Open controlled therapeutic trial of intravenous immune globulin in relapsing-remitting multiple sclerosis

Antibody-mediated Remyelination: Relevance to Multiple Sclerosis

Intravenous immunoglobulin (IVIG) is widely used for treatment of autoimmune neurological disorders and is currently in clinical trials as a therapy for multiple sclerosis. We have previously demonstrated that certain mouse monoclonal antibodies of the IgM isotype, promote significant remyelination when administered to mice with chronic Theiler's murine encephalomyelitis virus-induced demyelinating disease. These IgM antibodies bind to antigens expressed on oligodendrocytes. We now demonstrate that polyclonal human IgG (IVIG) and polyclonal human IgM also promote remyelination in this system. Although both polyclonal human IgG and IgM promote remyelination, IgM is more potent Polyclonal human IgM also differs from human IgG in its ability to bind strongly to antigens expressed in the CNS and by oligodendrocytes. We propose that polyclonal IgG and polyclonal IgM may function to promote remyelination by different mechanisms. IVIG may function based on its immunomodulatory activity, while the activity of IgM is critically dependent upon its reactivity with CNS antigens. This possibility has clear relevance to the use of antibodies as a therapy for multiple sclerosis, suggesting that combined treatment with antibodies exerting immunomodulatory activity, in concert with antibodies that function through direct binding to CNS antigens, may synergize to enhance the efficacy of the therapy.

ESIMS - An Ongoing Clinical Trial in Secondary Progressive Multiple Sclerosis

The design of a double-blind, placebo-controlled, European-Canadian Study on IVIG treatment in multiple sclerosis-ESIMS- is described. Three hundred and eighteen multiple sclerosis patients with a secondary progressive course, are treated with monthly infusions of immunoglobulin 10% I g/kg bodyweight or with 0.1 g albumin/vial for 27 months. The primary efficacy parameter is the percentage of patients with a confirmed treatment failure in the EDSS scale and/or the Nine Hole Peg Test Secondary outcome measures are MRI T2 lesion load, Magnetization Transfer Imaging, and MRI brainatrophy measures. Documentation of health resource utilisation and ability to work will cover socio-economic aspects. Recruitment of patients was completed in October 1998. The clinical part of the trial will be completed in April 2001.

A comparison of human natural monoclonal antibodies and aptamer conjugates for promotion of CNS remyelination: where are we now and what comes next?

INTRODUCTION

Multiple sclerosis (MS) is a chronic and progressive inflammatory demyelinating disease of the human central nervous system (CNS) and is the most common disabling neurological condition in young adults, resulting in severe neurological defects. No curative or long-term progression-inhibiting therapy has yet been developed. However, recent investigation has revealed potential strategies that do not merely modulate potentially pathogenic autoimmune responses, but stimulate remyelination within CNS lesions.

AREAS COVERED

We discuss the history and development of natural human IgM-isotype immunoglobulins (HIgMs) and recently-identified aptamer-conjugates that have been shown to enhance endogenous myelin repair in animal models of demyelination by acting on myelin-producing oligodendrocytes (OLs) or oligodendrocyte progenitor cells (OPCs) within CNS lesions. We also discuss future development aims and applications for these important novel technologies.

EXPERT OPINION

Aptamer conjugate Myaptavin-3064 and recombinant human IgM-isotype antibody rHIgM22 regenerate CNS myelin, thereby reducing axonal degeneration and offering the potential of recovery from MS relapses, reversal of disability and prevention of disease progression. Advancement of these technologies into the clinic for MS treatment is therefore a top priority. It remains unclear to what extent the therapeutic modalities of remyelinating antibodies and aptamers may synergize with other currently-approved therapies to yield enhanced therapeutic effects.

Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function that results from immune-mediated inflammation, demyelination, and subsequent axonal damage.

Clinically, most MS patients experience recurrent episodes (relapses) of neurological impairment, but in most cases (60–80%) the course of the disease eventually becomes chronic and progressive, leading to cumulative motor, sensory, and visual disability, and cognitive deficits.

The course of the disease is largely unpredictable and its clinical presentation is variable, but its predilection for certain parts of the CNS, which includes the optic nerves, the brain stem, cerebellum, and cervical spinal cord, provides a characteristic constellation of signs and symptoms. Several variants of MS have been nowadays defined with variable immunopathogenesis, course and prognosis. Many new treatments targeting the immune system have shown efficacy in preventing the relapses of MS and have been introduced to its management during the last decade.

No effect of intravenous immunoglobulins on cytokine-producing lymphocytes in secondary progressive multiple sclerosis

Intravenous immunoglobulins (IVIG) have been effective in reducing multiple sclerosis (MS) disease activity and improving disability scores. However, the mechanism by which this beneficial effect is achieved remains unclear. An effect of IVIG on pro- and anti-inflammatory cytokines- which are thought to play a role in the disease process- has been postulated in a number of animal and ex vivo studies. Hence, we performed a study on 34 patients with secondary progressive (SP) MS being treated with monthly IVIG or placebo for two years according to the protocol of the ESIMS study. Clinical outcome measures and cytokine production (interferon gamma, tumour necrosis factor alpha, interleukin-4 and -10) were recorded in all patients and compared with respect to the treatment group. Against our expectations, IVIG did not reduce the relapse rate or the progression of disability or cytokine production. Our data argue against an enduring immunomodulating effect of IVIG, at least in SPMS.

Do Antibodies Stimulate Myelin Repair in Multiple Sclerosis?

One of the major goals in the study of multiple sclerosis (MS) is to identify a beneficial therapeutic intervention that mimics the intrinsic reparative process and results in long-term clinical improvement. As yet, the therapeutic strategies tested in MS have failed to accomplish this task. However, one potential therapy that has shown some promise in rodent models of demyelination involves the administration of antibodies. Studies in various models of demyelination (virus-induced, autoimmune, and toxic) indicate that a subset of autoantibodies with reactivity to CNS antigens promote remyelination. We have identified a prototypic germline IgMk monoclonal antibody, designated SCH 94.03, with reactivity to a surface antigen on oligodendrocytes that promotes CNS remyelination. This antibody has the phenotypic features of polyreactive physiological natural autoantibodies. Additionally, treatment of MS patients with intravenous immunoglobulin, which contains these natural autoantibodies, may be efficacious in a subset of patients. We propose three mechanisms (direct stimulation of oligodendrocytes, immunomodulation, and opsonization of debris) by which polyreactive natural autoantibodies directed against CNS antigen may promote remyelination. Remyelination has the potential to not only improve conduction velocity but also may protect axons from injury and improve neurological function.

Immunotherapy of multiple sclerosis: the state of the art

It is widely accepted that the main common pathogenetic pathway in multiple sclerosis (MS) involves an immune-mediated cascade initiated in the peripheral immune system and targeting CNS myelin. Logically, therefore, the therapeutic approaches to the disease include modalities aiming at downregulation of the various immune elements that are involved in this immunologic cascade. Since the introduction of interferons in 1993, which were the first registered treatments for MS, huge steps have been made in the field of MS immunotherapy. More efficious and specific immunoactive drugs have been introduced and it appears that the increased specificity for MS of these new treatments is paralleled by greater efficacy. Unfortunately, this seemingly increased efficacy has been accompanied by more safety issues. The immunotherapeutic modalities can be divided into two main groups: those affecting the acute stages (relapses) of the disease and the long-term treatments that are aimed at preventing the appearance of relapses and the progression in disability. Immunomodulating treatments may also be classified according to the level of the 'immune axis' where they exert their main effect. Since, in MS, a neurodegenerative process runs in parallel and as a consequence of inflammation, early immune intervention is warranted to prevent progression of relapses of MS and the accumulation of disability. The use of neuroimaging (MRI) techniques that allow the detection of silent inflammatory activity of MS and neurodegeneration has provided an important tool for the substantiation of the clinical efficacy of treatments and the early diagnosis of MS. This review summarizes in detail the existing information on all the available immunotherapies for MS, old and new, classifies them according to their immunologic mechanisms of action and proposes a structured algorithm/therapeutic scheme for the management of the disease.

Polyclonal immunoglobulin G for autoimmune demyelinating nervous system disorders

Demyelinating diseases with presumed autoimmune pathogenesis are characterised by direct or indirect immune-mediated damage to myelin sheaths, which normally surround nerve fibres to ensure proper electrical nerve conduction. Parenteral administration of polyclonal IgG purified from multi-donor human plasma pools may beneficially modulate these misguided immune reactions via several mechanisms that are outlined in this review. Convincing therapeutic evidence from controlled trials now exists for certain disorders of the peripheral nervous system, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and multifocal motor neuropathy. In addition, there is evidence for potential therapeutic benefits of IgG in patients with chronic inflammatory demyelinating diseases of the central nervous system, including multiple sclerosis and neuromyelitis optica. This review introduces these disorders, briefly summarises the established treatment options, and discusses therapeutic evidence for the use of polyclonal immunoglobulins with a particular emphasis on recent clinical trials and meta-analyses.

Intravenous immunoglobulins as therapeutic option in the treatment of multiple sclerosis

Treatment of neurological disorders with intravenous immunoglobulin (IVIG) is an increasing feature of practice for an expanding range of indications. This article reviews the current literature regarding the role of IVIG treatment in multiple sclerosis (MS) and summarizes recommendations for the use of IVIG in different courses and clinical subsets of the disease. Principally based on the results of four randomized, double-blind, placebo-controlled trials (RCTs) and a corresponding meta-analysis, the amount of evidence for the efficacy of IVIG treatment is currently most convincing for the relapsing-remitting course of MS (RRMS); nevertheless, it lags clearly behind that for beta interferon due to smaller study sizes, partial deficits in study design and not established optimal dosage. This prompted the basis for a consensus statement in some countries to recommend IVIG as second-line treatment in RRMS, when other licensed therapies (i. e., beta interferon, glatiramer acetate) are individually not tolerated due to side effects or concomitant disease. Recent evidence indicates that IVIG is also effective in clinically isolated syndrome (CIS) and should be considered as a therapeutic option, particularly when licensed immunotherapy can not be offered. During an acute relapse additional IVIG administration to established steroid treatment showed no benefit. Despite promising experimental data on promotion of remyelination, fixed chronic deficits were not reversed or improved by long-term IVIG treatment either. Currently there is no indication for IVIG treatment in the chronic progressive disease stages, since a large and well-designed RCT failed to show any beneficial effect in patients with secondary progressive MS (SPMS) and data derived from primary progressive MS (PPMS) are still pending. However, preliminary results of a so far unpublished RCT including patients with PPMS and SPMS suggest a strong trend towards a beneficial effect in PPMS. So far, IVIG is the only therapy investigated for reducing postpartum relapses, whereas immunomodulatory drugs are contraindicated during pregnancy and lactation period. Data evaluating the peripartal use of IVIG along with the positive results of the trials in RRMS justify postpartal IVIG treatment particularly for mothers, who choose to breastfeed, under consideration of the recommendations specified for the relapsing-remitting disease course. As recently shown IVIG administration right from the early weeks of pregnancy appears to be a promising strategy, but cannot be recommended from the viewpoint of evidence-based medicine.

The natural history of multiple sclerosis: a geographically based study 9: observations on the progressive phase of the disease

The clinical features of relapses and progression largely define multiple sclerosis phenotypes. A relapsing course is followed by chronic progression in some 80% of cases within 2 decades. The relationship between these phases and long-term outcome remains uncertain. We have analysed these clinical features within a well-studied natural history cohort with mean follow-up of 25 years. For the entire cohort, median times to reach Disability Status Scale (DSS) 6, 8 and 10 were 12.7, 20.6 and 43.9 years, respectively. Among 824 attack-onset patients, the great majority entered a progressive phase with a mean time to progression of 10.4 years. The effects of relapses often cloud the clinical onset of progression. However, there are circumstances where onset of progression is early, relatively discrete and identifiable at DSS of 2 or less. Three subgroups allow for clarity of outcome comparison and they are (i) cases of primary progressive (PP) disease, (ii) attack-onset disease where only a single attack has occurred before onset of progression (SAP) and (iii) secondary progressive (SP) disease where recovery from relapses allows recognition of the earliest clinical stages when progression begins. Here we compare survival curves in these three groups. Among cohorts of SAP (n = 140), PP (n = 219) and SP (n = 146) where progression was stratified by DSS at its onset, there was no difference in time to DSS 6, 8 and 10. These findings demonstrate that the progressive course is independent of relapses either preceding the onset of relapse-free progression or subsequent to it. Among SAP patients, the degree of recovery from the single defining exacerbation had no significant effect on outcome. The site of the original attack was not usually where progression began. The relatively stereotyped nature of the progressive phase seen in all progressive phenotypes suggests regional and/or functional differential susceptibility to a process that appears degenerative in nature. The highly prevalent distal corticospinal tract dysfunction in progressive disease and the pathologically demonstrated selective axonal loss seen in this tract raises the possibility of a dying back central axonopathy, at least in part independent of plaque location or burden. Despite considerable individual variation, the progressive course of disability seen in groups of PP, SAP and SP-DSS2 is similarly stereotyped in quality and pace and may entail mechanisms common to all forms of progressive multiple sclerosis. The possibility that this is the primary process in some cases must be considered.

Intravenous immunoglobulin in secondary progressive multiple sclerosis: randomised placebo-controlled trial

BACKGROUND

Several double-blind placebo-controlled trials of relapsing-remitting multiple sclerosis have shown beneficial effects of intravenous immunoglobulin (IVIG) on relapse rate and disability. The European Study on Intravenous Immunoglobulin in Multiple Sclerosis set out to test IVIG in the secondary progressive phase of the disease.

METHODS

318 patients with clinically definite secondary progressive multiple sclerosis (mean age 44 years [SD 7]) were randomly assigned IVIG 1 g/kg per month (n=159) or an equivalent volume of placebo (albumin 0.1%; n=159) for 27 months. After baseline investigation, clinical assessments were made every 3 months and MRI was repeated after 12 months and 24 months. The primary outcome was confirmed worsening of disability as defined by the time to first confirmed progression on the expanded disability status scale (EDSS). Analyses were by intention to treat.

FINDINGS

19 patients in the IVIG group and 39 in the placebo group terminated study treatment prematurely but were included in the analyses. IVIG treatment had no beneficial effect on time to confirmed EDSS progression (hazard ratio 1.11 [95% CI 0.80-1.53] for IVIG versus placebo). The annual relapse rate was 0.46 in both groups. No significant differences between the treatment groups were found in any of the other clinical outcome measures or in the change of T2-lesion load over time. The treatment was generally well tolerated, although deep venous thrombosis, pulmonary embolism, or both occurred in seven patients with risk factors for thromboembolism (IVIG six, placebo one).

INTERPRETATION

Treatment with IVIG in this study did not show any clinical benefit and therefore cannot be recommended for patients with secondary progressive multiple sclerosis.

The role of qualitative and quantitative MRI assessment of multiple sclerosis lesions according to their in evaluating the efficacy of intravenous immunoglobulin G

We evaluation of the role of determining the distribution of brain-stem, cerebellar and cerebral lesions in number and volume by MRI in determining the efficiency of treatment of multiple sclerosis (MS). We studied 24 patients diagnosed as having relapsing and remitting MS, of whom 12 received intravenous immunoglobulin G; a control group of 12 were given placebo. In a double-blind study, MRI was obtained initially and at 3, 6 and 9 months, and interpreted without knowledge of clinical findings, laboratory tests or treatment. The lesions were classified according to their distribution and evaluated qualitatively and quantitatively. Each patient was also examined clinically and scored according to the expanded disability status scale (EDSS) following every MRI examination. All patients in the treatment group showed significant improvement. The lesions decreased in both in size and number in all sites. In the control group lesions increased both in number and size in all sites, but only the increase between 3()and 6 months was statistically significant. In both groups, significant apparent changes were detected in the cerebellum and brain stem. Volumetric evaluation was found to be more helpful than qualitative assessment.

The immunomodulatory properties of in vitro immunoglobulins are dose-dependent

OBJECTIVES

The mechanism by which intravenous immunoglobulins (immunoglobulin G, IgG) exert their beneficial effect on multiple sclerosis (MS) is unknown. Furthermore, there is uncertainty about the optimal dosage of IgG. Therefore, we investigated the influence of different IgG dosages on cytokine production in MS.

MATERIALS AND METHODS

Twenty-five MS patients and 15 healthy controls were enrolled. We measured the production of interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF) and interleukin 10 (IL-10) in peripheral blood lymphocytes by flowcytometry after stimulation without and with IgG in different doses (1, 5 and 10 mg/ml).

RESULTS

IFN-gamma and TNF were decreased significantly (P = 0.001) in the untreated and interferon beta (IFN-beta) treated patients after stimulation with IgG. In contrast, IL-10 production was significantly enhanced (P = 0.001) at least in the untreated patient group. The reduction of the pro-inflammatory cytokines IFN-gamma and TNF after stimulation with different IgG doses was clearly dose-dependent in all groups.

CONCLUSION

Besides a suppression of the pro-inflammatory cytokines IFN-gamma and TNF, IgG enhances the anti-inflammatory cytokine IL-10. This effect is dose-dependent, speaking in favour of higher IgG doses in the treatment of MS.

The role of intravenous immunoglobulin in the treatment of multiple sclerosis

Intravenous immunoglobulin (IVIG) has several effects on the immune system that could have a beneficial influence on disease processes in multiple sclerosis (MS). Owing to its anti-inflammatory properties, IVIG may be beneficial in the treatment of acute relapses and in prevention of new relapses. By promoting remyelination, IVIG could have a beneficial effect on disability and disease progression. Four double-blind trials in relapsing-remitting MS have demonstrated that IVIG reduces the relapse rate and the number of gadolinium enhancing lesions, and in this respect seems comparable to established therapies in relapsing-remitting MS, i.e. interferon-beta and glatiramer acetate. The doses of IVIG that have been used for treatment in relapsing-remitting have varied 10-fold, and the ideal dosage of IVIG for treating MS still needs to be determined. Three studies have been performed to assess the effect of IVIG on chronic visual impairment or established motor symptoms in MS. None of these trials could confirm that established symptoms in MS can be reversed by IVIG. In secondary progressive MS, a large randomized placebo-controlled trial has recently shown that IVIG is without beneficial effects in this phase of the disease. In conclusion, IVIG is a valuable alternative for treatment of relapsing-remitting MS in patients who do not tolerate or are unwilling to take the approved injectable medications, but additional studies are needed to establish the role of IVIG in the management of multiple sclerosis.

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

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

No difference in efficacy of two different doses of intravenous immunoglobulins in MS: clinical and MRI assessment

We performed a double-blind, placebo-controlled study to evaluate the efficacy of low and high dose of intravenous immunoglobulins (IVIG) in relapsing/remitting (RR) multiple sclerosis (MS). Patients (n = 49) with clinical definite RR MS were randomly allocated to three groups and treated with 0.2 g/kg (n = 17) or 0.4 g/kg (n = 15) once a month of IVIG and placebo (n = 17) for 12 months. Clinical data were assessed monthly and magnetic resonance imaging (MRI) was performed every 3 months during the study period. Annual relapse rate (ARR) and change of the mean Expanded Disability Status Scale (EDSS) and Neurological Rating Scale Score (NRSS) from baseline to study conclusion were used as the clinical end-points. For MRI activity total lesion volume on T2-weighted image (T2WI), new lesions and gadolinium (Gd)-enhanced lesions on T1WI were analysed. ARR in both IVIG groups (0.88 for 0.2 g/kg and 0.86 for 0.4 g/kg) was reduced compared with placebo (1.24) during treatment period. Neurological disability measured with EDSS decreased slightly in both the IVIG groups (0.029 and 0.066, respectively) and increased by 0.29 in placebo (P = 0.0117). The neurologic impairment measured by NRSS showed similar trend. The total lesion volume on T2WI increased by 13.56% in placebo whereas in the 0.4 g/kg IVIG group decreased by -3.95% and in the 0.2 g/kg IVIG group increased by 3.6%. The cumulative numbers of Gd-enhancing lesions and new T2WI lesions in the IVIG groups were reduced in comparison with the placebo group. Our findings suggest that the dose 0.2 g/kg of IVIG is equally effective as 0.4 g/kg in reducing MS activity.

Multiple sclerosis treatment 2001

Trials of new MS drugs now require MR imaging and clinical data and entail enormous expense. Therefore, science can ask and answer only a limited number of questions, so physicians must use their clinical acumen to judge (or conjecture) the best treatments for their patients. The drugs discussed earlier will dominate MS therapy in the next few years, but further advances may come from one of the more than forty new agents now under investigation for alleviating MS. It is an exciting time for patients and their doctors.

High-dose mouse immunoglobulin G administration suppresses Theiler's murine encephalomyelitis virus-induced demyelinating disease

We studied the effect of high-dose mouse IgG on TMEV-induced demyelinating disease (TMEV-IDD). We injected TMEV intracerebrally into susceptible SJL/J mice and induced TMEV-IDD. Mouse IgG were injected intraperitonealy, and clinical course and various immunological indicators were studied. The results show that TMEV-IDD was significantly suppressed both clinically and histologically (P<0.01) when IgG were administered in the effector phase. The delayed type hypersensitivity and T cell proliferative response specific for TMEV were decreased by this treatment. In an ELISPOT assay, the number of TNF-alpha producing lymphocytes in the spinal cords was low in high-dose IgG treated mice compared with PBS treated control mice. These data suggest that administration of IgG suppresses TMEV-IDD and may be promising treatment to prevent exacerbation of human multiple sclerosis.

Human monoclonal antibodies reactive to oligodendrocytes promote remyelination in a model of multiple sclerosis

Promoting remyelination, a major goal of an effective treatment for demyelinating diseases, has the potential to protect vulnerable axons, increase conduction velocity, and improve neurologic deficits. Strategies to promote remyelination have focused on transplanting oligodendrocytes (OLs) or recruiting endogenous myelinating cells with trophic factors. Ig-based therapies, routinely used to treat a variety of neurological and autoimmune diseases, underlie our approach to enhance remyelination. We isolated two human mAbs directed against OL surface antigens that promoted significant remyelination in a virus-mediated model of multiple sclerosis. Four additional OL-binding human mAbs did not promote remyelination. Both human mAbs were as effective as human i.v. Ig, a treatment shown to have efficacy in multiple sclerosis, and bound to the surface of human OLs suggesting a direct effect of the mAbs on the cells responsible for myelination. Alternatively, targeting human mAbs to areas of central nervous system (CNS) pathology may facilitate the opsonization of myelin debris, allowing repair to proceed. Human mAbs were isolated from the sera of individuals with a form of monoclonal gammopathy. These individuals carry a high level of monoclonal protein in their blood without detriment, lending support to the belief that administration of these mAbs as a therapy would be safe. Our results are (i) consistent with the hypothesis that CNS-reactive mAbs, part of the normal Ig repertoire in humans, may help repair and protect the CNS from pathogenic immune injury, and (ii) further challenge the premise that Abs that bind OLs are necessarily pathogenic.

Pregnancy and multiple sclerosis: a 2-year experience

OBJECTIVE

To present our experience with management of parturients with multiple sclerosis and to examine the role of intravenous immunoglobulin (IVIg) in the prevention of postpartum exacerbations of the disease.

METHODS

Fifteen patients with multiple sclerosis with a relapsing-remitting course were followed during pregnancy and 6 months postpartum. To prevent postpartum exacerbations, 14 of the patients had received IVIg after delivery.

RESULTS

None of the patients who received postpartum IVIg relapsed during the 6 months after delivery. None of the observed obstetric complications nor the operative deliveries could be related to the coexistence of multiple sclerosis.

CONCLUSION

Postpartum IVIg treatment is beneficial in preventing acute childbirth-associated exacerbations in patients with relapsing-remitting multiple sclerosis. Furthermore, this disease does not seem to increase obstetric complications.

A unique population of circulating autoantibodies promotes central nervous system remyelination

In previous studies we demonstrated that the humoral immune response directed against unique central nervous system (CNS) antigens enhanced CNS remyelination in the Theiler's virus experimental model of multiple sclerosis (MS). To expand on this observation, a mouse IgM kappa monoclonal antibody (mAb) which enhances CNS remyelination, was raised against normal mouse spinal cord homogenate. Characterization of this mAb revealed that it is polyreactive towards variety of intracellular antigens but also reacts to an unidentified surface antigen on oligodendrocytes. The mAb is encoded by germline immunoglobulin genes without somatic mutations consistent with the observation that it is a natural autoantibody. Recently we generated another mouse IgM kappa mAb raised against normal spinal cord homogenate, which also promotes CNS remyelination. Further characterization revealed that both mAbs which promote remyelination have similar binding characteristics. Conventionally Abs which recognize normal CNS components, especially oligodendrocytes or myelin, have been considered to be a disease marker or be involved in the pathogenesis of MS. However, we have identified a unique population of circulating autoantibodies which are beneficial for myelin repair. Therefore this observation indicates the need to reevaluate autoantibody production against myelin components in CSF and blood as markers of disease activity versus repair in MS.

Intravenous immunoglobulin treatment of children with autism

Since autism has been associated with immunologic abnormalities suggesting an autoimmune cause of autistic symptoms in a subset of patients, this study was undertaken to investigate whether intravenous immunoglobulin (i.v.Ig) would improve autistic symptoms. Ten autistic children with immunologic abnormalities, demonstrated on blood tests, were enrolled in this study. Their ages ranged from 4 to 17 years, with two girls and eight boys. Eight children (1 female and 7 male) historically had undergone autistic regression. Intravenous immunoglobulin, 200 to 400 mg/kg, was administered every 6 weeks for an intended treatment program of four infusions. In five children, there was no detectable change in behavior during the treatment program. In four children, there was a mild improvement noted in attention span and hyperactivity. In none of these children did the parents feel that the improvement was sufficient to warrant further continuation of the infusions beyond the termination of the program. Only in one child was there a very significant improvement, with almost total amelioration of autistic symptoms over the time period of the four infusions. Once the treatment program was completed, this child gradually deteriorated over a 5-month time period and fully reverted to his previous autistic state. In this treatment program, five children had no response to intravenous immunoglobulin. In the four children who showed mild improvements, those improvements may simply have been due to nonspecific effects of physician intervention and parental expectation (ie, placebo effect). However, in one child there was a very significant amelioration of autistic symptoms. There were no distinguishing historic or laboratory features in this child who improved. Given a positive response rate of only 10% in this study, along with the high economic costs of the immunologic evaluations and the intravenous immunoglobulin treatments, the use of intravenous immunoglobulin to treat autistic children should be undertaken only with great caution, and only under formal research protocols.

Current immunotherapy in multiple sclerosis

The underlying pathophysiology of multiple sclerosis is presumed to be autoimmune in nature. Attempts to find an effective treatment for this common disease of the central nervous system have primarily focused on immune-mediated therapies, both immunosuppressive and immunomodulatory. The wide variety of immunological abnormalities detected in multiple sclerosis and its animal model, experimental allergic encephalomyelitis, has prompted the testing of a diverse array of drugs to be used for treatment. Recent successes in the treatment of relapsing-remitting multiple sclerosis with interferon beta and glatiramer acetate have renewed interest in and raised expectations for the effective control of this neurological disorder. Improved methodology in clinical trials, the development of surrogate markers and the availability of novel therapies bode well for more rapid advances.

Intravenous immunoglobulin treatment of neurological autoimmune diseases

Intravenous immunoglobulin (IVIg) has been widely used in neurological diseases during the last decade. The current indications of IVIg in neurological diseases are reviewed and discussed on the basis of the available experimental data and clinical trials. Compared to other immunomodulating treatments used in neurological diseases, IVIg has only few side effects with a small risk of transmission of infectious agents. Good clinical evidence for the effectiveness is available for Guillain-Barré-Syndrome, chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. In conditions like myasthenia gravis and myositis favourable effects of IVIg were reported, but future studies have to be awaited. For all other neurological conditions where IVIg has been administered, there is currently no support for the use of IVIg other than in controlled trials. In conclusion, IVIg is a promising immunomodulary therapy that has been shown to be effective in some neurological autoimmune diseases. Routine use in neurological practice should be restricted to diseases for which a positive effect has been proven in controlled trials. For all other conditions no definite recommendations can presently be made.

Immunomodulating therapeutic approaches for multiple sclerosis

In this review we delineate the rationale for immunotherapy in multiple sclerosis and describe the various levels at which immune intervention, according to a modern model of the immune system organization, is feasible. Current and future immunosuppressive and immunomodulating therapeutic approaches at the level of antigen presentation and at the lymphocyte and cytokine network levels are discussed.

Effects of intravenous immunoglobulins on T-cell mediated, concanavalin A-induced hepatitis in mice

Concanavalin A (ConA) activates T lymphocytes and causes T-cell mediated hepatic injury in mice. The intravenous administration of human immunoglobulins has beneficial effects in T-cell mediated diseases such as experimental autoimmune encephalomyelitis and adjuvant arthritis. In the present study, we examined the effects of intravenous immunoglobulins in a mouse model of T-cell mediated, acute liver injury induced by concanavalin A. Balb/c mice were inoculated with 12 mg/kg concanavalin A with or without intravenous immunoglobulins at doses of 0.4, 0.6, 0.8 g/kg body wt. The serum levels of liver enzymes, tumor necrosis factor-alpha, interferon-gamma and interleukin-6 were assayed 2, 6 and 24 h after concanavalin A administration. Intravenous immunoglobulins did not prevent concanavalin A-induced hepatitis, as manifested by elevation of serum aminotransferases and histopathological evaluation. The serum levels of tumor necrosis factor-alpha in mice pretreated with immunoglobulins, measured 2 h after ConA treatment were reduced, while interferon-gamma levels measured 6 h after ConA inoculation were 5-fold higher than control levels. There was no effect of intravenous immunoglobulins on the release of interleukin 6. In conclusion, these results indicate that intravenous immunoglobulin is not effective in preventing T-cell mediated concanavalin A-induced hepatitis. The increased secretion of interferon-gamma and the incomplete suppression of tumor necrosis factor-alpha release may explain the lack of efficacy of intravenous immunoglobulin in this experimental model.

Failure of intravenous immunoglobulin to arrest progression of multiple sclerosis: a clinical and MRI based study

Due to the modest benefit, inconvenience and high cost of currently available therapies for MS, it is appropriate to seek alternative treatments. Based on anecdotal evidence suggestive of benefit for i.v.IG in MS, we conducted an open-label, unblinded protocol of i.v.IG in nine MS patients. The patients were given induction doses of i.v.IG followed by monthly boosters for 1 year and had clinical, MRI and CSF analyses performed. Patients included were both progressive and relapsing. There was no clinical benefit nor apparent MRI benefit utilizing this protocol. During treatment the majority of patients continued to progress or have attacks and MRI demonstrated continued accumulation of T2-weighted lesions. CSF was unaffected by treatment.

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.

Successful treatment of established relapsing experimental autoimmune encephalomyelitis in mice with a monoclonal natural autoantibody

We postulated that humoral autoimmunity can play a beneficial role in CNS demyelinating diseases such as multiple sclerosis. We previously demonstrated that monoclonal natural autoantibody SCH94.03 suppresses CNS inflammation and promotes remyelination in a virus-induced model of chronic progressive multiple sclerosis. To further investigate the relationship between natural autoimmunity and CNS demyelination, we examined the effect of SCH94.03 treatment on clinical relapses and pathological disease in SJL/J mice with established adoptive-transfer relapsing experimental autoimmune encephalomyelitis. Treatment with SCH94.03 after recovery from the initial episode of clinical disease reduced relapse rates by half, prolonged relapse onset by 6 days and reduced spinal cord demyelination and meningeal inflammation by 40%. These results are consistent with the hypothesized immunomodulatory function of natural autoantibodies, and are the first direct demonstration that natural humoral autoimmunity can be beneficial in an autoimmune T-cell-mediated CNS demyelinating disease.

Promotion of endogenous remyelination in multiple sclerosis

Studies in both human and experimental models demonstrate that myelin repair occurs in the central nervous system and is a normal physiologic response to myelin injury. However, remyelination in MS is often incomplete and limited. The outcome of an actively demyelinating lesion depends on the balance between factors promoting myelin destruction and myelin repair. Experimental models of CNS demyelination provide an opportunity to investigate the morphologic, cellular and molecular mechanisms involved in remyelination. This review focuses on experiments using the Theiler's virus model of demylination which indicate that manipulation of the immune response has the potential to promote endogenous CNS remyelination and functional recovery in MS.

A double-blind, cross-over trial of intravenous immunoglobulin G in multiple sclerosis: preliminary results

We enrolled 25 patients with relapsing-remitting or relapsing progressive multiple sclerosis (MS) in a randomized placebo-controlled double-blind study of intravenous immunoglobulin G (IVIG). IVIG 1 g/kg daily for 2 days was administered every 4 weeks for 24 weeks. Seventeen patients completed the whole trial, whereas eight patients discontinued the trial; four during IVIG treatment and four on placebo. Of the 17 patients who completed the trial, 11 had no exacerbations during IVIG treatment compared with only six on placebo (P=O.05). The total number of exacerbations in the IVIG period was 11 and in the placebo period 15 (NS), and the number of severe exacerbations requiring treatment with intravenous methylprednisolone was four during treatment with IVIG and six on placebo (NS). The results suggest that IVIG treatment may be of benefit for prevention of exacerbations in patients with relapsing MS.

Treatment effects of monthly intravenous immunoglobulin on patients with relapsing-remitting multiple sclerosis: further analyses of the Austrian Immunoglobulin in MS study

Recently, the Austrian Immunoglobulin in Multiple Sclerosis (AIMS) study showed patients with relapsing-remitting multiple sclerosis to benefit from repeated administration of intravenous immunoglobulin (IVIg). To provide a more detailed understanding of IVIg's action we performed further analyses on the time course of treatment effects and in regard to the impact of clinical disability at study entry on patients' response to medication. The AIMS trial was a randomized, placebo-controlled, double blind, multicenter trial. It included 148 patients (IVIg: 75; placebo 73) who suffered from relapsing-remitting MS, were 15-65 years old and scored from 1-6 on the Expanded Disability Status Score (EDSS). IVIg was given over 2 years in a monthly dosage of 0.15-0.2 g/kg body weight Within the first 6 months of the trial clinical disability of IVIg treated patients improved significantly from a baseline EDSS of 3.33 +/- 1.38 to a score of 3.05 +/- 1.73 (P=0.002). This improvement was retained over the subsequent 18 months of the trial (final EDSS: 3.09 +/- 1.62). In contrast, placebo-treated patients showed a slight trend for deterioration over the study period (baseline EDSS: 3.37 +/- 1.67; final EDSS: 3.49 +/- 1.83). IVIg treatment was associated with a significant reduction of relapses throughout the study which was independent of the patients' disability at baseline. The observation of clinical improvement in the early phase of IVIg medication may suggest the activation of repair mechanisms such as the promotion of remyelination while immunoregulatory effects would be expected as the cause of fewer exacerbations throughout the AIMS study. These hypotheses need to be tested in future trials.

Immunomodulation and remyelination: two aspects of human polyclonal immunoglobulin treatment in immune mediated neuropathies?

Intravenous immunoglobulin is used in inflammatory demyelinating diseases of the peripheral as well as the central nervous system. It is not known which mechanism(s) accounts for the beneficial effect observed in these diseases. The immunomodulatory effects of IVIg in two different models of T and B cell activation were investigated. IVIg inhibited a predominantly cellular immune response of the Th 1 type, which was partially reversed by addition of Th 1 cytokines. In contrast, in a model, which leads to B cell differentiation and antibody production, a synergistic stimulatory effect of IVIg and Th2 cytokines was observed. The ability of IVIg to interfere with cell proliferation and to manipulate the Th1/Th2 profile will have consequences for the induction, character, and amplification of an immune response. Apart from the immunomodulatory effects, evidence shows that IVIg promote remyelination not only by abrogation of the auto-immune attack but also by an effect on glial cells. We showed that IVIg induce growth arrest of normal human fibroblasts and Schwann cells. In fibroblasts this growth arrest is accompanied by upregulation of GAS-3/PMP-22 mRNA. The implications of this finding are discussed. Further studies in human Schwann cells are imperative to prove the hypothesis that IVIg directly stimulates remyelination.

Intravenous immunoglobulin (IVIG) treatment for patients with primary or secondary progressive multiple sclerosis -- outline of a double-blind randomized, placebo-controlled trial

We present the design of a double-blind, randomised placebo-controlled phase III study to evaluate safety and efficacy of IVIG in the treatment of patients suffering from primary or secondary chronic progressive multiple sclerosis. The primary endpoint is disability. Two measures of disability were chosen in order to assess the primary end point (a) sustained improvement (assessed at month 6, confirmed at month 9) and (b) progression to increasing disability of the disease (sustained for 3 months) at any time during the course of this 2 years study. The disability is measured by the Extended Disability Status Scale (EDSS). Secondary end points include the assessment of visual function, functions of the upper extremity, cognitive functions, depression and quality of life.

Randomised placebo-controlled trial of monthly intravenous immunoglobulin therapy in relapsing-remitting multiple sclerosis. Austrian Immunoglobulin in Multiple Sclerosis Study Group

BACKGROUND

Multiple sclerosis is an autoimmune disorder characterised by the repeated occurrence of demyelinating lesions within the central nervous system. Uncontrolled studies and experimental evidence suggest beneficial effects of repeated administration of intravenous immunoglobulin (IVIg) by immunomodulating mechanisms and induction or remyelination. We aimed to investigate the efficacy of IVIg in a randomised double-blind multicentre study.

METHODS

Patients with relapsing-remitting multiple sclerosis were randomly assigned a monthly dose of IVIg (0.15-0.2 g/kg bodyweight) or placebo. Duration of treatment was 2 years. The primary outcome measures were the effect of treatment on clinical disability-measured by the absolute change in Kurtzke's expanded disability status scale (EDSS) score- and the proportion of patients with improved, stable, or worse clinical disability (> or = 1.0 grade on EDSS score).

FINDINGS

Of the 243 patients screened, 150 met our eligibility criteria and were randomly assigned to IVIg or placebo. Before the start of treatment two patients in the placebo group dropped out, so there were 75 patients in the IVIg group and 73 in the placebo group. Intention-to-treat analysis showed that IVIg treatment had a beneficial effect on the course of clinical disability. The EDSS score decreased in the IVIg-treated patients and increased in the placebo group (-0.23 [95% CI -0.43 to -0.03] vs 0.12 [-0.13 to 0.37], p = 0.008). In the IVIg group, the numbers of patients with improved, stable, or worse clinical disability were 23 (31%), 40 (53%), and 12 (16%) compared with ten (14%), 46 (63%), and 17 (23%) in the placebo group. Side-effects were reported in three (4%) IVIg-treated patients and in four (5%) placebo-group patients, but were not directly linked to study medication.

INTERPRETATION

Monthly IVIg is an effective and well-tolerated treatment for patients with relapsing-remitting multiple sclerosis.

Intravenous immunoglobulin G therapy: effects of acute and chronic treatment in multiple sclerosis

High dose intravenous immunoglobulin (IVIG) exerts several effects on the immune system that could have a beneficial influence on the disease processes in multiple sclerosis (MS). IVIG may be useful in treatment of acute exacerbations, in prevention of new relapses, and in promotion of remyelination. Presently, the clinical evidence of effect of IVIG in MS is based on the results of small open trials, some of which, however, have been encouraging. Confirmation of a beneficial effect of IVIG must await the results of placebo-controlled, double-blind trials currently ongoing in several centers. If effective, IVIG administration would be a valuable supplement to the existing treatment of MS.

Intravenous immunoglobulin in rheumatic disease

With the advent of numerous commercial preparations of intravenous immunoglobulin preparations since 1981, it is now possible to administer these preparations in significant quantities to cause elevation of serum immunoglobulin levels both in patients with antibody-deficient states and in those with normal circulating immunoglobulin levels. This led to a report of dramatic improvement of thrombocytopenia in a child with agammaglobulinemia following the use of intravenous immunoglobulin preparations for recurrent infections, and further studies in both children and adults with associated symptoms suggested therapeutic efficacy of intravenous immunoglobulin preparations in controlling autoimmune symptoms.

Intravenous immunoglobulin treatment in the prevention of childbirth-associated acute exacerbations in multiple sclerosis: a pilot study

Acute exacerbations frequently occur after childbirth in patients with relapsing-remitting multiple sclerosis (MS). The present pilot study was initiated in an attempt to reduce the number of childbirth-associated acute exacerbations in the postpartum period. We treated nine MS patients with a history of 12 childbirth-associated acute exacerbations that had occurred 2-9 weeks after previous deliveries. The patients were administered intravenous immunoglobulin (IVIg) at a dose of 0.4 g/kg per day for 5 consecutive days during the 1st week after childbirth and at 6 and 12 weeks thereafter. None of the treated patients relapsed during the 6-month period after delivery. However, three patients had a remote relapse, two at 8 months and one at 10 months after childbirth, but these probably represented the natural course of disease and were not associated with childbirth. We conclude that IVIg treatment may prevent acute childbirth-associated exacerbations in relapsing-remitting MS patients.

Multiple sclerosis

Multiple sclerosis is a chronic disease that begins in late adolescence or adulthood. It is highly variable in its expression and severity. It is believed to be autoimmune in nature. The cause is unknown; both genetic and environmental factors have been implicated in the pathogenesis. MS generally presents with the acute or subacute onset of neurologic abnormalities that may wax and wane over many years. Diagnosis is generally made by means of observation of the clinical course in conjunction with a neurologic examination and laboratory tests. These tests may include magnetic resonance imaging of the head and spine, lumbar puncture, and evoked potentials. Treatment is based on general supportive care, the use of corticosteroids for relapses, and symptomatic management of ongoing problems. The frequency of relapses can be reduced with interferon-beta (Betaseron). Copolymer 1 and interferon-beta la are being evaluated by the U.S. Food and Drug Administration for approval for use for reduction in the frequency of relapses in relapsing-remitting MS. Treatment of chronic progression is often attempted with immunosuppressive agents such as corticosteroids, azathioprine, and cyclophosphamide. Use of other agents is being investigated.

Spontaneous and induced remyelination in multiple sclerosis and the Theiler's virus model of central nervous system demyelination

Remyelination in the central nervous system, originally thought to occur rarely, if ever, is now an established phenomena in multiple sclerosis patients. However, the extent of myelin repair is incomplete and limited. Experimental models of central nervous system demyelination provide an opportunity to study the cellular and molecular events involved in remyelination. These models may provide some clue to why remyelination in multiple sclerosis is incomplete as well as suggest potential methods to stimulate central nervous system repair. In this review we examine the morphological aspects of central nervous system remyelination and discuss both spontaneous and induced remyelination in multiple sclerosis and experimental models of central nervous system demyelination. We give special emphasis to the Theiler's virus model of central nervous system demyelination and its usefulness to identify therapeutic agents to promote remyelination. The role of immunoglobulins in promoting remyelination in both the Theiler's model system and in multiple sclerosis is discussed. Finally, we examine the potential physiological role of demyelination and remyelination and its relationship with clinical manifestations of central nervous system disease.

IL-3-LA production by mononuclear cells of patients with multiple sclerosis: effect of treatment with intravenous immunoglobulins

IL-3-like activity (IL-3-LA) is a growth factor that stimulates stem cell maturation. We examined the production of IL-3-LA by peripheral blood mononuclear cells of 10 patients with relapsing-remitting multiple sclerosis (MS) following one year of treatment with intravenous immunoglobulins (IVIG). The results were compared with those obtained in 13 age- and sex-matched untreated patients with relapsing-remitting MS and in 14 healthy controls. IL-3-LA was assayed using the IL-3-dependent 32-D-cl-23 murine cell line. IL-3-LA production was 60% higher in untreated MS patients than in healthy controls (134 +/- 19 u/ml and 78.7 +/- 15.9 u/ml, respectively; p < 0.01), and lower in patients treated with IVIG than in untreated patients (101.4 +/- 4.9 u/ml; p < 0.02). IL-3-LA production also decreased after incubation of mononuclear cells with IVIG of both untreated MS patients and controls. This study indicates a possible beneficial effect of IVIG on the immunological status of MS patients.

Experimental strategies to promote central nervous system remyelination in multiple sclerosis: insights gained from the Theiler's virus model system

The destruction of central nervous system (CNS) myelin, the lipid-rich insulator surrounding axons in the mammalian brain and spinal cord, is the primary pathological finding in multiple sclerosis. Myelin loss can result in a significant clinical deficit, and was originally thought to be permanent, similar to axonal destruction. However, myelin regeneration is now an established phenomenon in both human disease and animal models of CNS demyelination. In this review, the concept of remyelination in demyelinating diseases such as multiple sclerosis is discussed and the usefulness of animal models of CNS demyelination in developing experimental strategies to promote remyelination is examined. Special emphasis is given to the Theiler's murine encephalomyelitis model, which has been the primary animal model used to investigate therapies designed specifically to stimulate myelin repair.

Multiple sclerosis: immune mechanism and update on current therapies

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) afflicting approximately 250,000 individuals in the United States. This inflammatory disease has variable clinical manifestations, ranging from a relapsing-remitting course to a chronic progressive disease. Approximately one third of MS patients have chronic progressive disease often leading to severe impairment of mobility, paralysis, poor vision, and disturbances of bladder and bowel function. Although the etiology and pathogenesis remain unknown, accumulating evidence supports the hypothesis that exposure to an as-yet-unidentified infectious agent(s) triggers an aberrant immune response against self nervous tissue in genetically susceptible individuals. The tenfold higher concordance rate for MS in monozygotic twins compared to dizygotic twins, the increased incidence of MS in women compared to men (2:1), and the familial and racial occurrence of MS provide strong evidence that genetic factors influence susceptibility to MS. The major predisposing genes in MS are the human leukocyte antigen (HLA) class II molecules, DR15 and DQw6, molecularly defined as HLA-DRB1, 1501-DQA1 0102-DQB1 0602. In certain ethnic groups, MS susceptibility is more strongly associated with other DR molecules. Environmental factors are also believed to play a role, as suggested by the unique worldwide prevalence, migration effects, and epidemiological studies. Increased serum and cerebrospinal fluid antibody titers to numerous viruses have been reported; however, there have been no confirmed studies detecting viral RNA or antigen in MS brain tissue. At the present time, no known treatment can significantly alter the progression of MS. Based on the postulate that MS is an autoimmune disease associated with abnormalities in immunoregulation, a number of different immunosuppressive and immunomodulating agents have been tested as therapeutic modalities. In this article, we review the circumstantial evidence suggesting that immune system abnormalities are associated with the disease process, and provide an update on current therapies used in MS.

Inhibition of tumor necrosis factor is protective against neurologic dysfunction after active immunization of Lewis rats with myelin basic protein

Increasing evidence indicates that the cytokines, tumor necrosis factor (TNF), interleukin-1, and/or interferon-gamma, may play a crucial role in the pathogenesis of multiple sclerosis. Several reports demonstrated that inhibition of TNF is highly protective in experimental allergic encephalomyelitis (EAE) when sensitization is accomplished by the passive transfer of myelin basic protein (MBP) sensitized lymphocytes. However, successful protection has not been reported in EAE that is induced by active immunization with MBP. We examined the effects of a TNF inhibitor, dimeric polyethylene glycol linked form of the type I soluble receptor of TNF, PEG-(rsTNF-RI)2, on actively acquired EAE. Treatment with PEG-(rsTNF-RI)2 at 0.3-3 mg/kg every other day or every third day starting on Day 9 postimmunization with MBP during the effector phase of EAE significantly inhibited clinical signs in a dose-dependent manner. Histological examination of the central nervous system indicated that the administration of PEG-(rsTNF-RI)2 reduced, in part, the cellular infiltrate, particularly in the lumbar and sacral regions of the spinal cord. These studies suggest that TNF is a pivotal mediator of the inflammation resulting from the complete immune response induced by active immunization with MBP.