Multiple sclerosis: immune mechanism and update on current therapies

Genetics of Multiple Sclerosis: An Overview and New Directions

The contribution of genetic inheritance in multiple sclerosis was established early on. Although multiple sclerosis is not a Mendelian disease, its incidence and prevalence is higher in family members of affected individuals compared with the general population. Throughout the last decade, several small studies failed to identify any robust genetic associations besides the classic associations in the major histocompatibility complex region. During the past few years, genome-wide association studies (GWAS) have revolutionized the genetics of multiple sclerosis, uncovering more than 200 implicated genetic loci. Here, we describe these main findings and discuss the new avenues that these discoveries lay open.

Multiple Sclerosis: New Approaches to Immunotherapy

Until recently, the treatment of multiple sclerosis (MS) was restricted to symptomatic therapies. Advances in our understanding of the pathogenesis of MS are now resulting in the rapid proliferation of treatment strategies to slow or stop the progression of this disease. Clearly, immunological therapies can improve outcomes in MS and offer hope that this crippling disease can be controlled before patients develop major neurological disabilities. Immunological therapies under investigation for the treatment of MS are taking advantage of dramatic improvements in our understanding of immunoregulation. In addition, immunological treatment of MS is becoming selective relative to myelin antigens, enhancing efficacy and reducing toxicity. The Neuroscientist 2:127-136, 1996

Multiple sclerosis produces significant changes in urinary bladder innervation which are partially reflected in the lower urinary tract functional status-sensory nerve fibers role in detrusor overactivity

BACKGROUND

Detrusor overactivity is often observed in patients with multiple sclerosis (MS), and neurotoxins are emerging as second-line therapies albeit with different degrees of success per patient basis.

OBJECTIVE

To investigate lower urinary tract (LUT) functional status and bladder innervation (calcitonin gene related peptide [CGRP] and substance P [SP] positive nerve fibers) in patients with MS.

METHOD

Eighteen MS patients with LUT symptoms underwent urodynamic investigations, and six non-MS patients undergoing cystoscopy due to microscopic hematuria served as controls. Cold cut bladder biopsies were taken from the bladder trigone region. Neurotransmitter expression was determined by individual immunohistochemical staining.

RESULTS

Two distinct groups could be distinguished: group 1 with pronounced neurogenic detrusor overactivity and mild outflow obstruction; group 2 with some degree of neurogenic detrusor overactivity, detrusor hypocontractility during voiding, and high degree of an outflow obstruction. The presence of SP and CGRP immunoreactive + fiber density was observed in greater numbers in group 1.

CONCLUSION

Density of CGRP and SP positive nerve fibers within the urinary bladder of patients with MS may be suggestive of functional status of the lower urinary tract, namely denser innervation is observed in patients with mild outflow obstruction and strong detrusor overactivity. This observation could be useful when planning second-line treatment (neurotoxins) in these patients. Patients with denser innervation probably will respond better to such a therapy.

Therapeutic potential of IL-27 in multiple sclerosis?

BACKGROUND

Multiple sclerosis (MS) is a debilitating neurological disease, characterized by inflammatory demyelination and axonal degeneration in the CNS. Currently approved therapies are partially effective, however safer and more effective treatments are needed.

OBJECTIVE/METHODS

To assess the therapeutic potential of the heterodimeric cytokine, IL-27 in MS, based on the current literature.

RESULTS/CONCLUSIONS

IL-27 exerts profound anti-inflammatory effects in several infectious and experimental autoimmune models. In particular, suppressive effects on helper T cells, which are implicated in the pathogenesis of MS, suggest that IL-27 may be therapeutically relevant in MS. However, while exciting discoveries have been made, further work is required particularly in human health and disease, to understand the diverse roles of IL-27 and its therapeutic potential.

Role of B Cells in Pathogenesis of Multiple Sclerosis

Despite the current limited understanding of the etiology of multiple sclerosis (MS), genetic susceptibility and environmental influences are known driving factors. MS is considered a T-cell-mediated disease given the prevalence of T cells in plaques. Plaque formation is characteristic of this disease attributable to immune mechanisms, triggered by an autoimmune attack aimed at antigens in the myelin sheath or oligodendrocyte proteins. The attack consists of the following: The role of the B cells is twofold: first, as autoreactive B cells they produce autoantibodies, secrete cytokines, clonally replicate memory B cells, and long-living plasma cells which serve to advance the diseased state by their constant production of autoantibodies. Second, as antigen-presenting cells they activate the autoreactive T cells. For this reason, the stipulation that T cell is the cornerstone of MS must be reevaluated. Various studies on pathogenesis of MS have indicated that B cells, as the humoral component of the adaptive immune system, are active participants in pathogenesis and lesion maintenance throughout the disease process. The active role of B cells and autoantibodies makes them an encouraging therapeutic target. Advances in the understanding of B-cell development and activity would allow for an enhanced strategy in the design of autoimmune treatment. For this reason, further investigation is necessary to determine whether depletion of B cells or antibodies may restore immune function.

IgA antibodies against gliadin and gluten in multiple sclerosis

BACKGROUND

Multiple changes in antibodies against various antigens are found in multiple sclerosis (MS).

OBJECTIVE

We wanted to measure immunoglobulin A (IgA) antibodies to some common food antigens in MS and also IgG against gliadin and gluten.

METHODS

The IgA antibodies were measured in serum against gluten, gliadin, lactoglobulin, lactalbumin, casein and ovalbumin in patients with MS and controls using ELISA technique. IgG was likewise measured for gluten and gliadin.

RESULTS

Highly significant increases compared with controls were found for IgA and IgG antibodies against gliadin and gluten. IgA antibodies against casein were significantly increased. Anti-endomycium and anti-transglutaminase antibodies were negative.

CONCLUSIONS

The data presented indicate that there may be a possible moderately increased uptake of some specific proteins from the gut in MS compared with controls.

Cytokine-induced enhancement of autoimmune inflammation in the brain and spinal cord: implications for multiple sclerosis

Multiple sclerosis and experimental autoimmune encephalomyelitis (EAE) are autoimmune inflammatory diseases in which cytokines are intimately involved. Here we test the hypothesis that injection of pro-inflammatory cytokines, tumour necrosis factor-alpha (TNFalpha) and interferon gamma (IFNgamma) into the brain of animals in the prodromal phase of EAE significantly enhances inflammation in the central nervous system (CNS). We were particularly interested to learn whether a local increase in cytokines influenced the pathology locally, or more extensively, within the CNS. EAE was induced in female adult Lewis rats. Eight days post-inoculation, TNFalpha or INFgamma was injected into one cerebral hemisphere. Days 11 and 13 post-inoculation (3 and 5 days after the injection of cytokine) inflammation was quantified by the number of perivascular cuffs and the degree of major histocompatibility complex (MHC) class II expression by microglia. Normal animals injected with cytokines, and EAE animals with saline injection served as controls.

RESULTS

microglial activation was increased three- to fourfold in the brain and eightfold in the spinal cord (P </= 0.05); lymphocyte invasion was increased sixfold in the brain and three- to fourfold in the spinal cord (P </= 0.01) following injections of TNFalpha or INFgamma in EAE animals compared with controls. Significant axonal damage was observed in white matter associated with the perivascular cuffs.

CONCLUSION

local changes in the release of pro-inflammatory cytokines within the brain in EAE results in the widespread enhancement of autoimmune inflammation within the brain and cord, and exacerbation of clinical symptoms.

Evaluation of mitoxantrone for the treatment of multiple sclerosis

Mitoxantrone (Novantrone((R))), an antineoplastic agent, has been approved for treating patients with secondary progressive multiple sclerosis (MS). Mitoxantrone, which is usually categorised as an immunosuppressant drug, is now also considered to be a specific immunomodulator. Autoimmune mechanism of pathogenesis of MS is the basis of immunosuppressive therapeutic approaches to MS whereas immunoregulatory abnormalities including defective IFN-alpha production provide the rationale for immunomodulating therapies. Clinical trials have shown that mitoxantrone had a statistically significant impact on reduction of relapse rate and delay in disability progression in these patients. Advantages of mitoxantrone as therapy for MS are: (1) considerable information is available about its pharmacokinetics, metabolism and toxicology from previous use in oncology; (2) it requires administration only once in three months which is not only convenient for the patient but also cost-effective; (3) mitoxantrone is one of the two drugs to be approved for secondary progressive MS (the other is IFN-beta1) which offers an advantage over IFN-beta1a preparations and glatiramer acetate which are indicated only for relapsing remitting MS. However, the duration of therapy is usually limited to two to three years because the maximum cumulative dose recommended is 120 mg/m(2) due to concern for possible cardiotoxicity. Potential market value of the mitoxantrone, based on the cost of treatment per patient and the number of patients likely to be treated in the first year of introduction, is US$210 million.

Brain damage in preterm newborns: biological response modification as a strategy to reduce disabilities

Substances that promote the growth and maturation of oligodendrocytes and their precursors might protect against white matter injury. We suggest that neuroprotection can also be provided by such modulators of fetal and neonatal inflammatory responses as antiinflammatory cytokines, cytokine-binding proteins, and cytokine-receptor blockers. We briefly describe inflammatory responses in the fetus and newborn and show how they might contribute to brain damage. We conclude with the possibility that so-called biological response modifiers, which are drugs that modulate these inflammatory responses, might reduce the risk of brain damage and disabilities.

In vivo effects of recombinant-interferon-beta1b treatment on polymorphonuclear cell and monocyte functions and on T-cell-mediated antibacterial activity in patients with relapsing-remitting multiple sclerosis

Treatment with Interferon (IFN)-beta has been proposed as a therapeutic approach in multiple sclerosis (MS) patients, mostly in view of its immunomodulating actions. At the same time, evidence has been provided that MS patients exhibit polymorphonuclear cell (PMN) deficits, which can explain the increased susceptibility to infections in these subjects. Here, in 28 patients with relapsing-remitting (RR) MS under treatment with recombinant (r)-IFN-beta PMN polarization and PMN and monocyte (MO) phagocytosis and killing, as well as T-cell mediated antibacterial activity, were evaluated before treatment and over a period of nine months of treatment. Our results point out an enhanced rate of polarization (both "spontaneous" or N-formyl-methionyl-leucyl-phenylalanine-induced) in MS patients. After r-IFN-beta1b treatment the polarization rate was further increased. On the contrary, PMN and MO phagocytosis and killing were depressed in comparison to controls and values were further reduced by r-IFN-beta1b treatment. In patients T-cell mediated antibacterial activity was decreased at T0 and dramatically dropped in the course of r-IFN-beta1b therapy.

Multiple sclerosis--in need of a critical reappraisal

Multiple sclerosis (MS) is a disease that currently defies clinical and scientific definitions. Despite intensive clinical and basic research, very little is known about its possible cause(s) or pathogenesis, and the course and prognosis of MS practically remain unchanged. The aim of the present article is to outline some of the reasons for the constant failure to improve the therapy of MS. It also attempts to offer several guidelines which may enable a fresh and different approach to this devastating condition.

IL-6 plays a crucial role in the induction phase of myelin oligodendrocyte glucoprotein 35-55 induced experimental autoimmune encephalomyelitis

We investigated the role of IL-6 in myelin oligodendrocyte glycoprotein (MOG) peptide induced experimental autoimmune encephalomyelitis (EAE) using IL-6-deficient mice and found that IL-6-deficient mice were resistant to active induction of EAE, but that the treatment of those mice with IL-6 during the preclinical phase caused typical EAE. We also found that both wild-type and IL-6-deficient mice were resistant to passive transfer of EAE by lymphocytes from IL-6-deficient mice, but that passive transfer of lymphocytes from wild-type mice induced typical EAE in IL-6-deficient mice. Histological abnormalities of the central nervous system (CNS) in those IL-6-deficient mice with EAE were similar to those in wild-type mice with EAE. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed no difference in the production of inflammatory cytokines such as IL-1beta, IL-2, TNF-alpha, and IFN-gamma in the CNS of IL-6-deficient mice with EAE as compared to the CNS of wild-type mice with EAE. These results indicated that IL-6 might be an important factor in the induction phase, but might have little influence on the effector phase of EAE. We further estimated the production of cytokines in MOG-stimulated lymph node (LN) cells by enzyme-linked immunosorbent assay. Increased IL-4 and IL-10 production and reduced IL-2 and IFN-gamma production were observed in LN cells from IL-6-deficient mice as compared to LN cells from wild-type mice. These results suggested that a shift of T cell responses from Thl to Th2 might explain the resistance of IL-6-deficient mice to EAE. Taken together, IL-6 may play a crucial role in the induction phase of EAE by modulating Th1/Th2 balance.

Interferon gamma, IL2, IL4, IL10 and TNFalpha secretions in multiple sclerosis patients treated with an anti-CD4 monoclonal antibody

In order to better understand the mechanisms of action of a monoclonal anti-CD4/BF5 antibody(mAb), cytokine secretions were studied in 14 multiple sclerosis (MS) patients treated in a phase 1 trial. Secretion patterns of IFNgamma, IL2, IL4, IL10 and TNFalpha by peripheral blood mononuclear cells were studied before (DO) and after (D30) the treatment. We decided to undertake this study because in a previous one we observed no variations in serum levels of TNFalpha, IFNgamma, IL1, IL6. Results showed significant reductions in IFNgamma, IL2 and TNFalpha secretions after treatment. The anti-CD4 mAb seemed to act on both Th1- and Th2-cells but with preferential action on Th1-cells. Results on Th2-cells were less obvious even though a significant decrease in IL10 was observed. There was no correlation between any of the immunological markers studied and disease activity. This study demonstrates that pharmacological modifications of the CD4 receptor can induce variations in several cytokine secretion levels. It also stresses the role played by Th1- and Th2-cells in the etiopathogenesis of MS.

Recent developments in drug therapy for multiple sclerosis

Symptomatic treatment of multiple sclerosis (MS) includes a diverse range of drugs intended to relieve the specific symptoms with which a patient may present at a particular point in the progression of the disease. These drugs, not specifically designed for the treatment of MS, may include antispastic agents (e.g. baclofen), drugs to reduce tremor (e.g. clonazepam), anticholinergics (e.g. oxybutynin) which relieve urinary symptoms, anti-epileptics (e.g. carbamazepine) to control neuralgia, stimulants to reduce fatigue (e.g. amantadine), and antidepressants (e.g. fluoxetine) to treat depression. The treatment of acute relapses or exacerbations is dominated by corticosteroids such as methylprednisolone. The most active area of current investigation is the development of drugs which will inhibit the progression of the disease process itself, and in this category the beta- and alpha-interferons are the most effective drugs currently available, although many new treatments are currently in trials, including immunoglobulin, copolymer-1. bovine myelin, T-cell receptor (TCR) peptide vaccines, platelet activating factor (PAF) antagonists, matrix metallo-proteinase inhibitors, campath-1, and insulin-like growth factor (IGF).

Transforming growth factor beta1 (TGFbeta1) mRNA level correlates with magnetic resonance imaging disease activity in multiple sclerosis patients

Eight relapsing-remitting multiple sclerosis (MS) patients were tested for the level of transforming growth factor beta1 (TGFbeta1) mRNA in peripheral blood mononuclear cells every 15 days for 6 months. Disease activity was evaluated every 4 weeks by magnetic resonance imaging (MRI) and neurological examination. An inverse correlation was found between the level of TGFbeta1 mRNA and MRI disease activity. The level of TGFbeta1 mRNA predicted the presence of disease activity in the scans performed 2-4 weeks later with high sensitivity (88%) and specificity (87.5%) suggesting that TGFbeta1 mRNA quantification could be an indicator of disease activity in MS.

Cytokine flow cytometry differentiates the clinical status of multiple sclerosis (MS) patients

In this study we have examined intracellular cytokines in peripheral blood mononuclear cells (PBMC) of MS patients by flow cytometry (cytokine flow cytometry). MS progressive patients showed an increased number of cells producing interferon-gamma (IFN-gamma) after activation with phorbol 12-myristate 13-acetate and ionomycin, compared with patients with clinically inactive forms (P < 0001) and with healthy controls (P = 0001). These cells belonged to the CD4+ and CD8+ subsets in similar proportions. Clinically inactive patients showed a lower level of cells producing IL-2 than controls (P = 0.03) and active MS patients (P = 0.03). Most IL-2-producing cells were CD4+ lymphocytes, although a small part of the IL-2 was also produced by CD8+ cells. The percentage of cells producing simultaneously IL-2 and IFN-gamma was increased in active MS and they were mainly CD4+ lymphocytes. No differences in the production of IL-4 were observed between groups. However, we found an increased IL-10 production in clinically active MS patients (P = 0.03). Treatment with IFN-beta of active MS patients showed lower levels of cytokines when compared with untreated MS patients. This methodological approach could help in the follow up and therapeutic monitoring of MS patients.

Interferon-beta1A-induced polyarthritis in a patient with the HLA-DRB1*0404 allele

Human interferon-alpha (IFNalpha) and IFNbeta are administered for treatment of several diseases, including viral infections, malignancies, and multiple sclerosis (MS). IFNalpha therapy has been associated with the production of autoantibodies and the development of a variety of autoimmune disorders, including polyarthritis. This report describes the development of seronegative, symmetric polyarthritis in a patient with relapsing-remitting MS, after 8 weeks of therapy with IFNbeta1a. HLA phenotyping analysis of the patient revealed the presence of HLA-DRB1*0404, an allele known to be associated with the development of rheumatoid arthritis. Therefore, IFNbeta1a may have induced arthritis in a patient who was genetically predisposed to develop arthritis on the basis of HLA determinants. The English-language literature regarding IFNalpha- and IFNbeta-induced polyarthritis is reviewed, and possible mechanisms for IFNalpha- and IFNbeta-induced autoimmunity, including the contribution of HLA determinants and nitric oxide overproduction, are discussed.

Dual implication of 2',3'-cyclic nucleotide 3' phosphodiesterase as major autoantigen and C3 complement-binding protein in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) is characterized by intra-blood-brain barrier immunoglobulin synthesis that persists lifelong. Subcellular fractionation and two-dimensional electrophoresis were used in conjunction with immune precipitation and immunoblotting to identify antigenic determinants for this immunoglobulin. We report that 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein associated with oligodendrocyte/myelin membranes, also present in lymphocytes and retina, is one major target for the humoral response. Antibodies to CNP are detected in sera of 74% of MS patients. The antibodies are IgM and are present in serum in high titer as well as in cerebrospinal fluid. The antibody response is temporally persistent, consistent with systemic immune activation and persistent antigenic stimulation. Moreover, CNP is isolated as an immune complex from MS brain. CNP is expressed as two isoforms, with CNPII identical to CNPI but with a 20-amino acid extension at the amino terminus of CNPII; however, the antibody response is exclusively restricted to CNPI. In contrast, both isoforms bind the C3 complement, providing a plausible mechanism in MS central nervous system (CNS) for opsonization of myelin membrane CNP, mediated via the C3 receptor, and phagocytosis of CNP-Ig immune complexes, mediated by membrane Ig Fc receptors of macrophages and CNS microglia.

Nerve growth factor signal transduction in mature pig oligodendrocytes

It has previously been shown that nerve growth factor (NGF) is of functional significance for mature pig oligodendrocytes (OLs) in culture. The present data give evidence for the expression of TrkA, the so-called high-affinity NGF receptor, and of p75NTR, the so-called low-affinity NGF receptor. TrkA is upregulated during culturing, in contrast to the p75 receptor. Exposure of OLs to NGF induces an autophosphorylation of TrkA via its intrinsic tyrosine kinase. K-252a inhibits the TrkA autophosphorylation, which reduces the OL process formation to control levels. To the tyrosine-phosphorylated sites of TrkA several proteins, such as phospholipase C-gamma1, the adaptor protein SHC, the phosphotyrosine phosphatase SH-PTP2 (SYP) associate via their SH2 phosphotase SH-PTP2 domain. The association of SHC to TrkA is shown by co-immunoprecipitation. Indirect evidence for a possible activation of PLC-gamma1 is given by an NGF-induced increase of oligodendroglial [Ca2+]i. Downstream from TrkA, a mitogen-activated protein kinase cascade, which includes Erk1 and Erk2, is operating. An in-gel myelin basic protein kinase assay revealed that NGF activates predominantly Erk1. Finally, it is shown that NGF stimulates expression of c-fos.

Modified total lymphoid irradiation and low dose corticosteroids in progressive multiple sclerosis

In a double-blind prospective randomized trial, we assessed the efficacy and safety of modified total lymphoid irradiation (TLI) plus low dose prednisone (TLI-LDP) as compared to sham TLI plus identical prednisone therapy (sham TLI-LDP) in 46 patients with progressive forms of multiple sclerosis (MS). No significant difference existed between groups at study entry in patient age, sex, duration of MS, or disability status. However, following treatment, significantly fewer TLI patients showed a sustained one point decline in the Expanded Disability Status Scale, the primary study endpoint, as compared to the sham TLI group using the Kaplan-Meier Product-limit survival analysis, (P<0.005). Risk for relapse requiring treatment with intravenous methylprednisolone was reduced by 54% in the TLI-treated group (P<0.05). Significantly fewer TLI-LDP patients had gadolinium enhancing plus new T2-weighted lesions (P=0.018) when compared to the sham group post-treatment. There was also a substantial and significant decrease in blood lymphocytes in the TLI-LDP group when compared to either pretreatment values or to sham TLI-LDP through at least 12 months post-therapy. Side effects secondary to TLI were generally mild and well-tolerated. These results further support the hypothesis that TLI and systemic immunosuppression have a beneficial effect in progressive forms of MS.

Rational clinical immunotherapy for multiple sclerosis

In this article, we assess the roles and the efficacy of immunopharmacologic agents in the treatment of multiple sclerosis (MS) and other demyelinating disease syndromes. The initial clinical manifestations of demyelinating disease, immunotherapeutic goals, efficacy of individual agents, and specific immunopharmacologic recommendations are discussed. MS and other idiopathic demyelinating disease syndromes can be effectively managed with immunotherapy. Exacerbations are treatable, and the frequency and severity of exacerbations can be reduced. Although some agents have a minor effect on progression of disability, current approaches have not proved to have a major influence on treatment of progressive MS. Immunotherapy for inflammatory demyelinating disease necessitates a high degree of clinical certainty about the diagnosis. Because all available therapeutic agents have limitations and significant toxic effects, careful consideration is necessary before use. Treatment should be individualized on the basis of the clinical course of the disease and the degree of patient disability.

Immunomodulation of autoimmunity by linomide: inhibition of antigen presentation through down regulation of macrophage activity in the model of experimental autoimmune encephalomyelitis

Linomide (quinoline-3-carboxamide, LS-2616), a synthetic immunomodulator, protects animals against a variety of experimental autoimmune diseases. In experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), linomide blocks both the clinical and histological signs of the disease, without inducing generalized immunosuppression. In the first clinical trial in patients with MS, linomide was shown to inhibit the progression of the disease. In the present study we investigated several aspects of the mechanisms of action of this immunomodulator. We found that linomide can inhibit acute EAE even when given as pretreatment, prior to induction of disease (days - 10 to 0). This inhibitory effect was reversed by adoptive transfer of naive spleen cells. A short course (7 days) of linomide treatment also inhibited EAE, especially when administered immediately after disease induction. Spleen cells from linomide-treated mice failed to present myelin antigens to T-cell lines in vitro. The defective antigen presentation was normalized by anti-oxidants such as 2-mercaptoethanol. The proportion of Mac1+ cells in the spleens of linomide-treated mice was significantly reduced and macrophage growth was inhibited in long term cultures of spleen cells derived from linomide-treated animals. Our findings suggest that the effect of linomide on EAE may be attributed, at least in part, to inactivation of antigen presenting cells, possibly following a short period of over-stimulation and increased oxidant production. This mechanism may play a universal role in the regulation of autoimmune reactivity and merits further investigation.

Nursing management of MS patients receiving interferon beta-1b therapy

In 1993, recombinant interferon beta-1b (Betaseron, Berlex Laboratories) was approved by the Food and Drug Administration as a treatment for relapsing-remitting multiple sclerosis (MS). Betaseron is the first therapeutic agent licensed for use with therapeutic patients with MS in more than 20 years. Many patients and their families have expressed great interest in obtaining information about this agent. In response, MS centers throughout the United States have developed Betaseron training programs. This article describes how rehabilitation nurses can educate patients and families about Betaseron.

Search for retrovirus in patients with multiple sclerosis

Multiple sclerosis (MS) patient samples were screened for known or novel retroviruses using an ultrasensitive technique, IMx PERT, that detects the presence of reverse transcriptase (RT). This procedure has 10(5)- to 10(7)-fold greater sensitivity than conventional RT assays and is capable of detecting 10 to 50 virions. Moreover, IMx PERT is at least as sensitive as polymerase chain reaction, and requires no previous knowledge of viral nucleotide sequence. The MS specimens analyzed in this study included 136 sera from 79 patients and 128 cerebrospinal fluid samples from 53 patients with relapsing or chronic progressive disease. In addition, peripheral blood mononuclear cells from 19 MS patients were cultured in an attempt to amplify or induce expression of low-copy number or cell-associated retrovirus. No evidence of retrovirus was found in any of the specimens obtained from MS patients.

Immunomodulation with linomide: possible novel therapy for multiple sclerosis

Linomide, a synthetic quinoline carboxamide, has the ability to stimulate various lymphocyte subpopulations. We have shown its inhibitory effect on the clinical and histological signs of acute and chronic relapsing EAE. In these models linomide induces suppression of lymphocyte response to antigens, production of autoantibody, antigen presentation to specific T-cell lines and Mac-I expression, and induces activation of NK and suppressor-inducer cells. We have subsequently shown its inhibitory effect on clinical and MRI signs of patients with secondary progressive multiple sclerosis. Results of a double blind, placebo controlled, short term pilot study with p.o. linomide, showed a significant effect on the clinical disability scale (EDSS) (P = 0.045) and on the mean total number of new lesions in serial monthly MRI scans (P = 0.021). The increase of CD45Ra, CD8 and CD16 positive cells in linomide treated patients may indicate the importance of suppressor-inducer, suppressor and NK cells for the inhibition of the autoimmune response in the disease.