Seasonal variation of multiple sclerosis exacerbations in North Dakota

Seasonal and monthly variation in multiple sclerosis relapses: a systematic review and meta-analysis

BACKGROUND

Multiple Sclerosis (MS) relapses are episodes of transient disease exacerbation. There are contradictory findings regarding seasonal variation in MS relapses. In this systematic review and meta-analysis, we aimed to investigate the seasonal and monthly variation in relapse rates among patients with MS.

METHODS

We systematically queried PubMed, Scopus, and Web of Science for published papers until February 30, 2022.

RESULTS

A total of 24 studies were included in this systematic review and meta-analysis with a total of 29,106 patients with MS. We found that the relapse rate was significantly lower in fall compared to the average relapse rate in other seasons with a risk ratio (RR) of 0.97 (95% CI 0.95-0.98). Furthermore, patients with MS experienced a higher number of relapses in April (RR: 1.06, 95% CI 1.01-1.11) and March (RR: 1.08, 95% CI 1.00-1.16) compared to other months. Also, the risk of relapse was lower in August (RR: 0.92, 95% CI.85-0.98), September (RR: 0.97, 95% CI.94-0.99), October (RR: 0.92, 95% CI.89-0.96), and November (RR: 0.93, 95% CI.89-0.97).

CONCLUSION

Our systematic review and meta-analysis confirm the temporal fluctuations in the relapse of MS through a comprehensive review of the existing literature, with a lower relapse rate during late summer and fall and a higher relapse rate during early spring.

Seasonal distribution of attacks in aquaporin-4 antibody disease and myelin-oligodendrocyte antibody disease

BACKGROUND

Seasonal variation in incidence and exacerbations has been reported for neuroinflammatory conditions such as multiple sclerosis and acute disseminated encephalomyelitis (ADEM). It is unknown whether seasonality also influences aquaporin-4 antibody (AQP4-Ab) disease and myelin-oligodendrocyte antibody (MOG-Ab) disease.

OBJECTIVE

We examined the seasonal distribution of attacks in AQP4-Ab disease and MOG-Ab disease.

METHODS

Observational study using data prospectively recorded from three cohorts in the United Kingdom.

RESULTS

There was no clear seasonal variation in AQP4-Ab or MOG-Ab attacks for either the onset attack nor subsequent relapses. In both groups, the proportion of attacks manifesting with each of the main phenotypes (optic neuritis, transverse myelitis, ADEM/ADEM-like) appeared stable across the year. This study is the first to examine seasonal distribution of MOG-Ab attacks and the largest in AQP4-Ab disease so far.

CONCLUSION

Lack of seasonal distribution in AQP4-Ab and MOG-Ab disease may argue against environment factors playing a role in the aetiopathogenesis of these conditions.

Seasonal variations of 25-OH vitamin D serum levels in Multiple Sclerosis patients with relapse using MRI

An increasing body of evidence suggests that low vitamin D (25-[OH]-D) concentrations is linked to increased activity in multiple sclerosis (MS) patients and MS relapse. Therefore, the current study was aimed to evaluate vitamin D serum concentrations and its possible seasonal variations among MS patients with relapse. This prospective, descriptive study was conducted on patients with MS relapse who referred to the neurology center of Ali ibn Abi Talib Hospital in Zahedan during one year. Magnetic Resonance Imaging (MRI)-Spine was performed for 90 patients and serum samples were collected from patient to measure serum vitamin D levels using RIA KIT. Furthermore, the plaques in each patient's MRI were counted and then recorded. Descriptive and inductive statistics were conducted using statistical software. Our findings indicated a significant correlation between serum vitamin D level and cervical spinal cord plaques (p = 0.007, r = 0.28), while no association was revealed between serum vitamin D level and number of brain plaque. Furthermore, a significant association was also observed between number of cervical spinal cord plaques and serum vitamin D levels. In addition, a reverse correlation was observed between number of cervical spinal cord plaques and serum vitamin D levels in spring. In autumn, there was a statistically significant relationship between number of brain plaque and serum vitamin D level. Additionally, a statistically significant relationship was found between serum vitamin D levels and number of plaques in winter. Our findings are in agreement with some previous studies that reported conflicting result, where the association of season with the prevalence of relapse cases cannot be verified. Although the mean serum levels of vitamin D are inversely correlated with the incidence of relapses in winter. However, the values obtained in the spring do not confirm such an inverse relationship.

Vitamin D for the treatment of multiple sclerosis: a meta-analysis

OBJECTIVE

There is an association between latitude, relative vitamin D deficiency and risk of multiple sclerosis (MS), and an association between vitamin D and disease progression. We have performed a meta-analysis with the aim of investigating the role of therapeutic vitamin D in MS.

METHODS

A systematic search of databases was performed to identify clinical trials assessing vitamin D in patients with relapsing-remitting MS. Studies were selected based on inclusion and exclusion criteria. Analysis was performed using RevMan 5.3 software.

RESULTS

Twelve studies involving 950 patients were included in the final analysis. Studies were divided into four groups because of heterogeneity in study design. Studies were judged to be at low or unclear risk of bias, except in three studies, and this was confirmed by funnel plots. No statistically significant difference was seen for any of the outcome measures. There were non-significant trends in favour of vitamin D for all outcome measures, particularly when only placebo-controlled studies were included. Dose comparison studies showed a significant increase in annualised relapse rate (mean difference 0.15 [95%CI 0.01-0.30]) and non-significant trends of increased Expanded Disability Status Scale and gadolinium-enhancing lesions for the higher-dose arms.

CONCLUSION

These findings suggest that vitamin D supplementation may have a therapeutic role in the treatment of MS. However, there is uncertainty with regard to the most appropriate dose, with high doses potentially being associated with worse outcomes. There remains the need for further well-performed randomised, dose-ranging, placebo-controlled trials of vitamin D in MS.

Multiple Sclerosis and Schizophrenia

The psychiatric and neurological aspects of health may present methodological challenges in the diagnosis and treatment of disease. This is especially true for patients whose symptoms indicate the coexistence of multiple sclerosis (MS) and schizophrenia (SCZ). These cases raise critical questions regarding the relationship between the mind and the brain. Studies have noted that patients with MS have an increased risk of developing SCZ or bipolar disorder (BD). It is suggested here that MS and a subgroup of SCZ have similar etiologies. Factors such as gender, ethnicity, geography and season also have an influence on the occurrence of MS and SCZ. This paper aims to examine the differences and similarities between SCZ and MS. For this purpose, scientific papers examining various factors associated with these disorders were reviewed, and similarities and differences in genetic, immunological, seasonal, geographical, and gender-related risk factors and limited similarities in ethnic factors between the two diseases were identified. The findings suggest that subgroups of these two diseases may belong to the same class of disorders.

Multiple Sclerosis

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

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

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

A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data

This report describes a novel Stata-based application of trigonometric regression modelling to 55 years of multiple sclerosis relapse data from 46 clinical centers across 20 countries located in both hemispheres. Central to the success of this method was the strategic use of plot analysis to guide and corroborate the statistical regression modelling. Initial plot analysis was necessary for establishing realistic hypotheses regarding the presence and structural form of seasonal and latitudinal influences on relapse probability and then testing the performance of the resultant models. Trigonometric regression was then necessary to quantify these relationships, adjust for important confounders and provide a measure of certainty as to how plausible these associations were. Synchronization of graphing techniques with regression modelling permitted a systematic refinement of models until best-fit convergence was achieved, enabling novel inferences to be made regarding the independent influence of both season and latitude in predicting relapse onset timing in MS. These methods have the potential for application across other complex disease and epidemiological phenomena suspected or known to vary systematically with season and/or geographic location.

Infection as an Environmental Trigger of Multiple Sclerosis Disease Exacerbation

Over the past several decades, significant advances have been made in identifying factors that contribute to the pathogenesis of multiple sclerosis (MS) and have culminated in the approval of some effective therapeutic strategies for disease intervention. However, the mechanisms by which environmental factors, such as infection, contribute to the pathogenesis and/or symptom exacerbation remain to be fully elucidated. Relapse frequency in MS patients contributes to neurological impairment and, in the initial phases of disease, serves as a predictor of poor disease prognosis. The purpose of this review is to examine the evidence that supports a role for peripheral infection in modulating the natural history of this disease. Evidence supporting a role for infection in promoting exacerbation in animal models of MS is also reviewed. Finally, a few mechanisms by which infection may exacerbate symptoms of MS and other neurological diseases are discussed. Those who comprise the majority of MS patients acquire approximately two upper-respiratory infections per year; furthermore, this type of infection doubles the risk for MS relapse, underscoring the contribution of this relationship as being potentially important and particularly detrimental.

No effect of season of birth on risk of type 1 diabetes, cancer, schizophrenia and ischemic heart disease, while some variations may be seen for pneumonia and multiple sclerosis

Background: The risk of type 1 diabetes (T1DM), infections, cancer, schizophrenia and multiple sclerosis (MS) has been associated with environmental factors including vitamin D status.

Materials and Methods: Data were obtained from all children born in Denmark in 1940 (n = 72,839), 1977 (n = 89,570), and 1996 (n = 74,015). Information on contacts to hospitals (1977–2009) was obtained from the National Hospital Discharge Register. The main exposure variable was season of birth as a proxy variable for vitamin D status (summer: April–September and winter: October–March).

Results: No associations between season of birth and risk of MS were seen in the 1940 cohort or the 1996 cohort. In the 1977 cohort, there was a borderline statistically significant decreased risk of MS in those born during wintertime compared with those born during summertime (HR = 0.70, 95% CI: 0.47–1.04, p = 0.07). There were no significant differences within the groups regarding season and risk of T1DM at any age, T1DM before 10 y, infection, any type of cancer, schizophrenia and myocardial infarction. In the 1977 cohort the risk of pneumonia was significantly lower among those born in the summer compared with the winter at any age (HR 0.91, 95% CI 0.85–0.97, p < 0.01) and at age < 10 y (HR 0.90, 95% CI 0.84–0.97, p < 0.01).

Conclusion: MS and pneumonia in young subjects may be related to season of birth and thus maternal vitamin D exposure. Low sunlight exposure in the winter time leading to low vitamin D levels during pregnancy may be a potential explanation.

Historical changes of seasonal differences in the frequency of multiple sclerosis clinical attacks: a multicenter study

Previous papers show discordant patterns of monthly and seasonal differences in the frequency of multiple sclerosis relapses. Attacks are more often reported in spring and summer, but there are many variations, mainly as to summer peaks. This paper, an MSBase collaboration substudy, reports multiple series of relapses from 1980 to 2010, comparing ultradecennal trends of seasonal frequency of attacks in different countries. The MSBase international database was searched for relapses in series recording patient histories from 1980 up to 2010. The number of relapses by month was stratified by decade (1981-1990, 1991-2000, 2001-2010). Positive spring versus summer peaks were compared by odds ratios; different series were compared by weighted odds ratio (Peto OR). Decade comparison of the 1990s versus 2000s shows inversion of spring-summer peak (2000s = March; 1990s = July), significant in the whole group (Peto odds ratio = 1.31, CI = 1.10-1.56, p = 0.003) and in Salerno series (OR = 1.97, CI = 1.14-1.40). The global significance persisted also excluding Salerno series (Peto odds ratio = 1.25, CI = 1.04-1.50, p = 0.002). Multicentric data confirm a summer peak of relapses in the 1991-2000 decade, significantly different from the spring peak of 2001-2010. Seasonal frequency of relapses shows long-term variations, so that other factors such as viral epidemics might have more relevance than ultraviolet exposure.

Deficiency of serum concentration of 25-hydroxyvitamin D in psoriatic patients: a case-control study

BACKGROUND

Some autoimmune conditions have been associated with reduced vitamin D levels, including systemic lupus erythematosus, rheumatoid arthritis, diabetes mellitus, and multiple sclerosis.

OBJECTIVE

The main objective of this study was to analyze the 25-hydroxyvitamin D (OHD) status of patients with psoriasis in comparison with control subjects without this disease.

METHODS

This case-control study included 86 patients (43 with psoriasis and 43 age- and sex-matched control subjects) from the outpatient clinic of our hospital dermatology department in Granada, Spain. All patients and control subjects were studied during one 4-week period to avoid seasonal variations in vitamin D levels.

RESULTS

Serum 25-OHD levels were significantly lower in psoriatic patients than in control subjects even after adjusting for confounding factors in a multivariate analysis (odds ratio 2.89, 95% confidence interval 1.02-7.64, P < .03 for vitamin D insufficiency). Low 25-OHD levels were negatively associated with C-reactive protein (inflammatory activation marker) and body mass index in multiple linear regression analysis. Psoriatic patients with body mass index greater than or equal to 27 kg/m(2) had a higher risk of 25-OHD insufficiency (sensitivity of 82.3% and specificity of 51.7%).

LIMITATIONS

Further studies with larger numbers of patients are required to analyze the pathogenic mechanisms underlying the relationship between 25-OHD deficiency and psoriasis.

CONCLUSIONS

The 25-OHD values are significantly lower in psoriatic patients than in control subjects. Low 25-OHD levels are negatively associated with C-reactive protein, an inflammatory activation marker, and with obesity. Psoriatic patients with a body mass index of 27 or more are likely to have vitamin D insufficiency.

Multiple sclerosis: long time modifications of seasonal differences in the frequency of clinical attacks

Previous papers show different patterns of seasonal distribution of multiple sclerosis attacks. This paper compares long-time modifications. Salerno MS registry (Southern Italy), was reviewed, including 189 patients, age onset 12-51 years (mean = 29.88, SD = 8.4), disease duration mean = 6.94 years (1-29), attacks mean = 4.5 (2-25, SD = 3.41). Data were stratified by decades. Number of events/month was analyzed by odds ratios and forecast modeling (ARIMA); means by ANOVA and post hoc tests, and correlations by multiple regression. We found 869 relapses: J = 72, F = 48, M = 122, A = 75, M = 68, Jn = 59, Jl = 81, A = 74, S = 63, O = 70, N = 72, D = 65. In 2001-2008 there was one significant peak (March); in 1991-2000 many (greatest = July), and in 1984-1990, one positive (June), one negative (April). Differences between 1990s and 2000s are significant. It is the first study addressing ultradecennal trends, and finding that the season distribution of MS attacks is significantly different: the study confirms frequency peaks in early spring and summer, but they are different in different decades. This significant ultra-decade difference might support hypotheses more linked to infections or toxic substances than to sunlight, UV, or similar.

Beta-interferon protects multiple sclerosis patients against enhanced susceptibility to infections caused by poor air quality

BACKGROUND

The monthly multiple sclerosis relapse rate was studied from January 1995 to March 2001 from hospital records in Southwestern Finland as a retrospective open-label study.

METHODS

The relapse rates of beta-interferon users and nonusers were compared to ambient air inhalable particle levels and viral infections in the population with logistic regression.

RESULTS

In the non-user group, relapses were more frequent 1 month following the episodes when PM(10) was in the highest quartile [logistic regression odds ratio = 1.196 (95% CI = 1.019-1.404), p = 0.028] and following adenovirus epidemics in the general population [logistic regression odds ratio = 2.234 (95% CI = 1.013-4.926), p = 0.046]. PM(10) and virus infections had no significant effects in interferon users.

CONCLUSION

In addition to being antiviral, interferon also protected multiple sclerosis patients against an enhanced susceptibility to infections caused by PM(10).

Relationship of movements and behaviors to Group A Streptococcus infections in elementary school children

BACKGROUND

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus (PANDAS) research is based on the hypothesis that infections trigger changes in behavior and movement in children.

METHODS

We enrolled 693 children (ages 3 to 12 years) into a systematic, longitudinal study. Data were collected monthly for 8 months (October-May) to determine point prevalence of Group A Streptococcal (GAS) infections, tics, behavior, and choreiform movements. Simultaneous throat cultures were obtained, and relational analyses were made between GAS and movement/observation ratings.

RESULTS

Combined behavior/GAS associations (concurrent with or 3 subsequent months to GAS) revealed a strong relationship, relative risk (RR) of 1.71 (p < .0001). Detailed analysis revealed that balance/swaying and non-tic grimacing were responsible for a significant proportion of this association (RR = 2.92, p < .0001). A strong seasonal pattern was found, with fall being more significant for GAS infections and observation ratings (p < .0001) compared with winter/spring. Children with repeated streptococcus (n = 64) showed higher rates of behavior and distal choreiform observations (p = .005).

CONCLUSIONS

Motor/behavior changes were noted to occur in relationship to positive GAS culture with support that repeated GAS increases risk.

Does the Season or Month of Birth Influence Disease Progression in Multiple Sclerosis?

We investigated the influence of season and birth month on sustained progression to Expanded Disability Status Scale 6 (requires a cane) through a database review of 2,319 definite multiple sclerosis (MS) patients followed for a mean 19.3 years, until July 2003 in British Columbia, Canada. The season of birth had a marginal effect on disease progression (p = 0.051), with winter babies exhibiting the slowest progression (p = 0.048). Birth month had a significant effect on progression (p = 0.038), mainly due to those January born having a 40% (95% CI 32.9-47.4) chance of requiring a cane later than those born in other months. There was some evidence to suggest that the gestational period had a small but long-lasting effect on later disease progression in British Columbia, Canada.

Mounting evidence for vitamin D as an environmental factor affecting autoimmune disease prevalence

Low vitamin D status has been implicated in the etiology of autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, insulin-dependent diabetes mellitus, and inflammatory bowel disease. The optimal level of vitamin D intake required to support optimal immune function is not known but is likely to be at least that required for healthy bones. Experimentally, vitamin D deficiency results in the increased incidence of autoimmune disease. Mechanistically, the data point to a role for vitamin D in the development of self-tolerance. The vitamin D hormone (1,25-dihydroxy vitamin D(3)) regulates T helper cell (Th1) and dendritic cell function while inducing regulatory T-cell function. The net result is a decrease in the Th1-driven autoimmune response and decreased severity of symptoms. This review discusses the accumulating evidence pointing to a link between vitamin D and autoimmunity. Increased vitamin D intakes might decrease the incidence and severity of autoimmune diseases and the rate of bone fracture.

Gender, age, and season at immunization uniquely influence the genetic control of susceptibility to histopathological lesions and clinical signs of experimental allergic encephalomyelitis: implications for the genetics of multiple sclerosis

Multiple sclerosis (MS), the principal inflammatory demyelinating disease of the central nervous system (CNS), is believed to have an immunopathological etiology arising from gene-environment interactions. In this study, we examined the effect of sex, age, and season at immunization on the susceptibility of (B10.S x SJL/J) F(2) intercross mice to experimental allergic encephalomyelitis (EAE), the foremost animal model of MS. Results of logistic regression analyses suggest that female mice were more likely to exhibit CNS lesions than male mice [odds ratio (OR) = 2.28 for brain lesions; OR = 2.37 for spinal cord (SC) lesions]. Although statistically significant associations were seen between brain and SC lesions and age at the time of injection or month of injection when examined separately; these associations disappeared when controlling for sex in multiple logistic regression analyses. These results suggest that the sex of the mouse is more important in influencing the development of brain and SC lesions than was either age or month of immunization. When examining clinical disease as the endpoint, the OR for the age at immunization is 1.04, indicating that the odds of being affected increase by 4% for each increasing week of age. When controlled for age, the OR for injection in the summer months (July through September) is 1.90, suggesting that the odds of being clinically affected are 90% greater for F(2) intercross animals injected in the summercompared to those injected in the winter to spring months (February through May). In contrast to CNS lesions, the age and season at immunization significantly and independently influenced susceptibility to clinical EAE and did so equally in both males and females. Linkage analysis to eae5, the H2-linked locus controlling susceptibility to clinical disease, was performed using 6- to 12- and >12-week-old cohorts as well as summer and winter/spring cohorts of F(2) mice. Significant linkage of clinical EAE to eae5 was observed with the 6- to 12-week-old and summer populations. In contrast, linkage of clinical EAE to eae5 was not detected with the >12-week-old and winter/spring populations. These results indicate that age and seasonal effects are capable of overriding eae5-dependent genetic control of susceptibility to clinical EAE and have significant implications for the genetics of MS.

Remitting form of hemicrania continua with seasonal pattern

Hemicrania continua is a primary headache syndrome characterized by a continuous, unilateral headache that is completely responsive to indomethacin. Hemicrania continua exists in continuous and remitting forms. Ten cases of the remitting form have been reported, none of which have had a seasonal pattern. We report a patient with remitting hemicrania continua with a clear seasonal predilection.

Seasonal patterns in optic neuritis and multiple sclerosis: a meta-analysis

To quantify and characterize seasonal variation in monosymptomatic optic neuritis (MON) onsets, multiple sclerosis (MS) onsets and MS exacerbations (MSE), a meta-analysis was performed, using established methods and pooling weighted information obtained from nine reports on MON, six reports on MS onsets and nine reports on MSE, which fulfilled specific criteria for report quality and data homogeneity. The results suggested that MON, MS onsets and MSE in the Northern hemisphere present a similar pattern with highest frequencies in spring and lowest in winter. These differences were highest for MS onsets, 45% with 95% CI 36-55%, and lowest for MSE, 10% with 95% CI 7-13%, statistically significant and robust, insensitive to an alternative seasonal definition, not unduly influenced by any single primary study, and supported by fail-safe N calculations. Random variation, misclassification and publication bias were less likely to account for the reported generalized seasonal patterns.

Absence of seasonal variation in Graves disease

PURPOSE

To determine whether there is an identifiable pattern of seasonal variation in the onset of symptoms of orbitopathy and thyrotoxicosis in patients with Graves disease.

METHODS

This retrospective, noncomparative case series reviewed 305 randomly selected office records of patients referred to one author (M.K.) for evaluation of Graves orbitopathy between July 1990 and June 1998. All patients met inclusion criteria for the diagnosis of Graves orbitopathy. During initial evaluation for orbitopathy, patients identified the date of onset of orbital symptoms as well as the earliest date of either onset of thyroid symptoms or documented thyroid abnormality. Patients were excluded from analysis of seasonal variation if they could not recall the month of symptom onset or were euthyroid. The onset of orbital symptoms and identification of dysthyroid state were analyzed by calendar month and season. The chronological relationship of the development of orbital and thyroid symptoms was evaluated.

RESULTS

No significant seasonal variation appeared in the onset of orbital symptoms or identification of dysthyroidism. Out of 148 patients, 115 (78%) developed symptoms of orbital disease within 18 months of the identification of dysthyroidism. The most common presenting orbital symptoms were swelling of the lid or prominence of the globe.

CONCLUSIONS

This study fails to provide evidence for a seasonal influence on the incidence of Graves disease and the associated orbitopathy.

Spinal fluid lymphocytes from a subgroup of multiple sclerosis patients respond to mycobacterial antigens

Immune responses to heat shock or stress proteins are observed in several chronic autoimmune diseases. Such proteins are major antigens of many bacteria, especially mycobacteria. To determine whether immune responses to stress proteins occur in chronic inflammatory diseases of the central nervous system such as multiple sclerosis (MS) we measured proliferative responses of lymphocytes from spinal fluids and bloods of patients with MS and other neurological diseases to a sonicate of M. tuberculosis, an acetone extract of M. tuberculosis, a recombinant 65-kd heat shock protein of M. leprae, and tetanus toxoid as a control recall antigen. Significantly increased spinal fluid lymphocyte responses to mycobacterial sonicate, relative to responses from paired peripheral blood lymphocytes, were present in 14 of 20 specimens from patients with MS (p < 0.025) and 2 of 9 specimens from patients with other neurological diseases. Spinal fluid lymphocytes also responded to tetanus toxoid, but differences between blood and spinal fluid were not statistically significant. Lymphocytes from 1 patient with MS responded only to M. leprae. There were no proliferative responses to the M. tuberculosis acetone extract. When patients with MS were classified according to duration of disease (< 2- or > 2-yr duration) 9 of 10 patients with recent onset had cerebrospinal fluid cells that responded to M. tuberculosis compared with 5 of 10 with longer duration symptoms (p < 0.012). Our data suggest a selective recruitment and/or expansion of mycobacterial reactive cells to the central nervous system of a subpopulation of patients with MS.(ABSTRACT TRUNCATED AT 250 WORDS)