Interactions between High Seroreactivity to Human Herpes Virus 6A and Epstein-Barr Virus in MS Development: A Presymptomatic Case-Control Study.

Synergistic interactions between human herpesvirus 6A (HHV-6A) and Epstein-Barr virus (EBV) are hypothesized in the etiopathogenesis of multiple sclerosis (MS). This study investigated if HHV-6A and EBV seroreactivities interact regarding the risk of developing MS. Antibodies against viral antigens were analyzed in biobank samples from 670 individuals who later developed MS and matched controls. Additive interactions were analyzed. A significant interaction between HHV-6A and EBNA-1 seroreactivities was observed in study participants above the median age of 24.9 years (attributable proportion due to interaction = 0.45). This finding supports the hypothesis that HHV-6A and EBV infections interact in MS development. ANN NEUROL 2024.

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.

Genetics of immune response to Epstein-Barr virus: prospects for multiple sclerosis pathogenesis.

Epstein-Barr virus (EBV) infection has been advocated as a prerequisite for developing multiple sclerosis (MS) and possibly the propagation of the disease. However, the precise mechanisms for such influences are still unclear. A large-scale study investigating the host genetics of EBV serology and related clinical manifestations, such as infectious mononucleosis (IM), may help us better understand the role of EBV in MS pathogenesis. This study evaluates the host genetic factors that influence serological response against EBV and history of IM and cross-evaluates them with MS risk and genetic susceptibility in the Swedish population. Plasma IgG antibody levels against EBV nuclear antigen-1 (EBNA-1, truncated=aa[325-641], peptide=aa[385-420]) and viral capsid antigen p18 (VCAp18) were measured using bead-based multiplex serology for 8744 MS cases and 7229 population-matched controls. The MS risk association for high/low EBV antibody levels and history of IM was compared to relevant clinical measures along with sex, age at sampling, and associated HLA allele variants. Genome-wide and HLA allele association analyses were also performed to identify genetic risk factors for EBV antibody response and IM history. Higher antibody levels against VCAp18 (OR=1.74, 95% CI=1.60-1.88) and EBNA-1, particularly the peptide (OR=3.13, 95% CI=2.93-3.35), were associated with an increased risk for MS. The risk increased with higher anti-EBNA-1 IgG levels up to twelve times the reference risk. We also identified several independent HLA haplotypes associated with EBV serology overlapping with known MS risk alleles (e.g., DRB1*15:01). Although there were several candidates, no variants outside the HLA region reached genome-wide significance. Cumulative HLA risk for anti-EBNA-1 IgG levels, particularly the peptide fragment, was strongly associated with MS. In contrast, the genetic risk for high anti-VCAp18 IgG levels was not as strongly associated with MS risk. IM history was not associated with class II HLA genes but negatively associated with A*02:01, which is protective against MS. Our findings emphasize that the risk association between anti-EBNA-1 IgG levels and MS may be partly due to overlapping HLA associations. Additionally, the increasing MS risk with increasing anti-EBNA-1 levels would be consistent with a pathogenic role of the EBNA-1 immune response, perhaps through molecular mimicry. Given that high anti-EBNA-1 antibodies may reflect a poorly controlled T-cell defense against the virus, our findings would be consistent with DRB1*15:01 being a poor class II antigen in the immune defense against EBV. Lastly, the difference in genetic control of IM supports the independent roles of EBNA-1 and IM in MS susceptibility.

Seroreactivity against lytic, latent and possible cross-reactive EBV antigens appears on average 10 years before MS induced preclinical neuroaxonal damage.

BACKGROUND: Multiple sclerosis (MS) and presymptomatic axonal injury appear to develop only after an Epstein-Barr virus (EBV) infection. This association remains to be confirmed across a broad preclinical time range, for lytic and latent EBV seroreactivity, and for potential cross-reacting antigens. METHODS: We performed a case-control study with 669 individual serum samples obtained before clinical MS onset, identified through cross-linkage with the Swedish MS register. We assayed antibodies against EBV nuclear antigen 1 (EBNA1), viral capsid antigen p18, glycoprotein 350 (gp350), the potential cross-reacting protein anoctamin 2 (ANO2) and the level of sNfL, a marker of axonal injury. RESULTS: EBNA1 (latency) seroreactivity increased in the pre-MS group, at 15-20 years before clinical MS onset, followed by gp350 (lytic) seroreactivity (p=0.001-0.009), ANO2 seropositivity appeared shortly after EBNA1-seropositivity in 16.7% of pre-MS cases and 10.0% of controls (p=0.001).With an average lag of almost a decade after EBV, sNfL gradually increased, mainly in the increasing subgroup of seropositive pre-MS cases (p=8.10-5 compared with non-MS controls). Seropositive pre-MS cases reached higher sNfL levels than seronegative pre-MS (p=0.038). In the EBNA1-seropositive pre-MS group, ANO2 seropositive cases had 26% higher sNfL level (p=0.0026). CONCLUSIONS: Seroreactivity against latent and lytic EBV antigens, and in a subset ANO2, was detectable on average a decade before the appearance of a gradually increasing axonal injury occurring in the last decade before the onset of clinical MS. These findings strengthen the hypothesis of latent EBV involvement in the pathogenesis of MS.

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.

Molecular mimicry between Anoctamin 2 and Epstein-Barr virus nuclear antigen 1 associates with multiple sclerosis risk.

Multiple sclerosis (MS) is a chronic inflammatory, likely autoimmune disease of the central nervous system with a combination of genetic and environmental risk factors, among which Epstein-Barr virus (EBV) infection is a strong suspect. We have previously identified increased autoantibody levels toward the chloride-channel protein Anoctamin 2 (ANO2) in MS. Here, IgG antibody reactivity toward ANO2 and EBV nuclear antigen 1 (EBNA1) was measured using bead-based multiplex serology in plasma samples from 8,746 MS cases and 7,228 controls. We detected increased anti-ANO2 antibody levels in MS (P = 3.5 × 10-36) with 14.6% of cases and 7.8% of controls being ANO2 seropositive (odds ratio [OR] = 1.6; 95% confidence intervals [95%CI]: 1.5 to 1.8). The MS risk increase in ANO2-seropositive individuals was dramatic when also exposed to 3 known risk factors for MS: HLA-DRB1*15:01 carriage, absence of HLA-A*02:01, and high anti-EBNA1 antibody levels (OR = 24.9; 95%CI: 17.9 to 34.8). Reciprocal blocking experiments with ANO2 and EBNA1 peptides demonstrated antibody cross-reactivity, mapping to ANO2 [aa 140 to 149] and EBNA1 [aa 431 to 440]. HLA gene region was associated with anti-ANO2 antibody levels and HLA-DRB1*04:01 haplotype was negatively associated with ANO2 seropositivity (OR = 0.6; 95%CI: 0.5 to 0.7). Anti-ANO2 antibody levels were not increased in patients from 3 other inflammatory disease cohorts. The HLA influence and the fact that specific IgG production usually needs T cell help provides indirect evidence for a T cell ANO2 autoreactivity in MS. We propose a hypothesis where immune reactivity toward EBNA1 through molecular mimicry with ANO2 contributes to the etiopathogenesis of MS.

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.

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.

Epstein-Barr virus infection after adolescence and human herpesvirus 6A as risk factors for multiple sclerosis.

BACKGROUND AND PURPOSE: Infections with human herpesvirus 6A (HHV-6A) and Epstein-Barr virus (EBV) have been linked to multiple sclerosis (MS) development. For EBV, late infection has been proposed as a risk factor, but serological support is lacking. The objective of this study was to investigate how age affects the EBV and HHV-6A associated risks of developing MS. METHODS: In this nested case-control study, Swedish biobanks were accessed to find pre-symptomatically collected blood samples from 670 individuals who later developed relapsing MS and 670 matched controls. A bead-based multiplex assay was used to determine serological response against EBV and HHV-6A. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. RESULTS: Seropositivity against EBV exhibited a pattern where associations switched from a decreased risk of developing MS in the group below 20 years of age to an increased risk amongst individuals aged 20-29 and 30-39 years (p for trend 0.020). The age of transition was estimated to be 18.8 years. In contrast, HHV-6A was associated with increased MS risk in all age groups (total cohort odds ratio 2.1, 95% confidence interval 1.6-2.7). CONCLUSIONS: This study suggests EBV infection after adolescence and age independent HHV-6A infection as risk factors for MS.

Comparative effectiveness of dimethyl fumarate as the initial and secondary treatment for MS.

BACKGROUND: Population-based real-world evidence studies of the effectiveness and tolerability of dimethyl fumarate in relation to common treatment alternatives are still limited. OBJECTIVE: To evaluate the clinical effectiveness and tolerability of dimethyl fumarate (DMF) as the initial and secondary treatment for relapsing-remitting multiple sclerosis (RRMS) patients compared with common treatment alternatives in Sweden. METHODS: We conducted a nationwide retrospective observational cohort study of all RRMS patients identified through the Swedish MS registry initiating DMF (n = 641) or interferons/glatiramer acetate (IFN/GA; n = 555) as the initial therapy, or DMF (n = 703) or fingolimod (FGL; n = 194) after switch from IFN/GA between 1 January 2014 and 31 December 2016. RESULTS: The discontinuation rate was lower with DMF as the initial treatment than IFN/GA (adjusted hazard rate (HR): 0.46, 95% confidence interval (CI): 0.37-0.58, p < 0.001), but higher than FGL as the secondary treatment (HR: 1.51, CI: 1.08-2.09, p < 0.05). Annualized relapse rate (ARR) was lower with DMF compared to IFN/GA (0.04, CI: 0.03-0.06 vs 0.10, CI: 0.07-0.13; p < 0.05), but not FGL (0.03, CI: 0.02-0.05 vs 0.02, CI: 0.01-0.04; p = 0.41). Finally, time to first relapse (TTFR) was longer with DMF as the initial, but not secondary, therapy (p < 0.05 and p = 0.20, respectively). CONCLUSION: Our findings indicate that DMF performs better than IFN/GA as the initial treatment for RRMS. Compared to FGL, DMF displayed a lower tolerability, but largely similar effectiveness outcomes.

Intrathecal immunoreactivity in people with or without previous infectious mononucleosis.

OBJECTIVES: The risk of developing multiple sclerosis (MS) increases (OR: 3.1) after infectious mononucleosis (IM). However, the nature of this link is obscure. We tested the hypothesis that IM might incur long-term sequelae, including low-key inflammatory activity, with characteristics of an MS endophenotype (or presymptomatic trait) and that assays of MS-relevant cyto-/chemokines in the cerebrospinal fluid (CSF) post-IM may show a trend in this direction. MATERIALS AND METHODS: We selected seven CSF cytokines (IL-1b, IL-6, YKL-40, TNF-alpha) or chemokines (IL-8, CCL2, IP-10), representing pro-inflammatory factors previously associated with MS. We assayed the CSF levels of these seven cyto-/chemokines in healthy individuals with a median follow-up time of 10 years after serologically confirmed IM (post-IM group, n = 22), and in healthy controls without a history of IM (n = 19). A group of MS patients (n = 23) were included as reference. RESULTS: The CSF levels of IP-10, YKL-40, and CCL-2 were higher in the post-IM group than in our IM unexposed controls (P = .021, .049, .028). Seven of seven cyto-/chemokine assays showed a trend in the predicted direction (P of binomial ratio = .008). However, this trend was non-significant in a multivariate test (P = .22). A power analysis indicated that similar studies including a larger cohort would be numerically realistic. CONCLUSIONS: These results do not reject the hypothesis that the established epidemiological association between IM and MS results from a stepwise inflammatory propagation from IM sequelae to an MS endophenotype (or presymptomatic trait) in a proportion of IM patients, pending confirmation with adequate power.

Comparison of plasma and cerebrospinal fluid neurofilament light in a multiple sclerosis trial.

OBJECTIVE: The main objective of this study was to evaluate the axonal component neurofilament light protein (NFL) in plasma and cerebrospinal fluid (CSF) as an outcome measure in a clinical trial on disease-modifying treatments in multiple sclerosis. MATERIALS AND METHODS: Seventy-five patients with clinically stable relapsing-remitting multiple sclerosis (RRMS) participating in the clinical trial "Switch-To RItuXimab in MS" (STRIX-MS) were switched to rituximab from first-line injectable therapy and then followed up for 2 years. Thirty patients from the extension trial (STRIX-MS extension), accepting repeated lumbar punctures, were followed up for an additional 3 years. Plasma and CSF samples were collected yearly during the follow-up. NFL concentration in plasma was measured by an in-house NF-light assay on the Simoa platform with a Homebrew kit. NFL concentration in CSF was measured by sandwich ELISA. RESULTS: The mean levels of NFL, in both CSF and plasma, were low. The reduction of CSF-NFL was 25% during the first year of follow-up (from a mean of 471 [SD 393] to 354 [SD 174] pg/mL; P = 0.006) and was statistically significant. The corresponding reduction in plasma NFL was 18% (from 9.73 [SD 7.04] to 7.94 [SD 3.10] pg/mL; P = 0.055) and did not reach statistical significance. CONCLUSION: This study indicates that NFL in plasma is less sensitive as an endpoint in group comparisons than NFL in CSF. Given that plasma NFL is far easier to access, it is a promising and awaited method but further studies are needed to optimize the use in clinical trials.

The impact of adjusted work conditions and disease-modifying drugs on work ability in multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a neurological disorder that causes significantly reduced ability to work, and the Expanded Disability Status Scale (EDSS) is one of the main predictors for reduced work ability. OBJECTIVES: To investigate how work requirements, flexible work conditions and disease-modifying drugs (DMDs) influence the work ability in relation to different EDSS grades in two MS populations. METHODS: Work ability was studied in two MS populations: one in the southern and one in the northern part of Sweden, both demographically similar. In the latter population, more active work-promoting interventions have been practised and second-generation DMDs have been widely used from the onset of disease for several years. RESULTS: The proportion of MS patients who participated in the workforce or studied was significantly higher in the northern compared with the southern population ( p < 0.001). The employees in the northern population had significantly lower requirements, greater adapted work conditions and were able to work more hours per week. Higher EDSS was associated with lower reduction in number of worked hours per week in the northern population ( p = 0.042). CONCLUSION: Our data indicated that treatment strategy and adjusted work conditions have impact on work ability in MS.

Effect of high-dose vitamin D3 supplementation on antibody responses against Epstein-Barr virus in relapsing-remitting multiple sclerosis.

BACKGROUND: Elevated antibody levels against Epstein-Barr virus (EBV) and a poor vitamin D status are environmental factors that may interact in relapsing-remitting multiple sclerosis (RRMS) aetiology. OBJECTIVES: To examine effects of high-dose oral vitamin D3 supplementation on antibody levels against EBV nuclear antigen 1 (EBNA1) in RRMS. METHODS: Serum 25-hydroxyvitamin D3 (25(OH)D) and immunoglobulin G antibody levels against EBNA1 (whole protein and amino acid 385-420 fragment), EBV viral capsid antigen (VCA), cytomegalovirus (CMV) and varicella zoster virus (VZV) were measured in 68 RRMS patients enrolled in a 96-week randomised double-blinded placebo-controlled clinical trial of oral vitamin D3 supplementation (20,000 IU/week) (NCT00785473). RESULTS: The mean 25(OH)D level more than doubled in the vitamin D group and was significantly higher than in the placebo group at study conclusion (123.2 versus 61.8 nmol/L, p < 0.001). Compared to the placebo group, both anti-EBNA1 protein and fragment antibody levels decreased in the vitamin D group from baseline to week 48 ( p = 0.038 and p = 0.004, respectively), but not from baseline to week 96. Vitamin D3 supplementation did not affect antibodies against VCA, CMV or VZV. CONCLUSION: The results indicate that high-dose oral vitamin D3 supplementation can affect humoral immune responses against the latent EBV antigen EBNA1 in RRMS.

How to minimize the risk for headache? A lumbar puncture practice questionnaire study.

Background - To lower the risk for post lumbar puncture (LP) headache the American Academy of Neurology (AAN) recommended using small bore atraumatic needles together with stylet reinsertion in a report from 2005. It is unclear whether these recommendations are followed or not. Objectives - To investigate the diagnostic LP preferences with respect to the AAN guidelines among neurologists by use of a short online questionnaire, and to review previously published literature on the subject. Results - A total of 284 respondents who performed diagnostic LPs completed the questionnaire. Almost half (41%) answered that they always use atraumatic needles. The most common reason (73%) for not using atraumatic needles was that these were not available. Less than half of the respondents who performed LPs had knowledge about the AAN guidelines for diagnostic LPs, and 48-76% agreed with the different recommendations therein. Five previously (1998-2015) published studies investigating LP practice among neurologists were identified. The reported frequency of atraumatic needle use (always/routinely) varied between 2 and 16%. Discussion - Atraumatic needle use was more common in this study compared with previous publications. There is still skepticism regarding some of the AAN recommendations, and needle availability appears to be the most important factor preventing atraumatic needle use. To increase the use of atraumatic needles we may perform additional studies investigating their potential benefits, and arrange training sessions for neurologists to increase their awareness and level of comfort with the atraumatic LP technique.

The interaction between smoking and Epstein-Barr virus as multiple sclerosis risk factors may depend on age.

The multiple sclerosis (MS) risk factors smoking and remote Epstein-Barr virus (EBV) infection have been suggested to interact statistically, but the results are conflicting. In a prospective study on 192 MS cases and 384 matched controls, we analysed levels of cotinine as a marker of smoke exposure, and Epstein-Barr Nuclear Antigen-1 antibody reactivity. We assessed interaction on the additive and multiplicative scales, and estimated the effects of the risk factors across strata of each other. The results suggest that a negative interaction may be present in samples drawn at a young age, and a positive interaction among older subjects.

Immunosuppressive therapy reduces axonal damage in progressive multiple sclerosis.

BACKGROUND: In progressive multiple sclerosis (PMS), disease-modifying therapies have not been shown to reduce disability progression. OBJECTIVE: The impact from immunosuppressive therapy in PMS was explored by analyzing cerebrospinal fluid (CSF) biomarkers of axonal damage (neurofilament light protein, NFL), astrogliosis (glial fibrillary acidic protein, GFAP), and B-cell regulation (CXCL13). METHODS: CSF was obtained from 35 patients with PMS before and after 12-24 months of mitoxantrone (n=30) or rituximab (n=5) treatment, and from 14 age-matched healthy control subjects. The levels of NFL, GFAP, and CXCL13 were determined by immunoassays. RESULTS: The mean NFL level decreased by 51% (1781 ng/l, SD 2018 vs. 874 ng/l, SD 694, p=0.007), the mean CXCL13 reduction was 55% (9.71 pg/ml, SD 16.08, vs. 4.37 pg/ml, SD 1.94, p=0.008), while GFAP levels remained unaffected. Subgroup analysis showed that the NFL reduction was confined to previously untreated patients (n=20) and patients with Gd-enhancing lesions on magnetic resonance imaging (n=12) prior to study baseline. CONCLUSIONS: Our data imply that 12-24 months of immunosuppressive therapy reduces axonal damage in PMS, particularly in patients with ongoing disease activity. Determination of NFL levels in CSF is a potential surrogate marker for treatment efficacy and as endpoint in phase II trials of MS.

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.

Vitamin A and systemic inflammation as protective factors in multiple sclerosis.

BACKGROUND: Vitamin A is important for the immune system, and might suppress inflammatory activity in multiple sclerosis (MS). OBJECTIVES: We aimed to examine if vitamin A levels were associated with MS risk in samples collected prospectively and during gestation. METHODS: We measured Retinol Binding Protein (RBP--a surrogate marker for vitamin A) and high-sensitivity C-reactive protein (hs-CRP) levels, in (1) prospectively collected biobank blood samples from MS cases and controls, and (2) gestational samples where the offspring had later developed MS, and gestational control samples. The risk of MS was calculated using matched multivariable logistic regression adjusted for confounders. RESULTS: In prospective samples, RBP levels within the second quintile (vs. the first) were associated with a lower MS risk (OR = 0.38, 95% CI 0.19-0.74). No effect on MS risk in the offspring by gestational RBP levels was found. In young subjects hs-CRP levels ≥10 mg/l in prospective samples were associated with a lower MS risk (OR = 0.36, 95% CI 0.14-0.95). CONCLUSIONS: Our results suggest that sub-optimal vitamin A levels may be associated with MS risk. The association between hs-CRP levels and MS risk in young subjects may support the role of the hygiene hypothesis in MS aetiology.