Increased memory Th17 cells in patients with neuromyelitis optica and multiple sclerosis

Interferon-γ controls aquaporin 4-specific Th17 and B cells in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a CNS autoimmune inflammatory disease mediated by T helper 17 (Th17) and antibody responses to the water channel protein, aquaporin 4 (AQP4), and associated with astrocytopathy, demyelination and axonal loss. Knowledge about disease pathogenesis is limited and the search for new therapies impeded by the absence of a reliable animal model. In our work, we determined that NMOSD is characterized by decreased IFN-γ receptor signalling and that IFN-γ depletion in AQP4201-220-immunized C57BL/6 mice results in severe clinical disease resembling human NMOSD. Pathologically, the disease causes autoimmune astrocytic and CNS injury secondary to cellular and humoral inflammation. Immunologically, the absence of IFN-γ allows for increased expression of IL-6 in B cells and activation of Th17 cells, and generation of a robust autoimmune inflammatory response. Consistent with NMOSD, the experimental disease is exacerbated by administration of IFN-β, whereas repletion of IFN-γ, as well as therapeutic targeting of IL-17A, IL-6R and B cells, ameliorates it. We also demonstrate that immune tolerization with AQP4201-220-coupled poly(lactic-co-glycolic acid) nanoparticles could both prevent and effectively treat the disease. Our findings enhance the understanding of NMOSD pathogenesis and provide a platform for the development of immune tolerance-based therapies, avoiding the limitations of the current immunosuppressive therapies.

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Immune cell subpopulations and serum neurofilament light chain are associated with increased risk of disease worsening in multiple sclerosis

Changes is lymphocyte subpopulations in peripheral blood have been proposed as biomarkers for evaluation of disease activity in multiple sclerosis (MS). Serum neurofilament light chain (sNfL) is a biomarker reflecting neuro-axonal injury in MS that could be used to monitor disease activity, response to drugs and to prognosticate disease course. Here we show a moderate correlation between sNfL and lymphocyte cell subpopulations, and our data furthermore suggest that sNfL and specific immune cell subpopulations together could predict future disease worsening in MS.

Downregulation of lncRNA XIST may promote Th17 differentiation through KDM6A-TSAd pathway in neuromyelitis optica spectrum disorders

BACKGROUNDS

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease with significant female preponderance. X inactive specific transcript (XIST) is a long non-coding RNA (lncRNA) and a key regulator of X-chromosome inactivation which is related to the sex-bias of autoimmunity. And Th17 cell proportion was significantly elevated in NMOSD according to our previous study.

OBJECTIVES

This study aimed to explore the expression levels of lncRNA XIST-KDM6A-TSAd pathway in lymphocytes of female NMOSD patients, and investigate its possible relationship with pathogenesis of NMOSD.

METHODS AND RESULTS

The study enrolled 30 acute-phase untreated female NMOSD patients and 30 age-matched female healthy controls, their lymphocytes were collected for experiments. Microarray as well as validation experiments showed lncRNA XIST was significantly downregulated in the NMOSD group. And the levels of lysine demethylase 6A (KDM6A) decreased in NMOSD and showed significant positive correlation with XIST. The levels of T cell-specific adapter (TSAd) mRNA and protein levels were significantly lower in NMOSD. And Chromatin immunoprecipitation assay demonstrated that NMOSD had more H3K27me3 modification than control at TSAd promoter region.

CONCLUSIONS

The present study introduced a potential pathway that following lncRNA XIST downregulation, which process may promote Th17 differentiation in NMOSD. These findings shed new light on the immune regulation mechanism about lncRNA XIST and related epigenetic features, which may contribute to develop female-specific treatment plans.

BTN2A2-Ig protein inhibits the differentiation of pathogenic Th17 cells and attenuates EAE in mice

Pathogenic Th17 cells play a key role in the pathogenesis of many autoimmune diseases. Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE) is the commonly used animal model for human MS and is characterized by autoreactive CD4⁺ T cells attacking autoantigens in the CNS and causing myelin sheath damage. Although the recombinant BTN2A2-IgG2aFc (BTN2A2-Ig) fusion protein has been shown to inhibit T cell functions in vitro, it's unclear whether BTN2A2-Ig affects pathogenic Th17 cells and EAE development. We show here that BTN2A2-Ig protein attenuates established EAE, as compared with control Ig protein treatment. This is associated with reduced activation and proliferation of T cells in BTN2A2-Ig-treated EAE mice. Furthermore, BTN2A2-Ig protein inhibits the differentiation of CD4 naïve T cells into pathogenic Th17 cells and reduces the expression levels of Th1/Th17 cytokines and the Th1/Th17 pathway related genes and proteins but increases the expression levels of Th2-related genes and proteins. Our studies not only provide new insights into the mechanisms by which BTN2A2-Ig affects T cells, but also have the potential to provide a new strategy to treat MS and other autoimmune diseases.

Proinflammatory IL-17 levels in serum/cerebrospinal fluid of patients with neurodegenerative diseases: a meta-analysis study

IL-17 is one of the major proinflammatory cytokine implicated in the pathophysiology of various chronic inflammatory diseases. However, a clear association between the levels of IL-17 and various neurodegenerative diseases is inconclusive due to lack of consistent results reported in several studies. Therefore, we designed and performed a meta-analysis study to assess the levels of IL-17 cytokine in various neurodegenerative diseases. The aim of this meta-analysis study was to assess the level of IL-17 in cerebrospinal fluid/serum of the patients with neurodegenerative diseases such as Alzheimer's disease, Parkinson disease, multiple sclerosis, and amyotrophic lateral sclerosis. An extensive search was performed on electronic databases including PubMed, Cochrane, and Google Scholar to find out the relevant studies for analysis. The quality of selected studies was assessed by Newcastle-Ottawa scale for cohort and case control studies. The standardized mean difference of level of IL-17 in patients with neurodegenerative diseases and control was calculated using RevMan 5 software. A significant increase in the level of serum IL-17 was found to in the patients with neurodegenerative diseases like Alzheimer's disease (p = 0.001) and amyotrophic lateral sclerosis (p = 0.009), whereas IL-17 level in serum of Parkinson's disease (p = 0.22), multiple sclerosis (p = 0.09), and in peripheral blood mononuclear cells of MS patients (p = 0.34) was not found to be significant. IL-17 may be involved in regulation of neuronal inflammation during the pathogenesis of these neurodegenerative disease, and its specific inhibition could be a potential therapeutic target.

Therapeutic potential of targeting IL-17 and its receptor signaling in neuroinflammation

T helper 17 cells are thought to significantly contribute to the neuroinflammation process during neurogenerative diseases via their signature cytokine, interleukin (IL)-17. Recently, an emerging key role of IL-17 and its receptors has been documented in inflammatory and autoimmune diseases. The clinical studies conducted on patients with neurodegenerative disease have also shown an increase in IL-17 levels in serum as well as cerebrospinal fluid samples. Therapeutic targeting of either IL-17 receptors or direct IL-17 neutralizing antibodies has shown a promising preclinical and clinical proof of concept for treating chronic autoimmune neurodegenerative diseases such as multiple sclerosis. Thus, IL-17 and its receptors have a central role in regulation of neuroinflammation and can be considered as one of the major therapeutic targets in chronic neuroinflammatory diseases.

Alpha4 beta7 integrin controls Th17 cell trafficking in the spinal cord leptomeninges during experimental autoimmune encephalomyelitis

Th1 and Th17 cell migration into the central nervous system (CNS) is a fundamental process in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS). Particularly, leptomeningeal vessels of the subarachnoid space (SAS) constitute a central route for T cell entry into the CNS during EAE. Once migrated into the SAS, T cells show an active motility behavior, which is a prerequisite for cell-cell communication, in situ reactivation and neuroinflammation. However, the molecular mechanisms selectively controlling Th1 and Th17 cell trafficking in the inflamed leptomeninges are not well understood. By using epifluorescence intravital microscopy, we obtained results showing that myelin-specific Th1 and Th17 cells have different intravascular adhesion capacity depending on the disease phase, with Th17 cells being more adhesive at disease peak. Inhibition of αLβ2 integrin selectively blocked Th1 cell adhesion, but had no effect on Th17 rolling and arrest capacity during all disease phases, suggesting that distinct adhesion mechanisms control the migration of key T cell populations involved in EAE induction. Blockade of α4 integrins affected myelin-specific Th1 cell rolling and arrest, but only selectively altered intravascular arrest of Th17 cells. Notably, selective α4β7 integrin blockade inhibited Th17 cell arrest without interfering with intravascular Th1 cell adhesion, suggesting that α4β7 integrin is predominantly involved in Th17 cell migration into the inflamed leptomeninges in EAE mice. Two-photon microscopy experiments showed that blockade of α4 integrin chain or α4β7 integrin selectively inhibited the locomotion of extravasated antigen-specific Th17 cells in the SAS, but had no effect on Th1 cell intratissue dynamics, further pointing to α4β7 integrin as key molecule in Th17 cell trafficking during EAE development. Finally, therapeutic inhibition of α4β7 integrin at disease onset by intrathecal injection of a blocking antibody attenuated clinical severity and reduced neuroinflammation, further demonstrating a crucial role for α4β7 integrin in driving Th17 cell-mediated disease pathogenesis. Altogether, our data suggest that a better knowledge of the molecular mechanisms controlling myelin-specific Th1 and Th17 cell trafficking during EAE delevopment may help to identify new therapeutic strategies for CNS inflammatory and demyelinating diseases.

The antimicrobial peptide cathelicidin drives development of experimental autoimmune encephalomyelitis in mice by affecting Th17 differentiation

Multiple sclerosis (MS) is a highly prevalent demyelinating autoimmune condition; the mechanisms regulating its severity and progression are unclear. The IL-17-producing Th17 subset of T cells has been widely implicated in MS and in the mouse model, experimental autoimmune encephalomyelitis (EAE). However, the differentiation and regulation of Th17 cells during EAE remain incompletely understood. Although evidence is mounting that the antimicrobial peptide cathelicidin profoundly affects early T cell differentiation, no studies have looked at its role in longer-term T cell responses. Now, we report that cathelicidin drives severe EAE disease. It is released from neutrophils, microglia, and endothelial cells throughout disease; its interaction with T cells potentiates Th17 differentiation in lymph nodes and Th17 to exTh17 plasticity and IFN-γ production in the spinal cord. As a consequence, mice lacking cathelicidin are protected from severe EAE. In addition, we show that cathelicidin is produced by the same cell types in the active brain lesions in human MS disease. We propose that cathelicidin exposure results in highly activated, cytokine-producing T cells, which drive autoimmunity; this is a mechanism through which neutrophils amplify inflammation in the central nervous system.

Relationship between the Clinical Characteristics in Patients with Neuromyelitis Optica Spectrum Disorders and Clinical Immune Indicators: A Retrospective Study

Objective: T lymphocytes, complement, and immunoglobulin play an important role in neuromyelitis optica spectrum disorders (NMOSD). As common clinical examination indicators, they have been used as routine indicators in many hospitals, which is convenient for being carried out in clinical work, but there are few articles of guiding significance for clinical practice. The purpose of this study was to study the relationship between commonly used immune indicators and clinical characteristics in patients with NMOSD. Methods: We compared clinical characteristics and clinical immune indicators in 258 patients with NMOSD and 200 healthy controls (HCs). We used multiple linear regression to study the relationship between immunotherapy, disease phase, sex, age, AQP4-IgG, and immune indicators. In addition, lymphocyte subsets were compared before and after immunotherapy in 24 of the 258 patients. We explored the influencing factors and predictors of severe motor disability. Results: The percentages of CD3 ratio (71.4% vs. 73.8%, p = 0.013), CD4 ratio (38.8% vs. 42.2%, p < 0.001), and CD4/CD8 ratio (1.43 vs. 1.66, p < 0.001) in NMOSD patients were significantly lower than those in the HC group. In addition, complement C4 (0.177 g/L vs. 0.221 g/L, p < 0.001) and peripheral blood IgG (10.95 g/L vs. 11.80 g/L, p = 0.026) in NMOSD patients were significantly lower than those in the HC group. CD3 percentage was correlated with blood collection age and disease stage; CD8 percentage was correlated with blood collection age, disease stage, and treatment; CD4/CD8 percentage was correlated with blood collection age and treatment; complement C4 was correlated with blood collection age and sex; and IgG was correlated with disease stage and treatment. Twenty-four patients before and after treatment showed that the percentages of CD3 ratio (74.8% vs. 66.7%, p = 0.001) and CD8 ratio (32.4% vs. 26.2%, p < 0.001) after treatment in NMOSD patients were significantly increased, and the percentage of CD3 before treatment was moderately negatively correlated with ARR (r = −0.507, p = 0.011). Binary logistic regression analysis showed that peripheral blood complement C3 is a serious influencing factor for severe motor disability (EDSS score ≥ 6 points). Peripheral blood complement C3 and C4 are predictors of severe motor disability (p < 0.05). Conclusion: Our results suggest that peripheral blood T lymphocytes, C3, C4 and immunoglobulin are convenient and routine clinical indicators that are convenient for implementation in clinical work. They have certain reference values for disease staging, recurrence, drug efficacy, and motor disability. They have improved our understanding of clinical immune indicators for NMOSD patients, but whether they can be used as biomarkers for clinical prognosis remains to be further studied.

Can Immune Tolerance Be Re-established in Neuromyelitis Optica?

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that primarily affects the optic nerves and spinal cord of patients, and in some instances their brainstem, diencephalon or cerebrum as spectrum disorders (NMOSD). Clinical and basic science knowledge of NMO has dramatically increased over the last two decades and it has changed the perception of the disease as being inevitably disabling or fatal. Nonetheless, there is still no cure for NMO and all the disease-modifying therapies (DMTs) are only partially effective. Furthermore, DMTs are not disease- or antigen-specific and alter all immune responses including those protective against infections and cancer and are often associated with significant adverse reactions. In this review, we discuss the pathogenic mechanisms of NMO as they pertain to its DMTs and immune tolerance. We also examine novel research therapeutic strategies focused on induction of antigen-specific immune tolerance by administrating tolerogenic immune-modifying nanoparticles (TIMP). Development and implementation of immune tolerance-based therapies in NMO is likely to be an important step toward improving the treatment outcomes of the disease. The antigen-specificity of these therapies will likely ameliorate the disease safely and effectively, and will also eliminate the clinical challenges associated with chronic immunosuppressive therapies.

DICAM promotes TH17 lymphocyte trafficking across the blood-brain barrier during autoimmune neuroinflammation

[Figure: see text].

Lymphocyte Subsets Are Associated with Disease Status in Neuromyelitis Optica Spectrum Disorders

OBJECTIVE

At present, studies on lymphocytes are mostly conducted on CD19+ B cells and CD27+ B cells in neuromyelitis optica spectrum disorders (NMOSDs), but the exact changes in lymphocyte subsets (CD19+ B cells, CD3+ T cells, CD4+ Th cells, CD8+ Ts cells, the CD4+/CD8+ ratio, and NK [CD56+ CD16] cells) have rarely been studied. This study aimed to assess lymphocyte subset changes in patients with NMOSD.

METHODS

We performed a cross-sectional study of consecutive patients with acute NMOSD (n = 41), chronic NMOSD (n = 21), and healthy individuals (n = 44). Peripheral blood samples were obtained upon admission, and lymphocyte subsets were analyzed by flow cytometry. Levels of lymphocyte subsets among 3 groups were compared and its correlation with the length of spinal cord lesions was analyzed.

RESULTS

The levels of peripheral blood CD19+ B cells were significantly higher in patients with acute and chronic NMOSD than in healthy controls (HCs) (17.91 ± 8.7%, 13.08 ± 7.562%, and 12.48 ± 3.575%, respectively; p < 0.001) and were positively correlated with the length of spinal cord lesions in acute NMOSD (r = 0.433, p < 0.05). The peripheral blood CD4+/CD8+ ratio was significantly lower in patients with acute NMOSD and chronic NMOSD than in HCs (1.497 ± 0.6387, 1.33 ± 0.5574, and 1.753 ± 0.659, respectively; p < 0.05), and the levels of peripheral blood NK (CD56+ CD16) cells were significantly lower in patients with acute and chronic NMOSD than in HCs (13.6 ± 10.13, 11.11 ± 7.057, and 14.7 [interquartile range = 9.28], respectively; p < 0.01).

CONCLUSIONS

The levels of certain subsets of peripheral blood lymphocytes are associated with disease status in NMOSD.

A Comprehensive Review on the Role of Genetic Factors in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorders (NMOSD) comprise a variety of disorders being described by optic neuritis and myelitis. This disorder is mostly observed in sporadic form, yet 3% of cases are familial NMO. Different series of familial NMO cases have been reported up to now, with some of them being associated with certain HLA haplotypes. Assessment of HLA allele and haplotypes has also revealed association between some alleles within HLA-DRB1 or other loci and sporadic NMO. More recently, genome-wide SNP arrays have shown some susceptibility loci for NMO. In the current manuscript, we review available information about the role of genetic factors in NMO.

Th17-Related Cytokines as Potential Discriminatory Markers between Neuromyelitis Optica (Devic's Disease) and Multiple Sclerosis-A Review

Multiple sclerosis (MS) and Devic’s disease (NMO; neuromyelitis optica) are autoimmune, inflammatory diseases of the central nervous system (CNS), the etiology of which remains unclear. It is a serious limitation in the treatment of these diseases. The resemblance of the clinical pictures of these two conditions generates a partial possibility of introducing similar treatment, but on the other hand, a high risk of misdiagnosis. Therefore, a better understanding and comparative characterization of the immunopathogenic mechanisms of each of these diseases are essential to improve their discriminatory diagnosis and more effective treatment. In this review, special attention is given to Th17 cells and Th17-related cytokines in the context of their potential usefulness as discriminatory markers for MS and NMO. The discussed results emphasize the role of Th17 immune response in both MS and NMO pathogenesis, which, however, cannot be considered without taking into account the broader perspective of immune response mechanisms.

Aberrant Complement System Activation in Neurological Disorders

The complement system is an assembly of proteins that collectively participate in the functions of the healthy and diseased brain. The complement system plays an important role in the maintenance of uninjured (healthy) brain homeostasis, contributing to the clearance of invading pathogens and apoptotic cells, and limiting the inflammatory immune response. However, overactivation or underregulation of the entire complement cascade within the brain may lead to neuronal damage and disturbances in brain function. During the last decade, there has been a growing interest in the role that this cascading pathway plays in the neuropathology of a diverse array of brain disorders (e.g., acute neurotraumatic insult, chronic neurodegenerative diseases, and psychiatric disturbances) in which interruption of neuronal homeostasis triggers complement activation. Dysfunction of the complement promotes a disease-specific response that may have either beneficial or detrimental effects. Despite recent advances, the explicit link between complement component regulation and brain disorders remains unclear. Therefore, a comprehensible understanding of such relationships at different stages of diseases could provide new insight into potential therapeutic targets to ameliorate or slow progression of currently intractable disorders in the nervous system. Hence, the aim of this review is to provide a summary of the literature on the emerging role of the complement system in certain brain disorders.

Markedly Elevated Serum Level of T-Helper Cell 17-Related Cytokines/Chemokines in Acute Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis

Purpose: The purpose of this study was to examine the differences in immunopathogenesis based on the cytokine/chemokine profiles in myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-positive and -negative groups.

Methods: We measured the levels of T-helper cell 17 (Th17) cell-related cytokines/chemokines in 74 serum samples, which were divided into four groups: healthy control (HC) group (n = 15), idiopathic demyelinating optic neuritis (IDON) group (n = 20), aquaporin 4 (AQP4)-IgG-positive optic neuritis (ON) group (n = 18), and MOG-IgG positive-ON group (n = 21). Serum IL17, IL21, IL28, IL31, CXCL1, CXCL2, CCL2, CCL11, CCL20, and LT-α were detected.

Results: The serum of the MOG-IgG-positive ON patients showed an obvious elevation of Th17 cell-related cytokines/chemokines compared with that of all the MOG-IgG-negative ON patients. Serum IL17 and IL21 were significantly higher in the ON patients with MOG-IgG positive than in all the other three groups. The serum levels of IL28, IL31, CXCL1, and CCL11 were higher in the ON patients with MOG-IgG positive than in the HC group and the IDON group. The serum concentration of CCL2, CXCL2, and CCL20 in the MOG-IgG-positive and AQP4-IgG-positive group is higher than that of the HC group. No difference in serum LT-α level was found among the four groups. Adjusted multiple regression analyses showed a positive association of IL17 and IL21 levels with the serum concentration of MOG-IgG in the ON patients.

Conclusion: The elevated serum level of Th17 cell-related cytokine/chemokines may play an important role in the pathogenesis of MOG-IgG-positive demyelinating ON.

Metabolomic Profiling in Neuromyelitis Optica Spectrum Disorder Biomarker Discovery

There is no specific test for diagnosing neuromyelitis optica spectrum disorder (NMOSD), a disabling autoimmune disease of the central nervous system. Instead, diagnosis relies on ruling out other related disorders with overlapping clinical symptoms. An urgency for NMOSD biomarker discovery is underscored by adverse responses to treatment following misdiagnosis and poor prognosis following the delayed onset of treatment. Pathogenic autoantibiotics that target the water channel aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) contribute to NMOSD pathology. The importance of early diagnosis between AQP4-Ab⁺ NMOSD, MOG-Ab⁺ NMOSD, AQP4-Ab⁻ MOG-Ab⁻ NMOSD, and related disorders cannot be overemphasized. Here, we provide a comprehensive data collection and analysis of the currently known metabolomic perturbations and related proteomic outcomes of NMOSD. We highlight short chain fatty acids, lipoproteins, amino acids, and lactate as candidate diagnostic biomarkers. Although the application of metabolomic profiling to individual NMOSD patient care shows promise, more research is needed.

C-type lectin receptors Mcl and Mincle control development of multiple sclerosis-like neuroinflammation

Pattern recognition receptors (PRRs) are crucial for responses to infections and tissue damage; however, their role in autoimmunity is less clear. Herein we demonstrate that 2 C-type lectin receptors (CLRs) Mcl and Mincle play an important role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Congenic rats expressing lower levels of Mcl and Mincle on myeloid cells exhibited a drastic reduction in EAE incidence. In vivo silencing of Mcl and Mincle or blockade of their endogenous ligand SAP130 revealed that these receptors’ expression in the central nervous system is crucial for T cell recruitment and reactivation into a pathogenic Th17/GM-CSF phenotype. Consistent with this, we uncovered MCL- and MINCLE-expressing cells in brain lesions of MS patients and we further found an upregulation of the MCL/MINCLE signaling pathway and an increased response following MCL/MINCLE stimulation in peripheral blood mononuclear cells from MS patients. Together, these data support a role for CLRs in autoimmunity and implicate the MCL/MINCLE pathway as a potential therapeutic target in MS.

NLRP3 level in cerebrospinal fluid of patients with neuromyelitis optica spectrum disorders: Increased levels and association with disease severity

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) and MS are the most common autoimmune inflammatory demyelinating diseases of the CNS. However, the mechanisms of pathogenesis are still unclear. nucleotide-binding leucine-rich repeat (NLR) family pyrin domain containing 3 (NLRP3), an important protein of the innate immune system that is activated by mitochondrial DNA (mtDNA), has been reported to be associated with various autoimmune disorders.

OBJECTIVE

To assess the levels of cerebrospinal fluid (CSF) NLRP3, mtDNA and inflammation-associated cytokines (IL-1β, IL-6 and IL-17) in patients with NMOSD and MS, and to examine the correlations between these factors.

METHODS

28 NMOSD patients, 15 MS patients, and 16 controls with non-inflammatory neurological diseases were recruited. NLRP3 inflammasome, IL-1β, IL-6 and IL-17 were measured by ELISA. CSF extracellular mtDNA was measured by qPCR. The severity of clinical presentation was evaluated by EDSS score.

RESULTS

CSF levels of NLRP3, mtDNA, IL-1β, IL-6 and IL-17 were higher in NMOSD patients than in controls. Elevated CSF NLRP3, mtDNA and IL-6 were found in MS patients compared with controls. CSF NLRP3 and IL-6 levels were significantly higher in NMOSD patients than in MS patients. The EDSS scores of NMOSD patients during relapse were positively correlated with CSF NLRP3 and mtDNA.

CONCLUSION

Our findings suggest that CSF levels of the NLRP3 inflammasome may serve as a diagnostic biomarker for distinguishing NMOSD and MS. Pyroptosis mediated by the NLRP3 inflammasome following mitochondrial damage may play an important role in the pathogenesis of these neuroinflammatory disorders, especially NMOSD.

Vitamin D and Demyelinating Diseases: Neuromyelitis Optica (NMO) and Multiple Sclerosis (MS)

Vitamin D deficiency is prevalent in all ages regardless of climate or geographical location and evidence is emerging that the incidence of autoimmune diseases is increasing worldwide. Women make up a large proportion of autoimmune disease diagnoses, underscoring the importance of fully elucidating the complex synergistic relationships between estrogens and vitamin D. Vitamin D receptor-activating drugs appear to enhance remyelination in patients diagnosed with multiple sclerosis (MS) and other demyelinating diseases such as neuromyelitis optica (NMO). This review is intended to update health practitioners about the potential role of vitamin D deficiency demyelination and to motivate future research on dietary recommendations for vitamin D in preventing and treating demyel1nating diseases.

Proportions of Th17 cells and Th17-related cytokines in neuromyelitis optica spectrum disorders patients: A meta-analysis

BACKGROUND

T helper (Th17) cells play an important role in many autoimmune diseases. In this meta-analysis, we aimed to specify the proportion of Th17 cells and the levels of Th17-related cytokines in neuromyelitis optica spectrum disorders (NMOSD) patients, we did this meta-analysis.

METHODS

Using previously reported data from PubMed, EMBASE, and Web of Science and Cochrane, we explored the proportion of Th17 cells in CD4⁺ T cells in peripheral blood (PB) and the level of Th17-related cytokines, such as interleukin (IL)1β, IL6, IL17, IL21, IL22, IL23 and transforming growth factor -beta (TGFβ), in cerebrospinal fluid (CSF), plasma, and serum in NMOSD patients compared to control group and multiple sclerosis (MS) patients.

RESULTS

In total, 38 trials were included for our analysis. Results showed that the proportion of Th17 cells was higher in NMOSD patients than in the control and MS groups. The levels of IL1β, IL6, IL17 and IL21 in CSF and plasma, and IL6, IL21, IL22, and IL23 in the serum were higher in NMOSD patients than in the control group. The levels of IL6 in CSF and serum and IL17 in plasma and serum were higher in NMOSD patients than in MS patients.

CONCLUSION

The proportion of Th17 cells and the levels of Th17-related cytokines was increased in NMOSD patients compared with the control group and MS patients. The results of this meta-analysis indicated that Th17 cells and Th17-associated cytokines may play an essential role in the pathogenesis of NMOSD. PROSPERO registration: CRD42019128785.

Interleukin-36 alpha levels are elevated in the serum and cerebrospinal fluid of patients with neuromyelitis optica spectrum disorder and correlate with disease activity

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory neurological disease characterized by longitudinally extensive transverse myelitis (LETM) and optic neuritis. Interleukin (IL)-36 is a novel cytokine of the IL-1 family that is involved in the development of inflammatory diseases. The aim of this study was to investigate the role of IL-36α in NMOSD. We retrospectively collected 73 patients, who fulfilled the 2015 criteria for NMOSD diagnosis and were admitted to the Department of Neurology of the First Hospital of Jilin University from 2015 to 2016. Fifty age and gender matched patients with non-inflammatory neurological disorders (ONNDs) were collected in the same period and served as controls. Neurological function was evaluated by the expanded disability status scale (EDSS). All participants were assessed for the annual relapse rate (ARR). Blood and cerebrospinal fluid (CSF) samples were obtained and the levels of IL-36α in the serum and CSF were analyzed by enzyme-linked immunosorbent assay (ELISA). IL-36α levels in serum and CSF were found to be significantly increased in patients with NMOSD compared to those in the controls. Furthermore, IL-36α levels in both serum and CSF were positively correlated with the EDSS score. CSF IL-36α levels were positively correlated with CSF leukocyte counts, protein concentration and immunoglobulin IgG. Our results suggest that IL-36α may be a novel biomarker for monitoring disease severity in NMOSD.

Regulatory B and T lymphocytes in multiple sclerosis: friends or foes?

Current clinical experience with immunomodulatory agents and monoclonal antibodies in principle has established the benefit of depleting lymphocytic populations in relapsing–remitting multiple sclerosis (RRMS). B and T cells may exert multiple pro-inflammatory actions, but also possess regulatory functions making their role in RRMS pathogenesis much more complex. There is no clear correlation of Tregs and Bregs with clinical features of the disease. Herein, we discuss the emerging data on regulatory T and B cell subset distributions in MS and their roles in the pathophysiology of MS and its murine model, experimental autoimmune encephalomyelitis (EAE). In addition, we summarize the immunomodulatory properties of certain MS therapeutic agents through their effect on such regulatory cell subsets and their relevance to clinical outcomes.

Role of IL-6/RORC/IL-22 axis in driving Th17 pathway mediated immunopathogenesis of schizophrenia

The immuno-inflammatory origin of schizophrenia in a subset of patients is viewed as a key element of an overarching etiological construct. Despite substantial research, the immune components exerting major effect are yet to be fully clarified. Disrupted T cell networks have consistently been linked to the pathogenesis of schizophrenia. Amongst the Th cell subsets, the Th17 cells have emerged as a paradigmatic lineage with significant functional implications in a vast number of immune mediated diseases including brain disorders such as schizophrenia. The present study was aimed at examining the functional role of the Th17 pathway in schizophrenia. To address this, genotyping of IL17A (rs2275913; G197A) Single Nucleotide Polymorphism was carried out by the PCR-RFLP method in 221 schizophrenia patients and 223 healthy control subjects. Gene expression of two transcription factors STAT3 and RORC was quantified in a subset of drug naïve schizophrenia patients (n = 56) and healthy controls (n = 52) by TaqMan assay. The plasma levels of fifteen cytokines belonging to Th17 pathway were estimated in a subset of drug naïve schizophrenia patients (n = 61) and healthy controls (n = 50) by using Bio-Plex Pro Human Th17 cytokine assays. The AA genotype was associated with higher total score of bizarre behaviour and apathy in female schizophrenia patients. A high gene expression level of RORC was observed in drug naïve schizophrenia patients. In addition, significantly elevated plasma levels of IL-6 and IL-22, and reduced levels of IL-1β and IL-17F were noted in schizophrenia patients. Taken together, these findings indicate a dysregulated Th17 pathway in schizophrenia patients.

Increased expression of the membrane-bound CD40 ligand on peripheral CD4+ T cells in the acute phase of AQP4-IgG-seropositive neuromyelitis optica spectrum disorders

Currently, no data are available regarding the expression levels of CD40L on CD4⁺ T cells in patients with neuromyelitis optica spectrum disorders (NMOSD). The percentage of circulating CD40L⁺CD4⁺ T cells was measured by flow cytometry in 23 NMOSD patients and 10 healthy controls. The ratio of CD40L⁺CD4⁺ to CD4⁺ T cells in patients at acute phase (18.28 ± 15.56%) was significantly higher than that in healthy controls (7.23 ± 5.94%, P = .032) and was positively correlated with disease severity (r = 0.532, P = .041). Thus, our results suggest an important role of this molecule in acute attacks of NMOSD.

Association of Optic Neuritis with CYP4F2 Gene Single Nucleotide Polymorphism and IL-17A Concentration

Background

The aetiology and pathophysiology of optic neuritis (ON) is not absolutely clear but genetic and inflammatory factors may be also involved in its development. The aim of the present study was to determine the influence of single nucleotide polymorphism (SNP) of CYP4F2 (rs1558139) and serum levels of IL-17A on ON development.

Materials and Methods

Forty patients with ON and 164 control subjects were evaluated. Patients were divided by gender, also ON patients were divided into two subgroups: ON with and without multiple sclerosis (MS). CYP4F2 rs1558139 was genotyped using real-time PCR. Serum IL-17A levels were measured using ELISA IL-17A kits.

Results

We found that A/A genotype of CYP4F2 rs1558139 was statistically significantly more frequent in men with ON and MS than in women: 57.1% versus 0%, p = 0.009. Also, allele A was statistically significantly more frequent in men with ON and MS than in women: 71.4% versus 37.5%, p = 0.044. Serum levels of IL-17A were higher in ON group than in control group: (median, IQR): 20.55 pg/ml, 30.66 pg/ml versus 8.97 pg/ml, 6.24 pg/ml, p < 0.001.

Conclusion

The higher IL-17A levels were found to be associated with ON, while allele A at rs1558139 was associated only with ON with MS in male patients.

Cytokines and Tissue Damage Biomarkers in First-Onset Neuromyelitis Optica Spectrum Disorders: Significance of Interleukin-6

OBJECTIVE

We investigated the contribution of several cytokines in the pathogenesis of first-onset neuromyelitis optica spectrum disorder (NMOSD) and determined the differences between aquaporin 4 immunoglobulin G (AQP4-IgG)-positive and AQP4-IgG-negative subtypes.

METHODS

We enrolled 18 NMOSD (10 AQP4-IgG-positive and 8 AQP4-IgG-negative) and 8 multiple sclerosis (MS) patients, whose serum and cerebrospinal fluid (CSF) samples were collected during the acute phase of the first onset before immunotherapy. Fifteen patients with other noninflammatory neurological diseases (OND) were also included. The serum and CSF levels of interleukin (IL)-6, IL-10, IL-17, IL-21, IL-23, transforming growth factor (TGF)-β1 and the CSF levels of 3 biomarkers of axonal loss and astrocytic damage were measured using the human cytokine multiplex assay or ELISA.

RESULTS

Serum levels of IL-10 and TGF-β1 and CSF levels of IL-6, IL-10, and TGF-β1 were significantly increased in first-onset NMOSD compared to in OND patients. In a subgroup analysis, the CSF levels of IL-6, neurofilament light protein (NFL), S100B, and glial fibrillary acidic protein (GFAP) were significantly more elevated in the AQP4-IgG-positive patients than in the AQP4-IgG-negative NMOSD patients. Correlations were found between the CSF cytokines and tissue damage biomarkers and the clinical findings in NMOSD patients. Notably, the CSF IL-6 level had the strongest correlation with the tissue damage biomarkers and it also correlated with CSF white blood cell (WBC) count.

CONCLUSIONS

IL-6 plays a role in the pathogenetic process of NMOSD, especially in the AQP4-IgG-positive subtype. Distinct pathogenesis exists between AQP4-IgG-positive and AQP4-IgG-negative NMOSD in the initial phase of the disease.

Cerebrospinal Fluid Level of Soluble CD27 Is Associated with Disease Severity in Neuromyelitis Optica Spectrum Disorder

OBJECT

CD27 belongs to the tumor necrosis factor receptor family and is constitutively expressed on T cells. The concentration of cerebrospinal fluid (CSF) soluble (s)CD27 is elevated in patients with multiple sclerosis (MS). However, whether the level of CSF sCD27 is elevated in neuromyelitis optica spectrum disorder (NMOSD) remains unknown. The aim of this study was to measure the CSF concentration of sCD27 and to determine its relationship with NMOSD disease activity.

METHODS

CSF CXCL13 was measured by ELISA in neuromyelitis optica (NMO) (n = 31) and MS (n = 23) patients and in controls (CTLs) (n = 22).

RESULTS

The concentration of sCD27 was higher in the NMO group than in the MS (p = 0.082) and CTL (p = 0.002) groups, and there was a positive correlation with CSF IL-6 (p = 0.000) and a negative correlation with IL-10 (p = 0.073). In the NMO group, patients with higher sCD27 concentrations exhibited worse disease disability in their CSF (p = 0.006). Moreover, the sCD27 concentrations had a significantly positive correlation with the level of CSF total protein (p = 0.030). Furthermore, the patients positive for AQP4-IgG (n = 26) seemed to have higher levels of sCD27 in their CSF (p = 0.069) than those negative for AQP4-IgG (n = 5).

CONCLUSIONS

We revealed that the level of CSF sCD27 was elevated in NMOSD and correlated with NMOSD disease activity.

Levels of peripheral Th17 cells and serum Th17-related cytokines in patients with multiple sclerosis: A meta-analysis

BACKGROUND

Multiple reports have described the proportion of Th17 cells in peripheral blood and serum levels of Th17-related cytokines in patients with multiple sclerosis (MS). To clarify the status of Th17 cells and Th17-related cytokines in MS patients, we did a meta-analysis of the results published previously to assess the levels of peripheral Th17 cells and serum Th17-related cytokines in patients with MS.

METHODS

We searched Embase, PubMed, Cochrane, Web of Knowledge, FDA.gov, and Clinical Trials.gov systematically for studies reporting the proportion of Th17 cells and the serum levels of Th17-related cytokines (IL-17, IL23) in MS patients. Our main endpoints were the proportion of Th17 cells among CD4⁺ T cells in peripheral blood (PB), serum IL-17 levels, and serum IL-23 levels. We assessed pooled data by using a random-effects model. It has been registered at International Prospective Register of Systematic Reviews (PROSPERO) (number CRD42017059113).

RESULTS

Of 560 identified studies, a total of 12 studies were selected in our analysis. Compared with control subjects, MS patients had a higher proportion of Th17 cells [1.37, (0.53, 2.21)] in PB, an elevated levels of serum IL-17 [2.48, (1.25, 3.71)] and an increased IL-23 levels in serum [2.29, (0.58, 4.00)].

CONCLUSION

Under random effect model of meta-analysis, the data showed that the proportion of Th17 cells in PB and levels of serum IL-17 and IL-23 increased among MS patients compared to control subjects. This result demonstrated that Th17 cells and Th17-related cytokines may be involved in the pathogenic mechanisms of MS.

Influence of the Gut Microbiome on Autoimmunity in the Central Nervous System

Autoimmune disorders of the CNS have complex pathogeneses that are not well understood. In multiple sclerosis and neuromyelitis optica spectrum disorders, T cells destroy CNS tissue, resulting in severe disabilities. Mounting evidence suggests that reducing inflammation in the CNS may start with modulation of the gut microbiome. The lymphoid tissues of the gut are specialized for the induction of regulatory cells, which are directly responsible for the suppression of CNS-damaging autoreactive T cells. Whether cause or effect, the onset of dysbiosis in the gut of patients with multiple sclerosis and neuromyelitis optica provides evidence of communication along the gut-brain axis. Thus, current and future therapeutic interventions directed at microbiome modulation are of considerable appeal.

CCR6+ Th cells in the cerebrospinal fluid of persons with multiple sclerosis are dominated by pathogenic non-classic Th1 cells and GM-CSF-only-secreting Th cells

Considerable attention has been given to CCR6⁺ IL-17-secreting CD4⁺ T cells (Th17) in the pathology of a number of autoimmune diseases including multiple sclerosis (MS). However, other Th subsets also play important pathogenic roles, including those that secrete IFNγ and GM-CSF. CCR6 expression by Th17 cells allows their migration across the choroid plexus into the cerebrospinal fluid (CSF), where they are involved in the early phase of experimental autoimmune encephalomyelitis (EAE), and in MS these cells are elevated in the CSF during relapses and contain high frequencies of autoreactive cells. However, the relatively low frequency of Th17 cells suggests they cannot by themselves account for the high percentage of CCR6⁺ cells in MS CSF. Here we identify the dominant CCR6⁺ T cell subsets in both the blood and CSF as non-classic Th1 cells, including many that secrete GM-CSF, a key encephalitogenic cytokine. In addition, we show that Th cells secreting GM-CSF but not IFNγ or IL-17, a subset termed GM-CSF-only-secreting Th cells, also accumulate in the CSF. Importantly, in MS the proportion of IFNγ- and GM-CSF-secreting T cells expressing CCR6 was significantly enriched in the CSF, and was elevated in MS, suggesting these cells play a pathogenic role in this disease.

IL-17-triggered downregulation of miR-497 results in high HIF-1α expression and consequent IL-1β and IL-6 production by astrocytes in EAE mice

Interleukin 17 (IL-17) is increasingly recognized as a key factor that contributes to the pathogenesis of multiple sclerosis (MS) and its experimental mouse autoimmune encephalomyelitis (EAE) model. However, the roles and regulatory mechanisms of IL-17-induced pro-inflammatory cytokine production in EAE mice remain largely unclear. In this study, the expression of IL-17, hypoxia inducible factor-1α (HIF-1α), IL-1β, IL-6 and microRNA-497 (miR-497), as well as their intrinsic associations, was investigated using EAE model mice and cultured astrocytes exposed to IL-17 in vitro. We observed markedly increased production of IL-17, HIF-1α, IL-1β and IL-6 in the brain tissues of EAE mice, while the expression and secretion of HIF-1α, IL-1β and IL-6 were also significantly increased when cultured primary astrocytes from mice were stimulated with IL-17. Meanwhile, the expression of miR-497 was downregulated both in vivo and in vitro. Subsequent in vitro experiments revealed that IL-17 induced the production of IL-1β and IL-6 in astrocytes through the upregulation of HIF-1α as a transcriptional factor, indicating that IL-17-mediated downregulation of miR-497 enhanced HIF-1α expression. Furthermore, astrocyte-specific knockdown of IL-17RA and HIF-1α or astrocyte-specific overexpression of miR-497 by infection with different lentiviral vectors containing an astrocyte-specific promotor markedly decreased IL-1β and IL-6 production in brain tissues and alleviated the pathological changes and score of EAE mice. Collectively, these findings indicate that decreased miR-497 expression is responsible for IL-17-triggered high HIF-1α expression and consequent IL-1β and IL-6 production by astrocytes in EAE mice.Cellular & Molecular Immunology advance online publication, 1 May 2017; doi:10.1038/cmi.2017.12.

[The influence of catecholamines on Th17-cells in multiple sclerosis]

AIM

Тo investigate the possible association between clinical characteristics of multiple sclerosis (MS), quantitative and qualitative characteristics of Th17, dopamine and norepinephrine concentrations in the serum in patients with multiple sclerosis (MS).

MATERIAL AND METHODS

A comprehensive neurological and immunological examination of 43 patients with relapsing-remitting-MS (RR-MS) was performed. All patients were subjected to a standard neurological examination with assessment of the EDSS score. Dopamine and norepinephrine concentrations in serum were measured by enzyme-linked immunosorbent assay (ELISA). Percentage of Th17-cells was determined by flow cytometry. The functional activity of Th17- and Th1-cells was assessed by the production of interleukin-17 (IL-17) and interferon-gamma (IFN-γ), respectively, by peripheral blood mononuclear cells (PBMC) stimulated with microbeads coated with anti-CD3 and anti-CD28-antibodies.

RESULTS

The percent Th17-cells and cytokine production was significantly higher in MS patients with the exacerbation of disease than in the control group or remission, while the dopamine level was lower. Norepinephrine levels in MS patients in the acute stage and remission were comparable, but nevertheless, reliably lower than in the control group.

CONCLUSION

The results suggest the inhibitory effect of catecholamines on Th17 cells.

Monoclonal antibody therapy for neuromyelitis optica spectrum disorder: current and future

Monoclonal-antibody has been used for patients with autoimmune disorders for several years, and efficacy and safety were appreciated for these patients. Neuromyelitis optica specturm disorder (NMOSD) has been defined as an autoimmune demyelination disorder of the central nervous system (CNS) with a course of relapse-remission. Treatment of prevention is important for patients with NMOSD because of the increased disability after several attacks. Multiple factors were involved in the pathogenesis of NMOSD. Currently, targeting specific factor was favored in the research into the treatment for NMOSD. Previous studies reported the efficacy and tolerance in NMOSD for drugs such as rituximab, tocilizumab, and eculizumab. The aim of this article is to review the current monoclonal therapies for NMOSD patients, and also future alternative options.

Circulating Memory T Follicular Helper Cells in Patients with Neuromyelitis Optica/Neuromyelitis Optica Spectrum Disorders

OBJECTIVE

This study aimed to examine the potential role of memory T follicular helper (Tfh) cells in patients with neuromyelitis optica/neuromyelitis optica spectrum disorders (NMO/NMOSD).

METHODS

The percentages of different subsets of circulating memory Tfh cells in 25 NMO/NMOSD patients before and after treatment as well as in 17 healthy controls were examined by flow cytometry. The levels of IL-21 and AQP4 Ab in plasma and CSF were measured by ELISA.

RESULTS

The percentages and numbers of circulating memory Tfh cells, ICOS(+), CCR7(-), CCR7(-)ICOS(+), CCR7(+), CCR7(+)ICOS(+) memory Tfh cells, and the levels of IL-21 in plasma and CSF were significantly increased in NMO/NMOSD patients. The percentages of CCR7(-) and CCR7(-)ICOS(+) memory Tfh cells were positively correlated with ARR, plasma IL-21, and AQP4 Ab levels. The percentages of CCR7(+) and CCR7(+)ICOS(+) memory Tfh cells were positively correlated with CSF white blood cell counts, proteins, and IL-21 levels. Treatment with corticosteroids significantly reduced the numbers of CCR7(-)ICOS(+) and CCR7(+)ICOS(+) memory Tfh cells as well as plasma IL-21 levels in patients with partial remission.

CONCLUSIONS

Our findings indicate that circulating memory Tfh cells may participate in the relapse and development of NMO/NMOSD and may serve as a new therapeutic target.

The Immunology of Neuromyelitis Optica-Current Knowledge, Clinical Implications, Controversies and Future Perspectives

Neuromyelitis optica (NMO) is an autoimmune, demyelinating disorder of the central nervous system (CNS) with typical clinical manifestations of optic neuritis and acute transverse myelitis attacks. Previously believed to be a variant of multiple sclerosis (MS), it is now considered an independent disorder which needs to be differentiated from MS. The discovery of autoantibodies against aquaporin-4 (AQP4-IgGs) changed our understanding of NMO immunopathogenesis and revolutionized the diagnostic process. AQP4-IgG is currently regarded as a specific biomarker of NMO and NMO spectrum disorders (NMOsd) and a key factor in its pathogenesis. Nevertheless, AQP4-IgG seronegativity in 10%-25% of NMO patients suggests that there are several other factors involved in NMO immunopathogenesis, i.e., autoantibodies against aquaporin-1 (AQP1-Abs) and antibodies against myelin oligodendrocyte glycoprotein (MOG-IgGs). This manuscript reviews current knowledge about NMO immunopathogenesis, pointing out the controversial issues and showing potential directions for future research. Further efforts should be made to broaden our knowledge of NMO immunology which could have important implications for clinical practice, including the use of potential novel biomarkers to facilitate an early and accurate diagnosis, and modern treatment strategies improving long-term outcome of NMO patients.

Alemtuzumab long-term immunologic effect: Treg suppressor function increases up to 24 months

OBJECTIVE

To analyze changes in T-helper (Th) subsets, T-regulatory (Treg) cell percentages and function, and mRNA levels of immunologically relevant molecules during a 24-month follow-up after alemtuzumab treatment in patients with relapsing-remitting multiple sclerosis (RRMS).

METHODS

Multicenter follow-up of 29 alemtuzumab-treated patients with RRMS in the Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis (CARE-MS) I and CARE-MS II trials. Peripheral blood (PB) samples were obtained at months 0, 6, 12, 18, and 24. We evaluated (1) mRNA levels of 26 immunologic molecules (cytokines, chemokines, chemokine receptors, and transcriptional factors); (2) Th1, Th17, and Treg cell percentages; and (3) myelin basic protein (MBP)-specific Treg suppressor activity.

RESULTS

We observed 12 relapses in 9 patients. mRNA levels of the anti-inflammatory cytokines interleukin (IL)-10, IL-27, and transforming growth factor-β persistently increased whereas those of proinflammatory molecules related to the Th1 or Th17 subsets persistently decreased after alemtuzumab administration throughout the follow-up period. PB CD4+ cell percentage remained significantly lower than baseline while that of Th1 and Th17 cells did not significantly change. A significant increase in Treg cell percentage was observed at month 24 and was accompanied by an increase in Treg cell suppressive activity against MBP-specific Th1 and Th17 cells.

CONCLUSIONS

The long-lasting therapeutic benefit of alemtuzumab in RRMS may involve a shift in the cytokine balance towards inhibition of inflammation associated with a reconstitution of the PB CD4+ T-cell subsets that includes expansion of Treg cells with increased suppressive function.

Th17 Cells Pathways in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders: Pathophysiological and Therapeutic Implications

Several animal and human studies have implicated CD4+ T helper 17 (Th17) cells and their downstream pathways in the pathogenesis of central nervous system (CNS) autoimmunity in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), challenging the traditional Th1-Th2 paradigm. Th17 cells can efficiently cross the blood-brain barrier using alternate ways from Th1 cells, promote its disruption, and induce the activation of other inflammatory cells in the CNS. A number of environmental factors modulate the activity of Th17 pathways, so changes in the diet, exposure to infections, and other environmental factors can potentially change the risk of development of autoimmunity. Currently, new drugs targeting specific points of the Th17 pathways are already being tested in clinical trials and provide basis for the development of biomarkers to monitor disease activity. Herein, we review the key findings supporting the relevance of the Th17 pathways in the pathogenesis of MS and NMOSD, as well as their potential role as therapeutic targets in the treatment of immune-mediated CNS disorders.

Change of Th17 Lymphocytes and Treg/Th17 in Typical and Atypical Optic Neuritis

Background

Typical and atypical optic neuritis (ON) are two clinical types of autoimmune inflammatory diseases of the optic nerve that causes acute vision loss, and are difficult to distinguish in their early stages. The disturbance in the balance of Th17 and Treg lymphocytes is thought to play an essential role in these autoimmune inflammatory diseases.

Objectives

To detect the clinical relevance of Th17 and Treg in peripheral blood and the ratio of Treg/Th17 in patients with typical and atypical ON. To determine whether analysis of Th17 and Treg lymphocytes will provides insights into the different disease phenotypes of typical and atypical ON.

Methods

We studied a consecutive series of patients aged 14–70 years who presented to our neurological department with typical ON (n = 30) or atypical ON (n = 33) within 4 weeks of their acute attacks. Routine clinical tests and ophthalmological examination were performed in all patients. Blood samples were collected from untreated patients and from gender- and age-matched healthy controls (n = 30). The proportion of peripheral blood Th17 cells and Treg cells was determined by flow cytometry.

Results

Patients with atypical ON had a higher proportion of Th17 cells than patients with typical ON (3.61±1.56 vs 2.55±1.74, P<0.01) or controls (1.45±0.86, P<0.01). The proportion of Th17 cells in patients with typical ON was also markedly higher than in controls (P<0.01). The mean percentage of Treg cells in atypical ON (6.31±2.11) and typical ON (6.80±2.00) were significantly lower when compared to controls (8.29±2.32, both P<0.01). No significant difference in Treg frequency was observed between typical ON and atypical ON (p>0.05).

Conclusions

The frequency of Th17 cells is higher in atypical ON than typical ON, and patients with atypical ON have a greater imbalance of pro-inflammatory and regulatory cells than patients with typical ON when compared with controls. These changes are indicative of distinct pathological mechanisms and may provide useful information to distinguish typical and atypical ON.

Cytokine and Chemokine Profiles in Patients with Neuromyelitis Optica Spectrum Disorder

OBJECTIVE

To screen cytokines and chemokines and determine their dynamic changes in the serum and cerebrospinal fluid (CSF) of patients with neuromyelitis optica spectrum disorder (NMOSD).

METHODS

Eight NMOSD with seropositive aquaporin-4 antibody (AQP4-IgG) were enrolled, as well as 8 matched patients with multiple sclerosis (MS) and 8 with noninflammatory neurological diseases, who were included as controls. In total, 102 cytokines and 34 chemokines were detected in the CSF and serum of NMOSD patients and controls.

RESULTS

CSF interleukin (IL)-17A levels were significantly higher in NMOSD patients in the relapsing phase (27.15 ± 11.33) than in those in the remitting phase (10.04 ± 3.11, p = 0.0017), and patients with MS (14.72 ± 3.20, p = 0.0283) and other controls (10.39 ± 11.38, p = 0.0021). CSF IL-6 levels were higher in the NMOSD patients in the relapsing phase (12.23 ± 3.47) than in those in the remitting phase (5.87 ± 2.78, p = 0.0001), and MS patients (7.38 ± 2.35, p = 0.0033) and other controls (7.50 ± 0.37, p = 0.0043). CSF CCL19 levels were also significantly higher in NMOSD patients in the relapsing phase (35.87 ± 27.07) than in those in the remitting phase (10.71 ± 3.62, p = 0.0215). Serum IL-19 levels were lower in NMOSD patients in the relapsing phase (6.23 ± 1.95) than in those in the remitting phase (10.72 ± 4.46, p = 0.0092). Further, there was a positive, significant correlation between serum IL-9 concentration and the Expanded Disability Status Scale score in the NMOSD patients in the relapsing phase (p = 0.04).

CONCLUSION

In addition to IL-6 and IL-17A, IL-16 and CCL19 act as proinflammatory cytokines/chemokines, while IL-19 plays a protective role in NMOSD pathogenesis.

Copy number variations in multiple sclerosis and neuromyelitis optica

OBJECTIVE

To clarify the potential association of copy number variations (CNVs) with multiple sclerosis (MS) and neuromyelitis optica (NMO) in Japanese cases.

METHODS

Genome-wide association analyses of CNVs among 277 MS patients, 135 NMO/NMO spectrum disorder (NMOSD) patients, and 288 healthy individuals as a discovery cohort, and among 296 MS patients, 76 NMO/NMOSD patients, and 790 healthy individuals as a replication cohort were performed using high-density single nucleotide polymorphism microarrays.

RESULTS

A series of discovery and replication studies revealed that most identified CNVs were 5 to 50kb deletions at particular T cell receptor (TCR) gamma and alpha loci regions. Among these CNVs, a TCR gamma locus deletion was found in 16.40% of MS patients (p = 2.44E-40, odds ratio [OR] = 52.6), and deletion at the TCR alpha locus was found in 17.28% of MS patients (p = 1.70E-31, OR = 13.0) and 13.27% of NMO/NMOSD patients (p = 5.79E-20, OR = 54.6). These CNVs were observed in peripheral blood T-cell subsets only, suggesting the CNVs were somatically acquired. NMO/NMOSD patients carrying the CNV tended to be seronegative for anti-aquaporin-4 antibody or had significantly lower titers than those without CNV.

INTERPRETATION

Deletion-type CNVs at specific TCR loci regions contribute to MS and NMO susceptibility.

Circulating CCR7+ICOS+ Memory T Follicular Helper Cells in Patients with Multiple Sclerosis

Objective

This study is aimed at examining the potential roles of circulating memory T follicular helper (Tfh) cells in patients with multiple sclerosis (MS).

Methods

The numbers of different subsets of circulating memory Tfh cells in 25 patients with relapsed MS before and after treatment as well as 14 healthy controls (HC) were examined by flow cytometry. The levels of plasma IL-21 in all patients and cerebrospinal fluid (CSF) IL-21 in some MS patients and controls with non-inflammatory neuronal diseases (NND) were measured by ELISA.

Results

In comparison with that in the HC, the numbers of circulating CD3+CD4+CXCR5+CD45RA-, ICOS+, CCR7+ and CCR7+ICOS+ memory Tfh cells and the levels of plasma IL-21 significantly increased in MS patients, but significantly decreased in the patients with complete remission (CR). The levels of CSF IL-21 were significantly higher in the MS patients than that in the NND patients. The numbers of CCR7+ICOS+ memory Tfh cells were positively correlated with the EDSS scores, the levels of plasma and CSF IL-21, IgG, MBP-Ab or MOG-Ab.

Conclusions

Our findings indicated that circulating memory Tfh cells, especially CCR7+ICOS+ memory Tfh cells, may be associated with the relapse of MS and may serve as a new therapeutic target.

Epidemiological, clinical, and immunological characteristics of neuromyelitis optica: A review

The aim of this study was to review the epidemiological and clinical characteristics of neuromyelitis optica (NMO) and the immunopathological mechanisms involved in the neuronal damage. NMO is an inflammatory demyelinating autoimmune disease of the central nervous system that most commonly affects the optic nerves and spinal cord. NMO is thought to be more prevalent among non-Caucasians and where multiple sclerosis (MS) prevalence is low. NMO follows a relapsing course in more than 80-90% of cases, which is more commonly in women. It is a complex disease with an interaction between host genetic and environmental factors and the main immunological feature is the presence of anti-aquaporin 4 (AQP4) antibodies in a subset of patients. NMO is frequently associated with multiple other autoantibodies and there is a strong association between NMO with other systemic autoimmune diseases. AQP4-IgG can cause antibody-dependent cellular cytotoxicity (ADCC) when effector cells are present and complement-dependent cytotoxicity (CDC) when complement is present. Acute therapies, including corticosteroids and plasma exchange, are designed to minimize injury and accelerate recovery. Several aspects of NMO pathogenesis remain unclear. More advances in the understanding of NMO disease mechanisms are needed in order to identify more specific biomarkers to NMO diagnosis.

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.

Protective effect of tanreqing injection on axon myelin damage in the brain of mouse model for experimental autoimmune encephalomyelitis

OBJECTIVE

To evaluate the effect of Tanreqing injection on axon myelin in the mouse brain of experimental autoimmune encephalomyelitis (EAE).

METHODS

An EAE model was established by myelin oligodendrocyte glycoprotein (MOG)35-55 immunization in C57BL/6 mice. Mice were randomly divided into the following groups: normal, model, prednisone acetate (PA) (6 mg/kg), Tanreqing high dose (5.14 mL/kg), Tanreqing low dose (2.57 mL/kg). On the day of immunization, both Tanreqing groups were treated by intraperitoneal injection, with the PA group treated by intragastrical perfusion after T cell response, and the other groups treated with saline. Changes in body weight, neurological deficit score, incidence rate, mortality rate, and course of disease were observed for all mice. Brain tissue was isolated and stained with hematoxylin-eosin, and pathological investigations performed to evaluate axon myelin damage by transmission electron microscopy (TEM). Myelin basic protein and microtubule associated protein-2 were analyzed by immunohistochemistry.

RESULTS

Tanreqing injection significantly prolonged EAE latency and decreased the neurological deficit score, alleviated infiltration of inflammatory cells in the focus area, up-regulated hippocampal MBP expression at the acute stage and the remission stage, and increased microtubule associated protein-2 expression in the EAE brain to varying degrees in the acute stage. TEM analysis indicated that Tanreqing injection alleviates myelin damage in the EAE mouse and maintains the integrity of circular layer structures and alleviates axon mitochondrial swelling.

CONCLUSION

Tanreqing injection alleviates EAE symptoms.

Th22 cells are expanded in multiple sclerosis and are resistant to IFN-β

Th1 and Th17 cells have been considered as effectors in mouse EAE and in the human counterpart, MS. Recently, IL-22, a Th17-related, proinflammatory cytokine, has been associated with a new Th cell subset, defined as Th22, involved in chronic inflammatory conditions, such as psoriasis; the role of IL-22 in MS has not yet been elucidated. Here, we report that similar to Th17 cells, the number of Th22 cells increased in the PB and the CSF of RR MS patients, especially during the active phases of the disease. However, as opposed to Th17 cells, the expansion of Th22 cells occurred before the active phases of the disease. Th22 cells were found to be specific for the autoantigen MBP and also expressed high levels of CCR6 and T-bet, as for Th17 cells, indicating that Th22 self-reactive cells could have CNS-homing properties and be pathogenic in active RRMS patients. Conversely to Th17 cells, Th22 cells displayed lower levels of IFNAR1 and were insensitive to IFN-β inhibition. These data suggest that expansion of Th22 cells in MS could be one of the factors that critically influence resistance to IFN-β therapy.