Bone marrow CD34+/B220+ progenitors target the inflamed brain and display in vitro differentiation potential toward microglia

Recent evidence indicates that microglial cells may not derive from blood circulating mature monocytes as they express features of myeloid progenitors. Here, we observed that a subpopulation of microglial cells expressed CD34 and B220 antigens during brain development. We thus hypothesized that microglia, or a subset of microglial cells, originate from blood circulating CD34+/B220+ myeloid progenitors, which could target the brain under developmental or neuroinflammatory conditions. Using experimental allergic encephalomyelitis (EAE) as a model of chronic neuroinflammation, we found that a discrete population of CD34+/B220+ cells expands in both blood and brain of diseased animals. In EAE mice, intravenous transfer experiments showed that macrophage-colony stimulating factor (M-CSF) -expanded CD34+ myeloid progenitors target the inflamed central nervous system (CNS) while keeping their immature phenotype. Based on these results, we then assessed whether CD34+/B220+ cells display in vitro differentiation potential toward microglia. For this purpose, CD34+/B220+ cells were sorted from M-CSF-stimulated bone marrow (BM) cultures and exposed to a glial cell conditioned medium. Under these experimental conditions, CD34+/B220+ cells were able to differentiate into microglial-like cells showing the morphological and phenotypic features of native microglia. Overall, our data suggest that under developmental or neuroinflammatory conditions, a subpopulation of microglial cells derive from CNS-invading CD34+/B220+ myeloid progenitors.

A Phase II study of the safety and efficacy of teriflunomide in multiple sclerosis with relapses

BACKGROUND

Teriflunomide, a dihydro-orotate dehydrogenase inhibitor, has immunomodulatory effects, including the ability to suppress experimental allergic encephalomyelitis. In this randomized, double-blind, placebo-controlled Phase II study, the authors examined the safety and efficacy of oral teriflunomide in multiple sclerosis (MS) with relapses.

METHODS

Patients (n = 179) with relapsing-remitting MS (n = 157) or secondary progressive MS with relapses (n = 22) were randomized to receive placebo, teriflunomide 7 mg/day, or teriflunomide 14 mg/day for 36 weeks. MRI brain scans were performed every 6 weeks. The primary endpoint was the number of combined unique active lesions per MRI scan. Secondary endpoints included MRI-defined disease burden, relapse frequency, and disability increase.

RESULTS

The median number of combined unique active lesions per scan was 0.5, 0.2, and 0.3 in the placebo, teriflunomide 7 mg/day (p < 0.03 vs placebo), and teriflunomide 14 mg/day (p < 0.01 vs placebo) groups during the 36-week double-blind treatment phase. Teriflunomide-treated patients also had significantly fewer T1 enhancing lesions per scan, new or enlarging T2 lesions per scan, and new T2 lesions. Patients receiving teriflunomide 14 mg/day had significantly reduced T2 disease burden. Teriflunomide treatment resulted in trends toward a lower annualized relapse rate and fewer relapsing patients (14 mg/day only) vs placebo. Significantly fewer patients receiving teriflunomide 14 mg/day vs placebo demonstrated disability increase. Treatment was well tolerated; numbers of adverse events and serious adverse events were similar in all treatment groups.

CONCLUSION

Oral teriflunomide was effective in reducing MRI lesions and was well tolerated in patients with relapsing multiple sclerosis.

Unusual ocular motor findings in multiple sclerosis

In multiple sclerosis (MS), nystagmus or internuclear ophthalmoplegia (INO) are the usual ocular motor dysfunctions. However, in patients with focal brainstem lesions, other rare manifestations may be observed, such as an isolated ocular motor nerve palsy or complex ocular motor disturbances. We report five MS patients with unusual ocular motor disturbances (bilateral third nerve palsy [n = 2], opsoclonus, Horner's syndrome and one-and-a-half syndrome). We discuss possible correlations between clinical disturbances and MRI abnormalities. Patients were seen in two MS centres. They had a confirmed diagnosis of MS and underwent a brain MRI and a complete neuro-ophthalmological work-up. In one case (opsoclonus), ocular motor manifestations were the first manifestation of MS. In the other four cases they occurred 3 months (Horner syndrome), 6 years and 12 years (bilateral third nerve palsy) and 2 years (one-and-a-half syndrome) after the disease onset, respectively. Four out of five patients were still in a relapsing-remitting form of MS. In the opsoclonus case, there was no evidence of a brainstem lesion. A gadolinium-enhanced lesion (2 cases) or a new T2-weighted lesion located in the brainstem correlated with the clinical presentation. All patients completely or partially recovered after corticosteroid infusions. Our study shows some rare or previously undescribed complex ocular motor symptoms in MS.

Sclérose en plaques et grossesse

The influence of pregnancy in multiple sclerosis (MS) has been a matter of controversy for a long time. Women with MS were often discouraged to envisage pregnancy. The Pregnancy in Multiple Sclerosis (PRIMS) study was the first large-scale prospective study aimed at assessing the possible influence of pregnancy and delivery on the clinical course of MS. Two hundred and fifty-four women with a diagnosis of MS were included during pregnancy and followed-up till the end of the second year post partum. The results were a reduction in the relapse rate during pregnancy, in comparison to the year before pregnancy, especially marked in the third trimester, and a significant increase in the relapse rate in the first trimester post partum. From the second trimester post partum on however, the relapse rate did not significantly differ from the pre-pregnancy rate. About one third of the women experienced a post partum relapse. Pregnancy did not influence disability progression. The clinical factors likely to predict a relapse in the three months after delivery were analyzed by logistic regression analysis. Women with a greater disease activity in the year before pregnancy and during pregnancy had a higher risk of relapse in the post partum three months. Neither breast-feeding, nor epidural analgesia correlated with presence of a post partum relapse. When comparing the predicted and observed status however, only 72 percent of the women were correctly classified by the multivariate model. It seems unwise therefore to use this kind of model to select women that would benefit from a putative preventive therapy. The PRIMS study had other major consequences: it fostered the development of specific therapeutic strategies to prevent post partum relapses (IV immunoglobulins, IV methylprednisolone), and suggested a potential role of sexual hormones in the natural history of MS during pregnancy and the post partum, therefore identifying them as a preferential target for prevention. The preventive effect of progesterone combined with estradiol on post partum relapses will be tested in a large-scale randomized and placebo-controlled European trial, the POPART'MUS study.

Multiple Sclerosis Severity Score: Using disability and disease duration to rate disease severity

BACKGROUND

There is no consensus method for determining progression of disability in patients with multiple sclerosis (MS) when each patient has had only a single assessment in the course of the disease.

METHODS

Using data from two large longitudinal databases, the authors tested whether cross-sectional disability assessments are representative of disease severity as a whole. An algorithm, the Multiple Sclerosis Severity Score (MSSS), which relates scores on the Expanded Disability Status Scale (EDSS) to the distribution of disability in patients with comparable disease durations, was devised and then applied to a collection of 9,892 patients from 11 countries to create the Global MSSS. In order to compare different methods of detecting such effects the authors simulated the effects of a genetic factor on disability.

RESULTS

Cross-sectional EDSS measurements made after the first year were representative of overall disease severity. The MSSS was more powerful than the other methods the authors tested for detecting different rates of disease progression.

CONCLUSION

The Multiple Sclerosis Severity Score (MSSS) is a powerful method for comparing disease progression using single assessment data. The Global MSSS can be used as a reference table for future disability comparisons. While useful for comparing groups of patients, disease fluctuation precludes its use as a predictor of future disability in an individual.

Modafinil for fatigue in MS: A randomized placebo-controlled double-blind study

OBJECTIVE

To assess whether modafinil, a wakefulness-promoting agent, is useful for fatigue in patients with multiple sclerosis (MS).

METHODS

Patients with MS with stable disability, and a baseline score of 45 or more on the Modified Fatigue Impact Scale (MFIS), were eligible for the 5-week randomized, double-blind, placebo-controlled, parallel group study. The initial daily dose of modafinil was 200 mg for 1 week. Depending on tolerance, the dose was increased by 100 mg every week up to 400 mg/day and remained unchanged between day 21 and day 35. The primary outcome variable was the change of MFIS score at day 35.

RESULTS

A total of 115 patients with MS were enrolled in the study and in the intention to treat analysis. The mean MFIS score at baseline was 63 +/- 9 in the placebo group and 63 +/- 10 in the modafinil group. MFIS scores improved between day 0 and day 35 in both placebo-treated and modafinil-treated groups, but no significant difference was detected between the two groups. There was no major safety concern.

CONCLUSIONS

There was no improvement of fatigue in patients with multiple sclerosis treated with modafinil vs placebo according to the Modified Fatigue Impact Scale.

Clinical characteristics of responders to interferon therapy for relapsing MS

OBJECTIVE

To determine the proportion of patients with multiple sclerosis (MS) who respond to interferon-beta (IFNB) therapy and assess whether clinical characteristics differ in IFNB responders vs nonresponders.

METHODS

Data on all patients who received IFNB who were entered in the prospective European Database for Multiple Sclerosis (EDMUS) database in Lyon as of March 31, 2001, were reviewed. Responders were defined as having a lower relapse rate on IFNB compared with the year or 2 years prior to IFNB therapy.

RESULTS

Two hundred sixty-two patients with relapsing MS received at least 6 months of IFNB: 200 relapsing remitting (RR) and 62 relapsing secondary progressive (SP). One-third of patients experienced a higher or identical annual relapse rate while on IFNB treatment. Compared with nonresponders, responders were older and had longer disease duration at the time IFNB was initiated. RRMS responders also had a higher relapse rate during the year prior to IFNB therapy and SPMS responders had a higher Disability Status Scale score at initiation of IFNB.

CONCLUSION

Clinical profiles of patients with relapsing MS who respond to IFNB may differ from those who do not with a more inflammatory and less neurodegenerative disease at the time IFNB is initiated.

[Multiple sclerosis: spontaneous course, natural history]

Globally, the course and prognosis of multiple sclerosis are heterogeneous, and generally considered to be unpredictable. Advances in statistical techniques have made it possible to analyze representative cohorts of patients to clearly delineate the overall prognosis of the disease, beyond individual variations. For each individual however, there appears to be a steady progression as shown by serial quantified neurological examinations. At the present time early prediction of outcome remains impossible. In the near future, new imaging techniques may provide a solution to this problem allowing selection of patients at risk who could benefit from early treatment.

[Diagnostic criteria of different clinical forms ]

Multiple sclerosis (MS) is a disease of unknown origin and for which there is no specific diagnostic test. The diagnosis of MS is always the result of a more or less simple procedure, depending on the cases, and it remains uncertain until evidence of anatomo-pathological signs have been brought forward. An almost unanimous consensus does exist regarding several points. In the presence of suggestive or, at least, compatible neurological signs and in the absence of any alternative diagnosis according to a neurologist expert in MS, the diagnosis of MS is based on three criteria: the evidence of at least two different lesions in the white matter of the central nervous system, which is called the "space dissemination" criterion; the evidence of at least two different episodes in the disease course, which is called "time dissemination"; the evidence of a chronic inflammation of the central nervous system revealed through the analysis of the cerebrospinal fluid, i.e. the "infammatory" criterion. The observation of one or several of these criteria allows to establish the diagnosis of MS with more or less certainly, likely to be reassessed according to the subsequent course of the disease. There is a wide consensus today with Poser's classification (Poser et al., 1983) which combines the three criteria and distinguishes five different categories. According to Poser et al., space dissemination may be proved on clinical examination, but also with the brain MRI and, failing that, with the evoked potentials. Time dissemination is based only on clinical signs and the inflammatory criterion is as significant as the two other criteria. This classification has just been revised by an expert committee (McDonald et al., 2001) who wish to simplify it into two different categories (MS vs possible MS). It has been suggested that time dissemination should be proven by the observation of MRI signs three months at least after the previous clinical episode or the previous MRI. It has been suggested also to use the inflammatory criterion in second position in replacement of the space criterion when the latter is missing on the clinical and paraclinical levels. Time will say whether this new classification will replace the previous one.

Vaccinations and the risk of relapse in multiple sclerosis. Vaccines in Multiple Sclerosis Study Group

BACKGROUND

There has been some concern that vaccination may precipitate the onset of multiple sclerosis or lead to relapses. Since the recent hepatitis B vaccination program in France, there have been new reports of an increased risk of active multiple sclerosis after vaccination.

METHODS

We conducted a case-crossover study to assess whether vaccinations increase the risk of relapse in multiple sclerosis. The subjects were patients included in the European Database for Multiple Sclerosis who had a relapse between 1993 and 1997. The index relapse was the first relapse confirmed by a visit to a neurologist and preceded by a relapse-free period of at least 12 months. Information on vaccinations was obtained in a standardized telephone interview and confirmed by means of medical records. Exposure to vaccination in the two-month risk period immediately preceding the relapse was compared with that in the four previous two-month control periods for the calculation of relative risks, which were estimated with the use of conditional logistic regression.

RESULTS

Of 643 patients with relapses of multiple sclerosis, 15 percent reported having been vaccinated during the preceding 12 months. The reports of 94 percent of these vaccinations were confirmed. Of all the patients, 2.3 percent had been vaccinated during the preceding two-month risk period as compared with 2.8 to 4.0 percent who were vaccinated during one or more of the four control periods. The relative risk of relapse associated with exposure to any vaccination during the previous two months was 0.71 (95 percent confidence interval, 0.40 to 1.26). There was no increase in the specific risk of relapse associated with tetanus, hepatitis B, or influenza vaccination (range of relative risks, 0.22 to 1.08). Analyses based on risk periods of one and three months yielded similar results.

CONCLUSIONS

Vaccination does not appear to increase the short-term risk of relapse in multiple sclerosis.

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.

[18F]fluorodeoxyglucose positron emission tomography in the diagnosis of cancer in patients with paraneoplastic neurological syndrome and anti-Hu antibodies

The diagnosis of cancer is often difficult in patients with paraneoplastic neurological syndrome and anti-Hu antibodies. Fluorodeoxyglucose 18 positron emission tomography scanning is a highly sensitive and specific method to detect lung tumors. We investigated 15 patients with paraneoplastic neurological syndrome and anti-Hu antibodies. Radiological methods led to the diagnosis of cancer in 12 patients, and test results were negative in 3. Whole-body [18F]fluorodeoxyglucose positron emission tomography showed abnormal uptake in the mediastinum in these 3 patients in accordance with the expected location of the malignancy.

[Can the prognosis of multiple sclerosis be predicted?]

Though the global course of the disease is well known when considering large cohorts of patients, it is rather difficult to make a prognosis for a given patient. It is essential however to predict the course of the disease as early as possible in order to be able to give the patient the right treatment at the right time. Age at disease onset is one of the most important clinical predictive factors, as this has been proved by various analyses. The earlier the disease onset, the better the prognosis. The inaugural symptom of optic neuritis, the long interval between the first two relapses, a remitting form at onset are predictive factors of a good evolution. A normal brain magnetic resonance imaging performed on the occasion of a first isolated sign of the central nervous system is the marker of a good prognosis. Conversely, the presence of oligoclonal bands in the cerebrospinal fluid and the increase of IgG index increase the risk of occurrence of a second relapse. The new techniques of magnetic resonance imaging and the exhaustive initial clinical examination using several classifications of disability will allow a better prognosis for a given patient.

[Disease-modifying treatments in multiple sclerosis]

The number of available disease-modifying agents in multiple sclerosis has been increasing dramatically since 1993. First, interferon beta-1b has been licensed for exacerbating-remitting forms. Then, efficacy has been demonstrated for intramuscular or subcutaneously administered interferon beta-1a in the same indication. More recently, utility of interferon beta-1b in secondary progressive forms has also been proved. Concomitantly, with glatiramer acetate, the concept of a specific intervention on myelin auto-reactive T-cells been validated. Lastly, the classical approach of a global immunosuppression is still of interest. A better utilization of the currently available medications, an improvement of their efficacy/tolerance ratio, the exploration of new concepts such as neuro-protection and remyelination may soon lead to more significant advances.