Interferon (IFN)-beta treatment enhances CD95 and interleukin 10 expression but reduces interferon-gamma producing T cells in MS patients

Ocular immune privilege and retinal pigment epithelial cells

The ocular tissue microenvironment is immune-privileged and uses multiple immunosuppressive mechanisms to prevent the induction of inflammation. The retinal pigment epithelium plays an essential role in ocular immune privilege. In addition to serving as a blood barrier separating the fenestrated choriocapillaris from the retina, the retinal pigment epithelium is a source of immunosuppressive cytokines and membrane-bound negative regulators that modulate the activity of immune cells within the retina. This article reviews the current understanding of how retinal pigment epithelium cells mediate immune regulation, focusing on the changes under pathologic conditions.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

The role of B cells in the immunopathogenesis of multiple sclerosis

There is ongoing debate on how B cells contribute to the pathogenesis of multiple sclerosis (MS). The success of B-cell targeting therapies in MS highlighted the role of B cells, particularly the antibody-independent functions of these cells such as antigen presentation to T cells and modulation of the function of T cells and myeloid cells by secreting pathogenic and/or protective cytokines in the central nervous system. Here, we discuss the role of different antibody-dependent and antibody-independent functions of B cells in MS disease activity and progression proposing new therapeutic strategies for the optimization of B-cell targeting treatments.

Nanomodulation of Macrophages in Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic demyelinating autoimmune disease primarily affecting young adults. Despite an unclear causal factor, symptoms and pathology arise from the infiltration of peripheral immune cells across the blood brain barrier. Accounting for the largest fraction of this infiltrate, macrophages are functionally heterogeneous innate immune cells capable of adopting either a pro or an anti-inflammatory phenotype, a phenomenon dependent upon cytokine milieu in the CNS. This functional plasticity is of key relevance in MS, where the pro-inflammatory state dominates the early stage, instructing demyelination and axonal loss while the later anti-inflammatory state holds a key role in promoting tissue repair and regeneration in later remission. This review highlights a potential therapeutic benefit of modulating macrophage polarisation to harness the anti-inflammatory and reparative state in MS. Here, we outline the role of macrophages in MS and look at the role of current FDA approved therapeutics in macrophage polarisation. Moreover, we explore the potential of particulate carriers as a novel strategy to manipulate polarisation states in macrophages, whilst examining how optimising macrophage uptake via nanoparticle size and functionalisation could offer a novel therapeutic approach for MS.

Reassessing B cell contributions in multiple sclerosis

There is growing recognition that B cell contributions to normal immune responses extend well beyond their potential to become antibody-producing cells, including roles at the innate-adaptive interface and their potential to modulate the responses of other immune cells such as T cells and myeloid cells. These B cell functions can have both pathogenic and protective effects in the context of central nervous system (CNS) inflammation. Here, we review recent advances in the field of multiple sclerosis (MS), which has traditionally been viewed as primarily a T cell-mediated disease, and we consider antibody-dependent and, particularly, emerging antibody-independent functions of B cells that may be relevant in both the peripheral and CNS disease compartments.

IFN-β treatment modulates the CD28/CTLA-4-mediated pathway for IL-2 production in patients with relapsing -remitting multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system probably mediated by Th1 lymphocytes. IFN-b is an established therapy for relapsing MS patients, although the mechanisms underlying its efficacy are yet to be well characterized. We determined IL-2 production, CD25 expression and T-cell proliferation from relapsing -remitting MS patients before and three months after starting therapy. A decrease in the percentage of CD80-induced IL-2-producing cells was observed after in vivo IFN-b treatment. These data support that one of the immunomodulatory effects of IFN-b treatment in MS may be a limitation of the autoimmune response modifying the CD80:CD28/CTLA-4 pathway.

Interferon treatment may trigger primary headaches in multiple sclerosis patients

Recent data have suggested that interferon-b (IFN-β) may aggravate headaches in multiple sclerosis (MS) patients. The aim of this study was to investigate the life-time prevalence of primary headaches in MS patients treated with interferons in comparison with patients treated with other disease-modifying agents. Attention was focused on the onset of headache and the changes in pre-existing headaches in relation to the onset of therapy. The study was open-labelled and not randomized. We studied 150 consecutive MS patients treated with IFN-β (109 patients: 54 with 1b, 55 with 1a) and with other drugs (41 patients: 14 with glatiramer acetate, 27 with azathioprine). All patients underwent a semi-structured interview to diagnose headache type, according to the International Headache Society criteria. The frequency of primary headaches was higher in the interferon-group (72%) compared to patients in the other group (54%) ( P = 0.03). Worsening of pre-existing headaches or development of de novo headache occurred only in the interferon-group (41 and 48%, respectively) and not in the other group ( P<0.001). These results show that headache should be considered among the side-effects of interferon in MS patients.

The brain antigen-specific B cell response correlates with glatiramer acetate responsiveness in relapsing-remitting multiple sclerosis patients

B cells have only recently begun to attract attention in the immunopathology of multiple sclerosis (MS). Suitable markers for the prediction of treatment success with immunomodulatory drugs are still missing. Here we evaluated the B cell response to brain antigens in n = 34 relapsing-remitting MS (RRMS) patients treated with glatiramer acetate (GA) using the enzyme-linked immunospot technique (ELISPOT). Our data demonstrate that patients can be subdivided into responders that show brain-specific B cell reactivity in the blood and patients without this reactivity. Only in patients that classified as B cell responders, there was a significant positive correlation between treatment duration and the time since last relapse in our study. This correlation was GA-specific because it was absent in a control group that consisted of interferon-ß (IFN-β)-treated RRMS patients (n = 23). These data suggest that GA has an effect on brain-reactive B cells in a subset of patients and that only this subset benefits from treatment. The detection of brain-reactive B cells is likely to be a suitable tool to identify drug responders.

Signaling pathway STAT1 is strongly activated by IFN-β in the pathogenesis of osteoporosis

Background

Despite extensive research, the underlying pathological mechanisms of osteoporosis are not completely understood. Recent studies have indicated a distinct role for the IFN-β/STAT1 pathway in bone metabolism. An inhibitory effect of IFN-β on osteoclastogenesis has been detected and STAT1/2 has been shown to influence osteoblastic bone metabolism. So far, no data concerning the IFN-β/STAT1 pathways in osteoblasts and osteoclasts from osteoporotic and non-osteoporotic patients are available. The aim of the study was to analyze these pathways in both cell types.

Methods

Osteoblasts were isolated from the femoral heads of 12 osteoporotic and 11 non-osteoporotic patients and monocytes were differentiated into osteoclasts. After the differentiation period, cells were stimulated once with 20 and 100 ng/mL IFN-β for 4 days. Viability, activity, bone metabolism-related genes, and the proteins Fra1, SOCS1, STAT1, p-STAT1, and TRAF6 were analyzed.

Results

Viability, activity, and gene expressions were not affected by stimulating the osteoblasts. However, in osteoporotic osteoclasts, which display a significantly higher basal osteoclastic activity, the stimulation with IFN-β lead to significant inhibition. Further, an increased STAT1 activation was detected in both cell types with no significant differences between the groups. Regarding the phosphorylation of STAT1, no significant influence was detected in osteoblasts but the IFN-β stimulation led to a significant increase of p-STAT1 in osteoclasts of both groups.

Conclusions

IFN-β is a principal mediator in the pathogenesis of osteoporosis by inhibiting osteoclasts and inducing and activating STAT1. Our results also confirm this in cells from osteoporotic and non-osteoporotic patients. Strong inhibitory effects on the osteoclastogenesis of osteoporotic osteoclasts were detectable. Nevertheless, osteoblast activity was not negatively affected by IFN-β stimulation. These results may contribute to a better understanding of the underlying pathological signaling pathways of osteoporosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-014-0074-4) contains supplementary material, which is available to authorized users.

Interferon-β1bin multiple sclerosis

In 1993, interferon (IFN)-beta(1b) for subcutaneous injection became the first US FDA-approved immunomodulatory treatment for multiple sclerosis, a chronic inflammatory disease of the CNS. In this review of IFN-beta(1b), we first present a short introduction to multiple sclerosis and currently available therapeutics. We then summarize current knowledge about the biochemical structure of IFN-beta(1b), as well as pharmacokinetics and pharmacodynamics, including data on putative mechanisms underlying therapeutic as well as adverse effects. Furthermore, a critical review of ongoing and recently published clinical trials investigating IFN-beta(1b) in multiple sclerosis will be provided. Main topics are: trials investigating IFN-beta(1b) after a first clinical event, at higher dosages or in comparison to once-weekly subcutaneous IFN-beta(1a) injections, 16 years of long-term follow-up, IFN-beta(1b) in Japanese patients, the role of neutralizing antibodies, biomarkers for the prediction of therapy response, IFN-beta(1b) and pregnancy, and IFN-beta(1b) treatment of children with multiple sclerosis. Finally, we discuss how novel drugs, especially monoclonal antibodies and orally administered immunosuppressants, might soon challenge the position of this well-established agent on the multiple sclerosis therapeutics market.

Longitudinal interferon-β effects in multiple sclerosis: differential regulation of IL-10 and IL-17A, while no sustained effects on IFN-γ, IL-4 or IL-13

BACKGROUND

Recent studies in experimental models and in vitro indicate lowering of IL-17/Th17 as an important mechanism of interferon-beta (IFN-β) treatment in multiple sclerosis (MS).

MATERIAL AND METHODS

In this longitudinal study of MS patients (n=25), spontaneous and myelin antigen-induced secretion of IL-4, IFN-γ and IL-10 (ELISPOT), mitogen stimulated secretion of IL-13 and IL-17A (ELISA) and circulating cytokine levels (Luminex) were recorded at inclusion and after 1.5, 3, 6 and 12months of IFN-β treatment.

RESULTS

Early changes were noted for IL-4, while after one year of treatment the only recorded significant effects were a decrease in secreted IL-17A levels and an increase in IL-10 secreting cells. While IL-17A levels tended to be higher in non-responders (n=8), the decrease in IL-17A levels seemed to be more pronounced in responders (n=17) showing significantly lower IL-17A levels after one year as compared with non-responders.

CONCLUSION

IFN-β treatment seems to mainly affect IL-17/IL-10-associated pathways rather than the IFN-γ/IL-4 axis.

Type I and III interferons enhance IL-10R expression on human monocytes and macrophages, resulting in IL-10-mediated suppression of TLR-induced IL-12

Currently, only about 30-50% of chronic hepatitis C virus (HCV) and hepatitis B virus (HBV) patients respond to IFN-based therapy. It has been suggested that IL-10 is involved in suppressing the activity of type I IFNs on antigen-presenting cells (APCs). However, the interaction between type I IFNs and IL-10 is still not clear. Here we report that IFN-α priming upregulated the expression of IL-10R1 on monocytes, and subsequently IL-10 induced a higher level of STAT3 phosphorylation in IFN-primed cells. This indicates that IFN-α increased the sensitivity of monocytes to IL-10, and as a result, TLR-induced IL-12p70 by IFN-pretreated cells was suppressed. Interestingly, both IFN-β and IL-29, a member of the type III IFN family, comparably sensitized monocytes and macrophages to IL-10 stimulation, indicating a general effect of IFN on the activity of IL-10 in APCs. In summary, we demonstrate that one of the consequences of priming human APCs with IFN is to promote the cells' sensitivity to IL-10, which leads to the inhibition of TLR-induced IL-12p70 production. Therefore, type I and III IFNs induce a suboptimal activation of immune cells. These findings are relevant for the development of strategies to further improve IFN-based therapy for patients with multiple sclerosis or viral hepatitis.

Interferon β-1b directly modulates human neural stem/progenitor cell fate

Interferon beta (IFN-β) is a mainline treatment for multiple sclerosis (MS); however its exact mechanism of action is not completely understood. IFN-β is known as an immunomodulator; although recent evidence suggests that IFN-β may also act directly on neural stem/progenitor cells (NPCs) in the central nervous system (CNS). NPCs can differentiate into all neural lineage cells, which could contribute to the remyelination and repair of MS lesions. Understanding how IFN-β influences NPC physiology is critical to develop more specific therapies that can better assist this repair process. In this study, we investigated the effects of IFN β-1b (Betaseron®) on human NPCs in vitro (hNPCs). Our data demonstrate a dose-dependent response of hNPCs to IFN β-1b treatment via sustained proliferation and differentiation. Furthermore, we offer insight into the signaling pathways involved in these mechanisms. Overall, this study shows a direct effect of IFN β-1b on hNPCs and highlights the need to further understand how current MS treatments can modulate endogenous NPC populations within the CNS.

Lipopolysaccharide-mediated IL-10 transcriptional regulation requires sequential induction of type I IFNs and IL-27 in macrophages

IL-10 is a potent anti-inflammatory molecule that regulates excessive production of inflammatory cytokines during an infection or tissue damage. Dysregulation of IL-10 is associated with a number of autoimmune diseases, and so, understanding the mechanisms by which IL-10 gene expression is regulated remains an important area of study. Macrophages represent a major source of IL-10, which is generated in response to TLR signaling as a feedback mechanism to curtail inflammatory response. In this study, we identify a signaling pathway in murine bone marrow-derived macrophages in which activation of TLR4 by LPS induces the expression of IL-10 through the sequential induction of type I IFNs followed by induction and signaling through IL-27. We demonstrate that IL-27 signaling is required for robust IL-10 induction by LPS and type I IFNs. IL-27 leads directly to transcription of IL-10 through the activation of two required transcription factors, STAT1 and STAT3, which are recruited to the IL-10 promoter. Finally, through systematic functional promoter-reporter analysis, we identify three cis elements within the proximal IL-10 promoter that play an important role in regulating transcription of IL-10 in response to IL-27.

T-cell based immunotherapy in experimental autoimmune encephalomyelitis and multiple sclerosis

One of the reasons multiple sclerosis (MS) has been considered a T-cell mediated autoimmune disease is that a similar experimental disease can be induced in certain rodents and primates by immunization with myelin antigens, leading to T-cell-mediated inflammatory demyelination in the CNS. In addition, most if not all pharmacological treatments available for MS are biologically active on T cells. In this article we review the principles of T-cell-based immunotherapies and the specific actions of current and novel treatments on T-cell functions, when these are known. For both licensed and innovative agents, we also discuss biological actions on other immune cell types. Finally, we offer a brief perspective on expected changes in the use of MS immunotherapies in the near future.

Mitoxantrone treatment in multiple sclerosis induces TH2-type cytokines

OBJECTIVES

Mitoxantrone is a cytotoxic drug with immune modulatory properties used in the treatment of progressive forms of multiple sclerosis (MS). We explored the effect of mitoxantrone treatment in MS patients on cytokine patterns induced in peripheral blood mononuclear cells (PBMC) and T-cell subsets ex vivo.

MATERIALS AND METHODS

Blood was obtained before mitoxantrone infusion and 6, 12 and 18 days thereafter. Proliferation and prototypic TH1-, TH17- and TH2-type cytokines were determined following in vitro stimulation of PBMC, CD4+ and CD8+ T cells. In addition, a patient cohort receiving its first mitoxantrone treatment was cross-sectionally compared with a cohort of patients with more than 1 year of treatment.

RESULTS

Mitoxantrone treatment increased the ex vivo production of the TH2 cytokines interleukin-4 (IL-4; P < 0.05) and IL-5 (P < 0.001) in phytohemagglutinin-stimulated CD4+ T cells within 18 days of treatment. The cross-sectional study revealed that long-term treatment with mitoxantrone increased the inducibility of IL-4 and IL-5 secretion by PBMCs and CD4+ T cells even further. No significant changes were observed for interferon-γ, tumour necrosis factor-α, IL-17 and IL-10. Mitoxantrone did not alter the proliferative capacity of ex vivo-stimulated T cells.

CONCLUSION

Mitoxantrone treatment in MS enhances the inducibility of TH2-type cytokines, which may contribute to its beneficial effects in MS.

Effect of IFN-beta therapy on the frequency and function of CD4(+)CD25(+) regulatory T cells and Foxp3 gene expression in relapsing-remitting multiple sclerosis (RRMS): a preliminary study

Interferon-beta (IFN-beta) is an immunomodulatory drug of choice to control relapsing-remitting multiple sclerosis (RR-MS), although its function is still unclear. A reduced suppressive function of CD4(+)CD25(+) regulatory T cells (T(reg)) has been shown in RR-MS patients. In this study, to understand the effect of IFN-ss on CD4(+)CD25(+) regulatory T cells, we analyzed the frequency and function of these cells and Foxp3 gene expression before and after treatment. We evaluated the frequency and function of CD4(+)CD25(+)Foxp3(+) regulatory T cells by flow cytometry and co-culture inhibition test respectively and gene expression of Foxp3 by real-time PCR in a longitudinal follow-up study in 18 relapsing-remitting MS patients. Our data revealed that IFN-beta significantly improved frequency and suppressive function of T(reg) cells (P<0.05) without any significant effect on gene expression of Foxp3 after 6 months. The results of the present study indicate that IFN-beta therapy in some of patients with RR-MS may restore function of regulatory T cells and control the unchecked immune cascade activity. Larger longitudinal studies on more MS patients are required to confirm our findings.

Lymphocyte Subpopulations, Oxidative Burst and Apoptosis in Peripheral Blood Cells of Patients with Multiple Sclerosis–Effect of Interferon-β

At present, the most efficient therapeutical treatment of multiple sclerosis (MS) is achieved by IFN-beta. However, its in vivo effects remain incompletely understood. If applied parenterally, the hydrophobic IFN-beta acts primarily on blood cells with probable selectivity for functionally different lymphocyte subpopulations, monocytes and granulocytes. We have investigated the expression of the activation marker interleukin-2 receptor-alpha (CD25) on CD3+ T cells, CD19+ B cells, foetal-type gamma(delta)+CD3+ T cells and foetal-type CD5+CD19+ B cells of the peripheral blood. In addition, the oxidative burst activity and apoptosis have been determined in mononuclear and polymorphonuclear blood cells, respectively. The study accompanied a phase III trial with IFN-beta1b (BETAFERON, Schering). Two groups of MS patients with relapsing-remitting course of the disease have been investigated at 8 time points (days 0, 5, 15, 31, 60, 90, 180 and 270 after starting therapy): (1) verum group (n = 8) with application of 8 Mill. units IFN-beta1 b every other day, and (2) placebo group (n = 4) with application of placebo for 3 months and therapy as in (1) from day 90 onward. The main results were: (1) Activated T cells decreased until day 180 in the verum group and return thereafter to pre-treatment values, whereas in the placebo group the values remained relatively stable over the whole observation period. (2) Activated B cells increased between days 90 and 270 in both groups, i.e. after verum application in both groups. (3) Foetal-type B cells were more activated than total B and T cells with increase over time in both groups. (4) Foetal-type T cells exerted relatively stable intra-individual levels with generally low CD25 expression, but punctual CD25 peaks in both groups. (5) The spontaneous oxidative burst was higher in lymphocytes, more variable in monocytes and faster increasing in granulocytes in the verum group than in the placebo group. (6) Apoptosis of mononuclear cells and granulocytes showed similar variations in the verum and placebo groups with the exception of a selective increase over time of the proportion of granulocytes undergoing induced apoptosis in the verum group. It is concluded that IFN-beta has the following main effects on the immune system of MS patients: (1) the T cell immunity is systemically and reversibly suppressed, (2) the foetal-type lymphocytes, which are responsible for the first line of defence of infections, are stimulated in the long range, (3) the oxidative burst activity is increased in lymphocytes and granulocytes and instable in monocytes, and (4) the inducibility of apoptosis in granulocytes is increased. Re-examination of the altered blood cell parameters after long-term IFN-beta therapy is warranted.

Increased IL-10 mRNA and IL-23 mRNA expression in multiple sclerosis: interferon-beta treatment increases IL-10 mRNA expression while reducing IL-23 mRNA expression

BACKGROUND

Interferon (IFN)-beta therapy in multiple sclerosis (MS) has been suggested to promote a deviation from T lymphocyte production of pathogenic Th1 cytokines to less detrimental Th2 cytokines, but this is still controversial. We studied patterns of in vivo blood mononuclear cell (MNC) and whole blood cytokine and transcription factor mRNA expression before and during IFN-beta therapy in MS.

METHODS

Twenty patients with relapsing-remitting MS were sampled before and after 3 months of treatment with IFN-beta along with 15 healthy volunteers. An additional 39 patients and 50 healthy volunteers served to confirm initial findings. mRNA was analyzed by real-time reverse transcriptase polymerase chain reaction (PCR).

RESULTS

We found elevated expression of interleukin (IL)-23 and IL-10 in untreated MS patients. IFN-beta therapy increased IL-10 and decreased IL-23 expression independently of any Th1 or Th2 cytokines. The largest changes in cytokine mRNA levels occurred early (~9-12 h) after an IFN-beta injection.

CONCLUSION

We found no evidence of a Th1- or Th2-mRNA-promoting effect of IFN-beta therapy. The therapeutic effect of IFN-beta is more likely attributable to the induction of the regulatory cytokine IL-10. The elevated IL-23 mRNA levels in MS patients are noteworthy in view of the newly discovered IL-23-driven Th17 T-cell subset, which is crucial in animal models of MS. Since IFN-beta therapy resulted in decreased IL-23 mRNA levels, the Th17 axis could be another target of IFN-beta therapy.

Atorvastatin does not alter serum levels of sCD95 and sCD95L in multiple sclerosis

Elimination of autoreactive T cells by apoptosis is critical for restricting immune responses to self-antigens. An errant lytic interaction between the CD95 death receptor and its ligand CD95L is presumed to be involved in the pathogenesis of multiple sclerosis (MS). Statins are promising agents for the treatment of MS and were shown to modulate levels of soluble death receptors. Here, we evaluated the in vivo effects by interferon (IFN)-beta and atorvastatin on soluble CD95 (sCD95) and sCD95L in serum of patients with MS. Concentrations of sCD95 and sCD95L did not show any differences between MS and healthy control subjects. In patients with MS, treatment with IFN-beta increased serum levels of sCD95 and sCD95L significantly (P < 0.01 and P < 0.05 respectively). Addition of atorvastatin to IFN-beta did not alter serum levels of sCD95 and sCD95L significantly. Our study suggests that atorvastatin does not affect IFN-beta-induced increases of the soluble death receptors in the serum of patients with MS.

Multiple sclerosis and virus induced immune responses: autoimmunity can be primed by molecular mimicry and augmented by bystander activation

Polymicrobial infections have been associated with plausible immune mediated diseases, including multiple sclerosis (MS). Virus infection can prime autoimmune T cells specific for central nervous system (CNS) antigens, if virus has molecular mimicry with CNS proteins. On the other hand, infection of irrelevant viruses will induce two types of cytokine responses. Infection with a virus such as lymphocytic choriomeningitis virus (LCMV), can induce interferon (IFN)-alpha/beta production and suppress autoimmunity, while infection with a virus, such as murine cytomegalovirus (MCMV), can activate natural killer (NK), NKT and dendritic cells, resulting in interleukin (IL)-12 and IFN-gamma production. These cytokines can cause bystander activation of autoreactive T cells. We established an animal model, where mice infected with vaccinia virus encoding myelin protein can mount autoimmune responses. However, the mice develop clinical disease only after irrelevant immune activation either with complete Freund's adjuvant or MCMV infection. In this review, we propose that a combination of two mechanisms, molecular mimicry and bystander activation, induced by virus infection, can lead to CNS demyelinating diseases, including MS. Viral proteins having molecular mimicry with self-proteins in the CNS can prime genetically susceptible individuals. Once this priming has occurred, an immunologic challenge could result in disease through bystander activation by cytokines.

Curcumin modulation of IFN-beta and IL-12 signalling and cytokine induction in human T cells

Curcumin is a polyphenol derived from the dietary spice turmeric. It possesses diverse anti-inflammatory and anti-cancer properties. Curcumin has been shown to exhibit an inhibitory effect on the production of inflammatory cytokines by human monocytes and has inhibited the animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE) in association with a decrease in interleukin 12 (IL-12) production and signal transducer and activator of transcription 4 (STAT4) activation. The type I interferon (IFN) IFN-has the ability to suppress IL-12. Both IL-12 and IFN-alpha/beta signal through the activation by phosphorylation of STAT4. Our aim was to investigate the effects of curcumin on the ability of T cells to respond to IL-12 or IFN-alpha/beta. We report that curcumin decreases IL-12-induced STAT4 phosphorylation, IFN-gamma production, and IL-12 Rbeta1 and beta2 expression. IFN-beta-induced STAT4 phosphorylation, IL-10 production and IFN receptor (IFNAR) subunits 1 and 2 expression were enhanced by curcumin. Curcumin increased IFN-alpha-induced IL-10 and IFNAR1 expression. Prior exposure to curcumin decreased IFN-alpha-induced IFNAR2 expression and did not modify the level of IFN-alpha-induced pSTAT4 generation. Thus, the effect of curcumin on STAT4 activation in T cells is dependent upon the stimulus to which the T cells have been exposed.

Pharmacokinetics and pharmacodynamics of the interferon-betas, glatiramer acetate, and mitoxantrone in multiple sclerosis

Five disease-modifying agents are currently approved for long-term treatment of multiple sclerosis (MS), namely three interferon-beta preparations, glatiramer acetate, and mitoxantrone(1). Pharmacokinetics describes the fate of drugs in the human body by studying their absorption, distribution, metabolism and excretion. Pharmacodynamics is dedicated to the mechanisms of action of drugs. The understanding of the pharmacokinetics and pharmacodynamics of the approved disease-modifying agents against MS is of importance as it might contribute to the development of future derivatives with a potentially higher efficacy and a more favourable safety profile. This article reviews data thus far present both on the pharmacokinetics as well as on the putative mechanisms of action of the interferon-betas, glatiramer acetate, and mitoxantrone in the immunopathogenesis of MS.

Genome-wide network analysis reveals the global properties of IFN-beta immediate transcriptional effects in humans

IFN-beta effectively controls clinical exacerbations and magnetic resonance imaging activity in most multiple sclerosis patients. However, its mechanism of action has not been yet fully elucidated. In this study we used DNA microarrays to analyze the longitudinal transcriptional profile of blood cells within a week of IFN-beta administration. Using differential expression and gene ontology analyses we found evidence of a general decrease in the cellular activity of T lymphocytes resembling the endogenous antiviral response of IFNs. In contrast, most of the differentially expressed genes (DEGs) from untreated individuals were involved in cellular physiological processes. We then used mutual information (MI) to build networks of coregulated genes in both treated and untreated individuals. Interestingly, the connectivity distribution (k) of networks generated with high MI values displayed scale-free properties. Conversely, the observed k for networks generated with suboptimal MI values approximated a Poisson distribution, suggesting that MI captures biologically relevant interactions. Gene networks from individuals treated with IFN-beta revealed a tight core of immune- and apoptosis-related genes associated with higher values of MI. In contrast, networks obtained from untreated individuals primarily reflected cellular housekeeping functions. Finally, we trained a neural network to reverse engineer the directionality of the main interactions observed at the biological process level. This is the first study that incorporates network analysis to investigate gene regulation in response to a therapeutic drug in humans. Implications of this method in the creation of personalized models of response to therapy are discussed.

IL-10 induces IL-10 in primary human monocyte-derived macrophages via the transcription factor Stat3

IL-10 is an important immunosuppressive cytokine that can down-regulate expression of other cytokines and has been shown to down-regulate itself. We show, in this study, that treatment of human monocyte-derived macrophages with IL-10 induces IL-10 mRNA in a dose- and time-dependent manner with an optimum induction at 100 ng/ml and at 6 h, whereas IL-10-induced IL-10 protein can be detected at 18 h. In the same cells, IL-10 can partially suppress IL-10 mRNA induced by LPS, but only down to the level of IL-10-induced IL-10. An adenoviral luciferase reporter construct driven by the -195 IL-10 promoter, which contains a Stat motif, was readily induced by both IL-10 and LPS. Mutation of this Stat motif ablated IL-10 activation of this promoter, but not the LPS activation. Finally, we show that overexpression of a dominant-negative Stat3 protein will prevent IL-10 induction, but not LPS induction, of IL-10 mRNA. These data show that IL-10 induces IL-10 in monocyte-derived macrophages in an autocrine manner via activation of the transcription factor Stat3.

Cutting Edge: Involvement of the Type I IFN Production and Signaling Pathway in Lipopolysaccharide-Induced IL-10 Production

Macrophages respond to LPS by the rapid activation of proinflammatory cytokines that serve to initiate host defense against microbial invasion. To prevent injury to the host from excess production of these cytokines, IL-10 is up-regulated to feedback inhibit the proinflammatory response. However, the molecular events responsible for LPS-induced up-regulation of IL-10 remain to be elucidated. In this study, we provide evidence that production of and signaling by type I IFN is required for LPS-induced IL-10 up-regulation. In addition, we demonstrate that defect in type I IFN production and signaling results in a trend toward LPS-mediated superinduction of proinflammatory genes and cytokines in bone marrow-derived macrophages. Our findings suggest a novel anti-inflammatory role for the type I IFN production and signaling pathway in regulating LPS response in bone marrow-derived macrophages.

Time of interferon-β 1a injection and duration of treatment affect clinical side effects and acute changes of plasma hormone and cytokine levels in multiple sclerosis patients

During initiation of interferon-beta (IFN-β) therapy, many multiple sclerosis (MS) patients experience systemic side effects which may depend on the time point of IFN-β injection. We investigated the time course of plasma hormone-, cytokine- and cytokine-receptor concentrations after the first injection of IFN-β either at 8.00 a.m. (group A) or at 6.00 p.m. (group B) and quantified clinical side effects within the first 9 h in 16 medication free patients with relapsing-remitting MS. This investigation was repeated after 6-month IFN-β therapy.

Plasma ACTH and cortisol concentrations followed their physiological rhythms, with lower levels in the evening compared to the morning, but raised earlier and stronger in group B after IFN-β administration. IFN-β injection in the evening led to a prompter increase of plasma IL-6 concentrations and temperature during the first hours and correlated to more intense clinical side effects compared to group A. Plasma IL-10 concentrations increased more in group A compared to group B, but sTNF-RI and sTNF-RII concentrations raised 7 h after IFN-β injection only in group B. Acute effects on plasma hormone and cytokine concentrations adapted after 6-month IFN-β treatment, while diurnal variations were still present. Baseline sTNF-RII concentrations were elevated after 6-month IFN-β therapy only in group A.

Our results show that time point of IFN-β injection has differential effects on acute changes of plasma hormone and cytokine concentrations and is related to systemic side effects. This may have implications on the tolerability and effectiveness of IFN-β therapy. Multiple Sclerosis 2007; 13: 1138—1145. http://msj.sagepub.com

Interferon-beta mediates opposing effects on interferon-gamma-dependent Interleukin-12 p70 secretion by human monocyte-derived dendritic cells

Interferon-beta (IFN-beta) exposure during tumour necrosis factor-alpha (TNF-alpha)-induced human monocyte-derived dendritic cell (DC) maturation augments the capacity of DC to promote the generation of T helper 1 (Th1) cells, while IFN-beta exposure during naive Th cell stimulation inhibits Th1 cell generation (Nagai et al., J Immunol, 2003 171:5233-43). Investigating these contradictory outcomes of IFN-beta exposure, we find that isolated DC matured with both TNF-alpha and IFN-beta secrete more IL-12 p70 upon CD40L stimulation than DC matured with TNF-alpha alone. mAb blocking studies indicate that the basis for this enhanced IL-12 p70 production is augmentation of two successive CD40-dependent autocrine pathways in the DC: (1) a pathway in which low levels of IL-12 p70, IL-27, IL-18 and, possibly, IL-23 act to mediate autocrine induction of DC IFN-gamma secretion; and (2) an IFN-gamma-initiated autocrine pathway promoting optimal DC IL-12 p70 secretion. In contrast to the IL-12 p70 promoting effects of IFN-beta during DC maturation, IFN-beta pre-treatment before CD40L stimulation was found to inhibit IFN-gamma-mediated enhancement of DC IL-12 p70 secretion. Thus, IFN-beta exposure during TNF-alpha-mediated DC maturation may promote Th1 polarization by increasing DC IL-12 p70 secretion, through enhancement of autocrine-acting IFN-gamma production by the DC. Moreover, IFN-beta exposure during naive Th cell stimulation may inhibit Th1 cell generation by blocking the IFN-gamma-induced signals required for optimal CD40L-induced DC IL-12 p70 secretion. IFN-beta pre-treatment was also observed to inhibit CD40L-induced DC IL-23 secretion. Our findings may account for some of the beneficial effects of IFN-beta therapy in patients with relapsing remitting multiple sclerosis.

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.

Interferon-β regulates cytokines and BDNF: greater effect in relapsing than in progressive multiple sclerosis

The mechanism of action of interferon (IFN)-β therapy in multiple sclerosis (MS) is only partially known, and its efficacy changes with disease stage. In different forms of MS, we determined how IFN-β regulates mononuclear cell production of the important anti-inflammatory Th2 cytokine - IL-10, the Th1 cytokine - IFN-γ, and the brain-derived neurotrophic protein - BDNF. Activated T cells and monocytes from therapy-naïve patients secreted more IL-10 than healthy controls. During IFN-β therapy, however, T cells produced less IL-10. In vitro, IFN-β stimulated IL-10 production by activated T cells, but inhibited IL-10 secretion by activated monocytes, a richer source of IL-10 than T cells. The form of MS also affected cytokine production. IL-10 and BDNF levels in MNC were high during relapsing/remitting (RR) MS, but low in progressive MS. Surprisingly, IFN-β therapy increased BDNF levels in antidepressant-naïve patients, but BDNF was lower during concurrent antidepressant drug therapy, suggesting an interaction between MS, depression, and neurodegeneration. IFN-β in vitro strongly induced IL-10 and IFN-γ in activated T cells in RRMS, but not in progressive MS, suggesting IFN resistance. IFN-β effects are specific for disease state and immune subsets, possibly explaining why IFN-β therapy is most effective in early T cell-regulated RRMS, but less beneficial in progressive MS, where chronic plaques contain few T cells and high numbers of monocytes. Multiple Sclerosis 2007; 13: 459-470. http://msj.sagepub.com

Intraarticular interferon-beta gene therapy ameliorates adjuvant arthritis in rats

Interferon (IFN)-beta has significant immunomodulatory properties and has received much interest as a potentially therapeutic agent for rheumatoid arthritis (RA). Systemic IFN-beta treatment of patients with RA was not effective, probably because of pharmacokinetic issues. Therefore, we studied the effect of local IFN-beta production by adenovirus-mediated gene transfer to the ankle joints of arthritic rats. Adjuvant arthritis (AA) in rats was used as a model to study intraarticular gene therapy with an adenoviral vector encoding the rat IFN-beta gene (Ad.IFN-beta). The effect on paw swelling was measured by water displacement plethysmometry. Synovial tissue of the hind paws was examined by immunohistochemistry. Bone destruction was analyzed on the basis of radiographs. In addition, quantitative real-time polymerase chain reaction was used to assess IFN-beta expression. Levels of IFN-beta mRNA and protein peaked 2 days after intraarticular injection and declined thereafter. Local delivery of Ad.IFN-beta after the onset of disease reduced paw swelling significantly. This was accompanied by a reduction in synovial inflammation. The clinical effects in rat AA lasted up to 9 days. Strikingly, Ad.IFN-beta treatment protected bone from erosion, reduced levels of c-Cbl and Cbl-b (both signaling molecules essential for osteoclast activity), and reduced the matrix metalloproteinase-3:tissue inhibitor of metalloproteinase-1 ratio in the joint. Immunohistochemical analysis of the synovial tissue revealed a clear shift toward a more antiinflammatory cytokine profile. Local overexpression of IFN-beta inhibits arthritis progression and protects against bone destruction in rat AA. These findings validate IFN-beta as a therapeutic molecule for intraarticular gene therapy of arthritis.

Deficient Fas expression by CD4+ CCR5+ T cells in multiple sclerosis

OBJECTIVE

To evaluate whether T cells expressing CCR5 and CXCR3 from multiple sclerosis (MS) patients are more resistant to apoptosis.

METHODS

Expression of CD69, TNF-R1, Fas, FasL, bcl-2, and bax was investigated in 41 MS patients and 12 healthy controls by flow cytometry in CD4+ and CD8+ T cells expressing CCR5 and CXCR3.

RESULTS

In MS patients, the percentage of CD69 was increased and Fas expression decreased in CD4+ CCR5+ T cells.

INTERPRETATION

The lower Fas expression in activated CD4+ CCR5+ T cells might contribute to disease pathogenesis by prolonging cell survival and favoring their migration into the CNS.

The interleukin-10 levels as a potential indicator of positive response to interferon beta treatment of multiple sclerosis patients

OBJECTIVES

Only a part of MS patients treated with interferon beta (IFN) respond positively to the applied treatment and to date no parameter predicting the response to treatment has been found. The aim of the study was to determine whether the levels of interleukin-10 and -12 (IL-10 and IL-12) might be the parameters enabling us to distinguish those patients who would best respond to therapy before the IFN treatment.

PATIENTS AND METHODS

The study included 29 patients with clinically definite relapsing-remitting MS treated with IFN beta. In all of them the levels of IL-10 and IL-12 in blood serum and cerebrospinal fluid were determined before treatment using ELISA method. After the 2-year therapy the patients responding and nonresponding to IFN therapy were distinguished on the basis of clinical parameters.

RESULTS

In the patients responding positively to IFN treatment the level of IL-10 in blood serum before treatment was found to be significantly lower (p<0.05) and distinctively differentiated responders from nonresponders. The IL-12 levels were similar both in cerebrospinal fluid and serum and no significant differences between responders and nonresponders were found.

CONCLUSION

Our observations suggest that IL-10 level may be a useful parameter to identify the patients potentially responding to IFN therapy.

Anti-inflammatory properties of Type I interferons

The notion that Type I interferons (interferon-alpha and -beta) possess anti-inflammatory potential is supported by data from clinical application in multiple sclerosis, by studies on cultured immune-competent cells and by investigation of experimental diseases in whole animals. These observations deserve the attention of virologists for their potential role in the pathogenesis and clinical management of virus infections.

CD8+ T cell activation correlates with disease activity in clinically isolated syndromes and is regulated by interferon-beta treatment

An increased percentage of blood CD8+ T cells from patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) was found to express CD26 and CD69. The percentage of CD26 or CD69 positive CD8+ T cells was higher in patients with MRI evidence of disease dissemination in space or with active MRI lesions than in the remaining patients. Treatment of MS with interferon (IFN)-beta resulted in a decrease in the percentage of CD26 and CD71 positive CD8+ T cells and an increase in the percentage of CD8+ T cells that expressed interleukin (IL)-10 and IL-13. CD8+ T cell activation in MS may be linked to disease activity already at disease onset, and is regulated by treatment with IFN-beta.

Pharmacogenetics of autoimmune diseases: research issues in the case of Multiple Sclerosis and the role of IFN-beta

Pharmacogenetics of auto-immune diseases is a complex field of application for this relatively new discipline, since we still have a partial knowledge of the biological mechanisms of the disease and of the drugs currently used to treat it. We address a few key issues that emerge when planning a pharmacogenetic investigation in Multiple Sclerosis and that relate to the complexities existing at the biological-genetic level and at the phenotypic characterization. In fact, we think that a clearer characterization of the clinical phenotype representing the end-point of the investigation together with a critical appraisal of the multi-faceted dimension of the genetic component of either the disease and the pharmacogenetic profile of the drug investigated, will help to design more thorough study and to achieve deeper understanding of the practical results. We will primarily focus our research considerations on the role of Interferon Beta (IFN-beta) as a prototypal therapeutic agent in Multiple Sclerosis.

Ingested (Oral) IFN-α Represses TNF-α mRNA in Relapsing-Remitting Multiple Sclerosis

In a phase II trial in relapsing-remitting multiple sclerosis (RRMS), patients ingesting 10,000 IU, but not 30,000 IU, interferon-alpha (IFN-alpha) showed fewer gadolinium enhancements at months 5 and 6, along with decreased proinflammatory tumor necrosis factor-alpha (TNF-alpha) protein secretion. Therefore, we examined MxA mRNA induction and TNF-alpha mRNA repression after 100, 300, 1,000, 3,000, and 10,000 IU doses of ingested IFN-alpha in 24 RRMS patients to determine the optimal dose for future clinical trials in MS. Maximal TNF-alpha repression occurs at 100, 1,000, and 3,000 IU. These data provide new optimal doses for additional clinical studies using ingested IFN-alpha in MS.

Lack of IFN-γ Production in Response to Antigenic Stimulation in Human IFN-τ-Treated Lymphocytes

Interferon-tau (IFN-tau) is a type I IFN responsible for maternal recognition of the fetus in ruminants. In addition to its physiologic role, IFN-tau also inhibits HIV replication in human lymphocytes and macrophages and displays immunomodulatory effects but lacks the toxicity associated with other type I IFNs. Human IFN-alpha promotes a Th1 response, whereas IFN-tau has anti-inflammatory properties, inducing the production of Th2 cytokines in murine models of experimental autoimmune encephalitis (EAE) or fetal loss. We compared the effects of ovine IFN-tau (OvIFN-tau) and human IFN-alpha (HuIFN-alpha) on cytokine mRNA and protein production in human peripheral blood mononuclear cells (PBMCs) activated with a recall antigen, such as purified protein derivative (PPD) of tuberculin or with a proinflammatory stimulus, such as lipopolysaccharide (LPS). In both cases, IFN-alpha increased IFN-gamma production, whereas IFN-tau did not and thereby promoted Th2 cytokine production. This original property renders IFN-tau a potential candidate for therapeutic applications in immune disorders, such as multiple sclerosis (MS), but its therapeutic use in the treatment of HIV infection should be considered with caution.

Immunomodulatory Effects of IFN-β1a Treatment Alone or Associated with Pentoxifylline in Patients with Relapsing-Remitting Multiple Sclerosis (RRMS)

Interferon-beta1a (IFN-beta1a) and pentoxifylline (PTX) are reported to be active in relapsing-remitting multiple sclerosis (RRMS), but the mechanisms are not completely understood. In two groups of RRMS patients, we studied the phenotype of peripheral lymphocytes and the level of several cytokines both in sera and in supernatants of activated peripheral blood mononuclear cells (PBMC) before and after 8 months of therapy with IFN-beta1a alone or associated with PTX. Our data indicate that patients with RRMS, treated with IFN-beta1a, exhibited a significant increase in CD4(+)CD25(++) T suppressor cells, accompanied by a significant decrease in cytotoxic lymphocytes (CD8(+)CD28(-) and natural killer [NK] cells) and IFN-gamma production, which could both contribute to an explanation of the previously described beneficial effects of IFN-beta treatment in MS. The addition of PTX to IFN-beta1a treatment did not modify the immunomodulatory effects obtained with IFN-beta1a alone. Future studies are needed to demonstrate which immunologic parameters correlate with the clinical benefit of IFN-beta1a treatment.

Soluble vascular cell adhesion molecule (VCAM) is associated with treatment effects of Interferon beta-1b in patients with Secondary Progressive Multiple Sclerosis

BACKGROUND

Subcutaneous IFNbeta-1b (Betaferon) is an established immunomodulatory treatment for relapsing remitting MS and active secondary progressive multiple sclerosis (SPMS). It modulates cytokine and adhesion molecule expression but long term in vivo effects of IFNbeta-1b on the immune system are not known in multiple sclerosis.

OBJECTIVE

To address the effects of IFNbeta-1b on serum levels for soluble adhesion molecules and cytokine receptors from MS patients.

METHODS

Serial blood samples were obtained from 40 patients of the frequent MRI subgroup (20 patients each from the placebo and the IFNbeta-1b treatment group), participating in the European multi-center clinical trial with IFNbeta-1b for secondary progressive MS, at regular intervals for up to 36 months. Soluble adhesion molecules (sVCAM, sICAM-1, sL-Selectin) as well as TNF-receptor I and II were analysed in the serum of patients by enzyme linked immunosorbent assays (ELISAs). Monthly brain MRI was performed in 34 of these patients (16 patients from the placebo and 18 from the IFNbeta-1b group) during months 1-6 and 19-24 to monitor disease activity as assessed by newly occurring gadolinium (Gd) enhancing lesions.

RESULTS

An early and significant increase in sVCAM and sTNF-RII serum levels was detected in 16 out of 20 patients (80 %) treated with subcutaneous IFNbeta-1b already at month 1 but was absent in all but one patient during placebo treatment (p < 0.01). Raised sVCAM and TNF RII serum levels during months 1-6 inversely correlated with less MRI activity in the 19-24 months treatment interval in the IFNa-1b treatment group ( p = 0.0093 for TNF-RII; p = 0.047 for VCAM).

CONCLUSIONS

sVCAM and sTNF RII levels in the serum of SPMS patients are increased during IFNbeta-1b therapy and may at least in part explain some of the treatment effects, like reduced immune cell transmigration.

Correlation between disease severity and in vitro cytokine production mediated by MSRV (Multiple Sclerosis associated RetroViral element) envelope protein in patients with multiple sclerosis

MSRV is a retroviral element previously isolated in cell cultures from patients with multiple sclerosis. It is part of a new multi-copy endogenous retrovirus family named HERV-W and displays pro-inflammatory properties both in vitro in human PBMC cultures and in vivo in a humanized SCID mice model. In the present study, we have evaluated potential links between the pro-inflammatory properties of MSRV envelope protein and MS disease. Thus, cytokine productions mediated by the surface unit of MSRV envelope protein were evaluated in PBMC of MS patients and compared with healthy controls. Divergent reactivity to ENV-SU between MS and control PBMC was observed and was reflected by a significant increase of IFN-gamma, IL-6 and IL-12p40 production by the tested MS population. Interestingly, the overproduction of IL-6 and IL-12p40 was found to correlate with disease severity (EDSS) in most patients. Altogether our data suggest that MSRV envelope protein may induce an abnormal cytokine secretion, thus contributing to the inflammatory process in MS.

Role of Magnetic Resonance Imaging and Immunotherapy in Treating Multiple Sclerosis

Significant advances in magnetic resonance imaging (MRI) technology and treatment of multiple sclerosis (MS) have been made during the past decade. These advances have revealed evidence of profound heterogeneity in MS. There is a clear need to revisit the key issues in MS pathogenesis and treatment strategies, taking new data into consideration. This paper provides an overview of recent progress in MS research, including (a) a review of clinical, pathologic, and immunologic aspects of MS, (b) a discussion of the mechanism of action of currently available disease-modifying drugs for MS, (c) an account of the role of MRI in clinical management and clinical trials in MS, and (d) an overview of some emerging treatments for MS.

How outbreaks of infectious disease are detected: a review of surveillance systems and outbreaks

To learn how outbreaks of infectious disease are detected and to describe the entities and information systems that together function to identify outbreaks in the U.S., the authors drew on multiple sources of information to create a description of existing surveillance systems and how they interact to detect outbreaks. The results of this analysis were summarized in a system diagram. The authors reviewed a sample of recent outbreaks to determine how they were detected, with reference to the system diagram. The de facto U.S. system for detection of outbreaks consists of five components: the clinical health care system, local/state health agencies, federal agencies, academic/professional organizations, and collaborating governmental organizations. Primary data collection occurs at the level of clinical health care systems and local health agencies. The review of a convenience sample of outbreaks showed that all five components of the system participated in aggregating, analyzing, and sharing data. The authors conclude that the current U.S. approach to detection of disease outbreaks is complex and involves many organizations interacting in a loosely coupled manner. State and local health departments and the health care system are major components in the detection of outbreaks.

Immunotherapeutic approaches in multiple sclerosis

The progress in understanding the mechanisms of T cell activation, inactivation and modulation has been translated into different immunotherapeutic strategies aiming at treating multiple sclerosis (MS). Key attack points for selective immunointervention in MS include modulation of antigen recognition, costimulation blockade, induction of regulatory cells, deviation to non-pathogenic or protective responses, neutralization of proinflammatory cytokines and administration of anti-inflammatory cytokines. In addition, several attempts have been made using less specific forms of immunointervention. The two resounding successes in the immunotherapy of MS, IFN-failed and glatiramer acetate, contrast with the many attempts, equally based on sound reasoning and promising animal data. Nevertheless, antigen-based immunointervention will continue to be tested clinically, and we will certainly witness the application of more articulate strategies able to selectively target cytokine production by Th1 or Th2 cells or to modify the Th1/Th2 balance. Perhaps, an effective manipulation of pathogenic and protective cells in MS may eventually rely on a combination of antigen- and cytokine-based approaches to selectively target autoreactive T cells and divert them from autoaggression. Most importantly, new avenues are opening, such as the use of chemokine receptor antagonists, and others look very promising, as targeting dendritic cells to favour their capacity to induce regulatory T cells.