The natural history of multiple sclerosis: a geographically based study. 7. Progressive-relapsing and relapsing-progressive multiple sclerosis: a re-evaluation

Devic's neuromyelitis optica: study of nine cases

OBJECTIVE

Multiple sclerosis (MS) is by far the most popular diagnosis for patients with multifocal neurological disease. Owing to demyelinating inflammatory non-necrotic plaques of the white matter, MS can give remitting symptoms of virtually every part of the central nervous system. Corticosteroids are usually helpful. Devic's neuromyelitis optica (DNMO) is a neurological disease involving only the optic nerves and the spinal cord, where demyelination evolves towards necrosis and atrophy; the prognosis is poor and no satisfactory treatment is known. The objectives of this study are to describe clinical, biological, pathological and radiological data of patients with DNMO and to differentiate DNMO from MS.

MATERIAL AND METHODS

We studied the files of 14 patients diagnosed with possible DNMO in three French hospitals between 1980 and 1999 and reviewed the literature.

RESULTS

Nine patients were included as definite DNMO. Five were excluded because they did not fulfil the diagnostic criteria. For the nine patients with definite DNMO, DNMO was either monophasic or multiphasic. The prognosis was generally poor: two patients died and five others developed severe disability such as blindness, para or quadriplegia or both. Cerebrospinal fluid study and neuroimaging were essential to confirm the diagnosis of DNMO. Various immunosuppressive treatments generally failed to benefit the patients.

CONCLUSION

In the literature (as well as our 14 initial patients) only a few cases of patients described as suffering from DNMO fulfilled the diagnostic criteria. The others showed evidence that another disease like MS was involved. We stress that inclusion and exclusion criteria have to be kept in mind to differentiate clearly DNMO from MS and other central nervous system white matter diseases.

Prognostic factors for progression of disability in the secondary progressive phase of multiple sclerosis

Predicting clinical outcome is one of the major and most interesting issues in MS patients. If the global evolution of disability (usually chosen levels on the Kurtzke's Disability Status Scale) has been widely studied, much less is known about the progression of disability during the secondary progressive phase of the disease. It is usually said that there is a poorer prognosis once patients enter a progressive phase, whether from onset (like in primary progressive MS) or after an initial relapsing-remitting phase. The secondary progressive phase of multiple sclerosis (MS) is the one most often associated with the development of severe and irreversible disability. Despite this fact, there is a lot of information about the initial relapsing-remitting phase in the literature, but much less about the secondary progressive one. We review here information available from the literature and from the Lyon MS database about this secondary progressive phase.

Primary and secondary progressive multiple sclerosis

The progressive phase of multiple sclerosis (MS) is the one most often associated with irreversible accumulation of disability. An important question remains about the place of primary progressive MS (PP-MS): does it form an integral part of the disease spectrum, or is it maybe a distinct entity? This question could apparently be very theoretical, but it is not, as patients with PP-MS remain orphans when regarding disease-modifying treatments. Thus, they are usually excluded from therapeutic trials. A clue to this question could be the comparison between the different MS subtypes with a progressive phase. We discuss here the clinical similarities and differences between secondary and primary progressive MS.

Multiple sclerosis: report on 200 cases from Iran

Clinical findings of 200 patients in Iran with definite multiple sclerosis (MS) according to Poser et al.'s criteria and positive findings on magnetic resonance imaging (MRI) have been reviewed. The clinical course was relapsing-remitting (RR) for 88%, primary progressive (PP) for 7% and secondary progressive (SP) for 5% of cases. The mean age of onset was 27 +/- 7.4 years for the whole group and 37.1 +/- 8.8 years for PPMS. The gender ratio was 2.5:1 female:male. Involvement of the pyramidal system was the most common mode of presentation. Five per cent of patients had positive family history for the disease, 14% of patients had benign MS and 12% with disease duration longer than five years had an Expanded Disability Status Scale < or = 2. The optico-spinal form was not a common form of presentation in the group.

Multiple sclerosis in Finland: incidence trends and differences in relapsing remitting and primary progressive disease courses

OBJECTIVE

To compare the secular trends and geographical differences in the incidence of relapsing-remitting (RRMS) and primary progressive multiple sclerosis (PPMS) in Finland, and to draw inferences about aetiological differences between the two forms of the disease.

METHODS

New multiple sclerosis cases in southern Uusimaa and the western districts Vaasa and Seinäjoki of Finland in 1979-1993 were verified from hospital records and classified into RRMS and PPMS. Patients met the Poser criteria for definite multiple sclerosis or otherwise satisfied the criteria for PPMS. Disease course was categorised by the same neurologist. Crude and age adjusted incidence in 1979-1993 was estimated.

RESULTS

During 1979-1993 the age adjusted incidence was 5.1 per 100 000 person-years in Uusimaa, 5.2 in Vaasa, and 11.6 in Seinäjoki. The rates in Uusimaa remained stable, while a decrease occurred in Vaasa and an increase in Seinäjoki. Between 1979-86 and 1987-93 the incidence of PPMS increased in Seinäjoki from 2.6 to 3.7 per 10(5) and decreased in Vaasa from 1.9 to 0.2 per 10(5); the trends were similar for RRMS.

CONCLUSIONS

There are significant differences in secular trends for multiple sclerosis incidence in Finland by geographical area, but these are similar for PPMS and RRMS. The recent changes point to locally acting environmental factors. The parallel incidence trends for RRMS and PPMS suggest similar environmental triggers for the two clinical presentations of multiple sclerosis.

Is gadolinium enhancement predictive of the development of brain atrophy in multiple sclerosis? A review of the literature

BACKGROUND AND PURPOSE

Several studies have demonstrated that brain atrophy can be detected over relatively short intervals from the earliest stages of multiple sclerosis (MS). Reviewing the published data, the authors highlight some hypothetical pathological mechanisms proposed as determinants of brain atrophy.

METHODS

Using the terms multiple sclerosis, MRI (magnetic resonance imaging), and brain atrophy, 181 citations were identified. The authors considered only studies with prospective designs with natural-course MS patients and/or placebo-treated patients of therapeutic trials, in which patients underwent baseline and follow-up scans with a T1-weighted gadolinium diethylenetriamine penta-acetic acid sequence (0.1 mmol/kg body weight), and correlation analyses between Gd enhancement activity and brain atrophy progression.

RESULTS

Five hundred thirty-two patients of 5 natural history studies and 5 therapeutic trial studies participated in the review process. The main observation was that in patients with a relapsing-remitting (RR) disease course, there was a correlation between Gd enhancement activity and brain atrophy progression. This correlation was not influenced by any other demographic and clinical additional data considered in the review process.

CONCLUSIONS

Examination of the pathological mechanisms proposed in the reviewed studies led the authors to believe that inflammation is only in part responsible for the development of brain atrophy. This conclusion may have an implication for the strategies of tissue protection advocated in the early stages of the RR course and strengthen recent evidence indicating that anti-inflammatory immunomodulatory agents and immunosuppressive treatments, which predominantly act against the inflammatory component of disease activity, may not have similar effects on progressive tissue loss, either in RR or progressive MS.

Differentiation of multiple sclerosis subtypes: implications for treatment

There has been tremendous progress in the immunomodulatory treatment of multiple sclerosis (MS) during recent years. With the introduction of interferon-beta, glatiramer acetate and mitoxantrone (recently registered for MS in the US), there are at least three therapeutic strategies that have proven effective in large phase III studies. However, not all patients with MS respond well to treatment with these drugs. This may largely be a consequence of disease heterogeneity. From a clinical perspective, patients with different disease courses show different treatment responses. Patients with relapsing-remitting MS are more likely to respond to immunomodulatory therapy than those with a progressive disease course. Studies of patients with secondary progressive MS have yielded inconsistent results and, so far, there has been no positive phase III study of immunomodulatory therapy in patients with primary progressive MS. Pathological evidence indicates that subtyping based on clinical findings alone does not reflect actual disease heterogeneity. In a large series of biopsy and autopsy specimens, at least four subtypes could be identified with respect to oligodendrocyte/myelin pathology and immunopathology. As long as the only method of identifying subtypes of disease is histopathology, differential therapy will remain a future goal. Thus, there is an urgent need for in vivo markers of immunopathogenesis in an individual patient that would allow treatment to be specifically directed towards a given pathological focus. However, at least from a theoretical point of view, some therapeutic approaches appear very attractive. Plasmapheresis and/or intravenous immunoglobulins could most plausibly be the best approach for the immunopathological subtype of MS, which is characterised by antibody and complement deposition next to demyelinated axons, in order to remove antibodies. The subtype of MS that is associated with heavy macrophage activation, T cell infiltration and expression of inflammatory mediator molecules, including tumour necrosis factor-alpha, may be most likely to respond to immunomodulation with interferon-beta or glatiramer acetate. There are other subtypes of MS in which viral infection or oligodendrocyte degeneration, rather than autoimmunity, appear to play a role. It is possible that these could benefit from antiviral therapy, oligodendrocyte protection or oligodendrocyte transplantation, although therapies based on these latter approaches have yet to be developed.

Primary progressive multiple sclerosis: increasing clarity but many unanswered questions

Heterogeneity in the clinical course of multiple sclerosis (MS) is well recognised and patients following a primary progressive course, 10-15% of the MS population, have a distinct clinical and paraclinical phenotype. This review examines recent advances in our understanding of this subgroup of patients and examines the new criteria to be applied in diagnosis. It also highlights developments in genetic, immunological, magnetic resonance and pathological aspects of the disease, whilst also outlining the results of recent therapeutic trials.

Natural history of multiple sclerosis: implications for counselling and therapy

Recent advances in our knowledge of the natural history of multiple sclerosis deal with the influence of pregnancy and vaccination, the predictive value of magnetic resonance imaging-based criteria in terms of activity and severity of the disease, and the weighting of the interplay between relapses and clinical progression. These advances have implications for counselling of patients and adjusting the classification of the disease course. Thus multiple sclerosis should be considered to be as much neurodegenerative as inflammatory and disease-modifying therapeutic strategies should be reconsidered by focusing on protection and repair of the nervous system.

Multiple sclerosis

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system (CNS). Diagnosis rests upon identifying typical clinical symptoms and interpreting supportive laboratory and radiological investigations. The etiology is unknown; however, strong evidence suggests that MS is an autoimmune disease directed against CNS myelin or oligodendrocytes. Genetic factors are important in the development of MS. Contributing environmental determinants (possibly including infectious agents) appear important but remain unidentified. Both cell-mediated and humorally mediated immune mechanisms contribute to pathological injury. Axonal damage occurs in addition to demyelination and may be the cause of later permanent disability. Distinct pathological subtypes may differentiate among patients with MS. Treatment is directed at acute attacks (with corticosteroids) and reduction of attack frequency (primarily with type-1 beta interferons and glatiramer acetate). Research into the causes and treatments of MS has expanded our knowledge of this disease and promises improved care for MS patients in the future.

Observations on recent studies showing increased co-occurrence of autoimmune diseases

The co-occurrence of autoimmune diseases has been epidemiologically studied and has aided in our understanding of autoimmunity. However, as new perspectives develop on the pathogenesis and natural history of autoimmune diseases, a refinement in the methodology for the study of the co-occurrence of disease is warranted in order to maximize the information that one may realize from such studies. This paper presents some recent results of co-occurrence studies and then proposes several refinements in the design of epidemiological studies in light of current understanding of the natural history of autoimmune diseases. It also suggests an historical perspective on the results of past studies as to the type of information that can be inferred from them.

Two-year follow-up study of primary and transitional progressive multiple sclerosis

This study documents changes in clinical and magnetic resonance imaging (MRI) characteristics in a large cohort of patients with primary and transitional progressive multiple sclerosis (PP and TPMS) over 2 years. Patients with PPMS and TPMS were recruited from six European centres and underwent clinical and MRI examination at three time points: baseline, year one and year two. Of the 190 patients recruited clinical data were available on 125 patients (66%, five centres) and MRI data were available on 113 patients (59%, four centres) at 2 years. Significant increases were seen in T2 load and T1 hypointensity, while brain and cord volume decreased. In PPMS significantly higher lesion loads were found in those who presented with non-cord syndromes when compared to cord presentation and there was a trend to greater brain atrophy in those who deteriorated clinically over the course of the study compared to those who remained stable. Significant cord atrophy was only seen in those with a cord presentation. Measurable changes in MRI parameters can be detected in PPMS patients over a relatively short period of time. MRI quantification is likely to be useful in elucidating disease mechanisms in PPMS and in the execution of clinical trials.

Identifying disease modifying genes in multiple sclerosis

Evidence is mounting that genetic variation influences not only susceptibility to multiple sclerosis (MS), but also its course and severity. Identification of disease modifying genes, however, poses unique challenges, especially on how to classify the course and outcome of the disease in ways that may be relevant to analysis of biological factors that might be influenced by genes. The power of the statistical approaches to detect small effects of individual genes in complex disorders such as MS is problematic, and approaches to estimate power must be appropriate for the data. Nonetheless, using contemporary schemes of classification, genetic variants that influence disease course have been found; in fact, a small number have been confirmed to influence disease course in two or more independent studies. This review addresses strategies relevant to identification of disease modifying genes in MS, and summarizes and critically evaluates the current state of knowledge in this area.

Randomized study of antibodies to IFN-gamma and TNF-alpha in secondary progressive multiple sclerosis

Studies of cytokines in multiple sclerosis (MS) have shown that immune mechanisms connected with disturbance of the synthesis of cytokines probably play critical roles in the initiation and prolongation of MS. In a double-blind, placebo-controlled trial, 45 patients with active secondary progressive MS were randomized to three groups of 15 patients, each receiving a short course of antibodies to IFN-gamma, to tumor necrosis factor (TNF)-alpha, or a placebo. After 12 months with analysis of disability (Expanded Disability Status Scale scores), accompanied by interval determinations of lymphocyte subpopulations, cytokine production levels, MRI, and evoked potentials, it was found that only patients who received antibodies to IFN-gamma showed statistically significant improvement compared to the placebo group--a significant increase in the number of patients without confirmed disability progression. This was supported by MRI data (a decrease in the number of active lesions) and systemic changes in cytokine status (a decrease in IL-1beta, TNF-alpha, and IFN-gamma concentrations in supernatants of actvated blood cells of these MS patients and an increase in TGF-beta production). Neutralization of IFN-gamma could be a new approach to treating secondary progressive MS. Long-term administration of humanized monoclonal antibodies to IFN-gamma and simultaneous use of antibodies to IFN-gamma together with IFN-beta products are planned.

Predicting secondary progression in relapsing-remitting multiple sclerosis: a Bayesian analysis

With the aid of a Bayesian statistical model of the natural course of relapsing remitting Multiple Sclerosis (MS), we identify short-term clinical predictors of long-term evolution of the disease, with particular focus on predicting onset of secondary progressive course (failure event) on the basis of patient information available at an early stage of disease. The model specifies the full joint probability distribution for a set of variables including early indicator variables (observed during the early stage of disease), intermediate indicator variables (observed throughout the course of disease, prefailure) and the time to failure. Our model treats the intermediate indicators as a surrogate response event, so that in right-censored patients, these indicators provide supplementary information pointing towards the unobserved failure times. Moreover, the full probability modelling approach allows the considerable uncertainty which affects certain early indicators, such as the early relapse rates, to be incorporated in the analysis. With such a model, the ability of early indicators to predict failure can be assessed more accurately and reliably, and explained in terms of the relationship between early and intermediate indicators. Moreover, a model with the aforementioned features allows us to characterize the pattern of disease course in high-risk patients, and to identify short-term manifestations which are strongly related to long-term evolution of disease, as potential surrogate responses in clinical trials. Our analysis is based on longitudinal data from 186 MS patients with a relapsing-remitting initial course. The following important early predictors of the time to progression emerged: age; number of neurological functional systems (FSs) involved; sphincter, or motor, or motor-sensory symptoms; presence of sequelae after onset. During the first 3 years of follow up, to reach EDSS> or =4 outside relapse, to have sphincter or motor relapses and to reach moderate pyramidal involvement were also found to be unfavourable prognostic factors.

Immunologic therapy for secondary and primary progressive multiple sclerosis

Multiple sclerosis (MS) is generally considered an immune-mediated demyelinating disease, and treatments designed to modify the course of MS are immunosuppressive or immunomodulatory. Although most people with MS have a relapsing-remitting course initially, the majority will eventually experience a more gradual decline in neurologic function, termed secondary progressive MS. Some patients have gradual worsening from the beginning, termed primary progressive MS. Recent pathologic studies have revealed that axonal injury and neuronal degeneration are much more prominent in MS than previously recognized, and may be the explanation for the gradual decline in neurologic function that characterizes progressive MS. The results of several clinical trials in MS indicate that suppression of the immune-mediated inflammation may decrease the relapse rate in MS, but not stop the progressive loss of neurologic function. There are many promising approaches to this clinical dilemma, but none has been proven to be effective in stopping or retarding progressive MS. More well-designed, controlled, blinded, randomized clinical trials are needed to test these putative therapies. In the mean time, we should avoid subjecting patients to potentially dangerous and unproven regimens.

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.

Relapses and progression of disability in multiple sclerosis

BACKGROUND

The influence of the patterns of onset of multiple sclerosis and relapses of the disease on the time course of irreversible disability is controversial.

METHODS

In 1844 patients with multiple sclerosis who were followed for a mean (+/- SD) of 11 +/- 10 years, we determined the time of the clinical onset of the disease, the initial course (relapsing-remitting or progressive) and the subsequent course (relapsing-remitting, secondary progressive, or primary progressive), the times of relapses, the time to the onset of irreversible disability, and the time course of progressive, irreversible disability. We used three scores on the Kurtzke Disability Status Scale (range, 0 to 10, with higher scores indicating more severe disability) as measures of the severity and progression of disability: a score of 4 (limited walking ability but able to walk for more than 500 m without aid or rest), a score of 6 (ability to walk with unilateral support no more than 100 m without rest), and a score of 7 (ability to walk no more than 10 m without rest while leaning against a wall or holding onto furniture for support). We used Kaplan-Meier analyses to determine the influence of relapses on the time to the onset of irreversible disability.

RESULTS

The median times from the onset of multiple sclerosis to the assignment of a score of 4, a score of 6, and a score of 7 on the disability scale were longer among the 1562 patients with a relapsing-remitting onset of disease (11.4, 23.1, and 33.1 years, respectively) than among the 282 patients who had progressive disease from the onset (0.0, 7.1, and 13.4 years, respectively; P<0.001 for all comparisons). In contrast, the times from the assignment of a score of 4 to a score of 6 were similar in the two groups (5.7 and 5.4 years, P=0.74). The time course of progressive, irreversible disease among patients with the primary progressive type of multiple sclerosis was not affected by the presence or absence of superimposed relapses.

CONCLUSIONS

Among patients with multiple sclerosis, relapses do not significantly influence the progression of irreversible disability.

Diagnostic brain MRI findings in primary progressive multiple sclerosis

The clinical course of multiple sclerosis can be classified as relapsing from onset (relapsing-remitting), or progressive from onset (primary progressive - PPMS). These clinical phenotypes have been based on historical and clinical observations. It has been reported that PPMS patients tend to have quantitatively less MRI activity and disease burden. We evaluated the sensitivity and diagnostic value of conventional brain MRI scan in 143 PPMS patients. Brain MRIs were blindly evaluated to determine if they satisfied Paty and/or Fazekas diagnostic criteria. Patients were divided into those with typical, atypical or normal scans. They satisfied brain MRI criteria in 92% cases. Findings included: 131 typical, four atypical, and eight normal scans. All 12 non-typical scans' subjects had spinal onset; spinal MRI scans were positive in four of seven cases. Sex, age of onset, site and number of symptoms involved at onset among those groups were not significantly different but accumulation of disability had a tendency to be slower in these few individuals with normal or atypical head MRI's. Although there may be quantitative differences in lesion activity/burden, MRI scanning in PPMS unexpectedly has diagnostic sensitivity very similar to that seen in RRMS. A normal brain MRI is unusual in PPMS patients.