concomitantly boosting Treg responses and dampening inflammatory T cell responses. Analogous to our findings in mice, miR-92a was elevated in CD4+ T cells from patients with MS, and miR-92a silencing in patients' T cells promoted Treg development but limited Th17 differentiation. Together, our results demonstrate that miR-92a drives CNS autoimmunity by sustaining the Treg/Th17 imbalance and implicate miR-92a as a potential therapeutic target for MS.

Proportion of peripheral regulatory T cells in patients with autoimmune encephalitis

PURPOSE

Regulatory T cells (Tregs) play a crucial role in maintaining immune tolerance. Any deficiency or dysfunction of the Tregs can influence the pathogenesis of autoimmune disease. This study aimed to assess the role of Tregs among patients with autoimmune encephalitis (AE) with different autoantibody types and to evaluate their association with clinical features.

METHODS

This was a cross-sectional observational study involving 29 patients with AE. Peripheral blood was sampled from each patient for flow cytometric analysis. Proportions of CD4⁺CD25⁺ and CD4⁺CD25⁺Foxp3⁺ Tregs were calculated and compared between the antibody types (synaptic, paraneoplastic, and undetermined). Associations between the proportion of Tregs and clinical features were also evaluated.

RESULTS

Five patients had synaptic autoantibodies, five had paraneoplastic autoantibodies, and the others were of an undetermined type. The proportion of CD4⁺CD25⁺ Tregs tended to be higher in those with paraneoplastic antibodies than in those with synaptic antibodies (post-hoc p = 0.028) and undetermined antibody status (post-hoc p = 0.043). A significant negative correlation was found between the proportion of Tregs and the initial modified Rankin score (r = -0.391, p = 0.036). Those who received intravenous immunoglobulin had lower proportions of Tregs than those who did not.

CONCLUSION

The results of the present study suggest that Tregs may play different roles according to the type of AE and may be linked to disease severity.

Multiple sclerosis patients have reduced resting and increased activated CD4+CD25+FOXP3+T regulatory cells

Resting and activated subpopulations of CD4⁺CD25⁺CD127^loT regulatory cells (Treg) and CD4⁺CD25⁺CD127⁺ effector T cells in MS patients and in healthy individuals were compared. Peripheral blood mononuclear cells isolated using Ficoll Hypaque were stained with monoclonal antibodies and analysed by flow cytometer. CD45RA and Foxp3 expression within CD4⁺ cells and in CD4⁺CD25⁺CD127^loT cells identified Population I; CD45RA⁺Foxp3⁺, Population II; CD45RA⁻Foxp3^hi and Population III; CD45RA⁻Foxp3⁺ cells. Effector CD4⁺CD127⁺ T cells were subdivided into Population IV; memory /effector CD45RA⁻ CD25⁻Foxp3⁻ and Population V; effector naïve CD45RA⁺CD25⁻Foxp3⁻CCR7⁺ and terminally differentiated RA⁺ (TEMRA) effector memory cells. Chemokine receptor staining identified CXCR3⁺Th1-like Treg, CCR6⁺Th17-like Treg and CCR7⁺ resting Treg. Resting Treg (Population I) were reduced in MS patients, both in untreated and treated MS compared to healthy donors. Activated/memory Treg (Population II) were significantly increased in MS patients compared to healthy donors. Activated effector CD4⁺ (Population IV) were increased and the naïve/ TEMRA CD4⁺ (Population V) were decreased in MS compared to HD. Expression of CCR7 was mainly in Population I, whereas expression of CCR6 and CXCR3 was greatest in Populations II and intermediate in Population III. In MS, CCR6⁺Treg were lower in Population III. This study found MS is associated with significant shifts in CD4⁺T cells subpopulations. MS patients had lower resting CD4⁺CD25⁺CD45RA⁺CCR7⁺ Treg than healthy donors while activated CD4⁺CD25^hiCD45RA⁻Foxp3^hiTreg were increased in MS patients even before treatment. Some MS patients had reduced CCR6⁺Th17-like Treg, which may contribute to the activity of MS.

IL-37 exerts therapeutic effects in experimental autoimmune encephalomyelitis through the receptor complex IL-1R5/IL-1R8

Background: Interleukin 37 (IL-37), a member of IL-1 family, broadly suppresses inflammation in many pathological conditions by acting as a dual-function cytokine in that IL-37 signals via the extracellular receptor complex IL1-R5/IL-1R8, but it can also translocate to the nucleus. However, whether IL-37 exerts beneficial actions in neuroinflammatory diseases, such as multiple sclerosis, remains to be elucidated. Thus, the goals of the present study were to evaluate the therapeutic effects of IL-37 in a mouse model of multiple sclerosis, and if so, whether this is mediated via the extracellular receptor complex IL-1R5/IL-1R8.

Methods: We used a murine model of MS, the experimental autoimmune encephalomyelitis (EAE). We induced EAE in three different single and double transgenic mice (hIL-37tg, IL-1R8 KO, hIL-37tg-IL-1R8 KO) and wild type littermates. We also induced EAE in C57Bl/6 mice and treated them with various forms of recombinant human IL-37 protein. Functional and histological techniques were used to assess locomotor deficits and demyelination. Luminex and flow cytometry analysis were done to assess the protein levels of pro-inflammatory cytokines and different immune cell populations, respectively. qPCRs were done to assess the expression of IL-37, IL-1R5 and IL-1R8 in the spinal cord of EAE, and in blood peripheral mononuclear cells and brain tissue samples of MS patients.

Results: We demonstrate that IL-37 reduces inflammation and protects against neurological deficits and myelin loss in EAE mice by acting via IL1-R5/IL1-R8. We also reveal that administration of recombinant human IL-37 exerts therapeutic actions in EAE mice. We finally show that IL-37 transcripts are not up-regulated in peripheral blood mononuclear cells and in brain lesions of MS patients, despite the IL-1R5/IL-1R8 receptor complex is expressed.

Conclusions: This study presents novel data indicating that IL-37 exerts therapeutic effects in EAE by acting through the extracellular receptor complex IL-1R5/IL-1R8, and that this protective physiological mechanism is defective in MS individuals. IL-37 may therefore represent a novel therapeutic avenue for the treatment of MS with great promising potential.

Implications of CD39 in immune-related diseases

Extracellular adenosine triphosphate (eATP) mediates pro-inflammatory responses by recruiting and activating inflammatory cells. CD39 can hydrolyze eATP into adenosine monophosphate (AMP), while CD73 can convert AMP into the immunosuppressive nucleoside adenosine (ADO). CD39 is a rate-limiting enzyme in this cascade, which is regarded as an immunological switch shifting the ATP-mediated pro-inflammatory environment to the ADO- mediated anti-inflammatory status. The CD39 expression can be detected in a wide spectrum of immunocytes, which is under the influence of environmental and genetic factors. It is increasingly suggested that, CD39 participates in some pathophysiological processes, like inflammatory bowel disease (IBD), sepsis, multiple sclerosis (MS), allergic diseases, ischemia-reperfusion (I/R) injury, systemic lupus erythematosus (SLE), diabetes and cancer. Here, we focus on the current understanding of CD39 in immunity, and comprehensively illustrate the diverse CD39 functions within a variety of disorders.

CTLA4 mRNA expression in blood is lower in schizophrenia, but not in affective disorders

CTL-associated antigen 4 (CTLA4) and its downstream signals compose an important mechanism that suppresses immune activity. Recent studies have shown that immune abnormalities are associated with the pathogenesis of schizophrenia (SCZ), but little research has been performed on the relevance of CTLA4 and SCZ. In the present study, we investigated the relationship between CTLA4 mRNA expression and SCZ. We examined the expression of CTLA4 mRNA in blood from patients with SCZ, bipolar disorder (BD), and major depressive disorder (MDD). We compared 50 SCZ subjects, 46 BD subjects, and 63 MDD subjects with age- and sex-matched healthy controls (HCs). Quantitative real-time PCR was performed to examine CTLA4 mRNA expression in peripheral blood using TaqMan probes. Levels of CTLA4 mRNA expression were significantly lower in patients with SCZ compared with HCs (p < 0.001), whereas no differences were found between affective disorder (BD and MDD) patients and HCs. We analyzed the correlation between CTLA4 mRNA expression and clinical parameters, but no significant correlation was found. The expression of CTLA4 mRNA was lower specifically in SCZ, suggesting that abnormal CTLA4 expression may be particularly related to the pathogenesis of SCZ. CTLA4 may be a useful diagnostic marker and a potential therapeutic target of SCZ.

Repopulation of T, B, and NK cells following alemtuzumab treatment in relapsing-remitting multiple sclerosis

OBJECTIVE

To characterize long-term repopulation of peripheral immune cells following alemtuzumab-induced lymphopenia in relapsing-remitting MS (RRMS), with a focus on regulatory cell types, and to explore associations with clinical outcome measures.

METHODS

The project was designed as a multicenter add-on longitudinal mechanistic study for RRMS patients enrolled in CARE-MS II, CARE-MS II extension at the University of Southern California and Stanford University, and an investigator-initiated study conducted at the Universities of British Columbia and Chicago. Methods involved collection of blood at baseline, prior to alemtuzumab administration, and at months 5, 11, 17, 23, 36, and 48 post-treatment. T cell, B cell, and natural killer (NK) cell subsets, chemokine receptor expression in T cells, in vitro cytokine secretion patterns, and regulatory T cell (Treg) function were assessed. Clinical outcomes, including expanded disability status score (EDSS), relapses, conventional magnetic resonance imaging (MRI) measures, and incidents of secondary autoimmunity were tracked.

RESULTS

Variable shifts in lymphocyte populations occurred over time in favor of CD4+ T cells, B cells, and NK cells with surface phenotypes characteristic of regulatory subsets, accompanied by reduced ratios of effector to regulatory cell types. Evidence of increased Treg competence was observed after each treatment course. CD4+ and CD8+ T cells that express CXCR3 and CCR5 and CD8+ T cells that express CDR3 and CCR4 were also enriched after treatment, indicating heightened trafficking potential in activated T cells. Patterns of repopulation were not associated with measures of clinical efficacy or secondary autoimmunity, but exploratory analyses using a random generalized estimating equation (GEE) Poisson model provide preliminary evidence of associations between pro-inflammatory cell types and increased risk for gadolinium (Gd+) enhancing lesions, while regulatory subsets were associated with reduced risk. In addition, the risk for T2 lesions correlated with increases in CD3+CD8+CXCR3+ cells.

CONCLUSIONS

Lymphocyte repopulation after alemtuzumab treatment favors regulatory subsets in the T cell, B cell, and NK cell compartments. Clinical efficacy may reflect the sum of interactions among them, leading to control of potentially pathogenic effector cell types. Several immune measures were identified as possible biomarkers of lesion activity. Future studies are necessary to more precisely define regulatory and effector subsets and their contributions to clinical efficacy and risk for secondary autoimmunity in alemtuzumab-treated patients, and to reveal new insights into mechanisms of immunopathogenesis in MS.

TRIAL REGISTRATION

Parent trials for this study are registered with ClinicalTrials.gov: CARE-MS II: NCT00548405, CARE-MS II extension: NCT00930553 and ISS: NCT01307332.

The potentials of umbilical cord-derived mesenchymal stem cells in the treatment of multiple sclerosis

Stem cell therapy has indicated a promising treatment capacity for tissue regeneration. Multiple sclerosis is an autoimmune-based chronic disease, in which the myelin sheath of the central nervous system is destructed. Scientists have not discovered any cure for multiple sclerosis, and most of the treatments are rather palliative. The pursuit of a versatile treatment option, therefore, seems essential. The immunoregulatory and non-chronic rejection characteristics of mesenchymal stem cells, as well as their homing properties, recommend them as a prospective treatment option for multiple sclerosis. Different sources of mesenchymal stem cells have distinct characteristics and functional properties; in this regard, choosing the most suitable cell therapy approach seems to be challenging. In this review, we will discuss umbilical cord/blood-derived mesenchymal stem cells, their identified exclusive properties compared to another adult mesenchymal stem cells, and the expectations of their potential roles in the treatment of multiple sclerosis.

Molecular Mechanisms Controlling Foxp3 Expression in Health and Autoimmunity: From Epigenetic to Post-translational Regulation

The discovery of the transcription factor Forkhead box-p3 (Foxp3) has shed fundamental insights into the understanding of the molecular determinants leading to generation and maintenance of T regulatory (Treg) cells, a cell population with a key immunoregulatory role. Work over the past few years has shown that fine-tuned transcriptional and epigenetic events are required to ensure stable expression of Foxp3 in Treg cells. The equilibrium between phenotypic plasticity and stability of Treg cells is controlled at the molecular level by networks of transcription factors that bind regulatory sequences, such as enhancers and promoters, to regulate Foxp3 expression. Recent reports have suggested that specific modifications of DNA and histones are required for the establishment of the chromatin structure in conventional CD4⁺ T (Tconv) cells for their future differentiation into the Treg cell lineage. In this review, we discuss the molecular events that control Foxp3 gene expression and address the associated alterations observed in human diseases. Also, we explore how Foxp3 influences the gene expression programs in Treg cells and how unique properties of Treg cell subsets are defined by other transcription factors.

One, No One, and One Hundred Thousand: T Regulatory Cells' Multiple Identities in Neuroimmunity

As the Nobel laureate Luigi Pirandello wrote in his novels, identities can be evanescent. Although a quarter of a century has passed since regulatory T cells (Treg) were first described, new studies continue to reveal surprising and contradictory features of this lymphocyte subset. Treg cells are the core of the immunological workforce engaged in the restraint of autoimmune or inflammatory reactions, and their characterization has revealed substantial heterogeneity and complexity in the phenotype and gene expression profiles, proving them to be a most versatile and adaptive cell type, as exemplified by their plasticity in fine-tuning immune responses. Defects in Treg function are associated with several autoimmune diseases, including multiple sclerosis, which is caused by an inappropriate immune reaction toward brain components; conversely, the beneficial effects of immunomodulating therapies on disease progression have been shown to partly act upon the biology of these cells. Both in animals and in humans the pool of circulating Treg cells is a mixture of natural (nTregs) and peripherally-induced Treg (pTregs). Particularly in humans, circulating Treg cells can be phenotypically subdivided into different subpopulations, which so far are not well-characterized, particularly in the context of autoimmunity. Recently, Treg cells have been rediscovered as mediators of tissue healing, and have also shown to be involved in organ homeostasis. Moreover, stability of the Treg lineage has recently been addressed by several conflicting reports, and immune-suppressive abilities of these cells have been shown to be dynamically regulated, particularly in inflammatory conditions, adding further levels of complexity to the study of this cell subset. Finally, Treg cells exert their suppressive function through different mechanisms, some of which—such as their ectoenzymatic activity—are particularly relevant in CNS autoimmunity. Here, we will review the phenotypically and functionally discernible Treg cell subpopulations in health and in multiple sclerosis, touching also upon the effects on this cell type of immunomodulatory drugs used for the treatment of this disease.

Tolerance regeneration by T regulatory cells in autologous haematopoietic stem cell transplantation for autoimmune diseases

Autologous haematopoietic stem cell transplantation shows increasing promise as a therapeutic option for patients with treatment-refractory autoimmune disease, particularly systemic sclerosis and multiple sclerosis. However, this intensive chemotherapy-based procedure is not always possible due to potential treatment toxicities and comorbidities. The biological mechanisms of how this procedure induces long-term remission in autoimmune disease are increasingly understood. The focus of this review is on recent research findings on the role of CD4+ T regulatory cells (Tregs) in resetting the immune system leading to the eradication of the autoimmune disease after transplantation. Discovery of the precise mechanisms of this process will allow development of novel Treg-based therapies and thus avoid the need for intensive chemotherapy-based treatment for these autoimmune diseases in the future.

The Characterization of Regulatory T-Cell Profiles in Alzheimer's Disease and Multiple Sclerosis

Regulatory T Cells (Tregs) are a T-lymphocyte subset involved in the maintenance of immune peripheral tolerance. Despite evidence of the adaptive immune system's role in Alzheimer's Disease (AD), the involvement of Tregs is still not clear. We focused on the Flow-Cytometry analysis of the Treg frequencies and phenotypes in the AD. The aim of the study is to analyse similarities and differences in Tregs profile between Alzheimer's Disease and Multiple Sclerosis. Regulatory T Cells (CD4+/CD25high/CD127low-neg) were identified using an innovative Flow Cytometry method and subtyped as Resting (analysed CD45RApos/CD25dim), Activated (CD45RAneg/CD25bright) and Secreting (CD45RAneg/CD25dim) cells. Our data demonstrate a significant decrease in the total and Resting Tregs in AD patients when compared to healthy subjects. The percentage of the results of the Resting Tregs were also reduced in MS patients together with a parallel frequency increase of Activated Tregs. Our data suggest that altered Treg phenotypes observed in both diseases could play a role in the impairment of the Treg-mediated immunological tolerance, recalling a possible link between the two pathologies. Given that this study was conducted on a restricted population, if confirmed by a further and enlarged study, the implications of the autoimmune mechanisms in AD pathophysiology could open new immunotherapeutic perspectives based on Treg modulation.

The effects of a combination of ion channel inhibitors on pathology in a model of demyelinating disease

BACKGROUND

Multiple sclerosis (MS) has been shown to feature oxidative damage, which can be modelled using the cuprizone model of demyelinating disease. Oxidative damage can occur as a result of excessive influx of calcium ions (Ca²⁺) and oligodendroglia are particularly vulnerable. However, the effects of limiting excess Ca²⁺ influx on oxidative damage, oligodendroglia and myelin structure are unknown.

OBJECTIVE

This study investigated the effects of limiting excess Ca²⁺ flux on oxidative damage and associated changes in oligodendroglial densities and Node of Ranvier structure in the cuprizone model.

METHODS

The effects of three weeks of cuprizone administration and of treatment with a combination of three ion channel inhibitors (Lomerizine, Brilliant Blue G (BBG) and YM872), were semi-quantified immunohistochemically. Outcomes assessed were protein nitration (3-nitrotyrosine (3NT)) oxidative damage to DNA (8-hydroxy deoxyguanosine (8OHDG)), advanced glycation end-products (carboxymethyl lysine (CML)), immunoreactivity of microglia (Iba1) and astrocytes (glial acidic fibrillary protein (GFAP)), densities of oligodendrocyte precursor cells (OPCs) (platelet derived growth factor alpha receptor (PDGFαR) with olig2) and oligodendrocytes (olig2 and CC1), and structural elements of the Node of Ranvier (contactin associated protein (Caspr)).

RESULTS

The administration of cuprizone resulted in increased protein nitration, DNA damage, and astrocyte and microglial immunoreactivity, a decrease in the density of oligodendrocytes and OPCs, together with altered structure of the Node of Ranvier and reduced myelin basic protein immunoreactivity. Treatment with the ion channel inhibitor combination significantly lowered protein nitration, increased the density of OPCs and reduced the number of atypical Node of Ranvier complexes; other outcomes were unaffected.

CONCLUSION

Our findings suggest that excess Ca²⁺ influx contributes to protein nitration, and associated changes to OPC densities and Node of Ranvier structure in demyelinating disease.

Peripheral CD39-expressing T regulatory cells are increased and associated with relapsing-remitting multiple sclerosis in relapsing patients

CD39, an ectonucleotidase that hydrolyses pro-inflammatory ATP, is a marker of highly active and suppressive T regulatory cells (Tregs). Although CD39 has a role in Treg suppression and might be important in the control of neuroinflammation in relapsing-remitting multiple sclerosis (RR-MS), to date, there are contradictory reports concerning the Tregs expression of CD39 in RR-MS patients. Thus, our objectives were to assess the activity and expression of CD39, especially in Tregs from peripheral blood mononuclear cells (PBMCs) of relapsing RR-MS patients compared with control subjects and to evaluate the association of CD39+ Tregs with disability and the odds of RR-MS. The activity and expression of CD39 and the CD39⁺ Treg frequency were measured in PBMCs from 55 relapsing RR-MS patients (19 untreated and 36 receiving immunomodulatory treatment) and 55 age- and sex-paired controls. Moreover, the association between CD39⁺ Tregs and RR-MS was assessed by multivariate logistic regression. CD39 activity and the frequency of CD39-expressing Tregs were elevated in relapsing RR-MS patients. Moreover, CD39⁺ Tregs were significantly correlated with the EDSS score and were independently associated with the odds of RR-MS. Our results highlight the relevance of CD39⁺ Treg subset in the clinical outcomes of RR-MS.

Monocyte and Lymphocyte Activation and Regulation in Multiple Sclerosis Patients. Therapy Effects

Analysis of gut barrier status, monocyte and lymphocyte activation and T regulatory (Treg) cells at diagnosis before and after therapy, in patients with multiple sclerosis (MS). Analysis of differential effects of interferon beta (IFN-β), glatiramer acetate (GA) and natalizumab. Thirty-five patients with untreated MS were included. Gut barrier status (serum concentrations of intestinal fatty acid binding protein), monocyte (serum levels of soluble CD14, soluble CD163 and interleukin 6) and T lymphocyte activation (CD4 + DR+ and CD8 + DR+) and Treg (CD4 + CD25highFoxP3+) cells were analyzed. Patients with clinical isolated syndrome and relapsing-remitting forms were treated with IFN-β or GA, and immune characteristics were reevaluated following up after 6 months. A sample of 56 stable RR MS patients, in treatment with IFN-β, GA or natalizumab, and 50 healthy individuals were included as controls. Gut barrier status was similar in MS patients and healthy controls. Untreated patients with relapsing-remitting and primary progressive patterns of MS showed increased serum levels of soluble CD14. At baseline, significant increases in activated T lymphocytes and Treg were detected in patients. A significant decrease of CD4 + DR+, CD8 + DR+, and Treg percentages after 6 months of therapy was observed. In previously treated patients, IFN-β, GA, or natalizumab therapies were associated with a comparable cell proportion of activated lymphocytes and Treg. MS patients have a baseline state characterized by monocyte and lymphocyte activation, not related with gut barrier lesion. An increase in Treg number, correlated with activated T CD8+ lymphocytes, was detected. Treatment with IFN-β, GA or natalizumab was associated with a comparable decrease in activated lymphocytes and Treg. Graphical Abstract ᅟ.

CD39+ regulatory T cells accumulate in colon adenocarcinomas and display markers of increased suppressive function

Increasing knowledge of the function and regulation of tumor-infiltrating lymphocytes has led to new insights in cancer immunotherapy. Regulatory T cells (Treg) accumulate in colon tumors, and we recently showed that CD39⁺ Treg from cancer patients inhibit transendothelial migration of conventional T cells. CD39 mediates the hydrolysis of ATP to immunosuppressive adenosine and adds to the immunosuppressive effects of Treg. Here, we further investigated the regulatory features of intratumoral CD39⁺ Treg in colon cancer. Using flow cytometry analyses of cells from 46 colon cancer patients, we confirm the accumulation of CD39⁺ Treg in the tumor tissue compared to unaffected colon tissue, and also show that tumor-infiltrating Treg express more CD39 and Foxp3 on a per cell basis. Furthermore, CD39⁺ Treg in tumors express markers indicating increased turnover and suppressive ability. In particular, tumor-infiltrating CD39⁺ Treg have high expression of surface molecules related to immunosuppression, such as ICOS, PD-L1 and CTLA-4. Functional suppression assays also indicate potent suppressive capacity of CD39⁺ Treg on proliferation and IFN-γ secretion by conventional T cells. In conclusion, our results identify tumor-infiltrating CD39⁺ Treg as a numerous and potentially important immunosuppressive subset, and suggest that immunotherapy aimed at reducing the activity of CD39⁺ Treg may be particularly useful in the setting of colon cancer.

Umbilical cord-derived mesenchymal stem cells reversed the suppressive deficiency of T regulatory cells from peripheral blood of patients with multiple sclerosis in a co-culture - a preliminary study

The immunoregulatory function of T regulatory cells (Tregs) is impaired in multiple sclerosis (MS). Recent studies have shown that umbilical cord-derived mesenchymal stem cells (UC-MSCs) exert regulatory effect on the functions of immune cells. Thus, we investigated whether UC-MSCs could improve the impaired function of Tregs from MS patients. Co-cultures of UC-MSCs with PBMCs of MS patients were performed for 3 days. Flow cytometry was used to determine the frequency of Tregs. A cell proliferation assay was used to evaluate the suppressive capacity of Tregs. ELISA was conducted for cytokine analysis in the co-cultures. Our results showed that UC-MSCs significantly increased the frequency of CD4⁺CD25⁺CD127^low/− Tregs in resting CD4⁺ T cells (p<0.01) from MS, accompanied by the significantly augmented production of cytokine prostaglandin E2, transforming growth factor (−β1, and interleukin-10, along with a reduced interferon-γ production in these co-cultures (p<0.05 - 0.01). More importantly, UC-MSC-primed Tregs of MS patients significantly inhibited the proliferation of PHA-stimulated autologous and allogeneic CD4⁺CD25⁻ T effector cells (Teffs) from MS patients and healthy individuals compared to non-UC-MSC-primed (naïve) Tregs from the same MS patients (p<0.01). Furthermore, no remarkable differences in suppressing the proliferation of PHA-stimulated CD4⁺CD25⁻ Teffs was observed in UC-MSC-primed Tregs from MS patients and naïve Tregs from healthy subjects. The impaired suppressive function of Tregs from MS can be completely reversed in a co-culture by UC-MSC modulation. This report is the first to demonstrate that functional defects of Tregs in MS can be repaired in vitro using a simple UC-MSC priming approach.

Understanding Progressive Multifocal Leukoencephalopathy Risk in Multiple Sclerosis Patients Treated with Immunomodulatory Therapies: A Bird's Eye View

The increased use of newer potent immunomodulatory therapies for multiple sclerosis (MS), including natalizumab, fingolimod, and dimethyl fumarate, has expanded the patient population at risk for developing progressive multifocal leukoencephalopathy (PML). These MS therapies shift the profile of lymphocytes within the central nervous system (CNS) leading to increased anti-inflammatory subsets and decreased immunosurveillance. Similar to MS, PML is a demyelinating disease of the CNS, but it is caused by the JC virus. The manifestation of PML requires the presence of an active, genetically rearranged form of the JC virus within CNS glial cells, coupled with the loss of appropriate JC virus-specific immune responses. The reliability of metrics used to predict risk for PML could be improved if all three components, i.e., viral genetic strain, localization, and host immune function, were taken into account. Advances in our understanding of the critical lymphocyte subpopulation changes induced by these MS therapies and ability to detect viral mutation and reactivation will facilitate efforts to develop these metrics.

Beta and Gamma Human Herpesviruses: Agonistic and Antagonistic Interactions with the Host Immune System

Viruses are the most abundant and diverse biological entities in the planet. Historically, our main interest in viruses has focused on their pathogenic role, recognized by pandemics that have decimated the world population. However, viral infections have also played a major role in the evolution of cellular organisms, both through interchanging of genes with novel functions and shaping the immune system. Examples abound of infections that seriously compromise the host integrity, but evidence of plant and insect viruses mutualistic relationships have recently surfaced in which infected hosts are better suited for survival, arguing that virus-host interactions are initially parasitic but become mutualistic over years of co-evolution. A similar mutual help scenario has emerged with commensal gut bacteria. EBV is a herpesvirus that shares more than a hundred million years of co-evolution with humans, today successfully infecting close to 100% of the adult world population. Infection is usually acquired early in childhood persisting for the host lifetime mostly without apparent clinical symptoms. Disturbance of this homeostasis is rare and results in several diseases, of which the best understood are infectious mononucleosis and several EBV-associated cancers. Less understood are recently found inborn errors of the immune system that result in primary immunodeficiencies with an increased predisposition almost exclusive to EBV-associated diseases. Puzzling to these scenarios of broken homeostasis is the co-existence of immunosuppression, inflammation, autoimmunity and cancer. Homologous to EBV, HCMV, HHV-6 and HHV-7 are herpesviruses that also latently infect most individuals. Several lines of evidence support a mutualistic equilibrium between HCMV/EBV and hosts, that when altered trigger diseases in which the immune system plays a critical role. Interestingly, these beta and gamma herpesviruses persistently infect all immune lineages and early precursor cells. In this review, we will discuss the evidence of the benefits that infection of immune cells with these herpesviruses brings to the host. Also, the circumstances in which this positive relationship is broken, predisposing the host to diseases characterized by an abnormal function of the host immune system.

Gene Therapy-Induced Antigen-Specific Tregs Inhibit Neuro-inflammation and Reverse Disease in a Mouse Model of Multiple Sclerosis

The devastating neurodegenerative disease multiple sclerosis (MS) could substantially benefit from an adeno-associated virus (AAV) immunotherapy designed to restore a robust and durable antigen-specific tolerance. However, developing a sufficiently potent and lasting immune-regulatory therapy that can intervene in ongoing disease is a major challenge and has thus been elusive. We addressed this problem by developing a highly effective and robust tolerance-inducing in vivo gene therapy. Using a pre-clinical animal model, we designed a liver-targeting gene transfer vector that expresses full-length myelin oligodendrocyte glycoprotein (MOG) in hepatocytes. We show that by harnessing the tolerogenic nature of the liver, this powerful gene immunotherapy restores immune tolerance by inducing functional MOG-specific regulatory T cells (Tregs) in vivo, independent of major histocompatibility complex (MHC) restrictions. We demonstrate that mice treated prophylactically are protected from developing disease and neurological deficits. More importantly, we demonstrate that when given to mice with preexisting disease, ranging from mild neurological deficits to severe paralysis, the gene immunotherapy abrogated CNS inflammation and significantly reversed clinical symptoms of disease. This specialized approach for inducing antigen-specific immune tolerance has significant therapeutic potential for treating MS and other autoimmune disorders.

Narcolepsy Type 1 Is Associated with a Systemic Increase and Activation of Regulatory T Cells and with a Systemic Activation of Global T Cells

Narcolepsy is a rare neurologic disorder characterized by excessive daytime sleepiness, cataplexy and disturbed nocturnal sleep patterns. Narcolepsy type 1 (NT1) has been shown to result from a selective loss of hypothalamic hypocretin-secreting neurons with patients typically showing low CSF-hypocretin levels (<110 pg/ml). This specific loss of hypocretin and the strong association with the HLA-DQB1*06:02 allele led to the hypothesis that NT1 could be an immune-mediated pathology. Moreover, susceptibility to NT1 has recently been associated with several pathogens, particularly with influenza A H1N1 virus either through infection or vaccination. The goal of this study was to compare peripheral blood immune cell populations in recent onset pediatric NT1 subjects (post or non-post 2009-influenza A H1N1 vaccination) to healthy donors. We demonstrated an increased number of central memory CD4+ T cells (CD62L+ CD45RA-) associated to an activated phenotype (increase in CD69 and CD25 expression) in NT1 patients. Percentage and absolute count of regulatory T cells (Tregs) in NT1 patients were increased associated with an activated phenotype (increase in GITR and LAP expression), and of activated memory phenotype. Cytokine production by CD4+ and CD8+ T cells after activation was not modified in NT1 patients. In H1N1 vaccinated NT1 patients, absolute counts of CD3+, CD8+ T cells, and B cells were increased compared to non-vaccinated NT1 patients. These results support a global T cell activation in NT1 patients and thus support a T cell-mediated autoimmune origin of NT1, but do not demonstrate the pathological role of H1N1 prophylactic vaccination. They should prompt further studies of T cells, particularly of Tregs (such as suppression and proliferation antigen specific assays, and also T-cell receptor sequencing), in NT1.

Multiple Sclerosis and Obesity: Possible Roles of Adipokines

Multiple Sclerosis (MS) is an autoimmune disorder of the Central Nervous System that has been associated with several environmental factors, such as diet and obesity. The possible link between MS and obesity has become more interesting in recent years since the discovery of the remarkable properties of adipose tissue. Once MS is initiated, obesity can contribute to increased disease severity by negatively influencing disease progress and treatment response, but, also, obesity in early life is highly relevant as a susceptibility factor and causally related risk for late MS development. The aim of this review was to discuss recent evidence about the link between obesity, as a chronic inflammatory state, and the pathogenesis of MS as a chronic autoimmune and inflammatory disease. First, we describe the main cells involved in MS pathogenesis, both from neural tissue and from the immune system, and including a new participant, the adipocyte, focusing on their roles in MS. Second, we concentrate on the role of several adipokines that are able to participate in the mediation of the immune response in MS and on the possible cross talk between the latter. Finally, we explore recent therapy that involves the transplantation of adipocyte precursor cells for the treatment of MS.

Regulatory Cell Populations in Relapsing-Remitting Multiple Sclerosis (RRMS) Patients: Effect of Disease Activity and Treatment Regimens

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) of autoimmune etiology that results from an imbalance between CNS-specific T effector cells and peripheral suppressive mechanisms mediated by regulatory cells (RC). In this research, we collected blood samples from 83 relapsing remitting MS (RRMS) patients and 45 healthy persons (HC), to assess the sizes of their RC populations, including CD4⁺CD25(high)Foxp3⁺ (nTregs), CD3⁺CD4⁺HLA(-)G⁺, CD3⁺CD8⁺CD28(-), CD3⁺CD56⁺, and CD56(bright) cells, and how RC are affected by disease activity (acute phase or remission) and types of treatment (methylprednisolone, interferon, or natalizumab). In addition, we isolated peripheral blood mononuclear cells (PBMC) and cultured them with peptides mapping to myelin antigens, to determine RC responsiveness to autoantigens. The results showed decreased levels of nTregs in patients in the acute phase ± methylprednisolone and in remission + natalizumab, but HC levels in patients in remission or receiving interferon. Patients + interferon had the highest levels of CD3⁺CD4⁺HLA(-)G⁺ and CD3⁺CD8⁺CD28(-) RC, and patients in the acute phase + methylprednisolone the lowest. Patients in remission had the highest levels of CD3⁺CD56⁺, and patients in remission + natalizumab the highest levels of CD56(bright) cells. Only nTregs responded to autoantigens in culture, regardless of disease activity or treatment. The highest suppressive activity was exhibited by nTregs from patients in remission. In conclusion, in RRMS disease activity and type of treatment affect different RC populations. nTregs respond to myelin antigens, indicating that it is possible to restore immunological tolerance through nTreg induction.

General control non-derepressible 2 (GCN2) in T cells controls disease progression of autoimmune neuroinflammation

Relapsing-remitting multiple sclerosis (MS)(2) is characterized by phases of acute neuroinflammation followed by spontaneous remission. Termination of inflammation is accompanied by an influx of regulatory T cells (Tregs).(3) The molecular mechanisms responsible for directing Tregs into the inflamed CNS tissue, however, are incompletely understood. In an MS mouse model we show that the stress kinase general control non-derepressible 2 (GCN2),(4) expressed in T cells, contributes to the resolution of autoimmune neuroinflammation. Failure to recover from acute inflammation was associated with reduced frequencies of CNS-infiltrating Tregs. GCN2 deficient Tregs displayed impaired migration to a CCL2 gradient. These data suggest an important contribution of the T cell stress response to the resolution of autoimmune neuroinflammation.

Induction of regulatory T-cells from memory T-cells is perturbed during acute exacerbation of multiple sclerosis

Regulatory T-cells (Tregs) are vital for maintaining immunological self-tolerance, and the transcription factor FOXP3 is considered critical for their development and function. Peripheral Treg induction may significantly contribute to the total Treg pool in healthy adults, and this pathway may be enhanced in thymic-deficient conditions like multiple sclerosis (MS). Here, we evaluated iTreg formation from memory versus naïve CD4(+)CD25(-) T-cell precursors. We report the novel finding that memory T-cells readily expressed CD25 and FOXP3, and demonstrated significantly greater suppressive function. Additionally, the CD25(-)FOXP3(-) fraction of stimulated memory T-cells also displayed robust suppression not observed in naïve counterparts or ex vivo resting (CD25(-)) T-cells. This regulatory population was present in both healthy subjects and clinically-quiescent MS patients, but was specifically deficient during disease exacerbation. These studies indicate that iTreg development and function are precursor dependent. Furthermore, MS quiescence appears to correlate with restoration of suppressive function in memory-derived CD4(+)CD25(-)FOXP3(-) iTregs.

The Role of Latently Infected B Cells in CNS Autoimmunity

The onset of multiple sclerosis (MS) is caused by both genetic and environmental factors. Among the environmental factors, it is believed that previous infection with Epstein–Barr virus (EBV) may contribute in the development of MS. EBV has been associated with other autoimmune diseases, such as systemic lupus erythematous, and cancers like Burkitt’s lymphoma. EBV establishes a life-long latency in B cells with occasional reactivation of the virus throughout the individual’s life. The role played by B cells in MS pathology has been largely studied, yet is not clearly understood. In MS patients, Rituximab, a novel treatment that targets CD20⁺ B cells, has proven to have successful results in diminishing the number of relapses in remitting relapsing MS; however, the mechanism of how this drug acts has not been clearly established. In this review, we analyze the evidence of how B cells latently infected with EBV might be altering the immune system response and helping in the development of MS. We will also discuss how animal models, such as experimental autoimmune encephalomyelitis (EAE) and murine gammaherpesvirus-68 (γHV-68), can be used as powerful tools in the study of the relationship between EBV, MS, and B cells.

Evaluation of the expression and function of the P2X7 receptor and ART1 in human regulatory T-cell subsets

Regulatory T cells that express CD39 (CD39+ Treg) exhibit specific immunomodulatory properties. Ectonucleotidase CD39 hydrolyses ATP and ADP. ATP is a ligand of the P2X7 receptor and induces the shedding of CD62L and apoptosis. However, the role of ATP in CD39+ Treg cells has not been defined. Furthermore, NAD can activate the P2X7 receptor via ADP-ribosyltransferase (ART) enzymes and cause cell depletion in murine models. We evaluated the expression and function of P2X7 and ART1 in CD39+ Treg and CD39- Treg cells in the presence or absence of ATP and NAD. We isolated peripheral blood mononuclear cells from healthy subjects and purified CD4+ T cells, CD4+ CD25+ T cells and CD4+ CD25+ CD39+ T cells. P2X7 and ART1 expression was assessed by flow cytometry and real-time PCR. Our results showed low P2X7 expression on CD39+ Treg cells and higher levels of ART1 expression in CD4+ CD39+ T cells than the other subtypes studied. Neither shedding of CD62L nor cell death of CD39+ Treg or CD39- Treg cells was observed by 1mM ATP or 60μM NAD. In contrast, P2Xs receptor-dependent proliferation with 300μM ATP, was inhibited by NAD in the different cell types analysed. The NAD proliferation-inhibition was increased with P2Xs and A2a agonist and was reversed with P2Xs and A2a antagonist, therefore NAD inhibits P2Xs-dependent proliferation and A2a activation. In conclusion, our results suggest that the altered function and expression of P2X7 and ART1 in the human CD39+ Treg or CD39- Treg cells could participate in the resistance against cell death induced by ATP or NAD.

Deleterious versus protective autoimmunity in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disorder of central nervous system, in which myelin specific CD4(+) T cells have a central role in orchestrating pathological events involved in disease pathogenesis. There is compelling evidence that Th1, Th9 and Th17 cells, separately or in cooperation, could mediate deleterious autoimmune response in MS. However, the phenotype differences between Th cell subpopulations initially employed in MS pathogenesis are mainly reflected in the different patterns of inflammation introduction, which results in the development of characteristic pathological features (blood-brain barrier disruption, demyelination and neurodegeneration), clinically presented with MS symptoms. Although, autoimmunity was traditionally seen as deleterious, some studies indicated that autoimmunity mediated by Th2 cells and T regulatory cells could be protective by nature. The concept of protective autoimmunity in MS pathogenesis is still poorly understood, but could be of great importance in better understanding of MS immunology and therefore, creating better therapeutic strategies.

Mechanisms of immunological tolerance in central nervous system inflammatory demyelination

Multiple sclerosis is a complex autoimmune disease of the central nervous system that results in a disruption of the balance between pro-inflammatory and anti-inflammatory signals in the immune system. Given that central nervous system inflammation can be suppressed by various immunological tolerance mechanisms, immune tolerance has become a focus of research in the attempt to induce long-lasting immune suppression of pathogenic T cells. Mechanisms underlying this tolerance induction include induction of regulatory T cell populations, anergy and the induction of tolerogenic antigen-presenting cells. The intravenous administration of encephalitogenic peptides has been shown to suppress experimental autoimmune encephalomyelitis and induce tolerance by promoting the generation of regulatory T cells and inducing apoptosis of pathogenic T cells. Safe and effective methods of inducing long-lasting immune tolerance are essential for the treatment of multiple sclerosis. By exploring tolerogenic mechanisms, new strategies can be devised to strengthen the regulatory, anti-inflammatory cell populations thereby weakening the pathogenic, pro-inflammatory cell populations.

Regulation of Treg-associated CD39 in multiple sclerosis and effects of corticotherapy during relapse

Background:

Accumulating data highlight proinflammatory processes leading to MS relapses. Whether anti-inflammatory mechanisms are concomitantly activated is unclear. The ectonucleotidase CD39 has been described as a novel T regulatory cell (Treg) marker. The purpose of this study was to explore whether regulatory mechanisms are activated during MS relapses and reinforced by intravenous methylprednisolone (ivMP).

Methods:

Blood samples were collected from stable and relapsing MS patients and healthy controls. We used FOXP3 methylation-specific qPCR and CD4+CD25highFOXP3+ analysis to quantify Tregs. Cytokine mRNA expression levels were measured in peripheral blood mononuclear cells (PBMCs) and in CD4+ T cells. CD39 expression was determined by flow cytometry in monocytes, NK, T and B cells. CD39 enzymatic activity was assessed by ATP luminometry.

Results:

The proportion of Tregs was similar in relapsing MS patients and healthy controls. CD39 mRNA level was higher in PBMCs of relapsing MS patients than in controls. The proportion of CD39-expressing Tregs was higher in MS patients. IvMP decreased the overall proportion of Tregs while it increased CD39 mRNA levels, the proportions of CD39-expressing Tregs and monocytes as well as CD39 ectonucleotidase activity.

Conclusions:

Our data suggest that immunoregulatory mechanisms are ongoing in MS patients, particularly during relapses, and strengthened by ivMP.

The contribution of immune and glial cell types in experimental autoimmune encephalomyelitis and multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterised by widespread areas of focal demyelination. Its aetiology and pathogenesis remain unclear despite substantial insights gained through studies of animal models, most notably experimental autoimmune encephalomyelitis (EAE). MS is widely believed to be immune-mediated and pathologically attributable to myelin-specific autoreactive CD4+ T cells. In recent years, MS research has expanded beyond its focus on CD4+ T cells to recognise the contributions of multiple immune and glial cell types to the development, progression, and amelioration of the disease. This review summarises evidence of T and B lymphocyte, natural killer cell, macrophage/microglial, astrocytic, and oligodendroglial involvement in both EAE and MS and the intercommunication and influence of each cell subset in the inflammatory process. Despite important advances in the understanding of the involvement of these cell types in MS, many questions still remain regarding the various subsets within each cell population and their exact contribution to different stages of the disease.

How type I interferons work in multiple sclerosis and other diseases: some unexpected mechanisms

Type I interferons (IFNs) are important in innate and adaptive immunity. They are used to treat virus infections, cancer, and multiple sclerosis (MS). There are 5 type I IFN families in humans-IFN-α with 13 subtypes, plus IFN-β, ɛ, κ, and ω. Because their receptor binding affinities vary, these IFNs have different gene induction profiles and quite variable therapeutic effects. IFN-α subtypes may each be specific for certain viruses, but can be neurotoxic. IFN-β induces IFN-α, plus has additional direct effects on target cells. IFN-β was the first therapy approved that could change the course of MS. It has broader specificity than IFN-α, enhances cognition in MS, and may be neuroprotective and can potentially enhance fertility in women. Priming the IFN signaling system with an injection of IFN-β can enhance subnormal type I IFN signals in MS. Many other commonly used drugs and vitamins may potentiate clinical benefits of IFN-β.

Impact of alemtuzumab treatment on the survival and function of human regulatory T cells in vitro

Alemtuzumab is a humanized monoclonal antibody specific for the CD52 protein present at high levels on the surface of B and T lymphocytes. In clinical trials, alemtuzumab has shown a clinical benefit superior to that of interferon-β in relapsing-remitting multiple sclerosis patients. Treatment with alemtuzumab leads to the depletion of circulating lymphocytes followed by a repopulation process characterized by alterations in the number, proportions and properties of lymphocyte subsets. Of particular interest, an increase in the percentage of T cells with a regulatory phenotype (Treg cells) has been observed in multiple sclerosis patients after alemtuzumab. Since Treg cells play an important role in the control of autoimmune responses, the effect of alemtuzumab on Treg cells was further studied in vitro. Alemtuzumab effectively mediated complement-dependent cytolysis of human T lymphocytes and the remaining population was enriched in T cells with a regulatory phenotype. The alemtuzumab-exposed T cells displayed functional regulatory characteristics including anergy to stimulation with allogeneic dendritic cells and ability to suppress the allogeneic response of autologous T cells. Consistent with the observed increase in Treg cell frequency, the CD25(hi) T-cell population was necessary for the suppressive activity of alemtuzumab-exposed T cells. The mechanism of this suppression was found to be dependent on both cell-cell contact and interleukin-2 consumption. These findings suggest that an alemtuzumab-mediated increase in the proportion of Treg cells may play a role in promoting the long-term efficacy of alemtuzumab in patients with multiple sclerosis.

Adipocytokine profile, cytokine levels and foxp3 expression in multiple sclerosis: a possible link to susceptibility and clinical course of disease

Background

Adipocytokines may be involved in multiple sclerosis (MS) as well as other autoimmune and inflammatory-related diseases. This study aims to compare levels of resistin, visfatin and leptin in three subgroups of MS patients with healthy subjects and also to study their relationship with Foxp3 expression and levels of several pro-inflammatory mediators such as interleukine-1 β(IL-1 β),tumor necrosis factor-α (TNF-α) and human sensitive C-reactive protein (hs-CRP).

Methods

A total of 391 subjects including 200 healthy controls and 191 MS patients were recruited for this case-control study. Circulating adipocytokines and inflammatory mediators were measured using immunoassay methods. Foxp3 gene expression in peripheral blood mononuclear cells (PBMC) was determined by quantitative real-time PCR. Fat tissue mass was evaluated by using dual energy X-ray absorptiometery (DEXA).

Results

A significant difference was observed in levels of inflammatory mediators, adipocytokines, Foxp3 gene expression and adipose tissue mass between MS patients and healthy controls. All adipocytokines were positively correlated with levels of inflammatory mediators and negatively correlated with Foxp3 expression in MS patients. In controls, there were positive correlations between circulating leptin and resistin with TNF-α and IL-1β in subgroup analysis, the highest levels of TNF-α, IL-1β, hs-CRP, resistin and leptin were observed in primary progressive-MS (PP-MS) patients. Also, expression of Foxp3 and levels of visfatin in relapsing remitting-MS(RR-MS) patients were higher compared with the other subgroups.

Conclusions

Our findings suggest the potential role of adipocytokines in pathogenesis and severity of MS. Notably, the relationship of adipocytokines levels with inflammatory cytokines as well as clinical features of MS could be considerable in translational medicine and biomarker studies.

Myalgic encephalomyelitis/chronic fatigue syndrome and encephalomyelitis disseminata/multiple sclerosis show remarkable levels of similarity in phenomenology and neuroimmune characteristics

BACKGROUND

'Encephalomyelitis disseminata' (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS.

DISCUSSION

There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels.

SUMMARY

This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS.

Regulatory T cells in HIV infection: can immunotherapy regulate the regulator?

Regulatory T cells (Tregs) have a dominant role in self-tolerance and control of autoimmune diseases. These cells also play a pivotal role in chronic viral infections and cancer by limiting immune activation and specific immune response. The role of Tregs in HIV pathogenesis remains poorly understood as their function, changes according to the phases of infection. Tregs can suppress anti-HIV specific responses and conversely can have a beneficial role by reducing the deleterious impact of immune activation. We review the frequency, function and homing potential of Tregs in the blood and lymphoid tissues as well as their interaction with dendritic cells in the context of HIV infection. We also examine the new insights generated by recombinant IL-2 and IL-7 clinical trials in HIV-infected adults, including the immunomodulatory effects of Tregs. Based on their detrimental role in limiting anti-HIV responses, we propose Tregs as potential targets for immunotherapeutic strategies aimed at decreasing Tregs frequency and/or immunosuppressive function. However, such approaches require a better understanding of the time upon infection when interfering with Treg function may not cause a deleterious state of hyperimmune activation.

What do effective treatments for multiple sclerosis tell us about the molecular mechanisms involved in pathogenesis?

Multiple sclerosis is a potentially debilitating disease of the central nervous system. A concerted program of research by many centers around the world has consistently demonstrated the importance of the immune system in its pathogenesis. This knowledge has led to the formal testing of a number of therapeutic agents in both animal models and humans. These clinical trials have shed yet further light on the pathogenesis of MS through their sometimes unexpected effects and by their differential effects in terms of impact on relapses, progression of the disease, paraclinical parameters (MRI) and the adverse events that are experienced. Here we review the currently approved medications for the commonest form of multiple sclerosis (relapsing-remitting) and the emerging therapies for which preliminary results from phase II/III clinical trials are available. A detailed analysis of the molecular mechanisms responsible for the efficacy of these medications in multiple sclerosis indicates that blockade or modulation of both T- and B-cell activation and migration pathways in the periphery or CNS can lead to amelioration of the disease. It is hoped that further therapeutic trials will better delineate the pathogenesis of MS, ultimately leading to even better treatments with fewer adverse effects.

FoxP3(+) T regulatory cells in oral lichen planus and its correlation with the distinct clinical appearance of the lesions

The aim of this study was to evaluate the presence of FoxP3(+) cells in oral lichen planus (OLP) and to correlate the findings with clinical and histopathological features of these lesions. The sample consisted of 32 cases of OLP (17 reticular and 15 erosive cases) and 10 cases of inflammatory fibrous hyperplasia (IFH). Clinical examination, histopathological and histomorphometric analysis, and immunohistochemistry (anti-FoxP3 antibody) were performed. Cells were counted in juxtaepithelial and intraepithelial regions of the lesions, and the results are expressed as the mean and range. Most erosive lesions were keratinized and exhibited epithelial atrophy, whereas most reticular lesions were hyperkeratinized. Mean epithelial thickness and mean density of the inflammatory infiltrate were higher in reticular lesions than in erosive OLP. Juxtaepithelial FoxP3(+) cells were slightly more frequent in erosive lesions (mean: 1.7 and range: 0-9.4) than in reticular lesions (mean: 1.5 and range: 0-8.3). There was a significant difference in the frequency of these cells between OLP (mean: 1.6 and range: 0-9.4) and IFH (mean: 0.5 and range: 0-1.4) (P < 0.05). The number of intraepithelial FoxP3(+) cells was higher in reticular OLP and IFH when compared with erosive lesions. The larger number of juxtaepithelial FoxP3(+) cells in OLP compared to IFH might be related to the distinct etiopathogenesis of these lesions. High disease activity or action of the oral microbiota may explain the slightly higher frequency of FoxP3(+) cells in erosive lesions.