IL-22 secreting CD4+ T cells in the patients with neuromyelitis optica and multiple sclerosis

Immunopathogenesis of multiple sclerosis: molecular and cellular mechanisms and new immunotherapeutic approaches

BACKGROUND

Multiple sclerosis (MS) is a central nervous system (CNS) demyelinating autoimmune disease with increasing global prevalence. It predominantly affects females, especially those of European descent. The interplay between environmental factors and genetic predisposition plays a crucial role in MS etiopathogenesis.

METHODS

We searched recent relevant literature on reputable databases, which include, PubMed, Embase, Web of Science, Scopus, and ScienceDirect using the following keywords: multiple sclerosis, pathogenesis, autoimmunity, demyelination, therapy, and immunotherapy.

RESULTS

Various animal models have been employed to investigate the MS etiopathogenesis and therapeutics. Autoreactive T cells within the CNS recruit myeloid cells through chemokine expression, leading to the secretion of inflammatory cytokines driving the MS pathogenesis, resulting in demyelination, gliosis, and axonal loss. Key players include T cell lymphocytes (CD4+ and CD8+), B cells, and neutrophils. Signaling dysregulation in inflammatory pathways and the immunogenetic basis of MS are essential considerations for any successful therapy to MS. Data indicates that B cells and neutrophils also have significant roles in MS, despite the common belief that T cells are essential. High neutrophil-to-lymphocyte ratios correlate with MS severity, indicating their contribution to disease progression. Dysregulated signaling pathways further exacerbate MS progression.

CONCLUSION

MS remains incurable, but disease-modifying therapies, monoclonal antibodies, and immunomodulatory drugs offer hope for patients. Research on the immunogenetics and immunoregulatory functions of gut microbiota is continuing to provide light on possible treatment avenues. Understanding the complex interplay between genetic predisposition, environmental factors, and immune dysregulation is critical for developing effective treatments for MS.

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.

Berberine: A natural modulator of immune cells in multiple sclerosis

Berberine is a benzylisoquinoline alkaloid found in such plants as Berberis vulgaris, Berberis aristata, and others, revealing a variety of pharmacological properties as a result of interacting with different cellular and molecular targets. Recent studies have shown the immunomodulatory effects of Berberine which result from its impacts on immune cells and immune response mediators such as diverse T lymphocyte subsets, dendritic cells (DCs), and different inflammatory cytokines. Multiple sclerosis (MS) is a chronic disabling and neurodegenerative disease of the central nervous system (CNS) characterized by the recruitment of autoreactive T cells into the CNS causing demyelination, axonal damage, and oligodendrocyte loss. There have been considerable changes discovered in MS regards to the function and frequency of T cell subsets such as Th1 cells, Th17 cells, Th2 cells, Treg cells, and DCs. In the current research, we reviewed the outcomes of in vitro, experimental, and clinical investigations concerning the modulatory effects that Berberine provides on the function and numbers of T cell subsets and DCs, as well as important cytokines that are involved in MS.

The Role of Selected Interleukins in the Development and Progression of Multiple Sclerosis-A Systematic Review

Multiple sclerosis is a disabling inflammatory disorder of the central nervous system characterized by demyelination and neurodegeneration. Given that multiple sclerosis remains an incurable disease, the management of MS predominantly focuses on reducing relapses and decelerating the progression of both physical and cognitive decline. The continuous autoimmune process modulated by cytokines seems to be a vital contributing factor to the development and relapse of multiple sclerosis. This review sought to summarize the role of selected interleukins in the pathogenesis and advancement of MS. Patients with MS in the active disease phase seem to exhibit an increased serum level of IL-2, IL-4, IL-6, IL-13, IL-17, IL-21, IL-22 and IL-33 compared to healthy controls and patients in remission, while IL-10 appears to have a beneficial impact in preventing the progression of the disease. Despite being usually associated with proinflammatory activity, several studies have additionally recognized a neuroprotective role of IL-13, IL-22 and IL-33. Moreover, selected gene polymorphisms of IL-2R, IL-4, IL-6, IL-13 and IL-22 were identified as a possible risk factor related to MS development. Treatment strategies of multiple sclerosis that either target or utilize these cytokines seem rather promising, but more comprehensive research is necessary to gain a clearer understanding of how these cytokines precisely affect MS development and progression.

Recent Progress in Multiple Sclerosis Treatment Using Immune Cells as Targets

Multiple sclerosis (MS) is an autoimmune-mediated demyelinating disease of the central nervous system. The main pathological features are inflammatory reaction, demyelination, axonal disintegration, reactive gliosis, etc. The etiology and pathogenesis of the disease have not been clarified. The initial studies believed that T cell-mediated cellular immunity is the key to the pathogenesis of MS. In recent years, more and more evidence has shown that B cells and their mediated humoral immune and innate immune cells (such as microglia, dendritic cells, macrophages, etc.) also play an important role in the pathogenesis of MS. This article mainly reviews the research progress of MS by targeting different immune cells and analyzes the action pathways of drugs. The types and mechanisms of immune cells related to the pathogenesis are introduced in detail, and the mechanisms of drugs targeting different immune cells are discussed in depth. This article aims to clarify the pathogenesis and immunotherapy pathway of MS, hoping to find new targets and strategies for the development of therapeutic drugs for MS.

CCR1 antagonist J-113863 corrects the imbalance of pro- and anti-inflammatory cytokines in a SJL/J mouse model of relapsing-remitting multiple sclerosis

Multiple sclerosis (MS), an immune-mediated and neurodegenerative disorder of the central nervous system (CNS), is characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model used to study MS. To explore the impact of chemokine receptor CCR1 blockade in EAE and the underlying mechanisms, we used CCR1 antagonist J-113863 in PLP_139-151-induced EAE in SJL/J mice. Following EAE induction, mice were treated with J-113863 (10 mg/kg) daily from day 14 until day 25. We investigated the effect of J-113863 on expression levels of GM-CSF, IL-6, IL-10, IL-27 in CD4⁺ spleen cells, using flow cytometry. We also analyzed the effect of J-113863 on GM-CSF, IL-6, IL-10, IL-27 mRNA and protein expression levels using RT-PCR and Western blot analysis in brain tissues. J-113863 treatment decreased the populations of CD4⁺GM-CSF⁺ and CD4⁺IL-6⁺ cells and increased CD4⁺IL-27⁺ and CD4⁺IL-10⁺ cells in the spleen. J-113863 had a suppressive effect on the mRNA and protein expression levels of GM-CSF, and IL-6 in the brain tissue. On the other hand, J-113863 treatment increased the mRNA and protein expression of IL-10 and IL-27 in the brain tissue. Our results highlighted J-113863's potential role in suppressing pro-inflammatory expression and up-regulating anti-inflammatory mediators, which could represent a beneficial alternative approach to MS treatment.

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.

Cathepsin B inhibitor alleviates Th1, Th17, and Th22 transcription factor signaling dysregulation in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory infiltration in association with demyelination in the central nervous system. Among the factors involved in the immunological mechanisms of MS, Th1, Th17, and Th22 cells play a critical role. In the present study, we investigated the role of CA-074, a potent Cathepsin B inhibitor, in MS progression, using the SJL/J mouse model of experimental autoimmune encephalomyelitis (EAE). Following induction of EAE, mice were administered CA-074 (10 mg/kg) intraperitoneally each day, beginning on day 14 and continuing until day 28, and were evaluated for clinical signs. We further investigated the effect of CA-074 on Th1 (T-bet/STAT4), Th17 (IL-17A/RORγT), Th22 (TNF-α/IL-22), and regulatory T (Treg/Foxp3) cells in the spleen, using flow cytometry. We also analyzed the effect of CA-074 on T-bet, IL-17A, RORγT, IL-22, and mRNA and protein levels using RT-PCR and western blot analysis for brain tissues. Cathepsin B expression were also assessed by western blot in the brain tissues. The severity of clinical scores decreased significantly in CA-074-treated mice compared with that in EAE control mice. Moreover, the percentage of CD4⁺T-bet⁺, CXCR5⁺T-bet⁺, CD4⁺STAT4⁺, CD4⁺IL-17A⁺, CXCR5⁺IL-17A⁺, CD4⁺RORγT⁺, CCR6⁺RORγT⁺, CD4⁺TNF-α⁺, CD4⁺IL-22⁺, and CCR6⁺IL-22⁺ cells decreased while CD25⁺Foxp3⁺ increased in CA-074-treated EAE mice as compared to vehicle-treated EAE mice. Further, CA-074-treated EAE mice had downregulated Cathepsin B protein expression which was associated with decreased T-bet, IL-17A, RORγT, and IL-22 mRNA/protein expression. These results suggest that Cathepsin B could be a novel therapeutic candidate against for the treatment of MS.

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.

Role of Th22 Cells in the Pathogenesis of Autoimmune Diseases

Upon antigenic stimulation, naïve CD4+T cells differentiate into different subsets and secrete various cytokines to exert biological effects. Th22 cells, a newly identified CD4+T cell subset,are distinct from the Th1, Th2 and Th17 subsets. Th22 cells secrete certain cytokines such as IL-22, IL-13 and TNF-α, but not others, such as IL-17, IL-4, or interferon-γ (IFN-γ), and they express chemokine receptors CCR4, CCR6 and CCR10. Th22 cells were initially found to play a role in skin inflammatory diseases, but recent studies have demonstrated their involvement in the development of various autoimmune diseases. Here, we review research advances in the origin, characteristics and effector mechanisms of Th22 cells, with an emphasis on the role of Th22 cells and their main effector cytokine IL-22 in the pathogenesis of autoimmune diseases. The findings presented here may facilitate the development of new therapeutic strategies for targeting these diseases.

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.

Selective serotonin reuptake inhibitor attenuates the hyperresponsiveness of TLR2+ and TLR4+ Th17/Tc17-like cells in multiple sclerosis patients with major depression

Elevated frequency of Th17-like cells expressing Toll-like receptors (TLRs) has been recently associated with relapsing-remitting multiple sclerosis (MS) pathogenesis, a chronic inflammatory demyelinating autoimmune disease of the central nervous system. We aimed to investigate the impact of current major depressive disorder (MDD) on the behaviour of these cells following in vitro stimulation with TLR2, TLR4, TLR5 and TLR9 agonists. Here, the level of both cell proliferation and cytokine production related to Th17/Tc17 phenotypes in response to TLR2 (Pam3C) and TLR4 (LPS) ligands was significantly higher in CD4+ and CD8+ T-cell cultures from MS/MDD patients when compared to non-depressed patients. These cytokine levels were positively associated with neurological disabilities in patients. No difference for responsiveness to TLR5 (flagellin) and TLR9 (ODN) agonists was observed. LPS, but not Pam3C, induced significant IL-10 release, mainly in patients without MDD. Interestingly, more intense expression of TLR2 and TLR4 on these cells was observed in MDD patients. Finally, in vitro addition of serotonin and treatment of MDD patients with selective serotonin reuptake inhibitors (SSRIs) reduced the production of Th17/Tc17-related cytokines by CD4+ and CD8+ T cells in response to Pam3C and LPS. However, only SSRI therapy diminished the frequency and intensity of TLR2 and TLR4 expression on circulating CD4+ and CD8+ T cells. In summary, although preliminary, our findings suggest that adverse events that elevate circulating levels of TLR2 and TLR4 ligands can affect MS pathogenesis, particularly among depressed patients.

Advances in the role of helper T cells in autoimmune diseases

Autoimmune diseases are primary immune diseases in which autoreactive antibodies or sensitized lymphocytes destroy and damage tissue and cellular components, resulting in tissue damage and organ dysfunction. Helper T cells may be involved in the pathogenesis of autoimmune diseases under certain conditions. This review summarizes recent research on the role of helper T cells in autoimmune diseases from two aspects, helper T cell-mediated production of autoantibodies by B cells and helper T cell-induced activation of abnormal lymphocytes, and provides ideas for the treatment of autoimmune diseases. The abnormal expression of helper T cells promotes the differentiation of B cells that produce autoantibodies, which leads to the development of different diseases. Among them, abnormal expression of Th2 cells and T follicular helper cells is more likely to cause antibody-mediated autoimmune diseases. In addition, abnormal activation of helper T cells also mediates autoimmune diseases through the production of abnormal cytokines and chemokines. Helper T cells play an essential role in the pathogenesis of autoimmune diseases, and a full understanding of their role in autoimmune diseases is helpful for providing ideas for the treatment of autoimmune diseases.

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.

Targeting IL-6 receptor in the treatment of neuromyelitis optica spectrum: a review of emerging treatment options

Introduction: Recent research has shown that IL-6 receptor (IL-6 R) inhibitors like tocilizumab and satralizumab are effective in reducing the relapse rate in patients with NMOSD.Areas covered: This review article explores current concepts in NMOSD management and focuses on IL-6 R as a therapeutic target. The authors delve into the biological and immunological role of IL-6 in the pathogenesis of NMOSD. Further, the authors summarize the most recent findings on the use of anti-IL-6 R monoclonal antibodies, tocilizumab and satralizumab, in the treatment of NMOSD.Expert opinion: A better understanding of the role of cytokines in NMOSD may provide the neurologist with novel therapies for this disease. IL-6 R appears to be a central hub to NMOSD pathogenesis and a relevant therapeutic target.

T Helper Cells: The Modulators of Inflammation in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by the progressive loss of axonal myelin in several areas of the central nervous system (CNS) that is responsible for clinical symptoms such as muscle spasms, optic neuritis, and paralysis. The progress made in more than one decade of research in animal models of MS for clarifying the pathophysiology of MS disease validated the concept that MS is an autoimmune inflammatory disorder caused by the recruitment in the CNS of self-reactive lymphocytes, mainly CD4⁺ T cells. Indeed, high levels of T helper (Th) cells and related cytokines and chemokines have been found in CNS lesions and in cerebrospinal fluid (CSF) of MS patients, thus contributing to the breakdown of the blood-brain barrier (BBB), the activation of resident astrocytes and microglia, and finally the outcome of neuroinflammation. To date, several types of Th cells have been discovered and designated according to the secreted lineage-defining cytokines. Interestingly, Th1, Th17, Th1-like Th17, Th9, and Th22 have been associated with MS. In this review, we discuss the role and interplay of different Th cell subpopulations and their lineage-defining cytokines in modulating the inflammatory responses in MS and the approved as well as the novel therapeutic approaches targeting T lymphocytes in the treatment of the disease.

Lower serum interleukin-22 and interleukin-35 levels are associated with disease status in neuromyelitis optica spectrum disorders

AIMS

The exact pathogenesis of neuromyelitis optica spectrum disorder (NMOSD) remains unclear. A variety of cytokines are involved, but few studies have been performed to explore the novel roles of interleukin-22 (IL-22) and interleukin-35 (IL-35) in NMOSD. Therefore, this study was designed to investigate serum levels of IL-22 and IL-35, and their correlations with clinical and laboratory characteristics in NMOSD.

METHODS

We performed a cross-section study, 18 patients with acute NMOSD, 23 patients with remission NMOSD, and 36 healthy controls were consecutively enrolled. Serum levels of IL-22 and IL-35 were measured by enzyme-linked immunosorbent assay (ELISA). The correlations between serum IL-22 and IL-35 levels and clinical and laboratory characteristics were evaluated by Spearman's rank or Pearson's correlation coefficient.

RESULTS

The serum levels of IL-22 and IL-35 were significantly lower in patients with acute NMOSD and remission NMOSD than in healthy controls (IL-22: 76.96 ± 13.62 pg/mL, 87.30 ± 12.79 pg/mL, and 94.02 ± 8.52 pg/mL, respectively, P < .0001; IL-35: 45.52 ± 7.04 pg/mL, 57.07 ± 7.68 pg/mL, and 60.05 ± 20.181 pg/mL, respectively, P < .0001). Serum levels of IL-35 were negatively correlated with EDSS scores and cerebrospinal fluid protein levels (r = -.5438, P = .0002 and r = -.3523, P = .0258, respectively) in all patients.

CONCLUSIONS

Lower serum levels of IL-22 and IL-35 are associated with disease status in NMOSD. Additionally, lower serum levels of IL-35 are associated with disease severity in NMOSD.

Th17 cells increase in RRMS as well as in SPMS, whereas various other phenotypes of Th17 increase in RRMS only

Background

The nature and extent of inflammation seen in multiple sclerosis (MS) varies throughout the course of the disease. Changes seen in CD4+ T-helper cells in relapsing–remitting (RR) MS and secondary progressive (SP) MS might differ qualitatively and/or quantitatively.

Objective

The objective of this paper is to study the frequencies of all major CD4+ T-helper subtypes – Th17, Th22 and Th1 lineage cells – in relapse, remission and secondary progression alongside CCR6 status, a chemokine receptor involved in migration of these cells into the central nervous system.

Methods

We compared 100 patients (50 RRMS and 50 SPMS) and 50 healthy volunteers and performed flow cytometric analysis of lymphocytes in blood samples.

Results

We demonstrated raised frequencies of various cell types along the Th17 axis; Th17, Th17.1 (IL-17+ interferon gamma+) and dual IL-17+ IL-22+ cells in RRMS. Th22 and CCR6+ Th1 cells (nonclassical Th1) were also increased in RRMS. All these cells were CCR6+. Only Th17 frequencies were elevated in SPMS.

Conclusions

Increased frequencies of Th17 cells are implicated both in RRMS and SPMS. The CCR6 pathway includes Th17, Th22 and Th1 nonclassical cells, of which Th22 and Th1 cells represent the greatest subsets in MS.

The Rare IL22RA2 Signal Peptide Coding Variant rs28385692 Decreases Secretion of IL-22BP Isoform-1, -2 and -3 and Is Associated with Risk for Multiple Sclerosis

The IL22RA2 locus is associated with risk for multiple sclerosis (MS) but causative variants are yet to be determined. In a single nucleotide polymorphism (SNP) screen of this locus in a Basque population, rs28385692, a rare coding variant substituting Leu for Pro at position 16 emerged significantly (p = 0.02). This variant is located in the signal peptide (SP) shared by the three secreted protein isoforms produced by IL22RA2 (IL-22 binding protein-1(IL-22BPi1), IL-22BPi2 and IL-22BPi3). Genotyping was extended to a Europe-wide case-control dataset and yielded high significance in the full dataset (p = 3.17 × 10^-4). Importantly, logistic regression analyses conditioning on the main known MS-associated SNP at this locus, rs17066096, revealed that this association was independent from the primary association signal in the full case-control dataset. In silico analysis predicted both disruption of the alpha helix of the H-region of the SP and decreased hydrophobicity of this region, ultimately affecting the SP cleavage site. We tested the effect of the p.Leu16Pro variant on the secretion of IL-22BPi1, IL-22BPi2 and IL-22BPi3 and observed that the Pro16 risk allele significantly lowers secretion levels of each of the isoforms to around 50%-60% in comparison to the Leu16 reference allele. Thus, our study suggests that genetically coded decreased levels of IL-22BP isoforms are associated with augmented risk for MS.

Impact of interferon β-1b, interferon β-1a and fingolimod therapies on serum interleukins-22, 32α and 34 concentrations in patients with relapsing-remitting multiple sclerosis

Interleukins (ILs)-22, 32α and 34 were monitored in the sera of relapsing-remitting multiple sclerosis (RRMS) patients at different time intervals with or without interferon β-1b, interferon β-1a and fingolimod treatments. The results showed that sera of untreated RRMS patients were statistically higher in concentration of IL-22 (P < .001), but not IL-32α and IL-34, than those of healthy individuals. Interestingly, interferon β-1b, interferon β-1a and fingolimod treatments led to a significant decrease of serum concentrations of ILs-22 and 32α, but not 34, at 6 and 12 months of treatment, compared to their initial concentrations before initiating therapy. The correlation analysis revealed that the changes of serum IL-22 (r = 0.814) and, to a lesser extent, IL-32α (r = 0.381) concentrations were positively correlated with those of expanded disability status score. In conclusion, serum IL-22 concentration may be a potential marker for MS disease severity and efficacy of treatment.

Inhibition of tyrosine kinase signaling by tyrphostin AG126 downregulates the IL-21/IL-21R and JAK/STAT pathway in the BTBR mouse model of autism

Autism spectrum disorder (ASD) comprises a broad range of neurodevelopmental disorders that are associated with deficits in social interaction and communication. The tyrosine kinase inhibitor tyrphostin AG126 represents a promising therapeutic agent for several neuroinflammatory disorders. There are currently no treatments available that can improve ASD and we previously showed that AG126 treatment exerts beneficial effects on BTBR T⁺ Itpr3^tf/J (BTBR) mice, a model for autism that shows the core features of ASD; however, the immunological mechanisms and molecular targets associated with this effect were previously unclear. This study was undertaken to delineate the neuroprotective effect of AG126 on BTBR mice. Here, using this mouse model, we investigated the effects of AG126 administration on IL-21R, IL-21, IL-22, TNF-α, NOS2, STAT3, IL-27, and Foxp3 production by CD8⁺ T cells in the spleen by flow cytometry. We further explored the mRNA and protein expression of IL-21, IL-22, IL-1β, TNF-α, NOS2, JAK1, STAT3, IL-27, and Foxp3 in brain tissue by RT-PCR, and western blotting. We found that BTBR mice treated with AG126 exhibited significant decreases in IL-21R-, IL-21-, IL-22-, TNF-α-, NOS2-, STAT3-producing, and increases in IL-27- and Foxp3-producing, CD8⁺ T cells. Our results further demonstrated that AG126 treatment effectively decreased IL-21, IL-22, IL-1β, TNF-α, NOS2, JAK1, and STAT3, and increased IL-27 and Foxp3 mRNA and protein expression in brain tissues. Our findings suggest that AG126 elicits a neuroprotective response through downregulation of the IL-21/IL-21R and JAK/STAT pathway in BTBR mice, which could represent a promising novel therapeutic target for ASD treatment.

Fatigue in Multiple Sclerosis is related to relapses, autonomic dysfunctions and introversion: A quasi-experimental study

BACKGROUND

Fatigue in Multiple Sclerosis (MS) might be partially due to inflammatory processes. If so, relapses should increase the fatigue level.

METHODS

Two groups of MS patients participated in this study. One suffered from a relapse and was treated by Methylprednisolone. The other group experienced a deterioration of their neurological condition but no relapse and received neurological rehabilitation. We assessed fatigue before admission, at admission and after discharge (t1, t2, t3). Furthermore, autonomic dysfunctions, depressive mood, apathy and extraversion were assessed at admission. Changes in fatigue were analysed with ANCOVAs and fatigue levels were analysed with regression analyses using clinical data and scores for depressive mood, apathy, extraversion and autonomic dysfunctions.

RESULTS

Only patients suffering from a relapse showed a significant increment in fatigue from t1 to t2. Regression analyses revealed that autonomic dysfunctions and introversion best explained the fatigue level.

CONCLUSIONS

This study shows that a relapse is accompanied by an increase in MS-related fatigue. Moreover, autonomic dysfunctions and introversion, more than depression and apathy, play a major role in the explanation of MS-related fatigue. This finding represents additional evidence for the relationship between inflammation, vagal afferent signaling, autonomic dysfunctions, introversion and the feeling of MS-related fatigue.

The role of interleukin 22 in multiple sclerosis and its association with c-Maf and AHR

The aim of this paper was to summarise knowledge of IL-22 involvement in multiple sclerosis (MS) and the possible link between IL-22 and two transcription factors - AHR and c-Maf. The conclusion is that despite numerous studies, the exact role of IL-22 in the pathogenesis of MS is still unknown. The expression and function of c-Maf in MS have not been studied. It seems that the functions of c-Maf and AHR are at least partly connected with IL-22, as both directly or indirectly influence the regulation of IL-22 expression. This possible connection has never been studied in MS.

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.

CD28 Autonomous Signaling Up-Regulates C-Myc Expression and Promotes Glycolysis Enabling Inflammatory T Cell Responses in Multiple Sclerosis

The immunopathogenesis of multiple sclerosis (MS) depend on the expansion of specific inflammatory T cell subsets, which are key effectors of tissue damage and demyelination. Emerging studies evidence that a reprogramming of T cell metabolism may occur in MS, thus the identification of stimulatory molecules and associated signaling pathways coordinating the metabolic processes that amplify T cell inflammation in MS is pivotal. Here, we characterized the involvement of the cluster of differentiation (CD)28 and associated signaling mediators in the modulation of the metabolic programs regulating pro-inflammatory T cell functions in relapsing-remitting MS (RRMS) patients. We show that CD28 up-regulates glycolysis independent of the T cell receptor (TCR) engagement by promoting the increase of c-myc and the glucose transporter, Glut1, in RRMS CD4⁺ T cells. The increase of glycolysis induced by CD28 was important for the expression of inflammatory cytokines related to T helper (Th)17 cells, as demonstrated by the strong inhibition exerted by impairing the glycolytic pathway. Finally, we identified the class 1A phosphatidylinositol 3-kinase (PI3K) as the critical signaling mediator of CD28 that regulates cell metabolism and amplify specific inflammatory T cell phenotypes in MS.

Effector T Cells in Multiple Sclerosis

Multiple sclerosis (MS) has long been considered a CD4 T-cell disease, primarily because of the findings that the strongest genetic risk for MS is the major histocompatibility complex (MHC) class II locus, and that T cells play a central role in directing the immune response. The importance that the T helper (Th)1 cytokine, interferon γ (IFN-γ), and the Th17 cytokine, interleukin (IL)-17, play in MS pathogenesis is indicated by recent clinical trial data by the enhanced presence of Th1/Th17 cells in central nervous system (CNS) tissue, cerebrospinal fluid (CSF), and blood, and by research on animal models of MS, such as experimental autoimmune encephalomyelitis (EAE). Although the majority of research on MS pathogenesis has centered on the role of effector CD4 T cells, accumulating data suggests that CD8 T cells may play a significant role in the human disease. In fact, in contrast to most animal models, the primary T cell found in the CNS in patients with MS, is the CD8 T cell. As patient-derived effector T cells are also resistant to mechanisms of dominant tolerance such as that induced by interaction with regulatory T cells (Tregs), their reduced response to regulation may also contribute to the unchecked effector T-cell activity in patients with MS. These concepts will be discussed below.

The role of innate lymphoid cells in health and disease

Innate lymphoid cells (ILCs) are kind of innate immune cells which can be divided into three main subsets according to their cytokine release profile, transcription factors, and surface markers. ILCs affect the initial stages of immunity in response to microbes and participate in immunity, inflammation, and tissue repair. ILCs modulate immunity through resistance to the pathogens and regulation of autoimmune inflammation and metabolic homeostasis. Therefore dysregulation of ILCs may lead to chronic pathologies such as allergies (i.e., asthma), inflammation (i.e., inflammatory bowel disease), and autoimmunity (i.e., psoriasis, atopic dermatitis, rheumatoid arthritis, multiple sclerosis, and ankylosing spondylitis). Regarding the critical role of ILCs in the regulation of immune system, the elucidation of their function in different conditions makes an interesting target for improvement of novel therapeutic approach to modulate an immune response in different disease context.

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.

Autoimmunity in multiple sclerosis: role of sphingolipids, invariant NKT cells and other immune elements in control of inflammation and neurodegeneration

Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system. It is classified as being an autoimmune response in the genetically susceptible individual to a persistent but unidentified antigen(s). Both the adaptive and the innate immune systems are likely to contribute significantly to MS pathogenesis. This review summarizes current understanding of the characteristics of MS autoimmunity in the initiation and progression of the disease. In particular we find it timely to classify the autoimmune responses by focusing on the immunogenic features of myelin-derived lipids in MS including molecular mimicry; on alterations of bioactive sphingolipids mediators in MS; and on functional roles for regulatory effector cells, including innate lymphocyte populations, like the invariant NKT (iNKT) cells which bridge adaptive and innate immune systems. Recent progress in identifying the nature of sphingolipids recognition for iNKT cells in immunity and the functional consequences of the lipid-CD1d interaction opens new avenues of access to the pathogenesis of demyelination in MS as well as design of lipid antigen-specific therapeutics.

Interleukin-22 in human inflammatory diseases and viral infections

Interleukin-22 (IL22) is one of the members of IL10 family. Elevated levels of this cytokine can be seen in diseases caused by T lymphocytes, such as Psoriasis, Rheumatoid arthritis, interstitial lung diseases. IL22 is produced by different cells in both innate and acquired immunities. Different types of T cells are able to produce IL22, but the major IL22-producing T-cell is the TCD4. TH22 cell is a new line of TCD4 cells, which differentiated from naive T cells in the presence of TNFα and IL6; 50% of peripheral blood IL22 is produced by these cells. IL22 has important functions in host defense at mucosal surfaces as well as in tissue repair. In this review, we assess the current understanding of this cytokine and focus on the possible roles of IL-22 in autoimmune diseases.

Melatonin reduces inflammatory response in peripheral T helper lymphocytes from relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a neuroinflammatory disease of the central nervous system in which the immune system plays a central role. In particular, effector populations such as T helper (Th) 1, Th9, Th17, and Th22 cells are involved in disease development, whereas T regulatory cells (Tregs) are associated with the resolution of the disease. Melatonin levels are impaired in patients with MS, and exogenous melatonin ameliorates the disease in MS animal models by modulating the Th1/Th17/Treg responses and also improves quality of life and several symptoms in patients with MS. However, no study has examined melatonin's effect on T cells from relapsing-remitting MS (RR-MS) patients. Therefore, the objectives of the present study were to evaluate the effects of the in vitro administration of melatonin to peripheral blood mononuclear cells (PBMCs) from 64 RR-MS patients and 64 sex- and age-matched healthy subjects on Th1, Th9, Th17, Th22, and Treg responses and to analyze the expression of the melatonin effector/receptor system in these cells. Melatonin decreased Th1 and Th22 responses in patients, whereas it did not affect the Th17 and Treg subsets. Melatonin also promoted skewing toward a more protective cytokine microenvironment, as shown by an increased anti-inflammatory/Th1 ratio. Furthermore, for the first time, we describe the overexpression of the melatonin effector/receptor system in PBMCs from patients with MS; this alteration might be relevant to the disease because acetylserotonin O-methyltransferase expression significantly correlates with disease progression and T effector/regulatory responses in patients. Therefore, our data suggest that melatonin may be an effective treatment for MS.

Adenosine A2A receptor signaling affects IL-21/IL-22 cytokines and GATA3/T-bet transcription factor expression in CD4+ T cells from a BTBR T+ Itpr3tf/J mouse model of autism

Autism is a complex heterogeneous neurodevelopmental disorder; previous studies have identified altered immune responses among individuals diagnosed with autism. An imbalance in the production of pro- and anti-inflammatory cytokines and transcription factors plays a role in neurodevelopmental behavioral and autism disorders. BTBR T⁺ Itpr3tf/J (BTBR) mice are used as a model for autism, as they exhibit social deficits, communication deficits, and repetitive behaviors compared with C57BL/6J (B6) mice. The adenosine A2A receptor (A2AR) appears to be a potential target for the improvement of behavioral, inflammatory, immune, and neurological disorders. We investigated the effects of the A2AR antagonist SCH 5826 (SCH) and agonist CGS 21680 (CGS) on IL-21, IL-22, T-bet, T-box transcription factor (T-bet), GATA3 (GATA Binding Protein 3), and CD152 (CTLA-4) expression in BTBR mice. Our results showed that BTBR mice treated with SCH had increased CD4⁺IL-21⁺, CD4⁺IL-22⁺, CD4⁺GATA3⁺, and CD4⁺T-bet⁺ and decreased CD4⁺CTLA-4⁺ expression in spleen cells compared with BTBR control mice. Moreover, CGS efficiently decreased CD4⁺IL-21⁺, CD4⁺IL-22⁺, CD4⁺GATA3⁺, and CD4⁺T-bet⁺ and increased CD4⁺CTLA-4 production in spleen cells compared with SCH-treated and BTBR control mice. Additionally, SCH treatment significantly increased the mRNA and protein expression levels of IL-21, IL-22, GATA3, and T-bet in brain tissue compared with CGS-treated and BTBR control mice. The augmented levels of IL-21/IL-22 and GATA3/T-bet could be due to altered A2AR signaling. Our results indicate that A2AR agonists may represent a new class of compounds that can be developed for use in the treatment of autistic and neuroimmune dysfunctions.

IL-22 promotes Fas expression in oligodendrocytes and inhibits FOXP3 expression in T cells by activating the NF-κB pathway in multiple sclerosis

Multiple sclerosis (MS) is characterized by an increase in interleukin-22 and Fas, and a decrease in FOXP3, among other factors. In this study, we examined patients with MS and healthy control subjects and used the experimental autoimmune encephalomyelitis (EAE) animal model to identify the effects of IL-22 on oligodendrocytes and T cells in MS development. In MS, the expression of Fas in oligodendrocytes and IL-22 in CD4+CCR4+CCR6+CCR10+ T cells was enhanced. Ikaros and FOXP3 were both decreased in T cells. Depending on exogenous IL-22, Fas increased the phosphorylation of mitogen- and stress-activated protein kinase 1 and activated the nuclear factor-κB pathway in oligodendrocytes, leading to an increase in Fas and oligodendrocyte apoptosis. IL-22 decreased FOXP3 expression by activating NF-κB, and it further inhibited PTEN and Ikaros expression. Tregs reversed the functions of IL-22. Taken together, these findings help to elucidate the mechanisms of IL-22 in MS development.

Serum concentration of CD40L is elevated in inflammatory demyelinating diseases

It is believed that auto-inflammatory activity, including cellular and humoral immunity responses, especially T cell-B cell collaboration, is one of the most important components of the pathogenesis of inflammatory demyelinating disease. CD40L is critical for T cell-B cell collaboration. Actually, serum CD40L levels have been shown to increase in MS. In the present study, serum CD40L levels were measured by an enzyme-linked immunosorbent assay (ELISA) in NMO (n=27) and MS (n=19) patients and controls (n=14). We revealed elevation of CD40L in NMO patients, and discovered a correlation between CD40L and humoral immunity in inflammatory demyelinating disease.

Th9 and Th22 immune response in young patients with type 1 diabetes

Th17, Th22 and Th9 are recently discovered effector populations that may contribute to the pathogenesis of autoimmune and inflammatory diseases. The presented study aimed to investigate the link between Th22 and Th9 subsets in type 1 diabetes, as this disease involves different subsets of CD4+ T lymphocytes. The study groups consisted of 23 patients with type 1 diabetes and 11 healthy individuals. All subjects had CD4+IL-22 Th22 and CD4+IL-9 Th9 lymphocytes investigated by flow cytometry. In addition, the plasma concentrations of IL-22 as well as IL-9 were analyzed. Our study demonstrated that Th9 and Th22 cell counts as well as their plasma cytokines were upregulated in patients with type 1 and correlated with HbA1c and CRP values. Taking these all into account, one can conclude that Th22 and Th9 lymphocyte activities may contribute to chronic, low-level inflammation that is considered an integral part of type 1 diabetes.

Interleukin-17- and interleukin-22-secreting myelin-specific CD4(+) T cells resistant to corticoids are related with active brain lesions in multiple sclerosis patients

Multiple sclerosis (MS) is thought to be an autoimmune disorder. It is believed that immunological events in the early stages have great impact on the disease course. Therefore, we aimed to evaluate the cytokine profile of myelin basic protein (MBP)-specific T cells from MS patients in the early phase of the disease and correlate it to clinical parameters, as well as to the effect of in vitro corticoid treatment. Peripheral T cells from MS patients were stimulated with MBP with our without hydrocortisone for 5 days. The cytokines level were determined by ELISA. The number of active brain lesions was determined by MRI scans, and the neurological disabilities were assessed by Expanded Disability Status Scale scores. Our results demonstrated that MS-derived T cells responded to MBP by producing high levels of T helper type 1 (Th1) and Th17 cytokines. Although the production of interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor, IL-17 and IL-22 was less sensitive to hydrocortisone inhibition, only IL-17 and IL-22 levels correlated with active brain lesions. The ability of hydrocortisone to inhibit IL-17 and IL-22 production by MBP-specific CD4(+) T cells was inversely related to the number of active brain lesions. Finally, the production of both cytokines was significantly higher in cell cultures from Afrodescendant patients and it was less sensitive to hydrocortisone inhibition. In summary, our data suggest that IL-17- and IL-22-secreting CD4(+) T cells resistant to corticoids are associated with radiological activity of the MS in early stages of the disease, mainly among Afrodescendant patients who, normally, have worse prognosis.

Advances in T Helper 17 Cell Biology: Pathogenic Role and Potential Therapy in Multiple Sclerosis

The discovery of the T helper (Th) 17 lineage, involved in the protection against fungal and extracellular bacterial infections, has profoundly revolutionized our current understanding of T cell-mediated responses in autoimmune diseases, including multiple sclerosis (MS). Indeed, recent data demonstrate the pathogenic role of Th17 cells in autoimmune disorders. In particular, studies in MS and in its animal model (EAE, experimental autoimmune encephalomyelitis) have revealed a crucial role of Th17 cells in the pathogenesis of autoimmune demyelinating diseases in both mice and humans. Over the past years, several important aspects concerning Th17 cells have been elucidated, such as the factors which promote or inhibit their differentiation and the effector cytokines which mediate their responses. The identification of the features endowing Th17 cells with high pathogenicity in MS is of particular interest, and discoveries in Th17 cell biology and function could lead to the design of new strategies aimed at modulating the immune response in MS. Here, we will discuss recent advances in this field, with particular focus on the mechanisms conferring pathogenicity in MS and their potential modulation.

Prediction of disease severity in neuromyelitis optica by the levels of interleukin (IL)-6 produced during remission phase

T helper type 17 (Th17) cytokines have been implicated in the pathogenesis of neuromyelitis optica (NMO). As humanized anti-interleukin (IL)-6R (tocilizumab) immunoglobulin (Ig)G has been used as disease-modifying therapy for NMO, the objective of our study was to investigate the role of endogenous IL-6 on NMO-derived CD4(+) T cell behaviour. High production of IL-6, IL-17 and IL-21 by CD4(+) T-cells was detected in NMO patients. Further, IL-21 and IL-6 levels were related directly to the level of neurological disabilities. The addition of anti-IL-6R IgG not only reduced directly the production of these cytokines, but also almost abolished the ability of activated autologous monocytes in enhancing IL-6, IL-17 and IL-21 release by CD4(+) T cells. In contrast, the production of IL-10 was amplified in those cell cultures. Further, anti-IL-6R monoclonal antibodies (mAb) also potentiated the ability of glucocorticoid in reducing Th17 cytokines. Finally, the in-vivo and in-vitro IL-6 levels were significantly higher among those patients who experienced clinical relapse during 2-year follow-up. In summary, our results suggest a deleterious role of IL-6 in NMO by favouring, at least in part, the expansion of corticoid-resistant Th17 cells.

Immunologic and MRI markers of the therapeutic effect of IFN-β-1a in relapsing-remitting MS

OBJECTIVES

To assess potential roles of effector cells and immunologic markers in demyelinating CNS lesion formation, and their modulation by interferon β-1a (IFN-β-1a).

METHODS

Twenty-three patients with relapsing-remitting multiple sclerosis (RRMS) received IFN-β-1a for 6 months. Immunologic marker results were correlated with brain MRI lesion volumes, and volumes of normal-appearing brain tissue (NABT) with decreasing or increasing voxel-wise magnetization transfer ratio (VW-MTR), suggestive of demyelination and remyelination, respectively.

RESULTS

Baseline expression of Th22 cell transcription factor aryl hydrocarbon receptor (AHR) and interleukin (IL)-17F, and percentages of IL-22-expressing CD4(+) and CD8(+) cells, were significantly higher in patients vs 15 healthy controls; IL-4 in CD4(+) cells was lower. Baseline percentage of IL-22-producing CD8(+) cells positively correlated with T2 lesion volumes, while percentage of IL-17A-producing CD8(+) cells positively correlated with T2 and T1 lesion volumes. IFN-β-1a induced reductions in transcription factor AHR, T-bet, and retinoic acid-related orphan nuclear hormone receptor C (RORc) gene expression, while it increased GATA3's expression in CD4(+) cells. Percentages of IL-22-, IL-17A-, and IL-17F-expressing T cells significantly decreased following treatment. Increased percentages of IL-10-expressing CD4(+) and CD8(+) cells correlated with greater NABT volume with increasing VW-MTR, while decreased percentage of IL-17F-expressing CD4(+) cells positively correlated with decreased NABT volume with decreasing VW-MTR.

CONCLUSIONS

Findings indicate that IFN-β-1a suppresses Th22 and Th17 cell responses, which were associated with decreased MRI-detectable demyelination.

CLASSIFICATION OF EVIDENCE

This pilot study provides Class III evidence that reduced Th22 and Th17 responses are associated with decreased demyelination following IFN-β-1a treatment in patients with RRMS.

Increased prevalence of lymphoid tissue inducer cells in the cerebrospinal fluid of patients with early multiple sclerosis

BACKGROUND

Inflammatory cytokines produced by cells of the immune system are believed to play a central role in the pathogenesis of multiple sclerosis (MS). Innate lymphoid cells (ILCs) have been shown to produce and secrete a wide range of the cytokines involved in MS pathogenesis; however, a possible implication of ILCs in MS development and disease progression has not been investigated.

OBJECTIVE

With this study, we aimed to clarify a potential role of ILCs in the early stages of MS.

METHODS AND RESULTS

Using flow cytometry, we analysed the prevalence and phenotype of ILCs in the cerebrospinal fluid (CSF) of patients experiencing their first or second demyelinating event. We found a substantial increase in both frequency and number of ILCs, in particular the LTi subset, as compared to healthy controls. We also found an association between CSF pleocytosis and an increased frequency of LTi cells in the CSF, suggesting a favoured recruitment of blood derived LTi cells.

CONCLUSION

Our data suggests a role for ILCs, and in particular the LTi subset, in the early stages of MS. This finding represents an important contribution to the understanding of early inflammation in MS, and adds new knowledge beneficial for future MS therapies.

T-helper 22 cells as a new player in chronic inflammatory skin disorders

T-helper 22 (Th22) cell is a new subset of CD4+ T cells that secrets interleukin (IL)-22 but not IL-17 or interferon-γ. Th22 is distinct from Th17 and other known CD4+ T-cell subsets with distinguished gene expression and function. Th22 subsets have chemokine receptors CCR6+ CCR4+ CCR10+ phenotype and aryl hydrocarbon receptor as the key transcription factor. This T-helper subset, by producing cytokines such as IL-22, IL-13, and tumor necrosis factor-α, is implicated in the pathogenesis of inflammatory skin disorder. This review discusses the role of Th22 and its cytokine IL-22 in the immunopathogenesis of inflammatory skin disorders such as psoriasis and atopic dermatitis.

Decreased circulating Th22 and Th17 cells in patients with aplastic anemia

BACKGROUND

Aplastic anemia (AA) is an immune-mediated disorder and mainly related to active destruction of hematopoietic cells by effector T lymphocytes. T helper (Th) 22 cells characterized as a novel subset of CD4+ T cells participate in the pathogenesis of autoimmune and hematological diseases. However, the role of Th22 subset in AA remains unknown.

METHODS

31 untreated AA patients and 30 healthy controls were included in this study. The percentages of Th22, Th17 and pure Th17 cells in peripheral blood were detected by flow cytometry. ELISA to measure interleukin (IL)-22 and IL-17A plasma levels and qRT-PCR for the mRNA levels of Th22 and Th17 related molecules were performed.

RESULTS

The proportions of Th22, pure Th17, Th17 cells and plasma levels of IL-22 were significantly lower in untreated AA patients than those in normal controls. A positive correlation was found between Th22 and pure Th17 cells in AA. Moreover, percentages of Th22 cells correlated positively with reticulocyte counts and percentages. In addition, STAT3/STAT5 mRNA expression ratio was elevated in AA patients.

CONCLUSION

Together, our results showed Th22 cells correlating with clinical characteristics of AA patients, indicating a possible role of Th22 immune response in the pathogenesis and therapeutic intervention of AA.

First Demonstration of Antigen Induced Cytokine Expression by CD4-1+ Lymphocytes in a Poikilotherm: Studies in Zebrafish (Danio rerio)

Adaptive immunity in homeotherms depends greatly on CD4+ Th cells which release cytokines in response to specific antigen stimulation. Whilst bony fish and poikilothermic tetrapods possess cells that express TcR and CD4-related genes (that exist in two forms in teleost fish; termed CD4-1 and CD4-2), to date there is no unequivocal demonstration that cells equivalent to Th exist. Thus, in this study we determined whether CD4-1⁺ lymphocytes can express cytokines typical of Th cells following antigen specific stimulation, using the zebrafish (Danio rerio). Initially, we analyzed the CD4 locus in zebrafish and found three CD4 homologues, a CD4-1 molecule and two CD4-2 molecules. The zfCD4-1 and zfCD4-2 transcripts were detected in immune organs and were most highly expressed in lymphocytes. A polyclonal antibody to zfCD4-1 was developed and used with an antibody to ZAP70 and revealed double positive cells by immunohistochemistry, and in the Mycobacterium marinum disease model CD4-1⁺ cells were apparent surrounding the granulomas typical of the infection. Next a prime-boost experiment, using human gamma globulin as antigen, was performed and revealed for the first time in fish that zfCD4-1⁺ lymphocytes increase the expression of cytokines and master transcription factors relevant to Th1/Th2-type responses as a consequence of boosting with specific antigen.

Interleukin-22 is increased in multiple sclerosis patients and targets astrocytes

BACKGROUND

Increasing evidences link T helper 17 (Th17) cells with multiple sclerosis (MS). In this context, interleukin-22 (IL-22), a Th17-linked cytokine, has been implicated in blood brain barrier breakdown and lymphocyte infiltration. Furthermore, polymorphism between MS patients and controls has been recently described in the gene coding for IL-22 binding protein (IL-22BP). Here, we aimed to better characterize IL-22 in the context of MS.

METHODS

IL-22 and IL-22BP expressions were assessed by ELISA and qPCR in the following compartments of MS patients and control subjects: (1) the serum, (2) the cerebrospinal fluid, and (3) immune cells of peripheral blood. Identification of the IL-22 receptor subunit, IL-22R1, was performed by immunohistochemistry and immunofluorescence in human brain tissues and human primary astrocytes. The role of IL-22 on human primary astrocytes was evaluated using 7-AAD and annexin V, markers of cell viability and apoptosis, respectively.

RESULTS

In a cohort of 141 MS patients and healthy control (HC) subjects, we found that serum levels of IL-22 were significantly higher in relapsing MS patients than in HC but also remitting and progressive MS patients. Monocytes and monocyte-derived dendritic cells contained an enhanced expression of mRNA coding for IL-22BP as compared to HC. Using immunohistochemistry and confocal microscopy, we found that IL-22 and its receptor were detected on astrocytes of brain tissues from both control subjects and MS patients, although in the latter, the expression was higher around blood vessels and in MS plaques. Cytometry-based functional assays revealed that addition of IL-22 improved the survival of human primary astrocytes. Furthermore, tumor necrosis factor α-treated astrocytes had a better long-term survival capacity upon IL-22 co-treatment. This protective effect of IL-22 seemed to be conferred, at least partially, by a decreased apoptosis.

CONCLUSIONS

We show that (1) there is a dysregulation in the expression of IL-22 and its antagonist, IL-22BP, in MS patients, (2) IL-22 targets specifically astrocytes in the human brain, and (3) this cytokine confers an increased survival of the latter cells.

T helper 9 cells induced by plasmacytoid dendritic cells regulate interleukin-17 in multiple sclerosis

We have established a novel role in multiple sclerosis for a molecule, called IL-9, produced by immune cells. IL-9 reduces inflammation, and its expression in the cerebrospinal fluid of patients inversely correlates with the severity of multiple sclerosis.