Defective regulation of IFNgamma and IL-12 by endogenous IL-10 in progressive MS

The Role of Gut-derived Short-Chain Fatty Acids in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic condition affecting the central nervous system (CNS), where the interplay of genetic and environmental factors influences its pathophysiology, triggering immune responses and instigating inflammation. Contemporary research has been notably dedicated to investigating the contributions of gut microbiota and their metabolites in modulating inflammatory reactions within the CNS. Recent recognition of the gut microbiome and dietary patterns as environmental elements impacting MS development emphasizes the potential influence of small, ubiquitous molecules from microbiota, such as short-chain fatty acids (SCFAs). These molecules may serve as vital molecular signals or metabolic substances regulating host cellular metabolism in the intricate interplay between microbiota and the host. A current emphasis lies on optimizing the health-promoting attributes of colonic bacteria to mitigate urinary tract issues through dietary management. This review aims to spotlight recent investigations on the impact of SCFAs on immune cells pivotal in MS, the involvement of gut microbiota and SCFAs in MS development, and the considerable influence of probiotics on gastrointestinal disruptions in MS. Comprehending the gut-CNS connection holds promise for the development of innovative therapeutic approaches, particularly probiotic-based supplements, for managing MS.

Altered distributions in circulating follicular helper and follicular regulatory T cells accountable for imbalanced cytokine production in multiple sclerosis

Follicular T helper (Tfh) and regulatory (Tfr) cells are distinct subsets of CD4+ T lymphocytes, regulating humoral immune responses in the germinal center. It is widely accepted that dysregulated Tfh and Tfr cells are associated with autoimmunity. In this study, we evaluated the frequencies of circulating chemokine receptor (CXCR)5+ programmed cell death 1 (PD-1+ ) Tfh (cTfh) and CXCR5+ PD-1+ forkhead box protein 3 (FoxP3+ ) CD25+ Tfr (cTfr) cells, and their corresponding cytokines from the peripheral blood mononuclear cells of 28 patients with relapsing-remitting multiple sclerosis (MS) and 16 age- and sex-matched healthy controls (HC). Subsets of cTfh cells by Th1- and Th17-related surface markers (CXCR3 and CCR6) were also evaluated. We found that the frequency of cTfh cells was significantly higher in MS patients compared to that of HC. Conversely, the frequency of cTfr cells was lower in MS patients than that of HC. Interleukin (IL)-21-producing cTfh cells were significantly increased in MS patients, while IL-10-secreting cTfr cells were lower in MS patients compared to levels in HC. Among cTfh cells, cTfh17.1 cells were the major subtypes that were significantly increased in MS patients compared to HC, with the frequency of IL-21-secreting cells being the highest. These results suggest that an imbalanced distribution of cTfh and cTfr exist in MS patients, which contributes to the reciprocally altered IL-21 and IL-10 production.

Association of Delta-6-Desaturase Expression with Aggressiveness of Cancer, Diabetes Mellitus, and Multiple Sclerosis: A Narrative Review

Background: The phosphatidylinositol 3-kinase/ protein kinase B /mammalian target of rapamycin (PI3K/Akt/ mTOR) signaling regulates multiple cellular processes and organizes cell proliferation, survival, and differentiation with the available nutrients, in particular, fatty acids. Polyunsaturated fatty acids (PUFAs) are cytotoxic to cancer cells and play a critical role in the treatment of multiple sclerosis (MS) and diabetes mellitus (DM). PUFAs are produced in the body by desaturases and elongases from dietary essential fatty acids (EFAs), primarily involving delta-6-desaturase (D6D). D6D is a rate-limiting enzyme for maintaining many aspects of lipid homeostasis and normal health. D6D is important to recognize the mechanisms that regulate the expression of this enzyme in humans. A lower level of D6D was seen in breast tumors compared to normal tissues. Interestingly, the elevated serum level of D6D was seen in MS and DM, which explains the critical role of D6D in inflammatory diseases. Methods: We searched databases of PubMed, Web of Science (WOS), Google Scholar, Scopus and related studies by predefined eligibility criteria. We assessed their quality and extracted data. Results: Regarding the mTOR signaling pathway, there is remarkable contributions of many inflammatory diseases to attention to common metabolic pathways are depicted. Of course, we need to have the insights into each disorder and their pathological process. The first step in balancing the intake of EFAs is to prevent the disruption of metabolism and expression of the D6D enzyme. Conclusions: The ω6 and ω3 pathways are two major pathways in the biosynthesis of PUFAs. In both of these, D6D is a vital bifunctional enzyme desaturating linoleic acid or alpha-linolenic acid. Therefore, if ω6 and ω3 EFAs are given together in a ratio of 2: 1, the D6D expression will be down-regulated and normalized.

Nox2-dependent Neuroinflammation in An EAE Model of Multiple Sclerosis

Background

Multiple sclerosis (MS) is an inflammatory disease of the CNS, characterized by demyelination, focal inflammatory infiltrates and axonal damage. Oxidative stress has been linked to MS pathology. Previous studies have suggested the involvement of NADPH oxidase 2 (Nox2), an enzyme that catalyzes the reduction of oxygen to produce reactive oxygen species, in the MS pathogenesis. The mechanisms of Nox2 activation on MS are unknown. The purpose of this study was to investigate the effect of Nox2 deletion on experimental autoimmune encephalomyelitis (EAE) onset and severity, on astrocyte activation as well as on pro-inflammatory and anti-inflammatory cytokine induction in striatum and motor cortex.

Methodology

Subcutaneous injection of MOG35-55 emulsified with complete Freund’s adjuvant was used to evaluate the effect of Nox2 depletion on EAE-induced encephalopathy. Striatum and motor cortices were isolated and evaluated by immunoblotting and RT-PCR.

Results

Nox2 deletion resulted in clinical improvement of the disease and prevented astrocyte activation following EAE induction. Nox2 deletion prevented EAE-induced induction of pro-inflammatory cytokines and stimulated the expression of the anti-inflammatory cytokines IL-4 and IL-10.

Conclusions

Our data suggest that Nox2 is involved on the EAE pathogenesis. IL-4 and IL-10 are likely to be involved on the protective mechanism observed following Nox2 deletion.

Association of the IL-10 receptor A536G (S138G) loss-of-function variant with multiple sclerosis in Tunisian patients

Interleukin-10 (IL-10), a potent anti-inflammatory T-cell cytokine, has been shown to be a regulatory cytokine that is associated with disease remission in multiple sclerosis (MS) and exerts its activity through its cognate cell surface receptor complex, IL-10 receptor 1 (IL-10R1) and IL-10R2. The purpose of this study was to investigate the IL-10R1 S138G loss-of-function polymorphism (A536G: rs3135932) for possible influence on susceptibility and outcome of MS in Tunisian patients. A total of 103 Tunisian MS patients and 160 control subjects were studied. Genomic DNA samples were extracted from leukocytes and used to investigate S138G polymorphism in IL-10R1 gene by multiplex allele-specific polymerase chain reaction. Associations between G allele [odds ratio (OR) = 5.57; 95% confidence intervals (CI) = 3.26-9.54; p = 10^-7 ], GG genotypes [OR = 10.41; 95% CI = 2.28-47.58; p = 0.0007] and AG genotype [OR = 4.14; 95% CI = 2.16-7.93; p = 0.000016] with the risk development of MS were found. In contrast, the AA genotype seemed to be associated with protection against MS [OR = 0.17; 95% CI = 0.09-0.30; p = 10^-7 ]. No association was found between S138G SNP and clinical features or disease activity of MS patients. In conclusion, our results suggest that S138G loss-of-function polymorphism of the IL-10R1 may be important risk factor in increasing susceptibility to MS.

Do the Physical and Histologic Features and Time Course in Acute Generalized Exanthematous Pustulosis Reflect a Pattern of Cytokine Dysregulation?

Background:

Acute generalized exanthematous pustulosis (AGEP) is characterized by fever and an indurated erythematous eruption early, with the development of nonfollicular pinhead sterile pustules on an erythematous background. The eruption progresses and resolves relatively rapidly. Although drugs are believed to be the major etiologic agents, other immune modulators, including infections, heavy metals, and radiation, have been implicated.

Objective:

The purpose of this study was to document underlying diseases in patients with AGEP and to determine if this data and the histologic features suggested an underlying pattern of immune dysregulation.

Methods:

Twenty-one patients with new or recurrent episodes of AGEP were questioned concerning underlying diseases. The histopathologic features seen in the biopsy sections and the approximate time of biopsy during the course of their eruptions were recorded.

Results:

Two patients had a history of psoriasis and one patient had a family history of psoriasis, two patients had diagnoses of sarcoid, two patients had inflammatory bowel disease, one had autoimmune thyroiditis, and one patient had multiple sclerosis. Biopsies done at the onset of the eruption showed marked to moderate papillary dermal edema and a mixed dermal inflammatory infiltrate. Shortly thereafter, biopsies showed spongiform pustules within the epidermis and occasional dyskeratotic cells with residual perivascular dermal edema. Although no definitive vasculitis was seen, there was leukocytoclasis within the dermal infiltrate in the majority of biopsy specimens performed more than 48 hours after the onset of the eruption.

Conclusion:

The histologic features seen in AGEP and the disease associations suggest that patients who develop this eruption may have an underlying tendency for development of a pattern of immune dysregulation characterized by a T helper-1 cytokine pattern.

Serum immunologic markers in multiple sclerosis patients on continuous combined therapy with beta-interferon 1a, prednisone and azathioprine

Break-through symptoms (BTS) in multiple sclerosis (MS) patients on beta-interferon (beta-IFN) monotherapy are most frequently treated with a brief administration of steroids. Here, we report the results of monitoring serum immunologic markers recorded at three-month intervals for 1.5 years in responders to beta-INF 1a (Avonex) monotherapy ( n = 21) and MS patients placed on Avonex with prednisone ( n = 83) and Avonex, prednisone and azathioprine (AZA) ( n = 21) because of BTS. Compared to 23 healthy controls, patients on Avonex monotherapy and Avonex with prednisone, in individuals on Avonex, prednisone and AZA, a significant decrease in serum concentration of soluble intercellular adhesion molecule-1 (sICAM-1) ( P = 0.001) was established. Combined therapy with Avonex, prednisone and AZA was associated with a significant increase in the serum level of interleukin (IL)10 ( P < 0.001). Compared to Avonex monotherapy, combined therapy suppressed the serum level of IL12p40, antagonized elevation in the serum concentration of soluble IL2 receptor (sIL2R) and inhibited an increase in the serum soluble CD95 (sCD95) molecule. In patients studied, no significant differences in the serum level of IL18 and tumor necrosis factor-α (TNF-α) were established. These findings are important in understanding some of the immunoregulatory mechanisms induced by combined therapy in MS.

Immunological heterogeneity of multiple sclerosis in Sardinia and Sweden

Subjects from Sardinia, Italy, are relatively homogeneous compared to Swedes. Although ethnically distant, both populations have similarly high multiple sclerosis (MS) incidence rates. Pro- and anti-inflammatory cytokines and their receptors, signalling molecules and other immune response-associated factors might influence MS pathogenesis, though definite proof is missing. The study of populations with similar MS incidence but different genetic and environmental background could make possible the definition of factors that relate to such background differences. We selected untreated female MS patients from Sassari, Sardinia, and Stockholm, Sweden, and corresponding sexand age-matched healthy controls (HC), to study blood mononuclear cells (MNC) for mRNA expression of 20 immune response-related genes considered relevant in MS, employing real-time PCR. Higher expression of IL-12p40 mRNA was confined to MS from both Sassari and Stockholm, compared to corresponding HC. MS patients from Sassari, but not Stockholm, expressed higher TNF-a compared to corresponding HC. MS patients from Stockholm, but not Sassari, expressed higher IL-6. Indoleamine 2,3 dioxygenase (IDO), a molecule necessary in tolerance induction, was lower in MS from Stockholm compared to corresponding HC. This was not observed in Sassari. No differences were detected for other members of the IL-12 family, other Th1 and Th2 cytokines, and the signalling molecules Stat 4 and 6. The results corroborate a pro-inflammatory state in MS as reflected by high expression of IL-12, TNF-a and IL-6, although the extent of expression of TNF-a, IL-6 and IDO differs between strictly matched MS patients from different high-incidence areas. This might result from genetic and/or environmental differences. They may account for some of the discrepancies regarding immune response-related molecules previously reported in MS. In conclusion, a pro-inflammatory state exists in MS patients from Sassari as well as Stockholm. The changes of pro-inflammatory and other immune response-related variables differ however between the two MS populations. This may be attributed to the genetic and/or environmental background.

EBV and vitamin D status in relapsing-remitting multiple sclerosis patients with a unique cytokine signature

Multiple sclerosis, a debilitating autoimmune and inflammatory disease of the central nervous system, is associated with both infectious and non-infectious factors. We investigated the role of EBV infection, vitamin D level, and cytokine signature in MS patients. Molecular and serological assays were used to investigate immune biomarkers, vitamin D level, and EBV status in 83 patients with relapsing-remitting multiple sclerosis and 62 healthy controls. In total, 98.8 % of MS patients showed a history of EBV exposure compared to 88.6 % in the healthy group (p = 0.005). EBV DNA load was significantly higher in MS patients than healthy subjects (p < 0.0001). Using a panel of biomarkers, we found a distinct transcriptional signature in MS patients compared to the healthy group with mRNA levels of CD73, IL-6, IL-23, IFN-γ, TNF-α, IL-15, IL-28, and IL-17 significantly elevated in MS patients (p < 0.0001). In contrast, the mRNA levels for TGF-β, IDO, S1PR1, IL-10, and CCL-3 were significantly lower in MS patients compared to healthy controls (p < 0.0001). No significant differences were found with the mRNA levels of IL-13, CCL-5, and FOXP3. Interestingly, in MS patients we found an inverse correlation between vitamin D concentration and EBV load, but not EBNA-1 IgG antibody levels. Our data highlight biomarker correlates in MS patients together with a complex interplay between EBV replication and vitamin D levels.

Dysregulation of the IL-23/IL-17 axis and myeloid factors in secondary progressive MS

OBJECTIVE

In the current exploratory study, we longitudinally measured immune parameters in the blood of individuals with relapsing-remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), and investigated their relationship to disease duration and clinical and radiologic measures of CNS injury.

METHODS

Peripheral blood mononuclear cells (PBMCs) and plasma were obtained from subjects with RRMS, SPMS, and from healthy controls on a monthly basis over the course of 1 year. MRI and Expanded Disability Status Scale evaluations were performed serially. PBMCs were analyzed by enzyme-linked immunosorbent spot assay to enumerate myelin basic protein-specific interleukin (IL)-17- and interferon (IFN)-γ-producing cells. Plasma concentrations of proinflammatory factors were measured using customized Luminex panels.

RESULTS

Frequencies of myelin basic protein-specific IL-17- and IFN-γ-producing PBMCs were higher in individuals with RRMS and SPMS compared to healthy controls. Patients with SPMS expressed elevated levels of IL-17-inducible chemokines that activate and recruit myeloid cells. In the cohort of patients with SPMS without inflammatory activity, upregulation of myeloid-related factors correlated directly with MRI T2 lesion burden and inversely with brain parenchymal tissue volume.

CONCLUSIONS

The results of this exploratory study raise the possibility that Th17 responses and IL-17-inducible myeloid factors are elevated during SPMS compared with RRMS, and correlate with lesion burden. Our data endorse further investigation of Th17- and myeloid-related factors as candidate therapeutic targets in SPMS.

Human adipose-derived mesenchymal stem cells engineered to secrete IL-10 inhibit APC function and limit CNS autoimmunity

Interleukin (IL)-10 is an important immunoregulatory cytokine shown to impact inflammatory processes as manifested in patients with multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). Several lines of evidence indicate that the effectiveness of IL-10-based therapies may be dependent on the timing and mode of delivery. In the present study we engineered the expression of IL-10 in human adipose-derived mesenchymal stem cells (Adi-IL-10-MSCs) and transplanted these cells early in the disease course to mice with EAE. Adi-IL-10-MSCs transplanted via the intraperitoneal route prevented or delayed the development of EAE. This protective effect was associated with several anti-inflammatory response mechanisms, including a reduction in peripheral T-cell proliferative responses, a decrease in pro-inflammatory cytokine secretion as well as a preferential inhibition of Th17-mediated neuroinflammation. In vitro analyses revealed that Adi-IL-10-MSCs inhibited the phenotypic maturation, cytokine production and antigen presenting capacity of bone marrow-derived myeloid dendritic cells, suggesting that the mechanism of action may involve an indirect effect on pathogenic T-cells via the modulation of antigen presenting cell function. Collectively, these results suggest that early intervention with gene modified Adi-MSCs may be beneficial for the treatment of autoimmune diseases such as MS.

Systemic inflammation in progressive multiple sclerosis involves follicular T-helper, Th17- and activated B-cells and correlates with progression

Pathology studies of progressive multiple sclerosis (MS) indicate a major role of inflammation including Th17-cells and meningeal inflammation with ectopic lymphoid follicles, B-cells and plasma cells, the latter indicating a possible role of the newly identified subset of follicular T-helper (T_FH) cells. Although previous studies reported increased systemic inflammation in progressive MS it remains unclear whether systemic inflammation contributes to disease progression and intrathecal inflammation. This study aimed to investigate systemic inflammation in progressive MS and its relationship with disease progression, using flow cytometry and gene expression analysis of CD4⁺ and CD8⁺T-cells, B-cells, monocytes and dendritic cells. Furthermore, gene expression of cerebrospinal fluid cells was studied. Flow cytometry studies revealed increased frequencies of ICOS⁺T_FH-cells in peripheral blood from relapsing-remitting (RRMS) and secondary progressive (SPMS) MS patients. All MS subtypes had decreased frequencies of Th1 T_FH-cells, while primary progressive (PPMS) MS patients had increased frequency of Th17 T_FH-cells. The Th17-subset, interleukin-23-receptor⁺CD4⁺T-cells, was significantly increased in PPMS and SPMS. In the analysis of B-cells, we found a significant increase of plasmablasts and DC-SIGN⁺ and CD83⁺B-cells in SPMS. ICOS⁺T_FH-cells and DC-SIGN⁺B-cells correlated with disease progression in SPMS patients. Gene expression analysis of peripheral blood cell subsets substantiated the flow cytometry findings by demonstrating increased expression of IL21, IL21R and ICOS in CD4⁺T-cells in progressive MS. Cerebrospinal fluid cells from RRMS and progressive MS (pooled SPMS and PPMS patients) had increased expression of T_FH-cell and plasmablast markers. In conclusion, this study is the first to demonstrate the potential involvement of activated T_FH-cells in MS. The increased frequencies of Th17-cells, activated T_FH- and B-cells parallel findings from pathology studies which, along with the correlation between activated T_FH- and B-cells and disease progression, suggest a pathogenic role of systemic inflammation in progressive MS. These observations may have implications for the treatment of progressive MS.

Type 1 immune response in progressive multiple sclerosis

The aim of the study was to evaluate the type-1 immune response by analyzing T-bet expression in circulating T and B cells in Primary Progressive (PP) and Secondary Progressive (SP) Multiple Sclerosis (MS) patients. We found higher percentages of circulating CD4+T-bet+ and CD8+T-bet+ T cells in SPMS and PPMS than in remitting-relapsing MS patients and controls. Moreover, in SPMS, we observed a positive correlation between the percentages of circulating CD4+T-bet+ or CD8+T-bet+ T cells and disease severity. The increased percentages of Th1 and Tc1 cells suggest that MS progressive forms, unlike RRMS, are characterized by a permanent peripheral type-1 immune activation.

The modulation of adaptive immune responses by bacterial zwitterionic polysaccharides

The detection of pathogen-derived molecules as foreign particles by adaptive immune cells triggers T and B lymphocytes to mount protective cellular and humoral responses, respectively. Recent immunological advances elucidated that proteins and some lipids are the principle biological molecules that induce protective T cell responses during microbial infections. Polysaccharides are important components of microbial pathogens and many vaccines. However, research concerning the activation of the adaptive immune system by polysaccharides gained interest only recently. Traditionally, polysaccharides were considered to be T cell-independent antigens that did not directly activate T cells or induce protective immune responses. Here, we review several recent advances in “carbohydrate immunobiology”. A group of bacterial polysaccharides that are known as “zwitterionic polysaccharides (ZPSs)” were recently identified as potent immune modulators. The immunomodulatory effect of ZPSs required antigen processing and presentation by antigen presenting cells, the activation of CD4 T cells and subpopulations of CD8 T cells and the modulation of host cytokine responses. In this review, we also discuss the potential use of these unique immunomodulatory ZPSs in new vaccination strategies against chronic inflammatory conditions, autoimmunity, infectious diseases, allergies and asthmatic conditions.

Toll-like receptor 2 and poly(ADP-ribose) polymerase 1 promote central nervous system neuroinflammation in progressive EAE

Multiple sclerosis is an inflammatory disease of the central nervous system that begins as a relapsing-remitting disease (RRMS) and is followed by a progressive phase (SPMS). The progressive phase causes the greatest disability and has no effective therapy, but the processes that drive SPMS are mostly unknown. Here we found higher serum concentrations of 15alpha-hydroxicholestene (15-HC) in patients with SPMS and in mice with secondary progressive experimental autoimmune encephalomyelitis (EAE) but not in patients with RRMS. In mice, 15-HC activated microglia, macrophages and astrocytes through a pathway involving Toll-like receptor 2 (TLR2) and poly(ADP-ribose) polymerase 1 (PARP-1). PARP-1 activity was higher in monocytes of patients with SPMS, and PARP-1 inhibition suppressed the progression of EAE. Thus, the TLR2-PARP-1 pathway is a potential new therapeutic target in SPMS.

Exercise and brain health--implications for multiple sclerosis: Part II--immune factors and stress hormones

Part I of this review addressed the possible modulatory role of exercise on neuronal growth factors to promote brain health in neurodegenerative diseases such as multiple sclerosis (MS), which is characterized by varied patterns of inflammation, demyelination and axonal loss. Part II presents evidence that supports the potential neuroprotective effect of exercise on the modulation of immune factors and stress hormones in MS. Many current therapies used to attenuate MS progression are mediated, at least in part, through alterations in the relative concentrations of pro- and anti-inflammatory cytokines. Exercise-induced alterations in local and systemic cytokine production may also benefit immune function in health and disease. Exercise immunomodulation appears to be mediated by a complex interaction of hormones, cytokines and neural factors that may favorably influence immune variables in MS. The promising interplay between exercise and brain health in MS deserves further investigation.

Abnormal Tr1 differentiation in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). In the recent years, accumulating evidence has supported an immunosuppressive role for regulatory T cells (Tregs). Most studies in the context of autoimmunity have focused on the defects of the CD4+CD25 high Tregs. However, we recently demonstrated an altered function of Tr1 Treg cells in MS, characterized by a lack of IL-10 secretion. Therefore, several major regulatory T cell defects are involved in human autoimmune disease. Hence, the induction of Tregs or the stimulation of Treg activity may be beneficial for the treatment of such diseases.

Reciprocal effects of IFN-beta and IL-12 on STAT4 activation and cytokine induction in T cells

IL-12 is an immunoregulatory cytokine, which promotes Th1 cell differentiation and is a major inducer of IFN-gamma. IFN-beta, a Type I IFN used in the treatment of multiple sclerosis, has been shown to significantly increase the expression of the anti-inflammatory cytokine IL-10, a major suppressor of Th1 cytokines. The beneficial immunomodulatory effects of IFN-beta may in part be a result of its ability to suppress IL-12. However, IL-12 and IFN-beta signal via the STAT4 pathway. Our aim was to investigate the relationship between IL-12 and IFN-beta by observing the effect of prior exposure to IL-12 or IFN-beta on the ability of T cells to subsequently respond to the other cytokine. We report that IFN-beta increases IL-12-induced STAT4 phosphorylation and up-regulates IL-12 receptor beta1 and beta2 expression. However, despite this up-regulation, IFN-beta suppressed IL-12-induced IFN-gamma expression. Our results suggest that this may be a result of the parallel induction of IL-10 by IFN-beta.

The role of CD4 T cells in the pathogenesis of multiple sclerosis

T lymphocytes play a central role in the pathogenesis of multiple sclerosis (MS) (Zhang et al., 1992). Both CD4+ and CD8+ T cells have been demonstrated in MS lesions, with CD4+ T cells predominating in acute lesions and CD8+ T cells being observed more frequently in chronic lesions (Raine, 1994). Additionally, T cells are found in all four of the described histopathologic subtypes of MS (Lucchinetti et al., 2000). Activated myelin-reactive CD4+ T cells are present in the blood and cerebrospinal fluid (CSF) of MS patients; in contrast, only nonactivated myelin-reactive T cells are present in the blood of controls (Zhang et al., 1994). The success of several T-cell-targeted therapies in MS reinforces the importance of the role of the T cell in MS pathogenesis. Here, we outline basic concepts in CD4+ T-cell immunology and summarize the current understanding of the role of CD4+ T cells in the pathogenesis of MS.

Interferon-beta1b treatment modulates cytokines in patients with primary progressive multiple sclerosis

OBJECTIVES

It is unknown whether the immunological effects of beta-interferon (IFN-beta) differ in primary progressive multiple sclerosis (PPMS) when compared with relapsing-remitting multiple sclerosis (RRMS). Therefore, we investigated the effects of IFN-beta1b treatment in PPMS on proliferation and cytokine pattern of peripheral blood mononuclear cells (PBMC) and interleukin-10 (IL-10) serum level.

METHODS

Eighteen patients were treated with IFN-beta1b for 12 months in an open-label trial. Serum and PBMC were collected longitudinally.

RESULTS

Interleukin-10 serum levels increased (P = 0.02) during treatment. Tumor necrosis factor-alpha was increased in anti CD3 (OKT3) antibody stimulated PBMC during treatment (P = 0.04), whereas secretion of IL-10 was decreased in OKT3 (P = 0.04), but increased in concavalin A stimulated PBMC (P = 0.02).

CONCLUSIONS

Interleukin-10 serum levels rose in IFN-beta1b-treated patients as has been observed in RRMS. The changes in cytokine patterns secreted by T-lymphocytes of PPMS patients, however, differ from effects observed in RRMS supporting the hypothesis that PPMS differs in some immunological aspects from RRMS.

Glatiramer acetate-specific human CD8(+) T cells: increased IL-4 production in multiple sclerosis is reduced by glatiramer acetate treatment

Glatiramer acetate (GA) is an approved drug for therapy of relapsing remitting MS that acts as a T cell antigen. Here, we report the cloning of HLA restricted, GA-specific human CD8(+) T cells. In addition, we analyzed the cytokine profile of GA-reactive CD8(+) T cell lines. Unexpectedly, IL-4 was increased in untreated MS patients as compared to healthy individuals (p<0.001). In GA-treated patients, however, IL-4 (p<0.001), IL-10 (p<0.001) and TNF-alpha (p<0.001) were decreased. Thus, while GA is known to induce a TH2 bias in CD4(+) T cells, we detected a distinct pattern in GA-reactive CD8(+) T cells.

Differential inflammatory activation of IL-6 (−/−) astrocytes

IL-6 is a major immunomodulatory cytokine with neuroprotective activity. The absence of interleukin-6 (IL-6) results in increased vulnerability of dopaminergic neurons to the neurotoxicant, MPTP, and a compromised reactive microgliosis. To determine how astrogliosis may contribute to nigrostriatal degeneration in IL-6 (-/-) mice, the inflammatory profiles of astrocytes of IL-6 genotype were compared. Fourteen cytokines and four chemokines were simultaneously assayed in the supernatants of LPS-stimulated primary astrocyte cultures. In a time course of 6, 18 and 48 h and LPS stimulations of 0, 0.1, 1, 10 and 100 ng/ml, IL-6 (-/-) astrocytes secreted significantly greater amounts of the pro-inflammatory cytokines IL-1alpha, IL-1beta and TNFalpha than did IL-6 (+/+) cells. Elevated levels of IL-10 and IL-12p40 were only detected at 48 h post-stimulation with greater IL-10 in IL-6 (-/-) supernatants and greater IL-12p40 in IL-6 (+/+) supernatants. IL-6 (+/+) astrocytes produced more G-CSF and GM-CSF when compared with IL-6 (-/-) astrocytes. Chemokine levels were greater in supernatants of IL-6 (+/+) astrocytes than IL-6 (-/-) cells prior to 48 h post-stimulation. At that time, higher levels of MIP-1alpha were maintained in IL-6 (+/+) supernatant, while similar levels of MCP-1 in supernatants of both IL-6 (+/+) and IL-6 (-/-) cells were measured. Additionally, LPS (100 ng/ml) resulted in greater levels of KC and Rantes in IL-6 (-/-) astrocyte supernatants compared with IL-6 (+/+) supernatants at that time. These results suggest that the autocrine modulatory activities of IL-6 affect multiple cytokine secretory pathways, which could participate in neurodegenerative processes.

The Expression of Microfilament-Associated Cell-Cell Contacts in Brain Endothelial Cells Is Modified by IFN-β1a (Rebif®)

In multiple sclerosis (MS), a crucial step in the induction phase of the inflammatory process in the central nervous system (CNS) is the disruption of the endothelial blood-brain barrier (BBB). Its permeability depends on the expression of intercellular adhesion molecules, such as vinculin and N-cadherin in endothelial cells. Interferon-gamma (IFN-gamma), as a proinflammatory cytokine, decreases the expression of both adhesion molecules in epithelial and astrocytic cells, whereas IFN-beta1a, an established treatment for MS, increases the expression of N-cadherin and vinculin in astrocytic cells and is postulated to preserve endothelial cell barrier function and to inhibit transendothelial migration of activated leukocytes. We analyzed the expression of N-cadherin and vinculin in a murine brain endothelial cell line by immunofluorescence staining and Western blot to study the presumed reversal effects of IFN-beta1a (Rebif, Serono Pharma, Unterschleissheim, Germany) and IFN-gamma on the formation of intercellular contacts. Vinculin and N-cadherin expression in brain endothelial cells was decreased after treatment with IFN-gamma, whereas stimulation with IFN-beta1a caused increased expression of both adhesion molecules. Combined treatment with both IFNs did not affect vinculin and N-cadherin expression. These data suggest that IFN-gamma contributes to BBB disruption by decreasing and IFN-beta1a restores the BBB by an upregulation of vinculin and N-cadherin expression in brain endothelial cells. This action of IFN-beta1a may contribute to its beneficial effects in MS therapy.

Early-stage multiple sclerosis : what are the treatment options?

Converging evidence from recent years indicates that the current attitude to the use of immunomodulatory drugs in the treatment of multiple sclerosis (MS) may be too conservative. This evidence originates from studies of the pathophysiology and pathology of MS, magnetic resonance imaging (MRI) studies and clinical trials. Several studies have shown that antigen spreading and propagation of self-recognition seem to occur during the clinical progression of MS. The immunopathology may change during the course of disease. Primary selective demyelination can be followed by a secondary oligodendrocyte loss and remyelination becomes less effective. MRI studies have shown that patients with clinically isolated syndromes, who at presentation have more than a few brain lesions on MRI, have a high risk of disease progression over a period of 5-10 years. The most direct evidence comes from two placebo-controlled trials of interferon-beta in very early MS. A delay in time to conversion to clinically definite MS and a significant decrease in MRI activity support an early stage treatment strategy. Taken together, the evidence indicates that treatment with immunomodulatory therapy should be started at an early stage in patients with a high-risk profile for further disease activity, although this may result in over-treatment of a small number of patients. However, further prolonged studies are needed to investigate the long-term benefit of early-stage treatment in MS.

Cytokine shifts and tolerance in experimental autoimmune encephalomyelitis

Cytokines play an important role in the pathogenesis of both multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Effective treatments for both diseases have been shown to alter cytokines in the central nervous system and in activated mononuclear cells. EAE is an animal model that mimics many aspects of multiple sclerosis, and has been widely used to study the mechanisms of disease and therapeutic approaches to multiple sclerosis. Cytokines play an important role in regulation of disease expression in EAE, and in tolerance to disease induction. In this review, we will summarize the current findings on the role of cytokine shifts in the induction of tolerance in EAE. In addition, we will discuss modulation of EAE by altered expression of members of the cytokineregulated Jak/STAT intracellular signaling pathway.

Dysregulation of IL-10 and IL-12p40 in secondary progressive multiple sclerosis

Multiple sclerosis (MS) is a putative T helper 1 (Th-1) mediated inflammatory disorder of the central nervous system, and levels of pro-inflammatory and anti-inflammatory cytokines have been found to correlate with changes in MS relapses. However, it is unclear if cytokine profiles differ between relapsing-remitting (RRMS) versus secondary progressive (SPMS) disease stages. Cytokine production (IL-2, IL-4, IL-5, IL-10, IL-12p40, TNF-alpha, and IFN-gamma) was assessed by cytometric bead array (CBA) and intracellular cytokine staining from alphaCD3 antibody and mitogen stimulated peripheral blood mononuclear cells (PBMCs) from female RRMS and SPMS patients, and healthy controls. Significantly increased production of IL-12p40 and decreased production of IL-10 were observed in SPMS patients. Differences in immune responsiveness in RRMS and SPMS are important in the understanding of the evolution of the immunopathogenesis of the disease and for the development of disease type specific treatments.

Sex differences in in vitro pro-inflammatory cytokine production from peripheral blood of multiple sclerosis patients

We compared the patterns of the pro-inflammatory cytokines, interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha), and the anti-inflammatory cytokines, interleukin-10 (IL-10) and tumor growth factor-beta (TGF-beta) from peripheral blood of male and female patients with relapsing-remitting (RR) and secondary progressive (SP) forms of multiple sclerosis (MS). The relationships between pro-inflammatory cytokines and disability (expanded disability status scale, EDSS) were also examined. Peripheral blood anti-coagulated with heparin was obtained from 47 MS patients (30 women and 17 men) and activated with phorbol-12-myristate 13 acetate (PMA) and ionomycin in the presence of brefeldin A and stained for flow cytometry with fluorescently labeled antibodies against intracellular IFN-gamma, TNF-alpha, IL-2, IL-4 and IL-10. The T cells were delineated with peridinin chlorophyll protein (Per-CP) labeled anti-CD3 antibody. The stained samples were analyzed on a flow cytometer to assess the intracellular pro-inflammatory cytokine patterns. The levels of interleukin-10 (IL-10) and tumor growth factor-beta (TGF-beta) were measured in plasma using enzyme-linked immunoassay. The percentage of TNF-alpha-producing CD3 positive cells was significantly higher (P=0.045) in men (mean+/-S.D., 39+/-13%) than in women (mean+/-S.D., 29+/-13%) RR-MS patients. The percentage of CD3 positive cells producing IFN-gamma was significantly correlated with EDSS in females but not in males (Spearman rank correlation r(S)=0.49, P=0.018). The secretion of the pro-inflammatory cytokines, IFN-gamma and TNF-alpha, is influenced by gender in MS patients and may contribute to the sexual dimorphism of MS.

Low interleukin-10 production is associated with higher disability and MRI lesion load in secondary progressive multiple sclerosis

Abnormalities in T-cell-derived cytokine production are a well-known phenomenon in multiple sclerosis (MS). An association between disability and the production of interferon gamma has been demonstrated recently. The present study investigated associations between disability, cytokine production in stimulated blood lymphocytes and magnetic resonance imaging data in 37 patients with the secondary progressive course in the stable phase of the disease. Patients with high interleukin-10 (IL-10) production had significantly lower disability scores (p=0.009) and lower T2 lesion load (p=0.03). Interleukin-10 might not only play a role in the pathological process of multiple sclerosis but has an impact on disease outcome as well.

Monocyte-derived cytokines in multiple sclerosis

MS is an inflammatory, presumably autoimmune, disease mediated by the activation of T cells, B cells and monocytes (MO). Inflammation is thought to occur early during the relapsing-remitting phase of MS (RRMS), whereas in the later phases of MS such as secondary progressive MS (SPMS), inflammation tends to diminish. Our objective was to compare the types and amounts of proinflammatory and regulatory cytokines produced by MO from relapsing-remitting patients with or without treatment with IFN-beta (RRMS+ therapy, RRMS- therapy), respectively, from secondary progressive patients (SPMS) and from healthy controls (HC). MO were isolated by a density-gradient technique and three different techniques (RNase protection assay, ELISA and intracellular cytokine staining) were used to assess cytokine levels. An increase in IL6, IL12 and TNF-alpha was observed by all three methods for RRMS- therapy and for SPMS patients compared to HC and RRMS+ therapy patients. We conclude that proinflammatory and regulatory monokines can be derived from MO of MS patients and that these levels are modulated by IFN-beta therapy. Although it is believed that inflammation tends to diminish in SPMS patients, our data show that inflammatory cytokines continue to be released at high levels, suggesting that IFN-beta or IL10 treatment may be beneficial for this group.

IFN-beta1a (Rebif) modifies the expression of microfilament-associated cell-cell contacts in C6 glioma cells

Multiple sclerosis (MS) is a chronic inflammatory disease characterized by multifocal demyelination and axonal damage in the central nervous system (CNS). The disruption of the endothelial blood-brain barrier (BBB) with consecutive transmigration of inflammatory cells into the brain parenchyma is of critical importance in the pathogenesis of MS. The integrity of the BBB and the adjacent network of glial cells partially depends on the assembly of intercellular contacts between astrocytes. We demonstrate that recombinant interferon-gamma (rIFN-gamma), a proinflammatory cytokine critically involved in the disruption of the BBB, downregulates the expression of the cell adhesion molecules N-cadherin and vinculin in astrocytic C6 cells using Western blot and immunofluorescence microscopy. By contrast, IFN-beta1a, an established treatment for relapsing-remitting MS, increases the expression of N-cadherin and vinculin and partly inhibits the downregulation of these adhesion molecules by phytohemagglutinin (PHA)-stimulated IFN-gamma-secreting human T lymphocytes in coculture experiments. In summary, we demonstrate that IFN-beta1a modifies the assembly of N-cadherin- and vinculin-mediated intercellular contacts between astrocytic C6 cells in vitro. This effect may also contribute to the therapeutic action of IFN-beta1a in MS.

A comparison of the mechanisms of action of interferon beta and glatiramer acetate in the treatment of multiple sclerosis

BACKGROUND

The development of immunomodulatory agents has represented a major advance in the treatment of multiple sclerosis (MS). To date, immunomodulatory agents approved for the treatment of relapsing MS in the United States include 3 forms of recombinant interferon (IFN) beta (2 formulations of IFN beta-1a and 1 of IFN beta-1b) and synthetic glatiramer acetate (GA). Recognition of how these agents work to regulate the immune system may lead to a better understanding of disease mechanisms, as well as to development of more effective therapies or combinations of therapy.

OBJECTIVE

This article reviews the potential mechanisms of action of IFN beta products and GA in the context of their regulatory effects on autoimmune components that may be of importance in MS.

METHODS

MEDLINE and Current Contents/Clinical Medicine were searched for articles published in English from 1993 to the present using the search terms interferon beta, glatiramer acetate, and multiple sclerosis.

RESULTS

IFN beta products affect the disease process in MS through multiple potential mechanisms of action, including antiviral, antiproliferative, and anti-inflammatory effects. The mechanisms of action of GA are less clear, but may involve immune regulation induced by a gradual shift of T-cell phenotype from proinflammatory (type 1 T-helper cells) to anti-inflammatory (type 2 T-helper cells) and interference with antigen presentation.

CONCLUSION

Understanding the mechanisms of action of IFN beta products and GA provides important insights into the disease processes involved in MS.

Analysis of immunoregulatory T-helper cell subsets in patients with multiple sclerosis: relapsing-progressive course correlates with enhanced T H1, relapsing-remitting course with enhanced T H0 reactivity

In this study, we analysed the recall antigen-induced cytokine production by peripheral blood mononuclear cells (PBMC) from 31 patients with multiple sclerosis (MS) with a relapsing-remitting (rr) and a relapsing-progressive (rp) course and from 40 healthy controls. Cells were stimulated with purified protein derivative (PPD; type 1 response) and tetanus toxoid (TT; type 2 response). Cytokines were determined in the supernatants by ELISA. One of the interesting findings was that healthy controls showed more frequently an IL-5 production after incubation with TT than MS-patients (68% vs.37%; p<0.01), while the type 1 reactivity was only slightly enhanced in MS patients as compared to the controls. However, within the MS patients, there was a significant difference in the incidence of the type 1 reactivity comparing patients with an rp and an rr course (60% vs. 24%; p<0.05). Furthermore, the frequency of a type 0 profile (simultaneous PPD-induced IFN-gamma and TT-induced IL-5 production) was fourfold higher in rr than in the rp patients (43% vs. 10%, p<0.05). In vitro analysis of cytokine profiles in MS could therefore be an interesting approach to evaluate the prognosis of MS (rr vs. rp) already at the beginning of the disease. Thus, it seems that the presence of a type 0 profile is a valid indicator for a favorable course, while a type 1 profile is rather associated with rp MS.

The relative number of macrophages/microglia expressing macrophage colony-stimulating factor and its receptor decreases in multiple sclerosis lesions

The activation of macrophages/microglia in multiple sclerosis (MS) lesions plays a central role in the effector phase of myelin breakdown. The precise patterns of macrophage/microglia activation during demyelination have not yet been defined. The growth and activating factor macrophage-colony stimulating factor (M-CSF) and its specific receptor (M-CSFR) may be involved in this process. The present study investigated the expression of M-CSF and M-CSFR mRNA by in situ hybridization in 60 lesions from 32 MS patients. In the control and periplaque white matter, microglia was almost completely M-CSFR positive. Irrespective of the demyelinating activity, an increased number of cells expressed M-CSF or M-CSFR mRNA within the lesions. However, despite the tremendous increase in macrophages/microglia within the lesions, the relative number of these cells expressing M-CSF or M-CSFR decreased. There was no correlation of M-CSF or M-CSFR expression with active myelin breakdown. The correlation between the clinical course and the expression of M-CSF or M-CSFR mRNA revealed significant differences with the lowest expression in primary progressive MS. These results suggest a downregulation of M-CSF and M-CSFR inside the MS plaque probably due to the high amount of macrophage-derived cytokines or mediators. Nevertheless, the differences in the relative number of cells expressing the M-CSF/M-CSFR pathway implicate that this pathway may be an important contributory factor in different forms of MS pathology.

The role of interleukin-10 in autoimmune disease: systemic lupus erythematosus (SLE) and multiple sclerosis (MS)

Interleukin-10 (IL-10) is an immunoregulatory cytokine that plays a crucial role in inflammatory and immune reactions. It has potent anti-inflammatory and immunosuppressive activities on myeloid cell functions which forms a solid basis for its use in acute and chronic inflammatory diseases. Here, we discuss the role of IL-10 in autoimmune diseases and examine its beneficial effects in cellular-based autoimmune diseases such as multiple sclerosis (MS) or its involvement in humoral-based autoimmune diseases such as systemic lupus erythematosus (SLE). Inhibition of the immune stimulatory activities of IL-10 may provide novel approaches in the treatment of humoral autoimmune diseases, infectious diseases and cancer.

Monocyte/macrophage initiation of organ-specific autoimmunity: the ultimate 'bystander' hypothesis?

It is postulated that organ-specific autoimmune diseases could be initiated by dysregulated peripherally activated monocytes/macrophages penetrating into target organs nonspecifically. Failure of regulation of pro-inflammatory monocytes/macrophages might then result in autoimmune disease if secondary over-expansion of pre-existing autoantigen-specific T cell populations occurs in genetically predisposed individuals.

Interferon-beta therapy for multiple sclerosis induces reciprocal changes in interleukin-12 and interleukin-10 production

Interleukin-12 is critical to the pathogenesis of experimental autoimmune encephalomyelitis in multiple species. Interleukin-10, a dominant endogenous inhibitor of interleukin-12, is largely protective in these experimental surrogates for multiple sclerosis. Such data have suggested that an interleukin-12/interleukin-10 immunoregulatory circuit is a key determinant of disease expression in experimental autoimmune encephalomyelitis. For multiple sclerosis itself, compatible cytokine data have been reported. The mechanisms underlying the beneficial effects of interferon-beta in multiple sclerosis remain unclear, hampering the search for more effective therapies. Of note, interferon-beta has reciprocal effects on these cytokines in vitro, suppressing interleukin-12 and augmenting interleukin-10 production. To examine the effects of interferon-beta on the interleukin-12/interleukin-10 axis in multiple sclerosis, we characterized the production of these cytokines by peripheral blood mononuclear cells from patients beginning therapy with interferon-beta. Before therapy, multiple sclerosis patients exhibited increased stimulatable interleukin-12 production compared with controls. Interferon-beta therapy leads to inhibition of interleukin-12 and augmentation of interleukin-10 production, significantly elevating the ratio of secreted interleukin-10 to interleukin-12. These effects, observed equally in patients with relapsing-remitting and progressive disease, indicate that interferon-beta affects the interleukin-12/interleukin-10 axis in ways thought to be beneficial to multiple sclerosis patients. More specific therapeutic targeting of these pathways may be warranted.

Interferon-β in multiple sclerosis: altering the balance of interleukin-12 and interleukin-10?

Interferon-beta is a remarkably pleiotropic molecule. Antiviral, pro- and antiproliferative, pro- and antiapoptotic, and complex immunoregulatory activities have all been described. The precise mechanism(s) that underlie the beneficial effects of interferon-beta in multiple sclerosis remain poorly understood; this has hindered progress in the search for more effective therapies. An increasing body of literature supports the hypothesis that interferon-beta-mediated changes in the production and activities of the immunoregulatory cytokines interleukin-12 and interleukin-10 are important to the therapeutic benefits of interferon-beta in multiple sclerosis. These data are reviewed here.

Interferon beta1a treatment modulates TH1 expression in gammadelta + T cells from relapsing-remitting multiple sclerosis patients

A paradigm exists that multiple sclerosis is causally related to dysregulation of TH1 inflammatory cytokines and TH2 antiinflammatory cytokines. The cytokine source(s) that initiate the imbalances are unknown. In this study, gammadelta, CD4, and CD8 T cell receptor-positive (TCR+) cells were isolated from the blood of 26 definitive relapsing-remitting multiple sclerosis patients prior to interferon beta-1a (IFNbeta1a) therapy and following 8-10 weeks of this therapy. The bioactivities of interferon gamma (IFNgamma), interleukin 10 (IL10), and interleukin 12 (IL12) were determined. The concentrations of IFN-gamma, IL10, and IL12 from each cell type did not change significantly with IFNbeta1a treatment. The IL10 secreted by gammadelta TCR+ cells strongly correlated with the IL12 secreted by the same gammadelta TCR+ cells, supporting the paradigm. Furthermore, IFNbeta1a therapy decreased the gammadelta TCR+ cell secretion of TH1 cytokines after 8-10 weeks of therapy.

Correlação entre Hiperglicemia e Células do SNC, com Enfoque na Atividade Glial

Introdução. Entre os mecanismos biológicos que originam o qua­dro hiperglicêmico a predominância é do diabetes melittus (DM). O DM representa um grupo de desordens metabólicas caracterizadas por hiperglicemia crônica que ocasiona severas alterações celulares e teci­duais. Objetivo. O presente trabalho analisou através de revisão da literatura o comportamento de células gliais expostas a elevadas con­centrações de glicose, similares às observadas no DM. Método. Foi realizada uma revisão literária através de artigos científicos das bases de dados Pubmed, Science Direct, Scopus e Scielo. Resultados. Foram selecionados artigos e livros entre 1988 e 2009 que discutiam hiper­glicemia, sistema nervoso central e que relacionavam hiperglicemia e células gliais. Conclusão. A hiperglicemia crônica proporcionada pelo DM pode influenciar de maneira danosa o metabolismo cerebral exercendo ações sobre a atividade glial. Podendo afetar a sobrevivência neuronal através da excitotoxicidade glutamatérgica e da produção de espécies reativas de oxigênio (ERO) e de espécies reativas de nitro­gênio (ERN) que geram como consequência o processo de neuroin­flamação. Tal processo inflamatório pode resultar em dano e morte neural caracterizando um processo neurodegerativo.