Examining the environmental risk factors of progressive-onset and relapsing-onset multiple sclerosis: recruitment challenges, potential bias, and statistical strategies.

It is unknown whether the currently known risk factors of multiple sclerosis reflect the etiology of progressive-onset multiple sclerosis (POMS) as observational studies rarely included analysis by type of onset. We designed a case-control study to examine associations between environmental factors and POMS and compared effect sizes to relapse-onset MS (ROMS), which will offer insights into the etiology of POMS and potentially contribute to prevention and intervention practice. This study utilizes data from the Primary Progressive Multiple Sclerosis (PPMS) Study and the Australian Multi-center Study of Environment and Immune Function (the AusImmune Study). This report outlines the conduct of the PPMS Study, whether the POMS sample is representative, and the planned analysis methods. The study includes 155 POMS, 204 ROMS, and 558 controls. The distributions of the POMS were largely similar to Australian POMS patients in the MSBase Study, with 54.8% female, 85.8% POMS born before 1970, mean age of onset of 41.44 ± 8.38 years old, and 67.1% living between 28.9 and 39.4° S. The POMS were representative of the Australian POMS population. There are some differences between POMS and ROMS/controls (mean age at interview: POMS 55 years vs. controls 40 years; sex: POMS 53% female vs. controls 78% female; location of residence: 14.3% of POMS at a latitude ≤ 28.9°S vs. 32.8% in controls), which will be taken into account in the analysis. We discuss the methodological issues considered in the study design, including prevalence-incidence bias, cohort effects, interview bias and recall bias, and present strategies to account for it. Associations between exposures of interest and POMS/ROMS will be presented in subsequent publications.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease Presenting as Intracranial Hypertension: A Case Report.

The production of autoantibodies against myelin oligodendrocyte glycoprotein (MOG) can cause a spectrum of autoimmune disorders, including optic neuritis, transverse myelitis, brainstem encephalitis, and acute disseminated encephalomyelitis. In this study, we present the case of a 19-year-old woman with an unusual clinical presentation of intracranial hypertension (IH) and bilateral papilledema. The patient presented with symptoms of increased intracranial pressure, which followed a relapsing, remitting course over several months. Serial CSF studies showed an increased opening pressure during clinical relapses. The CSF and serum tested positive for MOG immunoglobulin G antibodies. Contrast-enhanced MRI of the brain showed mild meningeal enhancement in the left parietal region with subtle underlying cortical hyperintensities, indicating possible fluid-attenuated inversion recovery variable unilateral enhancement of the leptomeninges. The patient responded well to immunosuppressive therapy using rituximab. The presentation of MOG antibody-associated disease (MOGAD) as IH without optic neuritis is rare. This report presents the first description of a relapsing remitting course presenting each time with only symptoms of raised intracranial pressure, without developing any typical clinical manifestations of MOGAD.

Seronegative Autoimmune Limbic Encephalitis: A Case Report.

Autoimmune encephalitis (AE) is an immune-mediated disorder of the central nervous system (CNS). Its definitive diagnosis relies on the identification of a specific antibody. Autoimmune limbic encephalitis (LE) is a subset of AE characterized by inflammation of the limbic cerebral cortex. Cognitive decline, behavioral disturbance, and seizures are its cardinal manifestations. We present the case of a 70-year-old man with subacute progressive gait imbalance, cognitive impairment, and psychiatric manifestations. Extensive serum and cerebrospinal fluid (CSF) investigations did not reveal any abnormality. Autoimmune and paraneoplastic encephalitis antibody panels were negative. Magnetic resonance imaging (MRI) and positron emission tomography (PET) brain scans suggested LE. He responded well to immunotherapy. This case illustrates that AE must be suspected in the appropriate setting, even in the absence of a specific antibody. These patients should be given the benefit of early immunotherapy.

A real world multi center study on efficacy and safety of natalizumab in Indian patients with multiple sclerosis.

BACKGROUND: Natalizumab (NTZ) is increasingly being used in Indian multiple sclerosis (MS) patients. There are no reports on its safety and efficacy, especially with respect to the occurrence of progressive multifocal leukoencephalopathy (PML). OBJECTIVES: To describe the patient characteristics, treatment outcomes, and adverse events, especially the occurrence of PML in NTZ-treated patients. METHODS: A multicentre ambispective study was conducted across 18 centres, from Jan 2012 to Dec 2021. Patients at and above the age of 18 years treated with NTZ were included. Descriptive and comparative statistics were applied to analyze data. RESULTS: During the study period of 9 years, 116 patients were treated with NTZ. Mean age of the cohort was 35.6 ± 9.7 years; 83/116 (71.6%) were females. Relapse rate for the entire cohort in the year before NTZ was 3.1 ± 1.51 while one year after was 0.20±0.57 (p = 0.001; CI 2.45 -3.35). EDSS of the entire cohort in the year before NTZ was 4.5 ± 1.94 and one year after was 3.8 ± 2.7 (p = 0.013; CI 0.16-1.36). At last follow up (38.3 ± 22.78 months) there were no cases of PML identified. CONCLUSIONS: Natalizumab is highly effective and safe in Indian MS patients, with no cases of PML identified at last follow up.

Efficacy and Safety of Rituximab in Central Nervous System Demyelinating Disorders.

BACKGROUND: Rituximab, an anti-CD20 monoclonal antibody, has been used worldwide as an off-label therapy in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). OBJECTIVE: The aim of the present study was to evaluate the efficacy and safety of rituximab in central nervous system demyelinating disorders in the Indian context. METHODS: We conducted a retrospective analysis of patients with MS, NMOSD, and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) who were treated with rituximab at a single tertiary care centre in Mumbai. RESULTS: The study enrolled 102 patients (61 MS, 37 NMOSD and 4 MOGAD) from June 2008 to January 2020. Following rituximab therapy, 96.7% of MS, 67% of NMOSD, and 50% of MOGAD patients were free of relapses. The mean annualized relapse rate reduced from 2.17 to 0 for patients with relapsing remitting MS (RRMS), from 0.8 to 0 for secondary progressive MS (SPMS), from 2.5 to 0.14 for NMOSD, and from 3.43 to 1.04 for MOGAD. The median expanded disability status scale improved significantly in RRMS patients, worsened non-significantly in the SPMS group, and remained unchanged in NMOSD and MOGAD patients. On follow-up magnetic resonance imaging, there was a significant reduction in the number of MS patients developing new contrast enhancing lesions or new T2 lesions. Adverse events (infusion reactions or severe infections) occurred in 12 patients. CONCLUSION: Rituximab is effective and safe in Indian patients with MS and NMOSD.

Consensus Statement On Immune Modulation in Multiple Sclerosis and Related Disorders During the COVID-19 Pandemic: Expert Group on Behalf of the Indian Academy of Neurology.

Knowledge related to SARS-CoV-2 or 2019 novel coronavirus (2019-nCoV) is still emerging and rapidly evolving. We know little about the effects of this novel coronavirus on various body systems and its behaviour among patients with underlying neurological conditions, especially those on immunomodulatory medications. The aim of the present consensus expert opinion document is to appraise the potential concerns when managing our patients with underlying CNS autoimmune demyelinating disorders during the current COVID-19 pandemic.

Clinical and therapeutic predictors of disease outcomes in AQP4-IgG+ neuromyelitis optica spectrum disorder.

BACKGROUND: Aquaporin-4-IgG positive (AQP4-IgG+) Neuromyelitis Optica Spectrum Disorder (NMOSD) is an uncommon central nervous system autoimmune disorder. Disease outcomes in AQP4-IgG+NMOSD are typically measured by relapse rate and disability. Using the MSBase, a multi-centre international registry, we aimed to examine the impact immunosuppressive therapies and patient characteristics as predictors of disease outcome measures in AQP4-IgG+NMOSD. METHOD: This MSBase cohort study of AQP4-IgG+NMOSD patients examined modifiers of relapse in a multivariable proportional hazards model and expanded disability status score (EDSS) using a mixed effects model. RESULTS: 206 AQP4-IgG+ patients were included (median follow-up 3.7 years). Age (hazard ratio [HR] = 0.82 per decade, p = 0.001), brainstem onset (HR = 0.45, p = 0.009), azathioprine (HR = 0.46, p<0.001) and mycophenolate mofetil (HR = 0.09, p = 0.012) were associated with a reduced risk of relapse. A greater EDSS was associated with age (ß = 0.45 (per decade), p<0.001) and disease duration (ß = 0.07 per year, p<0.001). A slower increase in EDSS was associated with azathioprine (ß = -0.48, p<0.001), mycophenolate mofetil (ß = -0.69, p = 0.04) and rituximab (ß = -0.35, p = 0.024). INTERPRETATION: This study has demonstrated that azathioprine and mycophenolate mofetil reduce the risk of relapses and disability progression is modified by azathioprine, mycophenolate mofetil and rituximab. Age and disease duration were the only patient characteristics that modified the risk of relapse and disability in our cohort.

Long-term disability trajectories in primary progressive MS patients: A latent class growth analysis.

BACKGROUND: Several natural history studies on primary progressive multiple sclerosis (PPMS) patients detected a consistent heterogeneity in the rate of disability accumulation. OBJECTIVES: To identify subgroups of PPMS patients with similar longitudinal trajectories of Expanded Disability Status Scale (EDSS) over time. METHODS: All PPMS patients collected within the MSBase registry, who had their first EDSS assessment within 5 years from onset, were included in the analysis. Longitudinal EDSS scores were modeled by a latent class mixed model (LCMM), using a nonlinear function of time from onset. LCMM is an advanced statistical approach that models heterogeneity between patients by classifying them into unobserved groups showing similar characteristics. RESULTS: A total of 853 PPMS (51.7% females) from 24 countries with a mean age at onset of 42.4 years (standard deviation (SD): 10.8 years), a median baseline EDSS of 4 (interquartile range (IQR): 2.5-5.5), and 2.4 years of disease duration (SD: 1.5 years) were included. LCMM detected three different subgroups of patients with a mild ( n = 143; 16.8%), moderate ( n = 378; 44.3%), or severe ( n = 332; 38.9%) disability trajectory. The probability of reaching EDSS 6 at 10 years was 0%, 46.4%, and 81.9% respectively. CONCLUSION: Applying an LCMM modeling approach to long-term EDSS data, it is possible to identify groups of PPMS patients with different prognosis.

Rituximab in Neuromyelitis Optica Spectrum Disorders: Our Experience.

BACKGROUND: Neuromyelitis optica (NMO) is an inflammatory demyelinating central nervous system disease, with recurrent attacks of severe bilateral optic neuritis and longitudinally extensive transverse myelitis. Aggressive immunosuppression is essential to prevent clinical relapses and permanent disability. Rituximab, a monoclonal antibody to CD20, has been found effective in several reports and small uncontrolled studies. There is a paucity of data regarding its use in Indian patients. OBJECTIVES: The aim of this study was to report the results of rituximab treatment in NMO spectrum disorders (NMOSDs) in the Indian scenario. METHODS: This study is a retrospective, observational study including 13 NMOSD patients treated with rituximab. After initial therapy in the acute episode with IV methylprednisolone and if needed plasma exchange, therapy was initiated as a cycle of intravenous rituximab, two doses 2 weeks apart of 1 g each. Subsequent cycles were advised at intervals of every 6 months. The primary outcome measure was annualized relapse rate (ARR), defined as a number of clinical attacks per year. Clinical adverse events were recorded throughout the study. RESULTS: In the study, mean ARR reduced from 2.61 to 0.09 after therapy (P = 0.000685). Of 13 patients, 8 (61.54%) were completely relapse free after starting treatment with rituximab. Treatment was well tolerated and no serious adverse events were noted. CONCLUSIONS: The treatment of NMOSDs with rituximab in Indian patients reduces the frequency of relapses and is well tolerated.

Contribution of different relapse phenotypes to disability in multiple sclerosis.

OBJECTIVE: This study evaluated the effect of relapse phenotype on disability accumulation in multiple sclerosis. METHODS: Analysis of prospectively collected data was conducted in 19,504 patients with relapse-onset multiple sclerosis and minimum 1-year prospective follow-up from the MSBase cohort study. Multivariable linear regression models assessed associations between relapse incidence, phenotype and changes in disability (quantified with Expanded Disability Status Scale and its Functional System scores). Sensitivity analyses were conducted. RESULTS: In 34,858 relapses recorded during 136,462 patient-years (median follow-up 5.9 years), higher relapse incidence was associated with greater disability accumulation (ß = 0.16, p < 0.001). Relapses of all phenotypes promoted disability accumulation, with the most pronounced increase associated with pyramidal (ß = 0.27 (0.25-0.29)), cerebellar (ß = 0.35 (0.30-0.39)) and bowel/bladder (ß = 0.42 (0.35-0.49)) phenotypes (mean (95% confidence interval)). Higher incidence of each relapse phenotype was associated with an increase in disability in the corresponding neurological domain, as well as anatomically related domains. CONCLUSION: Relapses are associated with accumulation of neurological disability. Relapses in pyramidal, cerebellar and bowel/bladder systems have the greatest association with disability change. Therefore, prevention of these relapses is an important objective of disease-modifying therapy. The differential impact of relapse phenotypes on disability outcomes could influence management of treatment failure in multiple sclerosis.

Higher latitude is significantly associated with an earlier age of disease onset in multiple sclerosis.

BACKGROUND: Age at onset (AAO) in multiple sclerosis (MS) is an important marker of disease severity and may have prognostic significance. Understanding what factors can influence AAO may shed light on the aetiology of this complex disease, and have applications in the diagnostic process. METHODS: The study cohort of 22 162 eligible patients from 21 countries was extracted from the MSBase registry. Only patients with MS aged ≥16 years were included. To reduce heterogeneity, only centres of largely European descent were included for analysis. AAO was defined as the year of the first symptom suggestive of inflammatory central nervous system demyelination. Predictors of AAO were evaluated by linear regression. RESULTS: Compared with those living in lower latitudes (19.0-39.9°), onset of symptoms was 1.9 years earlier for those at higher latitudes (50.0-56.0°) (p=3.83×10-23). A reciprocal relationship was seen for ambient ultraviolet radiation (UVR), with a significantly increasing AAO for patients with MS per each quartile increment of ambient UVR (p=1.56×10-17). We found that the AAO of female patients was ∼5 months earlier than male patients (p=0.002). AAO of progressive-onset patients with MS were ∼9 years later than relapsing-onset patients (p=1.40×10-265). CONCLUSIONS: An earlier AAO in higher latitude regions was found in this worldwide European-descent cohort and correlated inversely with variation in latitudinal UVR. These results suggest that environmental factors which act at the population level may significantly influence disease severity characteristics in genetically susceptible populations.

HLA associations in South Asian multiple sclerosis.

BACKGROUND: Previous efforts to identify Human Leukocyte Antigen (HLA) gene associations with multiple sclerosis (MS) in the South Asian population have been underpowered. AIM: To identify the primary HLA class II alleles associated with MS in Indians. METHODS: We typed HLA-DRB1, -DQA1 and -DQB1 in 419 patients and 451 unrelated controls by polymerase chain reaction using sequence specific oligonucleotide probes (PCR-SSOP). RESULTS: At the gene level DRB1 showed significant evidence of association (p=0.0000012), DQA1 showed only marginal evidence of association (p=0.04) and there was no evidence for association at DQB1 (p=0.26). At the DRB1 locus association is confirmed with the *15:01 (p=0.00002) and the *03 (p=0.00005) alleles. CONCLUSION: Our study confirms that the risk effects attributable to the HLA- DRB1*15:01and DRB1*03 alleles seen in Europeans are also seen in Indians. The absence of any evidence of association with DQB1 alleles reflects the lower linkage disequilibrium between DQB1 alleles and DRB1 risk alleles present in this population, and illustrates the potential value of fine mapping signals of association in different ethnic groups.

Multiple sclerosis in India: An overview.

Multiple sclerosis (MS) is being increasingly diagnosed in India mainly due to increase in the number of practicing neurologists and easy and affordable availability of magnetic resonance imaging (MRI). The clinical features and course are largely similar to those seen in the West. The term optico-spinal MS (Asian MS) was coined in the pre-MRI days. Many such patients turn out to be cases of neuromyelitis optica - a distinct disorder and not a variant of MS. Others have shown the classical features of MS on MRI scan. Several of the disease-modifying agents, not all, are now available in India. Their use, however, has been limited in view of the high cost.

A clinical and radiological profile of neuromyelitis optica and spectrum disorders in an Indian cohort.

BACKGROUND: There is insufficient data on the clinical and radiological features of neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD) from India. OBJECTIVE: The objective of the following study is to examine the clinico-radiological features of NMO and NMOSD in an Indian cohort. MATERIALS AND METHODS: This retrospective study included 44 consecutive patients who (1) satisfied the 2006 Wingerchuk criteria for NMO (16 seropositive and 7 seronegative); or (2) had isolated or recurrent optic neuritis (ON) with seropositivity (n = 4); or (3) had isolated or recurrent myelitis with seropositivity (n = 17). RESULTS: The female:male ratio was 7.8:1 with median age of onset 26.5 (range 8-72). Annualized relapse rate (ARR) was comparable across all groups (F [3, 40] = 0.938 and P = 0.431). Various presentations other than ON and myelitis were noted. All 40 patients with myelitis had spinal cord lesions involving ≥3 vertebral segments during the course of the disease. Cervicomedullary involvement was seen in 32.5% (13/40) patients. Brain magnetic resonance imaging was available for 40 patients; eight of these (20%) had brain lesions in locations described in multiple sclerosis (MS), 27.5% (11/40) had lesions at sites unusual for MS and 52.5% (21/40) had normal brain imaging. CONCLUSION: NMO and NMOSD patients in this cohort have comparable ARR regardless of clinical presentation, supporting the emerging trend of treating all patients with immunotherapeutic agents at an early stage. Varied presentations seen in NMO and NMOSD highlight the need for a high index of suspicion for NMO in demyelinating episodes not classical for MS.

Risk of relapse phenotype recurrence in multiple sclerosis.

OBJECTIVES: The aim was to analyse risk of relapse phenotype recurrence in multiple sclerosis and to characterise the effect of demographic and clinical features on this phenotype. METHODS: Information about relapses was collected using MSBase, an international observational registry. Associations between relapse phenotypes and history of similar relapses or patient characteristics were tested with multivariable logistic regression models. Tendency of relapse phenotypes to recur sequentially was assessed with principal component analysis. RESULTS: Among 14,969 eligible patients (89,949 patient-years), 49,279 phenotypically characterised relapses were recorded. Visual and brainstem relapses occurred more frequently in early disease and in younger patients. Sensory relapses were more frequent in early or non-progressive disease. Pyramidal, sphincter and cerebellar relapses were more common in older patients and in progressive disease. Women presented more often with sensory or visual symptoms. Men were more prone to pyramidal, brainstem and cerebellar relapses. Importantly, relapse phenotype was predicted by the phenotypes of previous relapses. (OR = 1.8-5, p = 10(-14)). Sensory, visual and brainstem relapses showed better recovery than other relapse phenotypes. Relapse severity increased and the ability to recover decreased with age or more advanced disease. CONCLUSION: Relapse phenotype was associated with demographic and clinical characteristics, with phenotypic recurrence significantly more common than expected by chance.

Sex as a determinant of relapse incidence and progressive course of multiple sclerosis.

The aim of this work was to evaluate sex differences in the incidence of multiple sclerosis relapses; assess the relationship between sex and primary progressive disease course; and compare effects of age and disease duration on relapse incidence. Annualized relapse rates were calculated using the MSBase registry. Patients with incomplete data or <1 year of follow-up were excluded. Patients with primary progressive multiple sclerosis were only included in the sex ratio analysis. Relapse incidences over 40 years of multiple sclerosis or 70 years of age were compared between females and males with Andersen-Gill and Tweedie models. Female-to-male ratios stratified by annual relapse count were evaluated across disease duration and patient age and compared between relapse-onset and primary progressive multiple sclerosis. The study cohort consisted of 11 570 eligible patients with relapse-onset and 881 patients with primary progressive multiple sclerosis. Among the relapse-onset patients (82 552 patient-years), 48,362 relapses were recorded. Relapse frequency was 17.7% higher in females compared with males. Within the initial 5 years, the female-to-male ratio increased from 2.3:1 to 3.3:1 in patients with 0 versus ≥4 relapses per year, respectively. The magnitude of this sex effect increased at longer disease duration and older age (P < 10(-12)). However, the female-to-male ratio in patients with relapse-onset multiple sclerosis and zero relapses in any given year was double that of the patients with primary progressive multiple sclerosis. Patient age was a more important determinant of decline in relapse incidence than disease duration (P < 10(-12)). Females are predisposed to higher relapse activity than males. However, this difference does not explain the markedly lower female-to-male sex ratio in primary progressive multiple sclerosis. Decline in relapse activity over time is more closely related to patient age than disease duration.

Neuromyelitis optica-IgG testing in an Indian cohort with neuromyelitis optica and related demyelinating disorders: Our experience.

BACKGROUND: Neuromyelitis optica (NMO) is an immune-mediated inflammatory demyelinating disorder of the central nervous system with a predilection for the optic nerves and the spinal cord. Immunopathological evidence suggests that the target antigen of the disease is aquaporin-4. An IgG antibody against this protein has been explored as a molecular marker for the disease and as a diagnostic tool due to its high sensitivity and specificity in various populations. OBJECTIVE: To assess the value of NMO-IgG testing in Indian patients with clinical and magnetic resonance imaging features consistent with NMO and longitudinally extensive transverse myelitis (LETM). MATERIALS AND METHODS: Forty-five patients with clinical and magnetic resonance imaging features consistent with NMO, LETM, and MS were tested for serum NMO-IgG. Of these patients, 22 patients satisfied revised (2006) Wingerchuk criteria for NMO (excluding NMO-IgG status) and 11 patients had LETM. Twelve patients satisfied the revised (2010) McDonald criteria for multiple sclerosis (MS). RESULTS: Of the 21 patients, satisfying the criteria for NMO and for whom the test results were available, 17 were positive for NMO-IgG (80.9%), and of the 11 patients having LETM, 6 (54.5%) were positive for NMO-IgG. In one patient with NMO, the test result was not available. None of the 12 patients satisfying McDonald criteria for MS showed NMO-IgG seropositivity. CONCLUSION: Our study suggests that it is worthwhile to pursue NMO-IgG testing as a diagnostic tool for patients with clinical and Magnetic Resonance Imaging (MRI) features consistent with NMO and LETM in the Indian population.

Persistence on therapy and propensity matched outcome comparison of two subcutaneous interferon beta 1a dosages for multiple sclerosis.

OBJECTIVES: To compare treatment persistence between two dosages of interferon ß-1a in a large observational multiple sclerosis registry and assess disease outcomes of first line MS treatment at these dosages using propensity scoring to adjust for baseline imbalance in disease characteristics. METHODS: Treatment discontinuations were evaluated in all patients within the MSBase registry who commenced interferon ß-1a SC thrice weekly (n = 4678). Furthermore, we assessed 2-year clinical outcomes in 1220 patients treated with interferon ß-1a in either dosage (22 µg or 44 µg) as their first disease modifying agent, matched on propensity score calculated from pre-treatment demographic and clinical variables. A subgroup analysis was performed on 456 matched patients who also had baseline MRI variables recorded. RESULTS: Overall, 4054 treatment discontinuations were recorded in 3059 patients. The patients receiving the lower interferon dosage were more likely to discontinue treatment than those with the higher dosage (25% vs. 20% annual probability of discontinuation, respectively). This was seen in discontinuations with reasons recorded as "lack of efficacy" (3.3% vs. 1.7%), "scheduled stop" (2.2% vs. 1.3%) or without the reason recorded (16.7% vs. 13.3% annual discontinuation rate, 22 µg vs. 44 µg dosage, respectively). Propensity score was determined by treating centre and disability (score without MRI parameters) or centre, sex and number of contrast-enhancing lesions (score including MRI parameters). No differences in clinical outcomes at two years (relapse rate, time relapse-free and disability) were observed between the matched patients treated with either of the interferon dosages. CONCLUSIONS: Treatment discontinuations were more common in interferon ß-1a 22 µg SC thrice weekly. However, 2-year clinical outcomes did not differ between patients receiving the different dosages, thus replicating in a registry dataset derived from "real-world" database the results of the pivotal randomised trial. Propensity score matching effectively minimised baseline covariate imbalance between two directly compared sub-populations from a large observational registry.

Association of Epstein-Barr virus infection with multiple sclerosis in India.

OBJECTIVES: Epstein-Barr virus (EBV) seroprevalence is high from early childhood in Indian populations, though multiple sclerosis (MS) is uncommon. The present study aims to evaluate the association of EBV infection with MS in Indian patients. METHOD: In this study 140 MS patients and equal number of matched controls were included. Estimation of serum Immunoglobin G (IgG) for EBV Nuclear antigen 1 (EBNA1), viral capsid antigen (EBV-VCA) and early antigen (EB-EA) were obtained by quantitative enzyme linked immunosorbent assay (ELISA). Patients and controls were genotyped for the human leukocyte antigen (HLA) DRB1*1501 allele. RESULTS: A modest difference was observed for EBNA1 (p=0.02) and EBV-VCA (p=0.03) titres in MS patients as compared to healthy controls. There was no association between EBNA1 titres and MS. High EBNA1 titre (>99.75U/l) was significantly associated with HLA DRBI*15:01 (OR=4.92. CI=1.07-22.57) status in MS patients but not in healthy controls (OR=1.19, CI=0.53-2.63). CONCLUSION: Evidence for a strong association with remote EBV infection was lacking in this study of Indian patients with MS. Patients who are carriers of HLA DR15 allele may have high EBNA1 titres. These preliminary results need to be reproduced in an independent and larger dataset.