Interleukin-12 and tumor necrosis factor-alpha levels in cerebrospinal fluid of multiple sclerosis patients

Cerebrospinal Fluid and Blood Cytokines as Biomarkers for Multiple Sclerosis: A Systematic Review and Meta-Analysis of 226 Studies With 13,526 Multiple Sclerosis Patients

Background: Multiple sclerosis (MS) biomarker identification is important for pathogenesis research and diagnosis in routine clinical practice. Cerebrospinal fluid (CSF) and blood cytokines as potential biomarkers that can inform MS pathogenesis, diagnosis and response to treatment have been assessed in numerous studies. However, there have been no comprehensive meta-analyses to pool cytokine data and to address their diagnostic performance. We systematically reviewed literature with meta-analyses to assess the alteration levels of cytokines and chemokines in MS.

Methods: We searched PubMed and Web of Science for articles published between January 1, 1990 and April 30, 2018 for this systematic review and meta-analysis. Data were extracted from 226 included studies encompassing 13,526 MS patients and 8,428 controls. Biomarker performance was rated by a random-effects meta-analysis based on the standard mean difference between cytokine concentration in patients with MS and controls, or patients before and after treatments.

Results: Of the 26 CSF cytokines and 37 blood cytokines for potential differentiation between MS patients and controls, the random-effects meta-analysis showed that 13 CSF cytokines and 21 blood cytokines were significantly increased in MS patients in comparison to the controls. Interestingly, TNF-α, CXCL8, IL-15, IL-12p40, and CXCL13 were increased in both blood and CSF of MS patients. For those cytokines analyzed in at least 10 studies, differentiation between case and control was strong for CSF CXCL13, blood IL-2R, and blood IL-23; CSF CXCL8, blood IL-2, and blood IL-17 also performed well in differentiating between MS patients and controls, whereas those of CSF TNF-α and blood TNF-α, CXCL8, IL-12, IFN-γ were moderate. Furthermore, CSF IL-15, CCL19, CCL11, CCL-3, and blood CCL20, IL-12p40, IL-21, IL-17F, IL-22 had large effective sizes when differentiating between MS patients and controls but had a relatively small number of studies (three to seven studies).

Conclusion: Our findings clarified the circulating cytokine profile in MS, which provide targets for disease modifying treatments, and suggest that cytokines have the potential to be used as biomarkers for MS.

The autoimmune concept of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system (CNS). With growing evidence for environmental and genetic factors, MS is now accepted as an autoimmune disease. This complex disease seems to implicate various cell types in both innate and adaptive compartments. Here, we discuss recent advances in the immunological field of MS research.

Tumor necrosis factor stimulates expression of CXCL12 in astrocytes

It has been increasingly appreciated that tumor necrosis factor (TNF) performs various protective and anti-inflammatory functions in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Recently, CXCL12 has been identified as a key inhibitor of leukocyte entry into the central nervous system (CNS) and as a regulator of inflammation resulting from the invasion. Here, a positive correlation between expression of TNF and CXCL12 in the CNS samples of EAE rats is presented. Also, it is shown that TNF potentiates CXCL12 expression in astrocytes. These results contribute to a view that TNF produced within the CNS plays a protective role in neuroinflammation.

Body fluid biomarkers in multiple sclerosis: how far we have come and how they could affect the clinic now and in the future

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system, which affects over 2.5 million people worldwide. Although MS has been extensively studied, many challenges still remain in regards to treatment, diagnosis and prognosis. Typically, prognosis and individual responses to treatment are evaluated by clinical tests such as the expanded disability status scale, MRI and presence of oligoclonal bands in the cerebrospinal fluid. However, none of these measures correlates strongly with treatment efficacy or disease progression across heterogeneous patient populations and subtypes of MS. Numerous studies over the past decades have attempted to identify sensitive and specific biomarkers for diagnosis, prognosis and treatment efficacy of MS. The objective of this article is to review and discuss the current literature on body fluid biomarkers in MS, including research on potential biomarker candidates in the areas of miRNA, mRNA, lipids and proteins.

Immunopathogenesis and immunotherapeutic approaches in multiple sclerosis

Multiple sclerosis is an organ-specific autoimmune disease, characterized pathologically by cell-mediated inflammation, demyelination and variable degrees of axonal loss. Although inflammation is considered central to the pathogenesis of multiple sclerosis, to date, the only licensed and hence widely used multiple sclerosis immunotherapies are interferon-beta, glatiramer acetate and mitoxantrone. This review discusses the immunopathogenesis of multiple sclerosis, focusing on a number of emerging immunotherapies. A number of new approaches likely to manipulate the immunopathogenesis of multiple sclerosis and which may ultimately allow for the development of more effective immunotherapy are also highlighted.

First-line disease-modifying therapies in paediatric multiple sclerosis: a comprehensive overview

Paediatric multiple sclerosis (MS) is defined as the onset of MS before the age of 18 years. Immunomodulatory disease-modifying therapies (i.e. the interferons [IFNs] and glatiramer acetate) are considered first-line treatments in adult patients with MS, but they are largely understudied in the paediatric population. IFNβ is a type 1 IFN produced by fibroblasts. The therapeutic effect achieved by IFNβ in MS is believed to be the result of a variety of mechanisms, including the inhibition of T-cell proliferation and a shift in cytokine production. There are currently two forms of recombinant IFNβ used therapeutically for MS: IFNβ-1a and IFNβ-1b. Two formulations of IFNβ-1a exist, one administered as an intramuscular injection once weekly and the other by subcutaneous injection three times per week. Only one type of IFNβ-1b product is on the market, a subcutaneous injection administered every other day. Pharmacokinetic studies of these agents in children do not exist and available data are primarily from studies in healthy adults. It does not appear that the various formulations differ significantly in terms of bioavailability or efficacy in adults. The toxicity profiles of the interferon formulations are similar, with the most common adverse effects in children including flu-like symptoms, injection site reactions and transient elevations in liver enzymes. Glatiramer acetate is a mixture of synthetic polypeptide chains consisting of four different amino acids. Glatiramer acetate appears to mimic the antigenic properties of myelin basic protein (MBP), and by doing so, alters T-cell activation in the periphery. Glatiramer acetate is administered as a once-daily subcutaneous injection. Similar to the IFNβ formulations, there are no pharmacokinetic studies of this agent in children. The most common adverse effects include injection site reactions and transient chest tightness. Fingolimod, a sphingosine 1-phosphate receptor modulator, is a new disease-modifying therapy that was approved by the US FDA in 2010 for the first-line treatment of relapsing forms of MS in adults. However, due to a lack of information and clinical data on this agent in the paediatric population, it is not included in this discussion. Dose-finding studies of the IFNs and glatiramer acetate in the paediatric population are limited. Dosing recommendations are largely based on tolerability studies, with most children and adolescents tolerating the full adult doses. Clinical studies of IFNs in children have not been objectively designed to establish the efficacy of these therapies, and evidence is limited to that of observational trials and retrospective case reports. However, the largest cohort (130 cases) of paediatric MS patients studied to date reported a reduction in annual relapse rate with all three of the different IFNβ formulations and glatiramer acetate after a follow-up period of more than 4 years. Treatment with one of the first-line agents should be offered to any patient after the occurrence of a second demyelinating episode. The efficacy of the four first-line disease-modifying agents is considered to be relatively equivalent, and the choice of agent should be determined on an individual patient basis, taking into account potential adverse effects and patient preferences. Current data suggest that the IFNs and glatiramer acetate are safe and effective therapies in paediatric patients with MS. However, further studies evaluating the pharmacokinetics, appropriate dosing and comparisons of efficacy among these agents are needed to determine the most appropriate and evidence-based treatment decisions in this population.

Disease biomarkers in multiple sclerosis: potential for use in therapeutic decision making

Multiple sclerosis (MS) is an autoimmune disorder of the brain and spinal cord that predominantly affects white matter. MS has a variable clinical presentation and has no 'diagnostic' laboratory test; this often results in delays to definite diagnosis. In confronting the disease, early diagnosis and appropriate, timely therapeutic intervention are critical factors in ensuring favorable long-term outcomes. The availability of reliable biomarkers could radically alter our management of MS at critical phases of the disease spectrum. Identification of markers that could predict the development of MS in high-risk populations would allow for intervention strategies that may prevent evolution to definite disease. Work with anti-myelin antibodies and the ongoing analysis of microarray gene expression have thus far not yielded biomarkers that predict future disease development. Similarly, extensive studies with serum and cerebrospinal fluid (CSF) have not yielded a disease-specific and sensitive diagnostic biomarker for MS. Establishment of disease diagnosis always leads to questions about long-term prognosis because in an individual patient the natural history of the disease is clinically unpredictable. Biomarkers that correlate with myelin loss, spinal cord disease, grey matter and subcortical demyelination need to be developed in order to accurately predict the disease course. The bulk of effort in biomarker development in MS has been concentrated in the area of monitoring disease activity. At present, a disease 'activation' panel of CSF biomarkers would include the following: interleukin-6 or its soluble receptor, nitric oxide and nitric oxide synthase, osteopontin, and fetuin-A. Although disease activity in MS is predominantly inflammatory, disease progression is likely to be the result of neurodegeneration. Therefore, the roles of proteins indicative of neuronal, axonal, and glial loss such as neurofilaments, tau, 14-3-3 proteins, and N-acetylaspartate are all under investigation, as are proteins affecting remyelination and regeneration, such as Nogo-A. With the increasing awareness of cognition dysfunction in MS, molecules such as apolipoprotein and proteins in the amyloid precursor protein pathway implicated in dementia are also being examined. Serum biomarkers that help monitor therapeutic efficacy such as the titer of antibody to beta-interferon, a first-line medication in MS, are established in clinical practice. Ongoing work with biomarkers that reflect drug bioavailability and factors that distinguish between medication responders and nonresponders are also under investigation. The discovery of new biomarkers relies on applying advances in proteomics along with microarray gene and antigen analysis and will hopefully result in the establishment of specific biomarkers for MS.

Deficiency in regulatory T cells results in development of antimitochondrial antibodies and autoimmune cholangitis

There have been several descriptions of mouse models that manifest select immunological and clinical features of autoimmune cholangitis with similarities to primary biliary cirrhosis in humans. Some of these models require immunization with complete Freund's adjuvant, whereas others suggest that a decreased frequency of T regulatory cells (Tregs) facilitates spontaneous disease. We hypothesized that antimitochondrial antibodies (AMAs) and development of autoimmune cholangitis would be found in mice genetically deficient in components essential for the development and homeostasis of forkhead box 3 (Foxp3)(+) Tregs. Therefore, we examined Scurfy (Sf) mice, animals that have a mutation in the gene encoding the Foxp3 transcription factor that results in a complete abolition of Foxp3(+) Tregs. At 3 to 4 weeks of age, 100% of animals exhibit high-titer serum AMA of all isotypes. Furthermore, mice have moderate to severe lymphocytic infiltrates surrounding portal areas with evidence of biliary duct damage, and dramatic elevation of cytokines in serum and messenger RNAs encoding cytokines in liver tissue, including tumor necrosis factor alpha, interferon-gamma, interleukin (IL)-6, IL-12, and IL-23.

CONCLUSION

The lack of functional Foxp3 is a major predisposing feature for loss of tolerance that leads to autoimmune cholangitis. These findings reflect on the importance of regulatory T cells in other murine models as well as in patients with primary biliary cirrhosis.

Increase of CD4+TNF{alpha}+IL-2-T cells in cerebrospinal fluid of multiple sclerosis patients

Intracellular production of TNFalpha and IL-2 after stimulation with phorbol myristate/ionomycin was flowcytometrically measured in CD4(+) T cells from peripheral blood (PB) and cerebrospinal fluid (CSF) of 29 patients with multiple sclerosis (MS), and 16 with other inflammatory and 41 with other non-inflammatory neurological diseases. In CSF, the percentages of CD4(+)TNFalpha(+)IL-2(-)T cells were significantly higher in patients with MS than either of the controls, whereas no difference was found in CD4(+)TNFalpha(+)IL-2(+)T or CD4(+)TNFalpha(-)IL-2(+)T cells. The increase was more pronounced at relapse than in remission. No significant change was detected in PB. These findings suggested that CD4(+)TNFalpha(+)IL-2(-)T cells are intrathecally upregulated in MS.

APC-derived cytokines and T cell polarization in autoimmune inflammation

T cell-mediated autoimmune diseases such as multiple sclerosis and rheumatoid arthritis are driven by autoaggressive Th cells. The pathogenicity of such Th cells has, in the past, been considered to be dictated by their cytokine polarization profile. The polarization of such effector T cells relies critically upon the actions of cytokines secreted by APCs. While Th1 polarization has long been associated with the pathogenesis of autoimmune diseases, recent data obtained in gene-targeted mice and the discovery of Th17 cell involvement in autoimmunity conflict with this hypothesis. In light of these recent developments, we discuss in this review the actions of APC-derived cytokines and their emerging roles in T cell polarization in the context of autoimmune inflammatory responses.

Production of interferon-gamma by microglia

Neural cells do not usually interact with immune cells because of the lack of major histocompatibility complex (MHC) antigen expression. Interferon-gamma (IFN-gamma) enables this interaction via induction of MHC antigen expression in neural cells. Thus, IFN-gamma is a critical cytokine for the development of central nervous system (CNS) pathologies. IFN-gamma, however, is considered to be produced exclusively by lymphoid cells. Here, we show for the first time that murine microglia produce IFN-gamma in response to IL-12 and/or IL-18, using RT-PCR detection of IFN-gamma mRNA and Western blotting and immunohistochemical analysis for cytoplasmic expression of IFN-gamma. Stimulation of microglia with IL-12 and IL-18 resulted in MHC class II mRNA expression in microglia. Since IL-12 and IL-18 are produced in the CNS by glial cells, these cytokines may play a critical role in the initiation of neural-immune cell interaction and the induction of autoimmune processes in the CNS via induction of IFN-gamma and MHC antigens.

IL-23: changing the verdict on IL-12 function in inflammation and autoimmunity

IL-12 and IL-23 are molecules mainly produced by activated accessory and antigen-presenting cells. The tools for studying the biology of IL-12 in man and laboratory rodents have greatly advanced our appreciation of the central role of this molecule in cell-mediated immunity and inflammation. In particular, IL-12 is thought to be the prime-regulator of TH1 development. Targeting what was thought to be IL-12 function in vivo, resulted in drastic amelioration of inflammation and autoimmunity firmly linking TH1 polarisation to autoimmune development. Upon discovery of IL-23 and the fact that the large subunit of IL-23 is shared by IL-12, the research community only begins to grasp that the features attributed to IL-12 and TH1 development in inflammation are, in fact, dependent on IL-23 and not on IL-12. Hence, the perception of IL-12 biology is, to a large extent, based on a mistaken identity. In this review, the authors provide an overview of their current understanding of IL-12 and IL-23 biology in inflammation and autoimmunity, and how this viewpoint has been readjusted over the past 15 years.

Intrathecal activation of the IL-17/IL-8 axis in opticospinal multiple sclerosis

There are two distinct subtypes of multiple sclerosis in Asians, opticospinal (OS-multiple sclerosis) and conventional (C-multiple sclerosis). In OS-multiple sclerosis, selective and severe involvement of the optic nerves and spinal cord is characteristic, though its mechanisms are unknown. The present study aimed to find out possible differences in the cytokine/chemokine profiles in CSF between OS-multiple sclerosis and C-multiple sclerosis and to delineate the relationships between these profiles and neuroimaging and pathological features. Sixteen cytokines/chemokines, namely interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1beta (MIP-1beta), were measured simultaneously in CSF supernatants from 40 patients with relapsing-remitting multiple sclerosis (20 OS-multiple sclerosis and 20 C-multiple sclerosis) at relapse and 19 control patients with spinocerebellar degeneration (SCD), together with intracellular production of IFN-gamma and IL-4 in CSF CD4+ T cells. In CSF supernatants relative to controls, IL-17, MIP-1beta, IL-1beta and IL-13 were only significantly increased in OS-multiple sclerosis patients, while TNF-alpha was only significantly increased in C-multiple sclerosis patients, using a cut-off level of 1 pg/ml. IL-8 was significantly elevated in both OS-multiple sclerosis and C-multiple sclerosis patients. MCP-1 was significantly decreased in both OS-multiple sclerosis and C-multiple sclerosis patients, while IL-7 was only significantly decreased in C-multiple sclerosis patients. IL-17, IL-8 and IL-5 were significantly higher in OS-multiple sclerosis patients than in C-multiple sclerosis patients. The increases in IL-17 and IL-8 in OS-multiple sclerosis were still significant even after exclusion of the patients undergoing various immunomodulatory therapies. Assays of intracellular cytokine production revealed that both the IFN-gamma+IL-4- T-cell percentage and intracellular IFN-gamma/IL-4 ratio in CSF cells were significantly greater in C-multiple sclerosis patients than in controls. Contrarily, OS-multiple sclerosis patients showed not only a significantly greater percentage of IFN-gamma+IL-4- T cells than controls but also a significantly higher percentage of IFN-gamma-IL-4+ T cells than C-multiple sclerosis patients. Among the cytokines elevated in multiple sclerosis, only IL-8 showed a significant positive correlation with the Expanded Disability Status Scale of Kurtzke score. Both the length of the spinal cord lesions on MRI and the CSF/serum albumin ratio had a significant positive correlation with IL-8 and IL-17 in multiple sclerosis, in which the spinal cord lesions were significantly longer in OS-multiple sclerosis than in C-multiple sclerosis. Three of six spinal cord specimens from autopsied OS-multiple sclerosis cases demonstrated numerous myeloperoxidase-positive neutrophils infiltrating necrotic lesions. These findings strongly suggest that in OS-multiple sclerosis, in addition to the Th1 cell upregulation seen in C-multiple sclerosis, intrathecal activation of the IL-17/IL-8 axis inducing heavy neutrophil infiltration contributes to extensive spinal cord lesion formation.

Interleukin-12 and interferon-gamma are not detectable in the cerebrospinal fluid of patients with amyotrophic lateral sclerosis

The cause of sporadic amyotrophic lateral sclerosis (SALS) is unknown. We investigated the immune-mediated inflammatory hypothesis of SALS by assaying interleukin-12 (IL-12), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) in the cerebrospinal fluid (CSF) of patients with SALS. These cytokines were measured in the CSF from patients with SALS (n=11), patients with immune-mediated inflammatory central nervous system or nerve root disorders (n=12), and patients with other neurological diseases (n=15) by high sensitivity sandwich enzyme linked immunosorbent assay (ELISA). All samples were below the assay detection limits of 0.5 pg/ml for IL-12 and 8 pg/ml for IFN-gamma. There was no difference between the groups in the mean concentration of IL-6. There is no evidence in cerebrospinal fluid for induction of a T(H)1 immune response in SALS.

Intranasal administration of interferon beta bypasses the blood–brain barrier to target the central nervous system and cervical lymph nodes: a non-invasive treatment strategy for multiple sclerosis

Intranasal (i.n.) administration of IFN beta-1b was examined as a route for targeted delivery to the rat central nervous system (CNS). Intranasal administration resulted in significant delivery throughout the CNS and cervical lymph nodes with low delivery to peripheral organs. At similar blood levels, intravenous (i.v.) administration of IFN beta-1b yielded 88-98% lower CNS levels and 100-1650% greater peripheral organ levels compared to intranasal. Autoradiography confirmed much greater delivery to the CNS with intranasal administration. Intranasally administered IFN beta-1b reached the brain intact and produced tyrosine phosphorylation of IFN receptor in the CNS. Intranasal administration offers a non-invasive method of drug delivery for multiple sclerosis (MS) that bypasses the blood-brain barrier (BBB) and directly targets the CNS and lymph nodes.

Cytokines and chemokines in neuro-Behçet's disease compared to multiple sclerosis and other neurological diseases

Cytokines and chemokines in cerebrospinal fluid (CSF) can have implications on the pathogenesis of neuro-Behçet's disease (NB). CSF and serum samples from 33 patients with NB, 25 with multiple sclerosis (MS), 20 patients with infectious and/or inflammatory neurological diseases (IN) and 14 with other noninflammatory neurological diseases (NIN) were investigated by ELISA. In the CSF, CXCL10 levels were significantly higher in NB and IN than NIN and MS, whereas CXCL8 was increased in NB compared to NIN. CCL2 levels in MS CSF and sera were lower, whereas CXCL8 in MS sera was higher than the other groups. IL-12 was elevated in CSF of IN compared to NB and NIN and also in the CSF of MS compared to NIN. No difference was detected for IL-10 and IL-17. These results reflect that NB has a mediator pattern in resemblance with non-specific inflammations such as neuro-infections compared to autoimmune disorders such as multiple sclerosis, suggesting that a currently unknown infection might be the trigger of a vasculitic process in the central nervous system (CNS).

Generating hypotheses by discovering implicit associations in the literature: a case report of a search for new potential therapeutic uses for thalidomide

The availability of scientific bibliographies through online databases provides a rich source of information for scientists to support their research. However, the risk of this pervasive availability is that an individual researcher may fail to find relevant information that is outside the direct scope of interest. Following Swanson's ABC model of disjoint but complementary structures in the biomedical literature, we have developed a discovery support tool to systematically analyze the scientific literature in order to generate novel and plausible hypotheses. In this case report, we employ the system to find potentially new target diseases for the drug thalidomide. We find solid bibliographic evidence suggesting that thalidomide might be useful for treating acute pancreatitis, chronic hepatitis C, Helicobacter pylori-induced gastritis, and myasthenia gravis. However, experimental and clinical evaluation is needed to validate these hypotheses and to assess the trade-off between therapeutic benefits and toxicities.

TACE mRNA expression in peripheral mononudear cells precedes new lesions on MRI in multiple sclerosis

Tumor necrosis factor-alpha (TNF-alpha) is involved in the pathogenesis of multiple sclerosis (MS). It has to be released from its cell membrane-bound precursor by proteolytic cleavage. This is mainly performed by a member of the ADAM (a disintegrin and metalloproteinase) family of enzymes, TNF-alpha-converting enzyme (TACE, ADAM 17). In a longitudinal study on 11 relapsing-remitting MS patients, we qualitatively determined mRNA expression of TNF-alpha and TACE in peripheral blood mononuclear cells (PBMCs) without ex vivo stimulation. mRNA expression was related to disease activity as assessed by monthly gadolinium (Gd)-enhanced brain magnetic resonance imaging (MRI). Patients found positive for TACE mRNA in PBMCs showed a significantly higher mean number of new Gd-enhancing lesions per scan one month following PBMC sampling.

Mast cells: new targets for multiple sclerosis therapy?

Growing evidence suggests that mast cells (MCs) play a crucial role in the inflammatory process and the subsequent demyelination observed in patients suffering from multiple sclerosis (MS). Although no consensus exists on the role of mast cells in multiple sclerosis, recent results from animal models clearly indicate that these cells act at multiple levels to influence both the induction and the severity of disease. In addition to changing our views on the pathophysiology of multiple sclerosis, the concept that mast cells are critical for the outcome of the disease could have an important impact on the development of new therapeutic approaches.

Cortisol is increased in postmortem cerebrospinal fluid of multiple sclerosis patients: relationship with cytokines and sepsis

Hypothalmo-pituitary-adrenal (HPA) axis activity is altered in patients with multiple sclerosis (MS), resulting in elevated basal levels and enhanced response of cortisol in stimulation tests. HPA axis hyperactivation in MS is thought to be the result of complex interactions of genetic, immunologic, and neuroendocrinological mechanisms. In order to investigate whether cytokine levels in the central nervous system are associated with the activation of the HPA axis in MS, we measured cortisol, interleukin (IL)-6, IL-10 and TNF-alpha levels in postmortem cerebrospinal fluid (CSF) of 18 patients with severe MS and 50 controls. We also investigated the cortisol and cytokine levels in the CSF of a group of MS patients and controls who died with sepsis, in order to see whether acute infectious situations affect the association between cortisol and cytokines. The cortisol levels in MS patients were increased by 80% in comparison to controls (p=0.008). There was no difference in IL-6 levels between the groups, while IL-10 and TNF-alpha levels of the majority of subjects were below detection limits. There was a positive correlation between cortisol and IL-6 only in control patients with sepsis (r=0.89, p=0.019), but not within the MS patents with sepsis or MS and control groups without sepsis. Cortisol levels in postmortem serum and CSF were highly correlated (r>0.78, p<0.001). We concluded that the basal level of cortisol is significantly increased in the CSF of MS patients and that IL-6 is not responsible for this rise. The relationship between cortisol and IL-6 in sepsis is discussed.

The role of IL-12 in the induction of intravenous tolerance in experimental autoimmune encephalomyelitis

Intravenous administration of autoantigen is an effective method to induce Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). IL-12 is a potent Th1 stimulator and an essential cytokine in the induction of EAE. The role of IL-12 in the induction of i.v. tolerance is not clear. In this study, we induced tolerance by i.v. administering myelin basic protein (MBP) peptide Ac1-11 (MBP1-11) in EAE. We observed significant suppression of IL-12 production by the lymph node cells of MBP1-11-injected mice. To see whether the low level of IL-12 is the cause or effect of tolerance, we administered IL-12 to the EAE mice at the time of i.v. MBP1-11 injection. Exogenous IL-12 abrogated the suppression of clinical and pathological EAE by i.v. tolerance. IL-12 blocked the suppressive effect of i.v. tolerance on the proliferative response to MBP1-11 and MBP1-11-induced production of IL-12 and IFN-gamma. Furthermore, IL-12 completely blocked the i.v. tolerance-induced type 1 T regulatory cell response. These data suggest that i.v. administration of autoantigen results in the suppression of endogenous IL-12 and the consequent switching of the immune response from an immunogenic to a tolerogenic form.

Acute actions of tumor necrosis factor-alpha on intracellular Ca(2+) and K(+) currents in human microglia

The effects of acute application of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFalpha) on levels of intracellular Ca(2+) ([Ca(2+)]i) and on whole-cell outward and inward K(+) currents were studied in cultured human microglia. TNFalpha elicited a linear increase in [Ca(2+)]i to a plateau level in microglia bathed in either standard physiological saline solution or Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i or the level of [Ca(2+)]i attained was not significantly altered in the absence of external Ca(2+) indicating that Ca(2+) influx did not contribute appreciably to the cytokine-induced rise in [Ca(2+)]i. This point was directly confirmed using Mn(2+) quenching where no change in signal fluorescence was observed with TNFalpha treatment of microglia in Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i induced by TNFalpha in Ca(2+)-free physiological saline solution was not altered by prior application of ATP to deplete inositol triphosphate stores indicating that these stores did not contribute to the cytokine response. In whole-cell patch clamp recordings, the acute treatment of human microglia with TNFalpha led to the expression of an outward K(+) current in one-third (14 of 41) of cells. This current was activated at potentials positive to -30 mV, showed rapid kinetics of activation with no evident inactivation and had an I-V relation exhibiting outward rectification. Analysis of tail currents showed reversal of the outward K(+) current near -70 mV and tetraethylammonium (10 mM) inhibited the outward K(+) current to 24% of control level. Acute application of TNFalpha had no effect to alter inward rectifier currents generated from voltage ramps. The signaling pathways involving TNFalpha modulation of [Ca(2+)]i and K(+) channels in human microglia may contribute to functional and pathological actions of the cytokine in the brain.

CD40 engagement stimulates IL-12 p70 production by human microglial cells: basis for Th1 polarization in the CNS

The APC-derived cytokine interleukin (IL)-12 polarizes CD4 T cells towards the pro-inflammatory Th1 phenotype and has been shown to be crucial for the development of EAE in rodents. In this study we demonstrate that production of IL-12 by human adult CNS-derived microglial cells can be triggered by cell contact with activated T cells. Microglial activation and IL-12 production can be blocked by anti-CD154 mAbs. IL-12 production could also be induced by direct engagement of CD40 on microglia using a CD40 agonist. IL-12 secretion by microglia is significantly reduced by TNF and IFN-gamma antagonists showing that the IL-12 production is subject to regulation by auto- and paracrine stimuli.

Axonal degeneration in the pathogenesis of multiple sclerosis

Axonal degeneration plays an important role in the accumulation of disability in patients with multiple sclerosis (MS). Pathological studies have demonstrated axonal damage, particularly in areas of acute inflammation and demyelination, and in chronic lesions. Axonal loss and its progression, which is associated with neurological disability, has also been demonstrated by magnetic resonance imaging (MRI) studies. The mechanisms of axonal loss are uncertain, but may involve axonal degeneration secondary to demyelination, or damage to the axonal cytoskeleton. Inflammatory mediators, including cytokines and proteolytic enzymes may contribute to axonal damage, as may nitric oxide. Axonal destruction may also be due to immune attack directed at axonal components. The realisation that axonal degeneration is a fundamental component of MS that may occur early in the disease course should alter the approach to management and open avenues to a more targeted immunotherapy aimed at reducing the progression of disability.

Decreased interleukin-10 and increased interleukin-12p40 mRNA are associated with disease activity and characterize different disease stages in multiple sclerosis

It has been shown that proinflammatory and antiinflammatory cytokines correlate with disease activity in multiple sclerosis (MS). To establish whether such correlations depend on the disease stage, we assessed in a longitudinal fashion the expression of interleukin (IL)-12 (p40 and p35), tumor necrosis factor-alpha, interferon-gamma, and IL-10 mRNA by competitive polymerase chain reaction in unstimulated peripheral blood mononuclear cells of relapsing-remitting (RR) and secondary progressive (SP) MS patients, in relation to monthly clinical and magnetic resonance imaging monitoring. MS patients had increased levels of IL-12p40 and decreased levels of IL-10 mRNA compared with controls; this difference was most pronounced in SP patients. Both RR and SP patients had increased levels of IL-12p40 mRNA compared with controls during the development of active lesions. Moreover, in RR MS an increase was found before relapse. IL-12p35 mRNA was decreased in both groups, and in relation to disease activity it showed a pattern different from IL-12p40 mRNA. In RR MS, IL-10 mRNA was low 4 weeks before magnetic resonance imaging activity and 6 weeks before relapse; a significant increase to normal levels was noted when active lesions became apparent. In contrast, SP patients showed low IL-10 mRNA levels constitutively, suggesting that IL-10 plays an important role in the control of disease progression.

Inhibition of Th1 Polarization by Soluble TNF Receptor Is Dependent on Antigen-Presenting Cell-Derived IL-12

Th1-polarized CD4+ T cells are considered central to the development of a number of target-directed autoimmune disorders including multiple sclerosis. The APC-derived cytokine IL-12 is a potent inducer of Th1 polarization in T cells. Inhibition of IL-12 in vivo blocks the development of experimental allergic encephalomyelitis, the animal model for multiple sclerosis. Based on previous work that suggests that the production of IL-12 by activated human central nervous system-derived microglia is regulated by autocrine TNF-α, we wanted to determine whether inhibition of TNF could induce a reduction of Th1 responses by its impact on systemic APCs. We found that soluble TNFR p75-IgG fusion protein (TNFR:Fc) inhibited production of IFN-γ by allo-Ag-activated blood-derived human CD4 T cells. We documented reduced IL-12 p70 production by APCs in the MLR. By adding back recombinant IL-12, we could rescue IFN-γ production, indicating that TNFR:Fc acts on APC-derived IL-12. Consistent with an inhibition of the Th1 polarization, we found a decreased expression of IL-12R-β2 subunit on the T cells. Furthermore, the capacity of T cells to secrete IFN-γ upon restimulation when previously treated with TNFR:Fc is impaired, whereas IL-2 secretion was not altered. Our results define a TNF-dependent cytokine network that favors development of Th1 immune responses.

B7-1 (CD80), B7-2 (CD86), interleukin-12 and transforming growth factor-beta mRNA expression in CSF and peripheral blood mononuclear cells from multiple sclerosis patients

Costimulatory molecules B7-1 (CD80) and B7-2 (CD86) are differently involved in T cell stimulation. In chronic experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS), B7-1 was preferentially involved in pathophysiology of relapses. We used reverse transcription polymerase chain reaction (RT-PCR) to amplify the mRNA coding for these molecules in cerebrospinal fluid (CSF) cells and peripheral blood mononuclear cells (PBMC) from 18 MS patients and 21 other neurological patients. In CSF cells of MS cases, B7-1 mRNA was only detected in some patients who showed clinical signs of acute relapse at the time of the spinal tap, while B7-2 mRNA was widely detectable without difference between active or stable MS and controls. mRNA coding for transforming growth factor-beta (TGF-beta) was detectable in the majority of cases, with higher expression in CSF cells of MS and other inflammatory neurological diseases (OIND) than in noninflammatory controls, and higher expression in PBMC of MS patients than in all other cases. Finally, mRNA coding for interleukin (IL)-12p40 was only detected in a very few number of MS and inflammatory cases. These findings were related to previous detection of other cytokines in the same cases, showing relationships in CSF cells between high expression of B7-1, IL-12p40 and TNF-alpha.

Comparative study of the pharmacodynamic and pharmacologic effects of Betaseron and AVONEX

The aim of this 1 week study was to compare the biologic effects induced by Betaseron and AVONEX using their approved dose, route, and schedule. Sixteen healthy volunteers were randomly assigned to receive either a single i.m. dose of AVONEX (6 million International Units [MIU]) or, every other day s.c. doses of Betaseron (8 MIU). Common side effects associated with interferon-beta (IFN-beta) treatment and biologic response parameters (neopterin, beta2-microglobulin, interleukin-10 [IL-10], and MxA protein levels in blood) were measured. Ibuprofen was administered to all subjects throughout the study. Fever, chills, and myalgia occurred most frequently and with the greatest severity between 6 and 12 h after the first dose of either IFN-beta. Despite the additional dosing of subjects in the Betaseron group, the incidence, duration, and severity of the side effects were not significantly different from those in the AVONEX group. Biologic response parameters reached similar maximum concentrations in both treatment groups. In the Betaseron group, neopterin and beta2-microglobulin levels remained significantly greater than baseline throughout the 7 day study, whereas those in the AVONEX group were elevated only through day 5. Betaseron treatment significantly increased IL-10 levels above baseline, but AVONEX treatment did not. The overall induction of neopterin, beta2-microglobulin, and IL-10 (as measured by area under the concentration-time curve) was significantly greater in the Betaseron group than the AVONEX group (p = 0.031). The results of this study demonstrate that the approved Betaseron dosing regimen, in combination with ibuprofen use, provided a significantly greater and more consistently elevated biologic response compared with that of AVONEX and did so with a side effects profile comparable to that of once a week AVONEX dosing.

Reduced prevalence of allergic disease in patients with multiple sclerosis is associated with enhanced IL-12 production

BACKGROUND

We previously showed that the prevalence of allergic disease is decreased in patients with multiple sclerosis (MS); however, the mechanisms that explain this finding have not previously been defined.

OBJECTIVES

We have demonstrated that protection of patients with MS from allergic disease may be caused by the production in monocytes from these patients of elevated quantities of IL-12 compared with that observed in monocytes from individuals with allergies.

METHODS

Purified monocytes from peripheral blood of subjects with or without allergies and from individuals with MS were directly stimulated with Staphylococcus aureus Cowan strain I in the absence of T cells. IL-12 was quantitated by a sensitive reverse transcription, competitive PCR.

RESULTS

IL-12 production was 5-fold greater in monocytes from patients with MS (n = 11) than that from individuals with allergies (n = 10) (for subjects with MS, 1.90+/-0.18 vs 1.24+/-0.19 log10 fmol/microL for individuals with allergies) (P = .02). Although the production of IL-12 in monocytes from patients with MS was slightly higher than that from subjects without allergies, this difference was not statistically significant.

CONCLUSIONS

IL-12 production in individuals with MS is much greater than in individuals with allergies. Because IL-12 induces TH1 cytokine synthesis and reduces the production of TH2 cytokines, which amplify and prolong allergic inflammation, these studies suggest that enhanced IL-12 production may protect individuals with MS from the development of allergy but may predispose such individuals toward autoimmune inflammation in the central nervous system.

Serum interleukin-12 levels in patients with multiple sclerosis

Increasing body of evidence which suggests a crucial role for interleukin (IL)-12 in modulating immune responses in multiple sclerosis (MS) prompted us to analyze IL-12 in serum from MS patients. We measured the sera concentrations of IL-12, tumor necrosis factor (TNF)-alpha and transforming growth factor-beta1, in 21 MS patients and 13 patients with non-inflammatory nervous diseases. In clinically active MS, serum levels of IL-12 were detectable in 53% and TNF-alpha in 40% of patients. None of the patients with clinically inactive MS had detectable IL-12 and TNF-alpha sera levels. Analysis of serum concentrations of all three cytokines revealed no significant differences between MS patients and controls. These findings provide further evidence that both IL-12 and TNF-alpha might have an active role in immunopathogenesis of MS.

Increased interleukin-12 levels in human cerebrospinal fluid following severe head trauma

An overwhelming intracranial inflammatory response occurs as a consequence of severe head trauma, leading to cerebral edema and secondary brain injury. Cytokines are important mediators of post-traumatic cerebral inflammation. In the present study, levels of interleukin-12 (IL-12), a pro-inflammatory cytokine which activates cellular immune response mechanisms, were measured by ELISA in 140 matched serum and ventricular cerebrospinal fluid (CSF) samples from ten patients with severe traumatic brain injury. The mean IL-12 CSF levels were significantly elevated in all patients in the course of 14 days after trauma, compared to CSF samples from 15 control patients. Assessment of the IL-12 CSF/serum ratio and of the blood-brain barrier function, using the CSF/serum albumin ratio, suggest that elevated IL-12 CSF levels might be in part derived from intracerebral cytokine synthesis.

Serum levels of macrophage-derived protein MRP-8/14 are elevated in active multiple sclerosis

Serum concentrations of two macrophage-derived calcium-binding proteins, MRP-8 and MRP-8/14, were studied in 28 patients with relapsing multiple sclerosis (MS). Serum levels were determined with a commercially available sandwich ELISA and the one-tailed Mann-Whitney U test was used for statistical analysis. Median serum levels of MRP-8/14 were significantly higher in MS patients (5150 ng/ml) compared to 26 healthy controls (1482 ng/ml) and significantly higher in MS patients within an acute relapse (6690 ng/ml) compared to MS patients with stable disease (3050 ng/ml). MRP-8 levels were not elevated in MS patients. These results may indicate an early activation of macrophages in the formation of demyelinating MS plaques. In addition, increased serum levels of MRP-8/14 may prove to be a useful paraclinical disease activity parameter in MS patients.