Role of cytokines in multiple sclerosis and experimental autoimmune encephalomyelitis

High-intensity resistance training in multiple sclerosis - An exploratory study of effects on immune markers in blood and cerebrospinal fluid, and on mood, fatigue, health-related quality of life, muscle strength, walking and cognition

BACKGROUND

High-intensity resistance training is unexplored in people with multiple sclerosis.

OBJECTIVES

To evaluate effects of high-intensity resistance training on immune markers and on measures of mood, fatigue, health-related quality of life, muscle strength, walking and cognition. Further, to describe participants' opinion and perceived changes of the training.

METHODS

Twenty patients with relapsing-remitting multiple sclerosis performed high-intensity resistance training at an intensity of 80% of one-repetition maximum, twice a week for 12 weeks. Blood and optional cerebrospinal fluid samples, and data on secondary outcome measures were collected before and after intervention. A study-specific questionnaire was used for capturing participants' opinion.

RESULTS

Seventeen participants completed the study. Plasma cytokine levels of tumor necrosis factor were significantly decreased post-intervention (p=0.001). Exploratory cytokine analyses in cerebrospinal fluid (n=8) did not reveal major changes. Significant and clinically important improvements were found in fatigue (p=0.001) and health-related quality of life (p=0.004). Measures of mood (p=0.002), muscle strength (p ≤ 0.001), walking speed (p=0.013) and cognition (p=0.04) were also improved. A majority of participants evaluated the training as very good and perceived changes to the better.

CONCLUSION

High-intensity resistance training in persons with relapsing remitting multiple sclerosis with low disability had positive effects on peripheral pro-inflammatory cytokine levels, led to clinically relevant improvements in measures of fatigue and health-related quality of life, and was well tolerated. These results provide a basis for a larger randomized trial.

Interleukin-10 and tumor necrosis factor-alpha: model of immunomodulation in multiple sclerosis

OBJECTIVES

The mechanisms involved in the pathogenesis of relapsing-remitting multiple sclerosis are still unclear. The aim of the present study was to evaluate both cerebrospinal fluid (CSF) CD4+ CD7+ T cells and peripheral blood (PB) interleukin-10 (IL-10) as well as tumor necrosis-alpha (TNF-alpha) levels in patients with definite multiple sclerosis of the relapsing-remitting type.

METHODS

To assess the above-mentioned cytokine levels we performed our test by the means of ELI-spot assay; the T-helper cell subset was assayed using flow cytometry.

RESULTS

PB IL-10 levels of multiple sclerosis (MS) patients in remission were significantly (p<0.001) higher than in MS patients in the active phase. There was significant and increased evidence of TNF-alpha levels only in the MS patients in the active phase. CD4+ CD7+ T cells, characterized by a preferential Th1-like cytokine profile, were detectable only in seven patients in the active phase without evidence of a statistical significance with respect to cytokine levels.

CONCLUSION

The data indicate that the production of different cytokines characterized the expression of relapsing-remitting MS. The data also suggest that is it possible to control MS using the regulatory cytokine balance.

Magnetic brain stimulation upregulates adhesion and prevents Eae: MMP-2, ICAM-1, and VCAM-1 in the choroid plexus as a target

Clinical signs appearance and significant increases of ICAM-1 and MMP-2 expressions with the clusters of VCAM-1(+) immunoreactivity in the choroids plexus epithelium to transferred anti-myelin oligodendroglial antibodies into the third brain ventricle, indicate important role of choroids plexus in the induction of acute experimental autoimmune encephalomyelitis (EAE). Magnetic brain stimulation with AKMA micro-magnet flux density of 60 miliTesla, 5 mm in diameter, implanted upon the pineal gland (PG), immediately after antibody injection, significantly decreases the expression of MMP-2 and ICAM-1 in the choroids plexus of the rat brain and abruptly suppresses the induction of acute EAE.

Animal models of multiple sclerosis

Since its first description, experimental autoimmune encephalomyelitis, originally designated experimental allergic encephalitis (EAE), has been proposed as animal model to investigate pathogenetic hypotheses and test new treatments in the field of central nervous system inflammation and demyelination, which has become, in the last 30 years, the most popular animal model of multiple sclerosis (MS). This experimental disease can be obtained in all mammals tested so far, including nonhuman primates, allowing very advanced preclinical studies. Its appropriate use has led to the development of the most recent treatments approved for MS, also demonstrating its predictive value when properly handled. Some of the most exciting experiments validating the use of neural precursor cells (NPCs) as a potential therapeutic option in CNS inflammation have been performed in this model. We review here the most relevant immunological features of EAE in the different animal species and strains, and describe detailed protocols to obtain the three most common clinical courses of EAE in mice, with the hope to provide both cultural and practical basis for the use of this fascinating animal model.

Reaction of mouse brain oligodendrocytes and their precursors, astrocytes and microglia, to proinflammatory mediators circulating in the cerebrospinal fluid

The response of glial cells to the acute intracerebroventricular administration of interferon-gamma, and of this cytokine combined with the endotoxin lipopolysaccharide or with tumor necrosis factor-alpha, was investigated in the brain of adult mice over a time course of 1 week. Oligodendrocytes were identified by immunocytochemistry, using O4 to label their precursors and 2',3'-cyclic nucleotide 3'-phosphohydrolase as marker of mature cells. Astrocytes were labeled by glial fibrillary acidic protein immunoreactivity and microglial cells by tomato lectin histochemistry. Compared with ovalbumin-injected control cases, all cytokine treatments caused a marked decrease of immunostained mature oligodendrocytes in the brain since 1 day postinjection. O4+ oligodendrocyte precursors increased instead progressively from 2 to 7 days. Astrocytes, markedly activated by cytokine treatments, also exhibited a progressive quantitative increase from 2 days onward. Activation and proliferation of microglial cells were instead most evident at 24 h postinjection. Such glial responses to interferon-gamma injections were especially marked in the periventricular brain parenchyma and were enhanced by coadministration of lipopolysaccharide or tumor necrosis factor-alpha. The findings show that a pulse of proinflammatory mediators in the cerebrospinal fluid affects mature oligodendrocytes, concomitantly with the early appearance of activated microglia, and that such reactions are rapidly followed by an increase of oligodendrocyte precursors paralleled by astrocytic activation. The data, which allowed dissecting the events elicited in glial cell populations by inflammatory mediators via the cerebrospinal fluid, indicate that these molecules elicit in vivo a toxic effect on mature oligodendrocytes and a stimulation of their precursors in the adult brain.

Immunomodulatory effects of interferon-beta-1b in patients with multiple sclerosis

The mechanisms by which IFN beta-1b acts in the treatment of patients with multiple sclerosis (MS) are not completely known. Immunomodulatory effects of IFN beta-1b were investigated in patients with relapsing-remitting (RR) MS in vivo and in vitro. Compared to baseline and controls, defined as patients with RR-MS without immunomodulatory therapy, the expression of TGF beta-1-mRNA by peripheral blood mononuclear cells (PBMC) was persistently increased at week 6, month 3 and month 6 (p < or = 0.05), that of the TGF beta-1 receptor type II from day 5 up to month 6 (p < 0.01). The expression of TNF alpha-mRNA decreased from day 1 to month 3 compared to day 0 and the controls (p < 0.01). The in vitro investigations performed on isolated peripheral blood lymphocytes demonstrated that these effects were dose-dependent. The mRNA and protein expression of TNF alpha-R-I (55 kD-receptor) was only temporarily elevated at the beginning of the therapy in vivo. The expression of TNF alpha-R-I-mRNA increased dose-dependently after stimulation with IFN beta-1b for 24 h in vitro. Serum levels of soluble vascular cell adhesion molecule (sVCAM) were increased during the whole time of in vivo treatment (p < 0.01). The CD8CD38 lymphocyte subpopulation was continuously elevated from day 5 up to month 6 (p < 0.01) in the MS patients treated with IFN beta-1b in vivo. No persistent, significant changes were demonstrable concerning the percentage of total CD4, CD8, CD19 nor in CD4 subpopulations (CD4CD29, CD4CD45RA). The present data suggest that IFN beta-1b induces the mRNA expression of TGF beta-1 and TGF beta-R-II by PBMC, decreases that of TNF alpha and increases levels of sVCAM-1 and of circulating activated CD8 cells (CD8CD38) in blood. These might be other mechanisms by which IFN beta-1b mediates its positive effects in the treatment of MS patients.

Expression of interleukin-4 but not of interleukin-10 from a replicative herpes simplex virus type 1 viral vector precludes experimental allergic encephalomyelitis

We have used interleukin (IL)-4 and -10-producing HSV-1 gamma(1)34.5 deletion viruses in gene therapy of a BALB/c model of experimental allergic encephalomyelitis (EAE), a T cell-mediated demyelinating disease of the central nervous system. It is known that in EAE of mice the Th2-type cytokines are down-regulated and the Th1-type cytokines up-regulated during the onset and relapse of the disease. Therefore, we tested two HSV-1 recombinants expressing the Th2-type cytokines IL-4 and IL-10. The recombinant viruses were injected intracranially (i.c.) in BALB/c mice 6 days after induction of EAE. As control groups we used mice without any infection, mice infected with backbone virus R3659 and mock-infected mice. Weights and symptoms of the mice were recorded daily and the tissue specimens were collected at specific time-points. The results indicate that the intracranial infection with IL-4-producing virus (1) precludes EAE symptoms, (2) protects the spinal cord from massive leukocyte infiltrations and (3) prevents demyelination and axonal loss. The IL-10-expressing virus R8308 did not have a similar favorable effect on the recovery of the mice as did the IL-4 virus R8306.

Interleukin-6 and interleukin-1 receptor antagonist in cerebrospinal fluid from patients with recent tonic-clonic seizures

We have previously reported increased concentrations of interleukin (1L)-6 in CSF from patients with tonic-clonic seizures, where increased cytokine production most likely is a consequence of neuronal epileptic activity associated with seizures. The biological effects of IL-6 are mediated by other cytokines, which are studied here in addition to IL-6. The purpose of this study was to analyze levels of soluble cytokines from plasma and CSF from patients with newly developed tonic-clonic seizures. The concentrations of IL-6, IL-1 receptor antagonist (IL-1RA), IL-1beta, tumor necrosis factor (TNFalpha) and nerve growth factor (NGF) were measured from plasma and CSF from 22 patients with newly developed tonic-clonic seizures within 24 h from the seizure and 18 controls. The mean concentrations of IL-6 were significantly increased in CSF (P<0.001) and plasma (P<0.01) after tonic-clonic seizures, there was some indication of increased concentrations of IL-1RA and no significant change in NGF, IL-1beta or TNFalpha. Our study shows that cytokine network is activated in patients after recent tonic-clonic seizures. We provide evidence of intrathecal production of IL-6 associated with electrical seizure activity.

Inducible nitric oxide synthase expression elicited in the mouse brain by inflammatory mediators circulating in the cerebrospinal fluid

Expression of inducible nitric oxide synthase (iNOS) protein was studied in the brain after intracerebroventricular injections of interferon (IFN)-gamma, and IFN-gamma combined with lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-alpha, compared to ovalbumin as control. Wild-type mice and mice with targeted deletion of the IFN-gamma receptor gene were used. Findings based on iNOS immunoreactivity were evaluated at 1, 2, 4 and 7 days post-injection, using also quantitative image analysis and double labeling with glial cell markers. IFN-gamma administration induced iNOS immmunostaining in activated microglia and macrophages in the parenchyma surrounding the ventricular system, several cortical fields and fiber tracts. IFN-gamma-elicited iNOS immunoreactivity was down-regulated after 1 day. The number of iNOS-immunopositive cells was significantly enhanced by co-administration of LPS or TNF-alpha; IFN-gamma+TNF-alpha injections also resulted in longer persistence of iNOS immunoreactivity. No immunopositive cells were seen in the brain of IFN-gamma receptor knockout mice after IFN-gamma administration; very few immunostained macrophages were detected in these cases, mostly around the injection needle track, after co-administration of LPS or TNF-alpha. Western blot analysis confirmed a marked iNOS induction in the brain of wild-type mice 24 h after IFN-gamma+LPS injections. The findings show that inflammatory mediators circulating in the cerebrospinal fluid induce in vivo iNOS in the brain with topographical selectivity and temporal regulation. The data also demonstrate that the signaling cascade activated by IFN-gamma binding to its receptor is critical for iNOS induction, and the synergistic action of LPS and TNF-alpha as iNOS inducers in brain cells is largely mediated by the receptor-regulated action of IFN-gamma.

Biological markers in body fluids for activity and progression in multiple sclerosis

Reliable biological markers in body fluids for disease activity and progression are important for our understanding of the pathophysiology and therapeutic decisions in various subtypes of multiple sclerosis. Sampling from body fluids such as cerebrospinal fluid, blood, and urine constitutes the problem that the local immuno-inflammatory process takes place in the central nervous system whereas the disease activity is only to some extent reflected in the systemic immune compartment. Promising results have been obtained in studies of adhesion molecules, pro-inflammatory cytokines, co-stimulatory molecules and neopterin as markers of disease activity in relapsing-remitting multiple sclerosis. However, these results apply to groups of patients but not necessarily to individual patients. Currently no single body fluid marker is sufficiently correlated to disease activity to be used in the individual patient in monitoring disease activity, progression, or therapeutic effects.

Immunomodulatory effects of IFNbeta-1b on the mRNA-expression of TGFbeta-1 and TNFalpha in vitro

The mechanisms by which IFNbeta-1b acts in the treatment of multiple sclerosis (MS) patients are not completely known. We investigated the influence of IFNbeta-1b on the mRNA-expression of the immunosuppressive cytokine TGFbeta-1 and the proinflammatory mediator TNFalpha in an in vitro model by the method of non-radioactive in situ hybridization. Peripheral blood lymphocytes (PBL) were isolated from eight patients with relapsing remitting form of MS during remission and from six healthy controls. They were stimulated with IFNbeta-1b in different concentrations for 24 h. In both groups a statistically significant dose-dependent increase of TGFbeta-1-mRNA and decrease of TNFalpha-mRNA was demonstrable in the cultured stimulated blood lymphocytes compared to unstimulated cells. Stimulations with lipopolysaccharide (LPS) led to an increase of both cytokine-mRNAs in the lymphocytes. These data suggest specific and dose-dependent effects of IFNbeta-1b and hint at immunomodulatory properties of this drug to regulate the cytokine dysbalance in MS. This might be one mechanism by which IFNbeta-1b mediates its beneficial effects on the course of the disease.

Immunomodulatory effects of interferon-beta-1b in vivo: induction of the expression of transforming growth factor-beta1 and its receptor type II

The mechanisms by which interferon-beta-1b (IFNbeta-1b) acts in the treatment of patients with multiple sclerosis (MS) are not completely known. A total of 10 MS patients were treated with 8 million units of IFNbeta-1b every other day. Compared to baseline and control group the expression of TGFbeta-1-mRNA by PBMC was persistently increased at week 6, month 3 and month 6 (p < or = 0.04), that of the TGFbeta-1 receptor type II from day 5 up to month 6 (p < 0.01). The mRNA and protein expression of tumor necrosis factor-alpha (TNFalpha)-receptor (55 kDa) was only temporarily elevated at the beginning of the therapy. Serum levels of sVCAM were increased during the whole time of treatment (p < 0.01). The CD8CD38 lymphocyte subpopulation was continuously elevated from day 5 up to month 6 (p < 0.01). No persistently significant changes were demonstrable concerning the percentage of total CD4, CD8, CD19 or in CD4 subpopulations (CD4CD29, CD4CD45RA). The present data suggest that IFNbeta-1b induces the expression of TGFbeta-1- and TGFbeta-R-II-mRNA by PBMC and increases levels of sVCAM-1 and of circulating activated CD8 cells (CD8CD38) in serum. These might be other mechanisms by which IFNbeta-1b mediates its positive effects in the treatment of MS patients.

Selective downregulation of Th1 response by Linomide reduces autoimmunity but increases susceptibility to viral infection in BALB/c and SJL mice

Susceptibility to autoimmunity has been associated with polarization of Th1/Th2 balance in immune system towards the Th1-type of reactivity. We report here that orally administered quinoline-3-carboxamide (Linomide) selectively downregulates Th1 response in BALB/c and SJL mice, leading to reduction of autoimmunity in the BALB/c and SJL models of experimental allergic encephalomyelitis (EAE). This was shown by prevention of EAE in Th1 responding SJL mice and partial downregulation of EAE in Th2-prone BALB/c mice. In a BALB/c model of EAE, in which infection with Semliki Forest A7 virus (SFV-A7) is used for enhancement of autoimmunity, clinical signs of EAE were reduced while mortality due to viral infection in the CNS was enhanced. Selective downregulation of the Th1 response by Linomide also rendered initially resistant SJL mice susceptible to SFV-A7 CNS infection. This was shown by immunohistochemical detection of extensive deposits of viral antigen in numerous perivascular foci within the CNS and abolished virus antigen-specific lymphocyte reactivity in Linomide-treated SJL mice. In addition, analysis of spleen cell cytokine mRNA production profile revealed decreased number of IFN-gamma producing cells in both SJL and BALB/c mice, reduced number of IL-12p40 producing cells in SJL and increased number of 12p40 producing cells in BALB/c mice along with slightly increased IL-4 production in both strains of mice. These results indicate that oral treatment with Linomide induces selective downregulation of Th1 reactivity causing reduction of autoimmunity and increased susceptibility to SFV-A7 CNS infection. Selective downregulation of Th1 response is a desired effect in the treatment of autoimmune diseases but our results suggest that the benefits have to be balanced against the possible loss in immunoprotection against pathogens.

Profile of cerebrospinal fluid and serum cytokines in patients with relapsing-remitting multiple sclerosis: a correlation with clinical activity

Levels of tumor necrosis factor (TNF)-alpha, granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-10 and transforming growth factor (TGF)-beta in cerebrospinal fluid (CSF) and serum of 29 patients with multiple sclerosis (MS) of the relapsing-remitting type and of 20 controls with other non inflammatory neurological diseases were studied. Sixteen patients were in the active phase of disease and 13 in remission. In CSF, higher IL-10 and TGF-beta concentrations were found in patients with a stable phase of MS, while in the active phase there were elevated levels of TNF-alpha and GM-CSF. These results suggest that a different cytokine pattern could be probably involved in the pathogenesis of relapsing-remitting MS.

Relapse markers in multiple sclerosis: are in vitro cytokine production changes reflected by circulatory T-cell phenotype alterations?

In vitro tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) production, serum neopterin levels, and T-lymphocyte subpopulations were determined on a monthly basis in 22 MS patients. We found increased in vitro TNF-alpha production from 4 weeks on prior to the day of an exacerbation. There was a significant correlation with in vitro IFN-gamma release, the absolute blood monocyte count and the serum neopterin levels, suggesting that monocytes stimulated by IFN-gamma play an important role in the TNF-alpha production. Serial analysis of in vitro TNF-alpha production proved to be a helpful tool in predicting relapses in MS patients. Furthermore, elevated levels of IFN-gamma and IL-2 after stimulation with OKT3 during exacerbations were demonstrated. These increases were not reflected by changes in T-lymphocyte subpopulations. However, significant differences in T-cell subsets were observed between controls and relapsing progressive patients.

IL-15 mRNA expression is up-regulated in blood and cerebrospinal fluid mononuclear cells in multiple sclerosis (MS)

IL-15, produced by monocytes and epithelial cells, is a novel cytokine with actions similar to IL-2. IL-15 induces T cell proliferation, B cell maturation and natural killer (NK) cell cytotoxicity, and is a chemoattractant for T cells. We investigated the expression of IL-15 mRNA in blood and cerebrospinal fluid (CSF) mononuclear cells (MNC) in MS, an inflammatory disease of the central nervous system where cytokines are involved. MS patients had higher numbers of IL-15 mRNA-expressing blood MNC than patients with aseptic meningo-encephalitis (AM) and healthy controls. In CSF, MS patients had even higher numbers of IL-15 mRNA-expressing cells than in blood. This discrepancy between IL-15 mRNA expression between blood and CSF MNC was not seen in AM patients. Patients examined during the secondary chronic-progressive phase of MS had higher numbers of IL-15 mRNA-expressing blood MNC compared with patients examined during the relapsing-remitting phase. Levels of IL-15 mRNA-positive blood MNC were similar in patients with AM, myasthenia gravis, non-inflammatory neurological diseases and healthy controls. Taken together these data indicate that IL-15 mRNA expression is up-regulated in MS, further suggesting a role for proinflammatory cytokines in the pathogenesis of MS.

Expression of TNF alpha in central neurons of Lewis rat spinal cord after EAE induction

Experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis (MS), is a demyelinating autoimmune disease of the central nervous system (CNS). The proinflammatory cytokine TNF alpha, as an endogenous mediator of inflammation, plays an important role in the pathogenesis of EAE disease. In this study, we demonstrate the presence of TNF alpha in spinal cord of Lewis rats, during the critical phase of EAE. The expression of TNF alpha is observed mainly in the gray matter of thoracic and lumbar levels of the spinal cord, in the motoneurons and interneurons of the ventral horn. Surprisingly, one month after recovery, we still found an intense TNF alpha-neuronal expression, including in the cervical region, and this positivity lasted up to 40 days after recovery, with, however, a decrease in its intensity. These results suggest that central neurons respond directly to massive infiltration of lymphocytes and macrophages after the breakdown of the blood-brain barrier (BBB), by producing TNF alpha cytokine. In addition, neuronal-TNF alpha detection in the recovery stage of EAE may suggest a role other than its classical action in promoting inflammatory processes.

Biologically active TGF-beta 1 is increased in cerebrospinal fluid while it is reduced in serum in multiple sclerosis patients

OBJECTIVES

The polypeptide transforming growth factor-beta 1 (TGF-beta 1) is a product of activated monocytes, among other inflammatory cells, and it affects immune responsiveness, cellular growth and differentiation. TGF-beta 1 has potent T-cell inhibiting activities. It may play an important role in limiting autoimmune inflammation. We were interested about levels of biologically active and total TGF-beta 1 in serum and CSF in patients suffering from multiple sclerosis.

SUBJECTS AND METHODS

We measured biologically active and total TGF-beta 1 in serum and CSF using ELISA-technique in 64 MS patients with 57 during acute exacerbation of MS and 7 in remission (primary-relapsing: n = 59; primary-progressive: n = 5), 20 healthy subjects, and 21 patients with other non-inflammatory neurological diseases (OND).

RESULTS

Biologically active TGF-beta 1 in serum was reduced in MS patients compared to controls, on the other hand total TGF-beta 1 was elevated in CSF compared to patients with OND. Biologically active TGF-beta 1 in CSF correlated positively with the duration of the acute relapse in patients with primary-relapsing MS. The more relapses the patients had the higher was biologically active TGF-beta 1 in CSF. Total TGF-beta 1 in CSF correlated with macrophages in CSF and albumin quotient.

CONCLUSION

We found that an elevated level of biologically active TGF-beta 1 in CSF might be useful as an indicator of disease limitation while active TGF-beta 1 in serum is reduced in multiple sclerosis. Measuring TGF-beta 1 in body fluids by ELISA techniques produces valid results and might be used for further studies focusing on the role of this cytokine in MS.

Apoptosis of myelin-reactive T cells induced by reactive oxygen and nitrogen intermediates in vitro

Apoptosis is a major mechanism of T cell elimination during ontogeny and tolerance induction as well as in autoimmunity. To assess the possible involvement of reactive oxygen and nitrogen intermediates (ROI and NO.) in T-cell apoptosis during autoimmune demyelination we investigated the effects of H2O2 and NO. in vitro on activated autoreactive CD4+ T cell lines capable of transferring experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN). For detection and quantitation of apoptotic cells, DNA fragmentation was assessed by in situ tailing with fluorescein-ddUTP and subsequent flow cytometric analysis. H2O2 applied directly to the cell cultures for 6 to 18 hr at concentrations of 10 to 300 microM and ROI released by combination of hypoxanthine and xanthine oxidase (HX/XO) caused apoptosis in a dose-dependent manner in 13-33% of T cells of neuritogenic and encephalitogenic T cell lines. Apoptosis induction could be suppressed by the H2O2-neutralizing enzyme catalase. NO. released by the penicillamine derivative SNAP induced apoptosis to a similar extent as ROI. Maximum values were 38% in an encephalitogenic V beta 8.2-T cell receptor-bearing T cell line and 26% in a neuritogenic T cell line. T cell lines with specificity to ovalbumin revealed slightly lower susceptibility to apoptosis induction by all three kinds of trigger, which is, however, most probably not due to the different antigen specificity, but rather a result of fewer in vitro restimulation cycles of these cells. In neuritogenic cells high-dose (100 units/ml) exogenous interleukin-2 (IL-2) prevents H2O2-induced apoptosis. In conclusion, macrophage-derived reactive oxygen and nitrogen intermediates have the potency to limit inflammatory demyelination by elimination of autoreactive and bystander T cells via apoptotic cell death, and IL-2 is a rescue factor.

Soluble adhesion molecules (sVCAM-1 and sICAM-1) in cerebrospinal fluid and serum correlate with MRI activity in multiple sclerosis

We performed a prospective study to correlate quantiative brain magnetic resonance imaging activity (gadolinium-diethylenetriaminepentaacetic acid enhancement) to cerebrospinal fluid and serum levels of soluble adhesion molecules in 46 patients with newly diagnosed multiple sclerosis (MS) and 30 control subjects with other diseases of the central nervous system. In all patients, magnetic resonance imaging of the brain and lumbar puncture were performed on the same day. In 32 (70%) of 46 MS patients, 8 (80%) of 10 patients with acute viral encephalitis, but none of the control subjects with noninflammatory diseases, gadolinium-enhancing lesions were detected. There was a significant correlation between the cerebrospinal fluid/serum ratios for soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule-1 as well as serum levels for both molecules and the area of gadolinium-enhancing lesions. No obvious correlation was observed between magnetic resonance imaging findings and cerebrospinal fluid cell count, protein concentration, or intrathecal immunoglobulin production. In patients with a single periventricular gadolinium-enhancing lesion (n = 16), we observed a strong negative correlation between the distance from the lateral ventricles and the cerebrospinal fluid/serum ratios for soluble intercellular adhesion molecule-1/albumin and soluble vascular cell adhesion molecule-1/albumin. These results suggest that intrathecal production of the two soluble adhesion molecules, as well as serum levels for soluble vascular cell adhesion molecule-1, in patients with MS reflect magnetic resonance imaging activity of typical periventricular lesions.

Basic mechanisms of brain inflammation

The mechanisms, how the immune system surveys the nervous tissue and how brain inflammation is regulated are essential questions for therapy of neuroimmunological diseases. The nervous system is continuously patrolled by hematogenous cells, which may pass the blood brain barrier in an activated state. When these cells find their respective target antigen in the CNS compartment, an inflammatory reaction is started through the secretion of proinflammatory cytokines. This leads to the upregulation of endothelial adhesion molecules and the local production of chemokines, which in concert facilitate the entry of inflammatory effector cells into the lesions. T-lymphocytes are effectively removed from inflammatory brain lesions by local apoptosis. In addition some lymphatic drainage of the nervous system allows the removal of effector cells from the lesions and their migration into regional lymph nodes. In summary these data suggest that the immune surveillance of the central nervous system is much more tightly controlled compared to that in other organs.

Expression of tumor necrosis factor-alpha and transforming growth factor-beta 1 in cerebrospinal fluid cells in meningitis

Meningitis is an acute inflammatory disease of the pia and arachnoid and the fluid in the subarachnoid space, in which a participation of cytokines can be expected. While tumor necrosis factor-alpha (TNF alpha) promotes inflammatory reactions, transforming growth factor-beta 1 (TGF beta 1) has antagonistic effects and suppresses the inflammation in the subarachnoid space. We investigated the protein concentration and mRNA expression of TNF alpha and TGF beta 1 in cerebrospinal fluid (CSF) by ELISA and intracellularly by non-radioactive in situ hybridization in 23 patients with bacterial or viral meningitis. A higher amount of both cytokines on protein and mRNA level, especially of TNF alpha, could be detected in bacterial infection. While an imbalance of both cytokines with a preponderance of TNF alpha- compared to TGF beta 1-mRNA was visible in CSF cells of patients with bacterial meningitis, a balance of TNF alpha- and TGF beta 1-mRNA or a higher expression of TGF beta 1-mRNA could be detected in viral meningitis. In the acute phase of the disease neutrophil granulocytes expressed more TNF alpha- and TGF beta 1-mRNA than lymphocytes and monocytes/macrophages, while these cell types were dominating the cytokine synthesis during the healing phase. These data indicate that immunomodulatory mechanisms take place in the CSF compartment itself, regulated by CSF cells in different but specific ways. In addition, TGF beta 1 seems to be involved in the down-regulation of the inflammatory activity and to be one factor in the cytokine network, which could contribute to a lower rate of complications and positive outcomes. Moreover this study favors the possibility to monitor the immunomodulatory mechanisms by non-radioactive in situ hybridization.

In vitro TNF-alpha, IL-2 and IFN-gamma production as markers of relapses in multiple sclerosis

In 22 patients with definite multiple sclerosis (MS) we determined with monthly intervals over a period of 24 months the in vitro tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin-2 (IL-2) production and the serum neopterin levels. The results were compared with normative data collected from 14 healthy controls over the same period. Twenty-nine relapses in 13 patients were noticed. We found increased in vitro TNF-alpha production from 4 weeks on prior to the day of an exacerbation. There was a significant correlation with in vitro IFN-gamma release, the absolute blood monocyte count and the serum neopterin levels, suggesting that monocytes stimulated by IFN-gamma play an important role in the TNF-alpha production. Serial analysis of in vitro TNF-alpha production proved to be a helpful tool in predicting relapses in MS patients. Furthermore, elevated levels of IFN-gamma and IL-2 after stimulation with OKT3 during exacerbations were demonstrated. Serial analysis of these two biological markers revealed to be of no value in predicting relapses.

Systemic high-dose recombinant-alpha-2a-interferon therapy modulates lymphokine production in multiple sclerosis

Chronic systemic high-dose recombinant alpha 2a-interferon (rIFNA) therapy reduces exacerbation rate and MRI signs of disease activity in relapsing/remitting multiple sclerosis (RR MS) patients. In order to clarify the possible mechanisms underlying the clinical efficacy of rIFNA in MS, several immunologic studies were performed as a part of a pilot clinical trial. Twenty RR MS patients were treated with 9 x 10(6) IU of rIFNA (n = 12) or placebo (n = 8) intramuscularly every other day for 6 months. Cytokine production by cultured lymphocytes, major histocompatibility complex class II (MHC-II) antigen expression on cultured macrophages, peripheral blood (PB) and cerebrospinal fluid (CSF) lymphocyte phenotype, and IgG and beta 2 microglobulin levels were studied before therapy, after 6 months of therapy, and 6 months after stopping therapy. rIFNA therapy was associated with reduction of interferon-gamma and tumor necrosis factor-alpha production by PB lymphocytes (p < 0.04), and with slight, not significant, increase of transforming growth factor-beta 2 or interleukin (IL)-10 production. IL-4 was undetectable in the culture supernatants both before and after therapy. rIFNA therapy had no effect on macrophage MHC-II molecule expression. An increased percentage of CD8+, CD8+ high CD11b+ low, and CD3- CD16+ CD56+ cells, and of CD4+ absolute cell number was observed in CSF after rIFNA therapy. After rIFNA administration, IgG level significantly increased both systemically (p < 0.02) and intrathecally (p < 0.001). Serum beta 2 microglobulin level increased (p < 0.01), as well. Only 1 out of the 12 rIFNA treated patients developed neutralizing antibodies against rIFNA during therapy. Six months after stopping therapy all the immunologic changes returned to baseline. These data suggest that the beneficial effect of rIFNA therapy on MS disease activity is probably mediated by a downregulation of proinflammatory cytokine synthesis by PB lymphocytes rather than by macrophage MHC-II antigen expression. The immunologic effects of high-dose systemic rIFNA therapy are temporary and restricted to the period of drug administration.

Interferon alpha-2a treatment of relapsing-remitting multiple sclerosis: disease activity resumes after stopping treatment

We evaluated the long-lasting effects of systemic high-dose recombinant interferon alpha-2a (rIFNA) in relapsing-remitting (RR) MS after discontinuing treatment in a single-blind randomized placebo-controlled trial with 20 RR clinically definite MS patients using either nine million IU intramuscular rIFNA (n = 12) or placebo (n = 8) every other day for 6 months. Follow-up continued for a further 6 months without IFN treatment. In rIFNA-treated patients, main outcome measures, significantly different from placebo during treatment, returned, after discontinuing treatment, to values similar to placebo or baseline. Active MRI lesions per patient increased from 0.08 +/- 0.08 to 1.2 +/- 0.4 (p < 0.02), number of patients with clinical MRI signs of disease activity from 2 of 12 to 8 to 12 (P < 0.04), lymphocyte IFN gamma production from 3.0 +/- 0.7 to 12.4 +/- 2.2 IU/mL (p < 0.01), lymphocyte tumor necrosis factor alpha production from 5.8 +/- 0.9 to 18.9 +/- 6.3 pg/mL (p < 0.05). All side effects of rIFNA treatment disappeared after discontinuing the drug. The reduction of clinical MRI signs of disease activity and the immunologic effects were temporary and restricted to the period of rIFNA administration. The depression of many immunologic and clinical MRI responses during drug administration and their simultaneous return to baseline after discontinuing the drug strongly argue all observed changes were related to drug administration.

Long term recombinant interferon alpha treatment in MS with special emphasis to side effects

Twenty relapsing-remitting (RR) clinically definite MS patients were treated with 9 MIU intramuscular recombinant interferon alpha-2a (rIFNA) (Roferon-A, Roche) (n = 12) or placebo (n = 8) every other day for 6 months and followed up for a further 6 months after stopping treatment. Numbers of active lesions at MRI and of patients with clinical-MRI signs of disease activity and lymphocyte interferon gamma production, which were decreased during treatment, returned to values similar to baseline and placebos after stopping treatment. rIFNA chronic therapy seems therefore needed in order to maintain drug efficacy. Side effect profile was monitored, too, for over 1 year in the same 20 patients plus 25 additional RR MS patients. Besides the typical side effects of type I interferon therapy (fever, fatigue, depression, lymphopenia, hepatic enzyme elevation), occurrence of serum autoAbs was noted in 30% patients (in 60% antinuclear and in 80% antithyroid autoAbs). In two patients rIFNA treatment was stopped, in one case for antithyroid autoAbs and hypothyroidism, in the other for antinuclear autoAbs and a five-fold increase of ALT. A careful monitoring of serum autoAbs and of signs of thyroid or liver damage must always precede and accompany longterm type I IFN therapy.

Patterns of disease activity in multiple sclerosis patients: a study with quantitative gadolinium-enhanced brain MRI and cytokine measurement in different clinical subgroups

In this study we assessed the subclinical disease activity in 45 patients with primary progressive, secondary progressive or relapsing-remitting multiple sclerosis (MS). The patients had gadolinium-enhanced brain MRI scans, which were analysed using a semiquantitative method both for lesion load and for degree of enhancement. At the same time cerebrospinal fluid (CSF) and serum samples were collected and, from these, cytokine levels were measured in most cases by enzyme-linked immunoassay using commercially available kits. Enhancing lesions on MRI were found in 73% of the patients. The sensitivity of this test was greatly increased by our method of analysis as far as the primary progressive patients are concerned (70% vs 40% for conventional evaluation). CSF interleukin-1 beta (IL-1 beta) levels were above the normal range in 22% and IL-6 levels in 13% of patients, while tumour necrosis factor alpha (TNF-alpha) was undetectable or below the upper normal limits in all the samples tested. Serum IL-1 beta was above the normal limits in 40%, IL-6 in 42% and TNF-alpha in 7% of patients. No significant differences in cytokine profiles were found between the clinical subgroups. This study confirms the high sensitivity of gadolinium-enhanced MRI in detecting MS activity, which was further increased by our method of analysis. Longitudinal studies performed with more sensitive immunological techniques are needed to define better the relationship between cytokine, clinical and MRI data in MS patients.

Methylprednisolone prevents rejection of intrastriatal grafts of xenogeneic embryonic neural tissue in adult rats

We studied the effects of high-dose methylprednisolone on the survival of intrastriatal neural xenografts and the host responses against them. Dissociated mesencephalic tissue from inbred mouse (CBA-strain) embryos was transplanted to the intact striatum of adult Sprague-Dawley rats. The rats received either daily injections of methylprednisolone (30 mg/kg), or cyclosporin A (10 mg/kg), or no immunosuppressive treatment. Two or six weeks after transplantation, there was good survival of xenografts in both the methylprednisolone- and cyclosporin A-treated rats. In contrast, the xenografts in untreated control rats were all rejected by six weeks. There was no marked difference in the degree of expression of MHC class I and II antigens and the accumulation of activated astrocytes and microglial cells/macrophages between the three groups. However, both methylprednisolone and cyclosporin A reduced infiltration of T lymphocytes to the transplantation sites. The expression of pro-inflammatory cytokines (interferon-gamma, tumour necrosis factor-alpha, interleukin-6) in and around the grafts was lower in the methylprednisolone- and cyclosporin A-treated groups than in untreated control rats. Although high-dose methylprednisolone caused significant body weight loss, we conclude that this treatment can prevent rejection of intrastriatal grafts of xenogeneic embryonic neural tissue in the adult.

Transforming growth factor-beta 1 (TGF-beta1)-mediated inhibition of glial cell proliferation and down-regulation of intercellular adhesion molecule-1 (ICAM-1) are interrupted by interferon-gamma (IFN-gamma)

We utilized a model of myelin basic protein (MBP) activation in vivo and MBP-stimulated cultures in vitro to study the influence of TGF-beta1 on glial cell proliferation and ICAM-1/leucocyte function-associated antigen-1 (LFA-1) expression, and to observe the antagonistic effects of TGF-beta1 and IFN-gamma. TGF-beta1 inhibited MBP-stimulated and MBP-activated glial cell proliferation, especially in MBP-stimulated separated microglia and astrocytes, and down-regulated the expression of ICAM-1 on MBP-stimulated glial cells and separated microglia. ICAM-1 expression on MBP-activated glial cells was intensely suppressed, whereas its expression on MBP-stimulated astrocytes was not influenced. TGF-beta1 had no effect on LFA-1 expression. In contrast, IFN-gamma up-regulated ICAM-1 expression, but inhibited proliferative response on MBP-stimulated glial cells when cultured without TGF-beta1. Examination of TGF-beta1 and IFN-gamma interactions revealed that TGF-beta1-mediated inhibition of proliferation and down-regulation of ICAM-1 on glial cells were prevented by IFN-gamma. The suppressive effect was re-established with high doses of TGF-beta1 in cultures, indicating that biological effects of TGF-beta1 vary depending on nitric oxide (NO) production, its concentration in the microenvironment and regulation of the cytokine network.

Expression of interferon-gamma (IFN-gamma), IL-10, IL-12 and transforming growth factor-beta (TGF-beta) mRNA in synovial fluid cells from patients in the early and late phases of rheumatoid arthritis (RA)

The expression of immunoregulatory cytokines was investigated in freshly isolated synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) from patients with RA, using a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. IFN-gamma, TGF-beta, IL-10 and IL-12 (p40) transcripts were detected in SFMC of patients with early disease (<1 year duration) as well as in patients with long standing arthritis (>1 year). The expression of IFN-gamma, IL-10 and IL-12 mRNA was increased in SFMC compared with RA PBMC. In addition, the expression was higher in RA SFMC than in PBMC from health control individuals. Immunoassay analysis of the secreted IL-12 heterodimer demonstrated increased levels in RA SF compared with levels found in serum from RA patients and control individuals. High levels of TGF-beta mRNA were found in SFMC, but a significantly decreased TGF-beta/beta2-microglobulin (beta2-M) ratio was found compared with PBMC from both patients and control individuals. IL-4mRNA could not be detected, either in SFMC or in PBMC. Cytokine expression in RA PBMC did not differ from control PBMC, with the exception of a decreased TGF-beta/beta2-M ratio in RA patients with early disease. Our findings of IFN-gamma mRNA and IL-12, but undetectable levels of IL-4 mRNA, suggest that the synovitis is characterized by a type 1 immune response. The presence of TGF-beta and IL-10 mRNA indicates that immunosuppressive cytokines may also operate in the inflamed joint, although their level of expression may not be sufficient for down-modulation of immune activation.

Pentoxifylline, a phosphodiesterase inhibitor, induces immune deviation in patients with multiple sclerosis

The outcome of immune responses can be predicted by the lymphokine production pattern of the participating cells. Cytokines of the T helper type 1 (Th1) cells mediate inflammatory responses and delayed-type hypersensitivity (DTH), whereas Th2-like T cells predominantly produce cytokines, which stimulate antibody production by B cells. Immunoregulatory therapy of autoimmune diseases with unknown antigens may be achieved by inhibiting the production of inflammatory cytokines and induction of protective cytokines of Th2-like T cells. To determine the immunoregulatory capacity of the phosphodiesterase inhibitor pentoxifylline (PTX), which is known to suppress the production of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), this drug was used in mitogen and antigen-stimulated lymphocyte cultures as well as in patients with multiple sclerosis. PTX significantly decreased TNF-alpha and interleukin-12 (IL-12), whereas it increased IL-4 and IL-10 production. In addition, PTX inhibited cell proliferation, which was associated with a marked reduction in CD25 (IL-2 receptor alpha-chain) and CD54 (intercellular adhesion molecule-1; ICAM-1) expression. Increasing doses of PTX significantly reduced TNF-alpha and IL-12 mRNA expression of blood mononuclear cells, but increased IL-4 and IL-10 expression in eight patients with relapsing-remitting multiple sclerosis. These results indicate that PTX modulates immune reactions favouring a Th2-like response and may therefore be useful for the treatment of autoimmune diseases with a dominant Th1-like T cell response.

Myelin-induced experimental allergic encephalomyelitis in Lewis rats: tumor necrosis factor alpha levels in serum and cerebrospinal fluid immunohistochemical expression in glial cells and macrophages of optic nerve and spinal cord

Tumor necrosis factor alpha (TNFalpha) activity was measured in serum and cerebrospinal fluid (CSF) of Lewis rats after experimental allergic encephalomyelitis (EAE) induction and during the clinical course of acute disease. TNFalpha bioactivity expression preceded the clinical symptoms and paralleled the severity of disease. We further investigated the identity of the central nervous system (CNS) cells involved in TNFalpha expression and their regional localization during EAE. Tissue sections of brain, cerebellum, dorsal spinal cord and optic nerve were studied by indirect double labelling immunofluorescence. Spinal cord white matter and optic nerve showed a widespread TNFalpha immunoreactivity at critical stages of EAE in macrophages/microglia and astrocytes. We have shown changes in CSF/serum albumin ratio and immunoglobulin G index during EAE. Our results confirm the very important role of TNFalpha in EAE.

Apoptosis in brain-specific autoimmune disease

Recent neuropathological studies of experimental autoimmune encephalomyelitis have focused attention on the high number of cells in the lesions that show typical morphological features of apoptosis. Surprisingly, it has turned out that the vast majority of apoptotic cells are T lymphocytes and that they actually represent the antigen-specific T-cell population responsible for the induction of the disease. Taken together, these data suggest that clearance of autoimmune inflammation in the nervous system is accomplished by the destruction of the antigen-specific T-cell population within the lesions. This may explain the low level of central nervous system specific T-cell memory formation, as well as previously unexplained phenomena of 'epitope spreading', in autoimmune inflammation of the nervous system.

Expression of IFN-gamma, IL-4, and TGF-beta in multiple sclerosis in relation to HLA-Dw2 phenotype and stage of disease

Multiple sclerosis (MS) is associated with upregulation of both proinflammatory (interferon-gamma, IFN-gamma) and immunosuppressive (transforming growth factor-beta, TGF-beta) cytokines. To examine a possible relation between the MS-related HLA haplotype Dw2 and cytokine profiles, we used in situ hybridization with labeled cDNA oligonucleotide probes to detect transcripts of the T helper type 1 (Th 1) cell related IFN-gamma, the Th2 cell related interleukin-4 (IL-4) and of TGF-beta in blood and cerebrospinal fluid (CSF) mononuclear cells from 62 patients with MS. Compared to patients with other neurological diseases and healthy controls, MS patients had elevated numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing cells in blood and further augmented in CSF. Although several HLA-Dw2-positive individuals showed very high numbers of cells expressing these cytokines, no significant difference was found in comparison with Dw2-negative patients. However, expression of IL-4 and TGF beta mRNA was significantly increased in patients with shorter duration and minor disability and, for IL-4, in patients still in the relapsing-remitting phase compared to patients with secondary chronic progressive MS. Surprisingly, these changes which favour a beneficial, disease-downregulating effect of IL-4 and TGF-beta in MS, were found to be confined to HLA-Dw2-positive patients. Our findings suggest that the HLA phenotype does not influence the overall level of immune reactivity in MS, but may distinguish subgroups characterized by particular cytokine expression patterns.

Specific and long-lasting protection from collagen-induced arthritis and oil-induced arthritis in DA rats by administration of immunogens

DA rats develop transient arthritis after subcutaneous immunization with adjuvant-oil, while chronic arthritis and collagen autoreactivity ensues when collagen is added to the oil. We show here that DA rats can be protected from oil-induced arthritis (OIA) and rat collagen-induced arthritis (rCIA) by addition of antigen to these arthritogenic inocula. We have investigated this remarkable phenomenon and demonstrate that both foreign and self antigens can be protective, apparently provided they are immunogenic; hence HSP-65kDa, ovalbumin, rat myelin basic protein, rat IgG and bovine albumin are effective while rat albumin is not. This protection is long-lasting and disease-specific because rats protected from rCIA resist a later attempt to induce arthritis, but not experimental autoimmune encephalomyelitis (EAE). Protection from rCIA depends neither on the blocking of humoral autoreactivity to collagen nor on a change in the isotype profile of anti-collagen antibodies. We demonstrate that immunogens can also be protective when injected intraperitoneally only a few days before onset of arthritis. Our results indicate that protection is mediated through bystander immune reactions towards the co-immunized antigen and that the arthritogenicity of a given provocation, be it adjuvants, microbes or autoantigens, may be a complex net result of arthritogenic and contra-arthritogenic immune reactions.