Placebo-controlled clinical trials in multiple sclerosis: ethical considerations. National Multiple Sclerosis Society (USA) Task Force on Placebo-Controlled Clinical Trials in MS

The availability of partially effective therapies for some forms of multiple sclerosis (MS) raises practical and ethical issues for future placebo-controlled clinical trials. An international Task Force of clinicians, statisticians, ethicists and regulators was convened to discuss these issues and develop consensus. The Task Force concluded that placebo-controlled clinical trials in forms of MS for which partially effective therapies exist were ethical, so long as study subjects were fully apprised of the availability of such therapies and were encouraged to pursue them outside of a clinical trial. Patients who decline to utilize available treatments, after proper education and counseling, or those that fail all therapies can be considered to have no treatment alternatives and thus may participate in a placebo-controlled trial.

Spectrum and classification of inflammatory demyelinating diseases of the central nervous system

The aim of this review is to highlight recent observations concerning the pathogenesis of acute and chronic inflammatory demyelinating diseases in the central nervous system. Without attempting to provide a didactic classification or a complete survey, we emphasize the discriminative nature of new clinical, imaging, and immunopathologic data, which, even in the absence of specific molecular markers, modify our views about the nosologic relations among these overlapping clinicopathologic entities. In the light of new findings, multiple sclerosis may represent a spectrum of demyelinating diseases rather than a single entity.

Relationship of urinary myelin basic protein-like material with cranial magnetic resonance imaging in advanced multiple sclerosis

BACKGROUND

A significant correlation exists between disability and the volume of black holes (BHL VOL), defined as hypointense lesions on T1-weighted cranial magnetic resonance imaging. A consistent correlation has also been reported between urinary myelin basic protein-like material (MBPLM) and the transition toward secondary progression (SP) from relapsing-remitting (RR) multiple sclerosis (MS).

OBJECTIVE

To improve the management of MS through a noninvasive and cost-effective test for monitoring disease activity or disease status.

DESIGN AND METHODS

From 662 patients with MS (86 with RR MS, 259 with SP MS without continued attacks, and 317 with SP MS with continued attacks), 24-hour urine samples were obtained at enrollment in the phase 3 Linomide (roquinimex) drug study. The urine specimens were analyzed for MBPLM and correlated with clinical features and findings on cranial magnetic resonance imaging.

RESULTS

Significant but weak correlations existed between urinary MBPLM and BHL VOL in all patients with MS (r = 0.114, P =.003; n = 662), patients with SP MS without attacks (r = 0.185, P =.003; n = 259), and all patients with SP MS (r = 0.122, P =.003; n = 576). No significant correlations were detected in the RR MS group or any of the disease groups or subgroups whose Expanded Disability Status Scale score was 5.0 or lower. In subgroup analysis, the most significant correlation was detected between urinary MBPLM after adjustment for creatinine and BHL VOL in patients with SP MS with an Expanded Disability Status Scale score of 5.5 or higher but without continued relapses (r = 0.417, P<.001; n = 138).

CONCLUSIONS

In patients with advanced SP MS, urinary MBPLM may possibly serve as an indicator of failed remission and axonal damage. Urinary MBPLM correlates with disease status in MS, especially the transition of RR MS to SP MS with advancing disability.

The cellular response of JC virus T-antigen-induced brain tumor implants to a Murine intra-ocular model

In order to define the immunologic response to central nervous system tumors in a controlled fashion, we compared xenogeneic, allogeneic and syngeneic transplants of JC virus-induced neural tumor cell aggregates implanted into anterior ocular chambers of mice. Semiquantitative assessment of the level of leukocyte common antigen (CD45) of the transplants by immunohistochemistry was used to gauge rejection. Reticulin staining was used to monitor vascularization. Immunoreactivity to the viral oncoprotein, T-antigen, was confirmed by immunohistochemistry and immunoprecipitation/Western blot analysis. The results demonstrated that transplants were viable at all time-points and developed vascularization as early as three days after transplantation. Xenotransplants, 13-days post-transplantation, and allogeneic transplants, 25 days post-transplantation were infiltrated with polymorphonuclear leukocytes. Fewer CD45 positive cells were demonstrated in syngeneic transplants. High levels of JCV T-antigen stimulated rejection in syngeneic transplants. These results establish a model for further investigation of the natural and induced immunologic response to central nervous system tumors.

Linomide in relapsing and secondary progressive MS: part II: MRI results. MRI Analysis Center of the University of Texas-Houston, Health Science Center, and the North American Linomide Investigators

OBJECTIVE

To determine the safety and efficacy of roquinimex (linomide) in the management of relapsing-remitting and secondary progressive MS as monitored by MRI.

BACKGROUND

Preclinical studies and several short term randomized trials of linomide suggested clinical and MRI-measured benefits with acceptable risk for closely followed MS patients.

METHODS

The North American Linomide Trial formally screened 853 individuals for relapsing or secondary progressive, clinically definite MS; recent disease activity or progression; and an Expanded Disability Status Scale score at entry of 3.0 to 6.5 inclusive. MRI was obtained on 811 subjects at pre-enrollment, 718 cases at enrollment, and then at three monthly intervals until the trial was prematurely terminated for unacceptable toxicity.

RESULTS

Enhancement was found on 40.2% of 718 entry scans. Statistically robust correlations were found between clinical demographic data and several entry MRI measures including CSF volume, a reflection of brain atrophy. Assessment of the effect of treatment on MRI-measured disease was limited by early trial termination. However, active treatment for 3 months reduced the proportion of patients with one or more enhancements. An exploratory analysis suggested that 2.5 mg was the most active of three doses tested in limiting the total volume of enhanced tissue, the proportion of MRI-defined lesions designated as "black holes," and by a novel MRI composite disease measure.

CONCLUSIONS

The short term signature of the effect of linomide on MRI-measured aspects of the disease suggests that safer drugs of this class might be useful in the management of MS. The use of a composite index of the heterogeneous nature of the pathology of MS as captured by MRI may have merit as an outcome measure in clinical trials.

Linomide in relapsing and secondary progressive MS: part I: trial design and clinical results. North American Linomide Investigators

OBJECTIVE

To determine whether linomide (roquinimex) is better than placebo in slowing the time to confirmed clinical worsening in patients with relapsing-remitting (RR) and secondary progressive (SP) MS.

METHODS

In this 27-center, randomized, double-blind, placebo-controlled, multiple-dose, phase III trial, 715 patients with active RRMS (n = 90) or SPMS (n = 625) were randomized to receive either linomide (1.0, 2.5, or 7.5 mg orally daily) or placebo. Patients were evaluated at 3-month intervals clinically and with MRI. The planned primary outcome was the time to the development of "confirmed" clinical worsening (increase of >/= 1.0 Expanded Disability Status Scale [EDSS] score for an enrollment EDSS score </= 5.0, or >/= 0.5 point for an enrollment EDSS score of >/= 5.5) not associated with an acute relapse.

RESULTS

The trial was terminated 1 month after it became fully enrolled due to unanticipated serious cardiopulmonary toxicities (pericarditis, pleural effusion, myocardial infarction, and possible pulmonary embolism), pancreatitis, and death. Notable arthralgia, myalgia, bursitis, and facial and peripheral edema were common adverse events. The high dose of linomide (7.5 mg) was not well tolerated. The trial was too brief to determine unequivocal clinical benefits. Trends suggested an unconfirmed early effect on change in EDSS score at 6 months for the medium dose (2.5 mg daily).

CONCLUSION

MS patients may be more prone to develop important linomide treatment-related adverse events than other previously studied patients. However, linomide may be a potentially more toxic drug than was suspected from observations made in smaller studies for other indications. Phase III trials may identify infrequent and important toxicities that may not be anticipated by phase I and II trials.

The genetics of multiple sclerosis. A review

Multiple sclerosis (MS) is characterized by chronic inflammation and demyelination in the central nervous system (CNS). Although the etiology of MS is unknown, both genetic and environmental contributions to the pathogenesis are inferred from epidemiologic studies. Geographic distributions and epidemics of MS and data from migration studies provide evidence for some, thus far unidentified, environmental effects. The co-occurrence of MS with high and low frequencies in ethnic groups often sharing an environment, the increased recurrence rate in families, and the high concordance rate among identical twins point to inheritable determinants of susceptibility. Based on the autoimmune hypothesis of demyelination, genetic studies sought associations between MS and polymorphic alleles of candidate genes which regulate either the immune response or myelin production. The most consistent finding in case-control studies was the association with the major histocompatibility complex (MHC) (also called human leukocyte antigen--HLA) class II, DR15, DQ6, Dw2 haplotype. Studies on other gene products encoded within or close to the MHC complex on chromosome 6p21.3 (e.g., HLA DP, complement components, transporter proteins, tumor necrosis factor, and myelin-oligodendrocyte glycoprotein) resulted in conflicting observations in different patient populations. The potential contribution of polymorphic alleles within the genes of the T-cell receptor alpha beta chains, immunoglobulins, cytokines, and oligodendrocyte growth factors or their receptors to MS susceptibility either remains equivocal or is rejected. Studies on families with multiple affected members have revealed that MS is a complex trait, that the contribution of individual genes to susceptibility is probably small, and that differences are possible between familial and sporadic forms. The development of molecular and computer technologies have facilitated the performance of comprehensive genomic scans in multiplex families, which have confirmed the possible linkage of multiple loci to susceptibility, each with a minor contribution. Several provisional sites were reported, but only 6p21 (MHC complex), 5p14, and 17q22 were positive in more than one study. The British update demonstrated segregation among regions of interest depending on DR15 sharing, and excluded a gene of major effect from 95%, and one with a moderate effect from 65% of the genome. The extended study by the US collaboration group revealed that the MHC linkage was limited to families segregating HLA DR2 alleles, which suggested that linkage to the MHC is related to the HLA DR2 association, and that sporadic and familial MS share at least one common susceptibility marker. Further identification of MS susceptibility loci may involve additional family sets, more polymorphic markers, and the exploration of telomeric chromosomal regions. Data from these studies may further elucidate pathogenic mechanisms of MS.

Ibuprofen treatment versus gradual introduction of interferon beta-1b in patients with MS

Flu-like symptoms and injection site reactions are adverse effects of treatment with interferon beta-1b in patients with MS. We compared gradual dose escalation, ibuprofen treatment, or their combination in an open-label study. The combination reduced the incidence of flu-like symptoms to rates comparable with the placebo group in the pivotal trial but increased the frequency of injection site reactions, albeit modestly and transiently.

Modulation of T cell-endothelial adhesion by astrocyte conditioned medium

Astrocytes and derived factors maintain the morphologic, phenotypic, and physiological properties of the blood-brain barrier. Astroglial cells may also modulate endothelial cell properties associated with the entry of inflammatory cells into the brain. The study of mechanisms of lymphocyte migration through the blood-brain barrier is critical to understanding the pathophysiology of autoimmune (multiple sclerosis) and virus-induced central nervous system diseases (HIV-induced dementia). In this context the contribution of astrocyte derived factors in regulating the interactions between inflammatory cells and endothelial cells of the blood-brain barrier was studied. The treatment of endothelial cells derived from brain or peripheral sources (hepatic) with astrocyte conditioned medium resulted in a dose dependent enhancement of adhesion of T cells to endothelium. The antigen specificity of the T cells did not influence the findings. Identical results were obtained with fresh Concanavalin A activated T cells and T cell hybridomas generated using myelin basic protein or chicken ovalbumin as immunogens. Further studies are in progress to define the active components in astrocyte conditioned medium and endothelial cell adhesion molecules that are regulated in order to gain a better understanding of mechanisms of inflammatory cell entry into the central nervous system.

A multicenter, randomized, double-blind, placebo-controlled trial of influenza immunization in multiple sclerosis

We determined the effect of influenza vaccine in patients with relapsing/remitting MS. Considerable controversy surrounds the question of whether to administer influenza vaccines to MS patients. Prevention of a febrile viral illness is clearly desirable in MS, and previous studies suggest that immunization is safe. Despite this, many clinicians avoid vaccination because they fear precipitating an MS exacerbation. We conducted a multicenter, prospective, randomized, double-blind trial of influenza immunization in patients with relapsing/remitting MS. In the autumn of 1993, 104 patients at five MS centers received either standard influenza vaccine or placebo. Patients were followed for 6 months for evaluation of neurologic status and the occurrence of influenza. Influenza was operationally defined as fever > or = 38 degrees C in the presence of coryza, cough, or sore throat at a time when the disease was present in the community. Attacks were defined in the standard manner, requiring objective change in the examination. Patients were examined at 4 weeks and 6 months after inoculation and were contacted by telephone at 1 week and 3 months. They were also examined at times of possible attacks but not when they were sick with flu-like illness. Three vaccine patients and two placebo patients experienced attacks within 28 days of vaccine (no significant difference). Exacerbation rates in the first month for both groups were equal to or less than expected from published series. The two groups showed no difference in attack rate or disease progression over 6 months. Influenza immunization in MS patients is neither associated with an increased exacerbation rate in the postvaccination period nor a change in disease course over the subsequent 6 months.

Impairment of central and peripheral myelin in mitochondrial diseases

Clinical or sub-clinical impairment of central and peripheral myelin is often part of the overlapping multisystem disorders associated with a variety of mitochondrial (mt)DNA abnormalities. Suboptimal energy metabolism of the oligodendrocytes and Schwann cells carrying mitochondrial defects may cause insufficient production of myelin. Further, edema, vascular and toxic factors may directly damage myelin. The recognition that certain mtDNA point mutations are associated with inflammatory demyelination of the central nervous system suggests that additional mechanisms besides degeneration need to be considered in the development of some forms of myelin damage.

Screening for Leber's hereditary optic neuropathy associated mitochondrial DNA mutations in patients with prominent optic neuritis

Previous case reports demonstrated the presence of Leber's hereditary optic neuropathy (LHON) associated mitochondrial (mt) DNA mutations in patients presenting with prominent optic neuritis (PON). By screening the mtDNA, we have excluded the presence of these mutations in 22 patients with PON, indicating that the frequency of these mutations is less than 4.5% in our selected patient population. Reviewing the clinical data of these patients revealed that severe optic nerve atrophy developed in association with both the benign and the severely disabling form of Multiple Sclerosis (MS). This observation suggests that the prominent feature of ON in MS may be related to local factors or to a selective vulnerability of the optic nerve in some patients. However, it also may be consequence of a deleterious process associated with inflammatory demyelination in the central nervous system (CNS) of another, genetically probably distinct subgroup of severely disabled patients.

A CD4-CDR3 peptide analog inhibits both primary and secondary autoreactive CD4+ T cell responses in experimental allergic encephalomyelitis

A structure-based design approach was used to develop a cyclized peptide analog of the murine CD4-CDR3-like region as a potential inhibitor of autoimmune CD4+ T cells responsible for the pathogenesis of experimental allergic encephalomyelitis (EAE). Our results indicate that this peptide, referred to as rD-mPGPtide, is able to significantly inhibit the clinical and pathologic symptoms of EAE in the SJL mouse model when administered on day 12 of induction. The optimum effective dosage range for the peptide, injected i.v., was between 0.125 and 0.5 mg and dosages of as high as 5 mg had no observable toxic effects. Treated mice had normal levels of lymphocytes less than 2 wk later and exhibited normal in vitro primary responses to alloantigen and secondary responses to keyhole limpet hemocyanin Ag. The specificity of the rD-mPGPtide treatment for autoreactive T cells was demonstrated by inhibiting proteolipid protein (p139-151)-induced EAE and finding that the lymph node T cells from these mice had suppressed responses to this Ag, but normal responses to alloantigen or other nominal Ag. Importantly, rD-mPGPtide was found to be effective on secondary T cell responses in an EAE rechallenge situation and was able to establish conditions for long-term resistance to further Ag exposure. Analysis of the cytokine profile of responding T cells during late effector stages of disease revealed that the levels of IFN-gamma and IL-4 are significantly reduced in rD-mPGPtide-treated mice. These results strongly suggest that the administration of a CD4-CDR3 peptide analog is an effective therapeutic approach for the inhibition of the CD4+ T cell-mediated autoimmune response in EAE.

A CD4-CDR3 peptide analog inhibits both primary and secondary autoreactive CD4+ T cell responses in experimental allergic encephalomyelitis

A structure-based design approach was used to develop a cyclized peptide analog of the murine CD4-CDR3-like region as a potential inhibitor of autoimmune CD4+ T cells responsible for the pathogenesis of experimental allergic encephalomyelitis (EAE). Our results indicate that this peptide, referred to as rD-mPGPtide, is able to significantly inhibit the clinical and pathologic symptoms of EAE in the SJL mouse model when administered on day 12 of induction. The optimum effective dosage range for the peptide, injected i.v., was between 0.125 and 0.5 mg and dosages of as high as 5 mg had no observable toxic effects. Treated mice had normal levels of lymphocytes less than 2 wk later and exhibited normal in vitro primary responses to alloantigen and secondary responses to keyhole limpet hemocyanin Ag. The specificity of the rD-mPGPtide treatment for autoreactive T cells was demonstrated by inhibiting proteolipid protein (p139-151)-induced EAE and finding that the lymph node T cells from these mice had suppressed responses to this Ag, but normal responses to alloantigen or other nominal Ag. Importantly, rD-mPGPtide was found to be effective on secondary T cell responses in an EAE rechallenge situation and was able to establish conditions for long-term resistance to further Ag exposure. Analysis of the cytokine profile of responding T cells during late effector stages of disease revealed that the levels of IFN-gamma and IL-4 are significantly reduced in rD-mPGPtide-treated mice. These results strongly suggest that the administration of a CD4-CDR3 peptide analog is an effective therapeutic approach for the inhibition of the CD4+ T cell-mediated autoimmune response in EAE.

Characterization of the mitochondrial DNA in patients with multiple sclerosis

Mitochondrial DNA (mtDNA) abnormalities with primary pathogenic significance for optic nerve atrophy have been detected in inflammatory demyelinating conditions indistinguishable from multiple sclerosis (MS). However, the degree of involvement of mtDNA alterations in the pathogenesis of MS is not clear. To further clarify this question, we sequenced the entire mtDNA in three MS patients. A number of nucleotide alterations were defined relative to the standard mtDNA sequence in each patient. After excluding the silent mutations and common polymorphisms, eight unusual mtDNA variants within the ribosomal (r) RNA, transfer (t) RNA or protein encoding regions were identified and characterized. Two mutations remained as putative MS related alterations after screening a population of 49 patients and 63 controls for the presence of these mutations. An A to G transition at nucleotide (nt) 13966 causing a threonine to phenylalanine exchange in a non-conserved region of the ND-5 was detected in two independent MS patients and in none of the sixty-three controls or in any of the large control population in the literature. The second mutation of interest at 14798 is a T to C transition changing a phenylalanine to leucine in a relatively conserved domain of the cytochrome b. Although it is a known polymorphism, a tendency for prominent optic nerve involvement was observed among patients carrying this mutation. As we have performed the first complete mtDNA sequence analysis on MS patients, we conclude that MS may occur without mtDNA abnormalities of primary pathogenic significance. However, contribution of the mtDNA to genetic susceptibility or phenotypic presentation of MS is possible in certain subgroups of patients, and merits further investigation.

The evolutionary relationship among Caucasian MS patients and controls

Previous observations suggest that the mitochondrial (mt)DNA may confer susceptibility to multiple sclerosis (MS). However, the proportion of affected individuals and the range of contributing mtDNA abnormalities are unknown. To help clarify this question, we analyzed the first hypervariable D-loop sequences of the mtDNA in a group of randomly selected Caucasian MS patients, in MS patients with prominent optic neuritis (PON) and in controls. Phylogenetic analysis of these D-loop sequences revealed that individuals in both groups of patients are generally scattered in the Caucasian phylogeny. However, a small cluster of unrelated MS patients identified by this analysis suggests that a maternal lineage with MS relevant mtDNA sequences may exist, and merits a more comprehensive study.

Defining the clinical course of multiple sclerosis: results of an international survey. National Multiple Sclerosis Society (USA) Advisory Committee on Clinical Trials of New Agents in Multiple Sclerosis

Standardization of terminology used to describe the pattern and course of MS is essential for mutual understanding between clinicians and investigators. It is particularly important in design of, and recruitment for, clinical trials statistically powered for expected outcomes for given patient populations with narrowly defined entry criteria. For agents that prove safe and effective for MS, knowledge of the patient populations in definitive clinical trials assists clinicians in determining who may ultimately benefit from use of the medication. An international survey of clinicians involved with MS revealed areas of consensus about some terms classically used to describe types of the disease and other areas for which there was lack of consensus. In this report, we provide a summary of the survey results and propose standardized definitions for the most common clinical courses of patients with MS.

Cutaneous ulcerations and pustular psoriasis flare caused by recombinant interferon beta injections in patients with multiple sclerosis

Seven patients with multiple sclerosis who were receiving subcutaneous injections of recombinant interferon beta had pain followed by ulceration at the injection site. An eighth patient had a pustular flare of her usually mild psoriasis. No evidence of infection or contaminated medication was found.

Guidelines for the use of magnetic resonance techniques in monitoring the treatment of multiple sclerosis. US National MS Society Task Force

Because of the major difficulties in measuring clinical end points in multiple sclerosis (MS) treatment trials, there has been much enthusiasm for using magnetic resonance imaging (MRI) findings as an alternative outcome. To provide international consensus guidelines for the use of MRI in MS clinical trials, a task force of the US National MS Society was convened. The recommendations of the task force are presented in this review. Given the high sensitivity for detecting pathological activity in relapsing-remitting and secondary progressive MS, monthly T2-weighted and gadolinium-enhanced brain MRI is an excellent tool for short-term exploratory trials of new agents where it serves as the primary end point; in particular, failure to demonstrate a reduction in lesion activity avoids the time, cost, and risks of a larger clinical end point study. However, conventional MRI findings have a limited correlation with disability in established MS. The primary end point of a definitive trial should therefore be clinical, although serial MRI at 6- to 12-month intervals is a useful secondary end point in providing an index of pathological progression. In trials of patients presenting with clinically isolated syndromes suggestive of MS, MRI findings can be used in the entry criteria, and as a secondary outcome measure, but conversion to clinically definite MS should be the primary outcome. The pathological substrates of irreversible disability are demyelination and axonal loss. Putative magnetic resonance markers for these processes include decreased N-acetylaspartate on proton magnetic resonance spectroscopy, decreased magnetization transfer ratios, hypointensity on T1-weighted images, and loss of short T2 water fractions, some of which relate more closely to disability than conventional MRI findings. Further technical developments should lead to more accurate quantitation, greater pathological specificity, and stronger clinical correlations.

Management of patients receiving interferon beta-1b for multiple sclerosis: report of a consensus conference

Results of a double-blind, placebo-controlled study in ambulatory patients with relapsing-remitting MS showed that interferon beta-1b reduced the rate of exacerbations by one-third compared with placebo and limited new disease activity in the brain as evidenced by MRI. Interferon beta-1b, administered subcutaneously at a dosage of 0.25 mg (8 million IU) every other day is indicated for the treatment of ambulatory patients with relapsing-remitting MS. Interferon beta-1b may help a wider range of patients, but it should be prescribed only for patients with a diagnosis of clinically definite or laboratory-supported definite MS. The decision to treat a patient with interferon beta-1b should be individualized; that is, based on each patient's clinical presentation and course of MS. The most common adverse effects include (1) injection-site reactions and (2) flu-like symptoms, which are generally manageable and usually abate after the first few months of treatment. Spasticity may increase. Patients with severe depression or suicidal ideation should be monitored carefully, and symptomatic treatment should be pursued. Interferon beta-1b is contraindicated in pregnant and nursing women. Interferon beta-1b is effective in reducing the progression of total disease burden as seen on MRI in patients with MS. Its use is relatively straightforward and generally does not require alteration in the symptomatic treatment of MS. Patient education and support remain the mainstays of maintaining compliance through the early phases of therapy.

Characteristics of the T lymphocytes involved in experimental allergic encephalomyelitis

Both heterogeneity and restricted heterogeneity of the encephalitogenic myelin basic protein (MBP) peptide-specific T cell receptors (TCRs) were demonstrated in inbred animals depending on the strain-specific genetic characteristics, the stage of the disease, the compartment of the lymphocytes obtained and the methodology used. Nevertheless, the similar features of some MBP-specific TCRs demonstrated across species suggest that conservation of these autoantigen-specific molecules undoubtedly exists, even though the degree of this conservation is controversial. However, the unequivocal heterogeneity of the immune response directed at one of the most important myelin constituents, proteolipid lipoprotein (PLP), which occurs either as a primary or a secondary event during experimental allergic encephalomyelitis (EAE), indicates the complexity of the in vivo situation. Intramolecular and intermolecular spreading of antigen specificity during the course of the disease indicates that a TCR directed therapy may not be the choice of intervention in established disease even in individual strains of laboratory animals with restricted heterogeneity of the primary MBP-specific response. Studying the sequence of events, the recruited regulatory cells and cytokines, and the stromal factors controlling persistence or death of activated, memory cells in the tissue lesion, may reveal new therapeutic modalities with more universal applicabilities.

Multiple sclerosis in the spinal cord: MR appearance and correlation with clinical parameters

PURPOSE

To determine the characteristic magnetic resonance (MR) imaging features of multiple sclerosis (MS) that affect the spinal cord.

MATERIALS AND METHODS

Sixty-eight patients underwent MR imaging of the cervical and/or thoracic spine. Plaques were analyzed for lesion length, cross-sectional area and location, signal intensity, and morphology. The clinical parameters of MS type, duration of disease, sex, and age were also correlated with these MR imaging findings.

RESULTS

One hundred twenty-four demyelinating plaques were found in these 68 patients; 38 had more than one plaque. The majority of plaques were two body segments in length or less and peripherally located, and occupied less than 50% of the cross-sectional area of the cord. Plaques associated with cord atrophy were more likely to occur with the relapsing-progressive form of MS. Cord swelling was found only in the relapsing-remitting form of MS.

CONCLUSION

Spinal cord MS plaques are characteristically peripherally located, are less than two vertebral segments in length, and occupy less than half the cross-sectional area of the cord.

Mitochondrial DNA mutations in multiple sclerosis

The presence of mitochondrial DNA mutations, including eight of those frequently associated with Leber's hereditary optic neuropathy (LHON), was investigated by sequencing and restriction endonuclease analysis in randomly selected patients with MS. Class I LHON mutations with primary pathogenic significance for blindness were not detected in any of the MS patients studied. A trend was observed for higher frequency of class II LHON mutations with unknown pathogenic significance in the MS patients than in the controls. Specifically, the mutation at position 4216 and its associated simultaneous mutations occurred with a higher frequency. Eleven of the 53 patients (20.8%) were positive for at least two (4216 and 4917 or 13,708) or three (4216, 13,708, 15,257) simultaneous class II LHON mutations, while 7 of the 74 controls (9.5%) carried simultaneous mutations (P = 0.036). Earlier studies reported the occurrence of either the 11,778 or 3460 LHON type mutations in MS patients with a positive LHON pedigree and/or with a disease course predominantly involving the optic nerves. The mutations we detected did not correlate with the severity of visual loss in either LHON or MS, rather they seemed to be present in randomly selected MS patients. We conclude that the mutations with primary pathogenic significance for blindness are not shared between LHON and randomly selected MS. However, the presence of further mitochondrial mutations cannot be excluded in MS. The increased incidence of the simultaneous class II LHON mutations in MS patients (and LHON) vs controls may indicate that certain sets of mitochrondrial DNA mutations/variants are associated with and predispose to MS, a possibility which needs to be investigated further. Alternatively, a biological disadvantage may be associated with the coexistence of the mutations detected.

Tizanidine treatment of spasticity caused by multiple sclerosis: results of a double-blind, placebo-controlled trial. US Tizanidine Study Group

This multicenter, stratified, randomized, placebo-controlled, double-blind trial evaluated tizanidine for use in the United States for spasticity secondary to MS. The 15-week trial was divided into baseline (weeks 0 and 1), titration (2 mg to a maximum of 36 mg/d; weeks 2 to 4), and plateau (weeks 5 to 13) phases, followed by dose tapering (week 14) and a final visit (week 15). Primary efficacy parameters were scores on muscle tone (Ashworth Scale) and type and frequency of muscle spasms (patient diaries). All efficacy parameters were evaluated by the physician/assessor, and the physician/prescriber was responsible for all dosage adjustments. The patient, physician/assessor, and physician/prescriber made global evaluations of antispastic efficacy. Tizanidine produced a significantly greater reduction than placebo in spasms and clonus (patient diaries) but no significant differences in Ashworth scores. Patients and physician/prescribers, but not physician/assessors, gave significantly better scores in the overall assessment of efficacy and tolerability. No significant differences in other secondary efficacy parameters were noted. Adverse events were reported for 66 (61%) of the 109 placebo-treated patients and 101 (91%) of the 111 tizanidine-treated patients; 6 (6%) and 14 (13%) discontinued treatment, respectively. Patient and physician perception of improvement demonstrated more consistent differences between groups than did the Ashworth Scale, perhaps because of inexperience with this measure or failure to consider time between drug administration and assessment.

Distributional patterns of multiple sclerosis brain lesions. Magnetic resonance imaging--clinical correlation

Forty-one patients with multiple sclerosis were studied with magnetic resonance imaging (MRI) and a battery of neuropsychological tests to determine the pattern of lobar distribution of lesions in the relapsing-progressive and relapsing-remitting forms of the disease. Correlation of lesions with the patient's cognitive and emotional dysfunction was also obtained. The results of this study indicate that patients with relapsing-progressive multiple sclerosis are characterized by the large or coalescent lesions located predominantly in the periventricular area. These lesions were more frequently found in the parietooccipital areas and were accompanied by significant cognitive dysfunction and severe personality changes. The patients with relapsing-remitting disease, however, were characterized by punctiform or small discrete lesions predominantly located in the intermediate and subcortical areas. These lesions were more frequently seen in the parietooccipital regions and the patients had significantly less severe cognitive and emotional involvement than did the patients with relapsing-progressive disease. Recognition of these patterns was easily accomplished by MRI. In this investigation MRI studies were utilized as an index of the pathological changes occurring at one point in time in the evaluation of the disease. Only repeated MRI studies and continuous clinical observation can establish the final diagnosis.

Preferential but not exclusive T cell receptor V beta chain utilization of myelin basic protein and peptide-specific T cell clones in mice

The repertoire of T cell receptor (TCR) V beta chain utilization was investigated in PL/J, CXJ-1, SJL/J and B10.S-->SJL/J chimeric mice in response to either myelin basic protein (MBP) or the strain-specific encephalitogenic peptide. Our analysis showed that there was an overlapping predominance in the TCR V beta gene utilization in the MBP-specific responses, which were independent of the major histocompatibility complex (MHC) class II haplotype present, and the immunodominant peptide region recognized in these different strains. In those mice having the TCR V beta b haplotype (PL/J, CXJ-1, and the B10.S-->SJL chimera) either the TCR V beta 4, 8, and 13 or the TCR V beta 4, 6, and 13 predominated. In contrast, in mice with TCR V beta a haplotype (SJL/J) V beta 4, 6, and 17a were found. However, the quantitative distribution of these preferentially utilized TCR V beta chains in each strain was defined by the MHC class II haplotype and the immunodominant peptide recognized. The expression of the V beta 8 gene product in the peripheral TCR repertoire did not always correlate with predominant V beta 8 utilization in the MBP-specific response.

Systemic recombinant human interferon-beta treatment of relapsing-remitting multiple sclerosis: pilot study analysis and six-year follow-up

A pilot study was undertaken to test the safety and establish the side effect profile of recombinant human interferon-beta 1b (Betaseron, Berlex Laboratories, Richmond, CA), in patients with relapsing-remitting multiple sclerosis (RRMS). During the initial dose finding period (24 weeks), five groups of 6 patients each were treated by subcutaneous injection three times each week with either 0.8, 4, 8, or 16 million units (mU) of Betaseron or placebo (WHO Standard). Although some side effects were noted in all groups, a dose-related trend in reduction of exacerbation frequency and side-effect profile was noted. Patients given 16 mU had no exacerbations during the initial dosing period, but associated side effects led to dose reduction or dropout. An 8 mU dose was selected for further study after 24 weeks, and continuous dosing at 8 mU in 15 patients has now exceeded 6 years. Side effects abated over time. Neutralizing antibody developed in most patients, but titers were variable, fluctuated independently of clinical course, and tended to fall with prolonged treatment. A dose-dependent rise in neopterin levels was observed during the initial dosing period. This pilot study has demonstrated responsiveness to Betaseron, shown a stable safety profile over time, and established guidelines for a dosing regimen to evaluate and optimize further the efficacy of Betaseron in RRMS.

Interferon-gamma-inducible endothelial cell class II major histocompatibility complex expression correlates with strain- and site-specific susceptibility to experimental allergic encephalomyelitis

The interaction between encephalitogenic lymphocytes and the cerebral microvascular lining is considered to be an important initial step in the recruitment of immune cells into the central nervous system (CNS) under pathological conditions such as multiple sclerosis (MS) and its investigative analog, experimental allergic encephalomyelitis (EAE). This study was conducted in order to examine whether differences in microvascular endothelial cell expression of several molecules involved in lymphovascular interactions correlate with the strain and organ-specific development of EAE. Cerebral and epididymal microvascular endothelial cells (EC) were isolated from SJL and B10.S mice, which, despite MHC-compatibility (H-2S), differ in their ability to develop EAE. The subcultured cells were then analyzed by flow cytometry for their ability to express class I MHC, class II MHC and ICAM-1 molecules in response to treatment with murine recombinant interferon-gamma (IFN-gamma). Over a range of doses and times, cerebral EC cultures derived from EAE-susceptible SJL mice expressed two-fold higher levels and higher cell surface densities of class II molecules than cerebral EC cultures derived from EAE-resistant B10.S mice, whereas class I and ICAM-1 molecules were comparably upregulated on both SJL and B10.S cerebral EC. In contrast, both SJL and B10.S epididymal EC cultures expressed lower but comparable levels of class II molecules in response to IFN-gamma. Class I and ICAM-1 molecules, however, were upregulated to at least the same degree as that observed on cerebral EC derived from both strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of staphylococcal enterotoxin B on T cell receptor V beta utilization and clinical manifestations of experimental allergic encephalomyelitis

Staphylococcal enterotoxin B (SEB) is a superantigen (SA) that up-regulates and then subsequently down-regulates and deletes T cells expressing V beta 8 T cell receptor (TcR) chains (Marrack and Kappler, 1990; Johnson et al., 1991). We have investigated the effect of SEB on experimental allergic encephalomyelitis (EAE) in PL/J mice, where the predominant encephalitogenic T cells are V beta 8+ (Acha Orbea et al., 1988; Zamvil et al., 1988). SEB did not enhance induction of EAE when administered prior to or after immunization for EAE. PL/J mice pretreated with SEB developed anergy and deletion of V beta 8 bearing cells and concomitant reduction in the incidence of EAE. Following SEB pretreatment, a redistribution in the TcR utilization of MBP-specific lymphocytes occurred. As a result, there was a low frequency of V beta 8 and expansion of other, normally less frequent, myelin basic protein (MBP)-specific clones. These observations indicate that systemic exposure to superantigen can influence organ-specific autoimmune diseases. We observed V beta-specific elimination, rather than activation, of autoimmune clones, a finding of potential therapeutic value. Modification of the TcR repertoire by systemic exposure to this SA indicates plasticity of immune reactivity and demonstrates a mechanism by which an environmental exposure (SEB) can influence a genetically determined, T cell mediated autoimmune disease.

Immunopathogenic mechanisms in experimental allergic encephalomyelitis

Experimental allergic encephalomyelitis, a cell-mediated autoimmune disease, continues to provide interesting data on the mechanisms subserving organ-specific autoimmunity. The elements of the trimolecular complex have been further defined and the conserved molecular basis of the interaction between the T-cell receptor and the major histocompatibility complex class II-peptide antigen complex is better understood. This model also provides new insights into the cellular interactions within the brain during the course of the autoimmune inflammatory response.

T cell receptor V beta gene utilization in myelin basic protein specific clones from CXJ1 recombinant inbred mice

CXJ1 mice are a recombinant inbred strain generated from experimental allergic encephalomyelitis (EAE) resistant BALB/c and EAE susceptible SJL/J progenitors. CXJ1 derive their major histocompatibility complex (MHC) class II and TCR genes from the BALB/c progenitor. However, their susceptibility to EAE is similar to SJL/J. Utilizing myelin basic protein (MBP)-specific CD4+ hybridoma clones and a MBP-specific T cell line (TCL) from CXJ1, we found the predominant T cell receptor (TCR) V beta chain expression to be V beta 8 and V beta 13. Our data support the concept of preferential, but not exclusive, TCR V beta usage in the MBP-specific response which is independent of MHC class II haplotype or immunodominant peptide.

Interleukin-6 induction in vitro in mouse brain endothelial cells and astrocytes by exposure to mouse hepatitis virus (MHV-4, JHM)

Interleukin-6 (IL-6) induction, as detected by bioassay and Northern analysis, was examined in vitro in endothelial cells or astrocytes derived from BALB/c (susceptible) or SJL (resistant) mice following exposure to mouse hepatitis virus (MHV-4) or UV inactivated MHV-4 (UV-MHV-4). In BALB/c endothelial cells, up to 16-fold more IL-6 (> 640 U/ml) was induced, compared to SJL cells which showed a minimal response (40 U/ml), relative to basal levels (< 20 U/ml). In contrast, both BALB/c and SJL astrocytes showed a substantial IL-6 response to MHV-4 and UV-MHV-4 exposure, although a strain difference persisted. Despite strain and cell specific differences in released IL-6, equivalent levels of IL-6 mRNA were induced in all cell types following exposure to MHV-4 or UV-MHV-4.

Monoclonal anti-gamma interferon antibodies enhance experimental allergic encephalomyelitis

Interferon-gamma (IFN-gamma) is a cytokine with multiple activities on a variety of cells. Under various circumstances, IFN-gamma can exhibit either pro-inflammatory or inhibitory actions. Treatment of SJL/J mice with a monoclonal antibody (Mab) to IFN-gamma during the afferent limb of the immune response to myelin protein produced an enhancement of acute experimental allergic encephalomyelitis (EAE), with increased morbidity, mortality and earlier onset of disease. Systemic administration of IFN-gamma did not improve or worsen clinical outcome, but delayed disease onset. Passive transfer of immune lymph node cells co-activated with MBP and anti-IFN-gamma Mab resulted in more sever disease than that induced by MBP stimulated cells or MBP and IFN-gamma co-stimulated cells. However, in vitro proliferation of an MBP specific T cell line was not influenced by IFN-gamma nor anti-IFN-gamma treatment. Mab to IFN-gamma inhibited suppressor function, in a non-specific assay. These in vivo and in vitro results suggest that systemic IFN-gamma serves as a physiological regulator of a suppressor mechanism in EAE. The abrogation of this regulatory mechanism by anti-IFN-gamma administration contributes to a more severe form of experimental allergic encephalomyelitis.

The sensitivity of the Mini-Mental State Exam in the white matter dementia of multiple sclerosis

Fifty-six patients diagnosed with definite multiple sclerosis (MS) according to Poser criteria were administered the Mini-Mental State Examination (MMSE) and a comprehensive battery of neuropsychological tests. Extent of cerebral lesion involvement was determined by quantitative magnetic resonance imaging (MRI) ratings. The MMSE correlated with overall levels of physical disability, but did not correlate with total lesion area on MRI. Sensitivity of the MMSE to the subcortical dementia of MS was low (28%) when performance on the neuropsychological testing battery was used as the criterion. Impairment on tests of memory, speed of information processing, abstract reasoning, naming/verbal fluency, as well as visuoperceptual organization, were correlated highly with total lesion area on MRI. The low sensitivity of the MMSE to cognitive impairment in MS is discussed in terms of its item composition and the characteristic pattern of deficits found in MS.

Autoimmune inflammation of astrocyte transplants

Astrocytes have been shown to be capable of serving as antigen-presenting cells and as targets for encephalitogenic cytotoxic T lymphocytes. The role of astrocytes in central nervous system (CNS) autoimmune inflammation is unclear. To study this further, we transplanted astrocyte aggregates into the anterior eye chamber of the mouse. The astrocytic nature of these transplants was confirmed by immunohistochemical detection of glial fibrillary acidic protein and the inability to detect oligodendrocyte or microglial markers. When mice bearing transplants were induced to develop experimental allergic encephalomyelitis by either passive or active protocols, the astrocyte transplants developed a perivascular inflammatory response similar to that seen in the host CNS during the course of the encephalomyelitis. The data suggest that astrocytes could serve as targets for the autoimmune attack of experimental allergic encephalomyelitis and support the possibility that the pathogenesis of this disease may involve an autoimmune reaction against a site other than the myelin sheath.

Susceptibility to experimental allergic encephalomyelitis in animal models of autoimmunity

Experimental allergic encephalomyelitis (EAE) continues to serve as a useful model of organ-specific autoimmunity and as a model for the human demyelinating disease, multiple sclerosis. Current studies focus on the role of the various cellular components involved in mediating disease, the nature and molecular characterization of the immune process, and the target site within the central nervous system (CNS). The results of these studies are providing new therapeutic rationales.

Distribution of the Blood-Brain Barrier in Heterotopic Brain Transplants and its Relationship to the Lesions of EAE

The blood-brain barrier (BBB) is recognized as a barrier to the trafficking of molecules and cellular elements into the central nervous system (CNS). Horseradish peroxidase (HRP) exclusion is used as a measure of BBB integrity. The BBB is altered and becomes permeable during the course of experimental allergic encephalomyelitis (EAE). Heterotopic brain transplantation into the anterior eye chamber is a technique for studying genetic influences and the role of individual cell types on the development of EAE. Prior to EAE induction, HRP is excluded from the central portion of the transplant, demonstrating an intact BBB. In contrast, HRP localization is found at the periphery of the transplant, suggesting an incomplete barrier. However, EAE lesions typically occur within the more central regions of the transplant, where the BBB is intact, and not at peripherally located "leaky" areas. This suggests that endothelial cells at intact BBB sites may direct trafficking of lymphocytes (gating) into the CNS during the development of EAE, rather than the passive entry of lymphocytes into the CNS through a leaky BBB.

Lower extremity motor evoked potentials in multiple sclerosis

Transcranial magnetic stimulation was performed on 25 patients with definite multiple sclerosis. Motor evoked potentials were recorded from the anterior tibial muscle. Central motor conduction time was calculated using the equation (F + M-1)/2 by stimulation of the common peroneal nerve. Motor evoked potentials were capable of detecting subclinical pyramidal tract lesions in multiple sclerosis. In patients with multiple sclerosis, the incidence of abnormality of motor and somatosensory evoked potentials was similar. Central motor conduction time was correlated with overall and pyramidal tract subscores on the Kurtzke Disability Status Scale and the Scripps Neurological Rating Scale. Central motor conduction time abnormalities correlated best with the presence of a Babinski's sign but also correlated significantly with weakness and hyperreflexia.

Mouse hepatitis virus (MHV-4, JHM) blocks gamma-interferon-induced major histocompatibility complex class II antigen expression on murine cerebral endothelial cells

The regulation of gamma-interferon-induced major histocompatibility complex (MHC) class II antigen expression on mouse cerebral endothelial cells by the neurotropic mouse hepatitis virus (MHV-4, JHM) was studied in vitro. The results presented demonstrate that MHV-4 can selectively block gamma-interferon-induced class II antigen expression on cerebral endothelial cells. The blocking effect of class II expression occurs in a strain-dependent manner, and is limited to virus-susceptible mouse strains. Virus replication is not required to obtain the blocking effect since UV-inactivated MHV-4 produces the same result. MHV-4 blocking of gamma-interferon-induced class II antigen expression is observed at both the cell surface (flow cytometry) and transcriptional level (Northern analysis).