Prevalence and disease disability in immigrants with multiple sclerosis in Malmö, southern Sweden.

BACKGROUND: Multiple sclerosis (MS) is the most common chronic demyelinating disease of the central nervous system and the major non-traumatic cause of permanent disability in young adults. Several migration studies have been performed over the years suggesting a pattern of higher disease disability in certain ethnic groups. To our knowledge, differences in disease progression in immigrants have not been studied in Sweden before. Thus, the aims of our study were to estimate the prevalence of multiple sclerosis among first-generation immigrants in the City of Malmö and to compare differences in disease severity with the native population. METHODS: All persons with multiple sclerosis living in Malmö on prevalence day 31 Dec 2010 were included. Cases were classified according to the country of birth into Scandinavians, Western and non-Western. RESULTS: The crude prevalence was 100/100,000 (95% CI, 80-124) among first-generation immigrants, 154/100,000 (95% CI, 137-173) among individuals with Scandinavian background, 123/100,000 (95% CI, 94-162) in the Western group and 76/100,000 (95% CI, 53-108) in the non-Western group. The mean Multiple Sclerosis Severity Score (MSSS) value among Scandinavians was 4.2 (SD 3.5), whereas the figures in the immigrant group were 4.6 (SD 3.3) and 5.2 (SD 3.7) among Westerns respectively non-Westerns, which differences were not statistically significant. When adjusting for gender, age at onset and initial disease course, the mean MSSS difference between the non-Western and the Scandinavian individuals was 1.7 (95% CI 0.18-3.3, p = 0.030). There were no differences on time to diagnosis or the time from diagnosis to treatment initiation between the three groups. CONCLUSIONS: We found a lower prevalence among Western and non-Western first-generation immigrants compared to the Scandinavian population and a more severe disease in non-Western immigrants than in Scandinavians.

Human herpesvirus 6A and axonal injury before the clinical onset of multiple sclerosis.

Recent research indicates that multiple sclerosis is preceded by a prodromal phase with elevated levels of serum neurofilament light chain (sNfL), a marker of axonal injury. The effect of environmental risk factors on the extent of axonal injury during this prodrome is unknown. Human herpesvirus 6A (HHV-6A) is associated with an increased risk of developing multiple sclerosis. The objective of this study was to determine if HHV-6A serostatus is associated with the level of sNfL in the multiple sclerosis prodrome, which would support a causative role of HHV-6A. A nested case-control study was performed by crosslinking multiple sclerosis registries with Swedish biobanks. Individuals with biobank samples collected before the clinical onset of multiple sclerosis were included as cases. Controls without multiple sclerosis were randomly selected, matched for biobank, sex, sampling date and age. Serostatus of HHV-6A and Epstein-Barr virus was analysed with a bead-based multiplex assay. The concentration of sNfL was analysed with single molecule array technology. The association between HHV-6A serology and sNfL was assessed by stratified t-tests and linear regressions, adjusted for Epstein-Barr virus serostatus and sampling age. Within-pair ratios of HHV-6A seroreactivity and sNfL were calculated for each case and its matched control. To assess the temporal relationship between HHV-6A antibodies and sNfL, these ratios were plotted against the time to the clinical onset of multiple sclerosis and compared using locally estimated scatterplot smoothing regressions with 95% confidence intervals (CI). Samples from 519 matched case-control pairs were included. In cases, seropositivity of HHV-6A was significantly associated with the level of sNfL (+11%, 95% CI 0.2-24%, P = 0.045) and most pronounced in the younger half of the cases (+24%, 95% CI 6-45%, P = 0.007). No such associations were observed among the controls. Increasing seroreactivity against HHV-6A was detectable before the rise of sNfL (significant within-pair ratios from 13.6 years versus 6.6 years before the clinical onset of multiple sclerosis). In this study, we describe the association between HHV-6A antibodies and the degree of axonal injury in the multiple sclerosis prodrome. The findings indicate that elevated HHV-6A antibodies both precede and are associated with a higher degree of axonal injury, supporting the hypothesis that HHV-6A infection may contribute to multiple sclerosis development in a proportion of cases.

Systemic inflammation and risk of multiple sclerosis - A presymptomatic case-control study.

Background: C-reactive protein (CRP) is a marker of systemic inflammation. Increased levels of CRP in young persons have been suggested to decrease the risk of multiple sclerosis (MS). Objectives: To assess CRP as a risk factor for MS. Methods: Levels of CRP were measured with a high-sensitive immunoassay in biobank samples from 837 individuals who later developed MS and 984 matched controls. The risk of developing MS was analysed by conditional logistic regression on z-scored CRP values. Results: Levels of CRP were not associated with MS risk. Conclusions: We found no association between CRP levels and risk of MS development.

Axonal injury in asymptomatic individuals preceding onset of multiple sclerosis.

Axonal loss is the main cause of irreversible disability in multiple sclerosis (MS). Serum neurofilament light (sNfL) is a biomarker of axonal disintegration. In this nested case-control study, blood samples from 519 presymptomatic persons (age range 4-39 years) who later received an MS diagnosis showed higher sNfL concentrations than 519 matched controls (p < 0.0001), noticeable at least 10 years before clinical MS onset. Mean values for pre-MS and control groups were 9.6 pg/mL versus 7.4 pg/mL 0-5 years before onset, and 6.4 pg/mL versus 5.8 pg/mL 5-10 years before onset. These results support that axonal injury occurs early in MS pathogenesis.

Free vitamin D3 index and vitamin D-binding protein in multiple sclerosis: A presymptomatic case-control study.

BACKGROUND AND PURPOSE: High levels of 25-hydroxyvitamin D3 (25[OH]D3 ) are associated with a lower risk for multiple sclerosis (MS). The bioavailability of 25(OH)D3 is regulated by its main plasma carrier, vitamin D-binding protein (DBP). Free 25(OH)D3 can be estimated by also measuring DBP concentration. In addition, DBP has immunomodulatory functions that may independently affect MS pathogenesis. No previous studies have assessed free 25(OH)D3 or DBP in presymptomatically collected samples. This study was undertaken to assess free 25(OH)D3 and DBP as risk factors for MS. METHODS: A nested case-control study was performed with presymptomatic serum samples identified through cross-linkage of MS registries and Swedish biobanks. Concentration of 25(OH)D3 was measured with liquid chromatography and DBP levels with sandwich immunoassay. Free 25(OH)D3 was approximated as free vitamin D3 index: (25[OH]D3 /DBP) × 103 . MS risk was analyzed by conditional logistic regression, calculating odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Serum samples from 660 pairs of matched cases and controls were included. At <20 years of age, high levels of free vitamin D3 index were associated with a lower risk of MS (highest vs. lowest quintile: OR = 0.37, 95% CI = 0.15-0.91, p for trend across quintiles = 0.04). At age 30-39 years, high levels of DBP were associated with a lower MS risk (highest vs. lowest quintile: OR = 0.36, 95% CI = 0.15-0.85, p for trend = 0.02). CONCLUSIONS: These findings support the hypothesis that high levels of free 25(OH)D3 at a young age reduce the risk of MS later in life. They also implicate a role for DBP in MS etiology.

Incidence and Prevalence of Multiple Sclerosis in Malmö, Southern Sweden.

Objectives: To estimate the incidence and prevalence of multiple sclerosis (MS) in Malmö municipality in southwestern Sweden. Materials and Methods: Multiple sources were used in the case identification process. Case ascertainment was assessed by medical chart review including examinations such as magnetic resonance imaging, cerebrospinal fluid analyses, and relevant laboratory tests. Cases were classified according to the 2010 McDonald's diagnostic criteria. Onset-adjusted prevalence and a definition of onset symptoms were applied. Results: The crude incidence of MS in 2001-2010 in Malmö municipality was 5.3/100,000 (95% confidence interval (CI): 4.5 to 6.2). There was a relapsing onset in 90.5% of cases. The female to male ratio was 1.8. The onset-adjusted prevalence for Dec 2010 was 133/100,000 (95% CI, 120 to 146) with a female to male ratio of 2.1. Conclusions: This is the first population-based epidemiological study in Skåne, the most southwestern part of Sweden showing a high incidence and prevalence. We found a lower incidence than expected according to previous nationwide figures, probably due to methodological differences between the studies. Our findings support the presence of a north-south gradient of MS prevalence in Sweden.

Cytomegalovirus seropositivity is associated with reduced risk of multiple sclerosis-a presymptomatic case-control study.

BACKGROUND AND PURPOSE: Epstein-Barr virus (EBV) and human herpesvirus 6A (HHV-6A) are associated with increased risk of multiple sclerosis (MS). Conversely, infection with cytomegalovirus (CMV) has been suggested to reduce the risk of MS but supporting data from presymptomatic studies are lacking. Here, it was sought to increase the understanding of CMV in MS aetiology. METHODS: A nested case-control study was performed with presymptomatically collected blood samples identified through crosslinkage of MS registries and Swedish biobanks. Serological antibody response against CMV, EBV and HHV-6A was determined using a bead-based multiplex assay. Odds ratio (OR) with 95% confidence interval (CI) for CMV seropositivity as a risk factor for MS was calculated by conditional logistic regression and adjusted for EBV and HHV-6A seropositivity. Potential interactions on the additive scale were analysed by calculating the attributable proportion due to interaction (AP). RESULTS: Serum samples from 670 pairs of matched cases and controls were included. CMV seropositivity was associated with a reduced risk for MS (OR = 0.70, 95% CI 0.56-0.88, p = 0.003). Statistical interactions on the additive scale were observed between seronegativity for CMV and seropositivity against HHV-6A (AP 0.34, 95% CI 0.06-0.61) and EBV antigen EBNA-1 (amino acid 385-420) at age 20-39 years (AP 0.37, 95% CI 0.09-0.65). CONCLUSIONS: Cytomegalovirus seropositivity is associated with a decreased risk for MS. The protective role for CMV infection in MS aetiology is further supported by the interactions between CMV seronegativity and EBV and HHV-6A seropositivity.

Increased intestinal permeability in primary Sjögren's syndrome and multiple sclerosis.

There is increasing evidence suggesting a role of intestinal dysfunction in a number of autoimmune diseases. Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease with a documented increased level of intestinal inflammation, whereas multiple sclerosis (MS) is an organ-specific autoimmune disease known to exhibit increased intestinal permeability. In this study we determine to what extent intestinal inflammation, analysed by a faecal calprotectin ELISA, is accompanied by altered intestinal wall permeability, as measured by a lactulose and mannitol intestinal absorption assay. Intestinal permeability was increased in both pSS and MS patients, while faecal calprotectin was elevated in pSS but normal in MS. Our findings suggest different mechanisms mediating a leaky gut in these two diseases: in pSS there is autoimmune attack directly on the intestinal wall; in MS, with autoimmunity being limited to the CNS, it may be due to a disturbed CNS regulation of enteric nerve function.

Leptin levels are associated with multiple sclerosis risk.

BACKGROUND: Obesity early in life has been linked to increased risk of developing multiple sclerosis (MS). Leptin and insulin are both associated with obesity, making them suitable candidates for investigating this connection. OBJECTIVE: To determine if leptin and insulin are risk factors for relapsing-remitting multiple sclerosis (RRMS). METHODS: In this nested case-control study using blood samples from Swedish biobanks, we compared concentrations of leptin and insulin in 649 individuals who later developed RRMS with 649 controls matched for biobank, sex, age and date of sampling. Only pre-symptomatically drawn samples from individuals below the age of 40 years were included. Conditional logistic regression was performed on z-scored values to calculate odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A 1-unit leptin z-score increase was associated with increased risk of MS in individuals younger than 20 years (OR = 1.4, 95% CI = 1.1-1.9) and in all men (OR = 1.4, 95% CI = 1.0-2.0). In contrast, for women aged 30-39 years, there was a lower risk of MS with increased leptin levels (OR = 0.74, 95% CI = 0.54-1.0) when adjusting for insulin levels. CONCLUSION: We show that the pro-inflammatory adipokine leptin is a risk factor for MS among young individuals.

High serum concentration of vitamin D may protect against multiple sclerosis.

BACKGROUND: High 25-hydroxyvitamin D concentrations have been associated with a reduced risk of multiple sclerosis, with indications of a stronger effect among young individuals. OBJECTIVE: Investigate the 25-hydroxyvitamin D association with multiple sclerosis and test if this association is age dependent. METHODS: Prospectively drawn blood samples from individuals later developing relapsing-remitting multiple sclerosis and controls matched for biobank, sex, age and date of sampling, were analysed with liquid chromatography tandem mass spectrometry. RESULTS: High levels of 25-hydroxyvitamin D (top quintile) were associated with a reduced multiple sclerosis risk (odds ratio 0.68, 95% confidence interval 0.50-0.93). CONCLUSION: These findings further support a role for vitamin D in MS aetiology.

Benefit-risk Assessment of Cladribine Using Multi-criteria Decision Analysis (MCDA) for Patients With Relapsing-remitting Multiple Sclerosis.

PURPOSE: We applied Multi-Criteria Decision Analysis (MCDA) methods in a structured benefit-risk assessment of cladribine and newer approved disease-modifying drugs (DMDs) for patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: Decision conferencing with clinical neurologists as decision makers was used to create an MCDA model that incorporated available evidence on DMDs for RRMS and clinical judgments about the relevance of the evidence. Benefit-risk assessments were conducted for DMDs in both patients with RRMS and patients with RRMS with high disease activity (HDA; defined as ≥2 relapses in the previous year). Treatment options included cladribine and recently approved DMDs available in European Union countries at the time of assessment (December 2015): alemtuzumab, dimethyl fumarate, fingolimod, natalizumab, and teriflunomide. To account for the relative importance of DMD effects, scores for the MCDA model were weighted to ensure that the most clinically important attributes carried more weight in the final benefit-risk calculation. The neurologists weighted different efficacy and safety profile attributes without any reference to individual DMDs to disassociate the assessment of weights with any specific DMD. The neurologists did not do direct comparisons between DMDs. FINDINGS: The highest overall weighted preference value for the RRMS model was for dimethyl fumarate (63) followed closely by cladribine (62). For patients with RRMS and HDA, cladribine had the highest overall weighted preference value (76), followed by alemtuzumab (62) and natalizumab (61). The benefit-risk balance of cladribine in patients with RRMS and specifically patients with RRMS who exhibited HDA characterized by high relapse activity (≥2 relapses in the previous year) was more favorable than the other DMDs included in the model. IMPLICATIONS: The balance of high efficacy and the safety profile makes cladribine an important treatment option to consider, both in patients with RRMS and patients with HDA. Regular, single-country meetings could be organized to explore how differences in cultural values (scores and weights) and updated input data might affect the usefulness of MCDA in different, real-world, dynamic clinical settings.

Increased Serological Response Against Human Herpesvirus 6A Is Associated With Risk for Multiple Sclerosis.

Human herpesvirus (HHV)-6A or HHV-6B involvement in multiple sclerosis (MS) etiology has remained controversial mainly due to the lack of serological methods that can distinguish the two viruses. A novel multiplex serological assay measuring IgG reactivity against the immediate-early protein 1 from HHV-6A (IE1A) and HHV-6B (IE1B) was used in a MS cohort (8,742 persons with MS and 7,215 matched controls), and a pre-MS cohort (478 individuals and 476 matched controls) to investigate this further. The IgG response against IE1A was positively associated with MS (OR = 1.55, p = 9 × 10-22), and increased risk of future MS (OR = 2.22, p = 2 × 10-5). An interaction was observed between IE1A and Epstein-Barr virus (EBV) antibody responses for MS risk (attributable proportion = 0.24, p = 6 × 10-6). In contrast, the IgG response against IE1B was negatively associated with MS (OR = 0.74, p = 6 × 10-11). The association did not differ between MS subtypes or vary with severity of disease. The genetic control of HHV-6A/B antibody responses were located to the Human Leukocyte Antigen (HLA) region and the strongest association for IE1A was the DRB1*13:01-DQA1*01:03-DQB1*06:03 haplotype while the main association for IE1B was DRB1*13:02-DQA1*01:02-DQB1*06:04. In conclusion a role for HHV-6A in MS etiology is supported by an increased serological response against HHV-6A IE1 protein, an interaction with EBV, and an association to HLA genes.

Apolipoprotein alleles and the response to interferon-ß-1b in multiple sclerosis.

BACKGROUND: Results for the e4/e2 alleles of the ApoE gene as markers of susceptibility, clinical and radiological progression, and cognitive deterioration in patients with multiple sclerosis (MS) are contradictory. AIM: The usefulness of these markers in predicting the response to interferon-ß-1b (IFNß-1b) was evaluated. MATERIAL AND METHODS: 95 patients with relapsing-remitting MS treated with IFNß-1b (mean follow-up 7.44 years) were studied. We correlated the e4 and e2 alleles with the time to the first relapse or to a 1-point worsening on the Expanded Disability Status Scale, time to moderate disability, progression index, and treatment discontinuation due to inefficacy. RESULTS: We found no association between the e4 allele and any of the variables. The e2 allele was associated with increased time to moderate disability. CONCLUSION: The e4 allele of ApoE has no prognostic value for the response to IFNß-1b. The e2 allele delayed the progression of disability in our MS patient cohort.

Interferon-beta1b in multiple sclerosis: effect on progression of disability and clinical markers of treatment response.

There is limited long-term data on the effect of interferon-beta1b (IFN-beta1b) on disability progression in patients with multiple sclerosis (MS). There is also no reliable way of predicting individual responses to IFN-beta1b treatment. This prospective study investigated early clinical prognostic markers of disease activity and progression in 115 patients with relapsing-remitting MS (RRMS) treated with IFN-beta1b for almost 5 years. The study also compared progression of disability in IFN-beta1b-treated patients with a historic untreated cohort of MS patients (n = 44). The number of relapses in the first 2 years of MS and in the 2 years before treatment predicted an early relapse after IFN-beta1b treatment. The IFN-beta1b-treated group experienced a slower progression of disability than the untreated cohort, suggesting that IFN-beta1b treatment delays progression of disability in RRMS.