Mortality trends of amyotrophic lateral sclerosis in Norway 1951–2014: an age–period–cohort study

Recent studies suggest that the incidence and mortality of amyotrophic lateral sclerosis (ALS) are increasing. Changing environmental factors could influence disease risk differently throughout life span, and also between genders, birth cohorts, and seasons of birth. We aimed at describing long-term ALS mortality trends in Norway between 1951 and 2014 using age–period–cohort analysis. The Norwegian Cause of Death Registry provided ALS mortality data that were age- and sex-adjusted through direct standardization. Poisson regression analyses were used for identification of mortality trends and potential month of birth effects. We identified 5345 ALS cases, of which 54.7 % were men. ALS mortality increased throughout the whole period (p < 0.001), with a mean annual increase of 1.14 %. The increase was confined to those older than 60 years, but rates consistently dropped amongst the absolute oldest. The increase was mainly driven by birth cohort effects that increased from 1860 until 1934 (p < 0.001). No month of birth effect or change in sex ratio was found. The continuous increase in ALS mortality since 1951 is best explained by the long-term changes in exposure to risk factors or in case ascertainment, affecting men and women equally in the generations born since 1860 and at least into 1934.acceptedVersio

G1m1 predominance of intrathecal virus-specific antibodies in multiple sclerosis

We have previously shown that plasmablasts of the G1m1 allotype of IgG1 are selectively enriched in the cerebrospinal fluid of G1m1/G1m3 heterozygous patients with multiple sclerosis, whereas both allotypes are equally used in neuroborreliosis. Here, we demonstrate a strong preference for the G1m1 allotype in the intrathecal humoral immune responses against measles, rubella, and varicella zoster virus in G1m1/G1m3 heterozygous multiple sclerosis patients. Conversely, intrathecally synthesized varicella zoster virus‐specific IgG1 in varicella zoster virus meningoencephalitis comprised both allotypes. This implies that G1m1 B cells are selected to the central nervous system of multiple sclerosis patients regardless of specificity and suggests that an antigen‐independent mechanism could drive the intrathecal humoral immune response.publishedVersio

Ethical challenges in tracheostomy-assisted ventilation in amyotrophic lateral sclerosis

Author's accepted version (post-print).This is a post-peer-review, pre-copyedit version of an article published in Journal of Neurology. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00415-018-9054-x.Available from 15/09/2019.acceptedVersio

Strong tuberculin response after BCG vaccination is associated with low multiple sclerosis risk: a population-based cohort study

Background: Multiple sclerosis (MS) is characterized by inflammatory lesions in the central nervous system involving pro-inflammatory T-cells. Immune dysregulation is well described in prevalent disease, but it is not known whether this precedes disease development. Bacillus Calmette–Guerin (BCG) vaccination ameliorates MS-like disease in mice. In people vaccinated with BCG, the tuberculin skin test (TST) offers a standardized measure of a T-cell-mediated immune response. We therefore hypothesized that the strength of the TST response after BCG vaccination is associated with subsequent MS risk. Methods: Using data from a Norwegian tuberculosis screening programme (1963–1975), we designed a population-based cohort study and related the size of TST reactions in individuals previously vaccinated with BCG to later MS disease identified through the Norwegian MS registry. We fitted Cox proportional hazard models and flexible parametric survival models to investigate the association between TST reactivity, MS risk and its temporal relationship. Results: Among 279 891 participants (52% females), 679 (69% females) later developed MS. Larger TST reactivity was associated with decreased MS risk. The hazard ratio for MS per every 4-mm increase in skin induration size was 0.86 (95% confidence interval 0.76–0.96) and similar between sexes. The strength of the association persisted for >30 years after the TST. Conclusion: A strong in vivo vaccine response to BCG is associated with reduced MS risk >30 years later. The immunological mechanisms determining TST reactivity suggest that skewed T-cell-mediated immunity precedes MS onset by many decades.publishedVersio

Humoral response to Epstein-Barr virus in patients with multiple sclerosis treated with B cell depletion therapy

Background B cell depletion therapy is highly effective in relapsing-remitting multiple sclerosis (RRMS). However, the precise underlying mechanisms of action for its biological effects in MS have still not been clarified. Epstein-Barr virus (EBV) is a known risk factor for MS and seems to be a prerequisite for disease development. EBV resides latently in the memory B cells, and may not only increase the risk of developing MS, but also contribute to disease activity and disability progression. Therefore, the effects of B cell depletion in MS could be associated with the depletion of EBV-infected cells and the altered immune response to the virus. In this study, we investigate the impact of B cell depletion on the humoral immune response specific to EBV in patients with MS. Methods Newly diagnosed, treatment-naïve patients with RRMS were followed up to 18 months after initiation of B-cell depletion therapy in the Overlord-MS study, a phase III trial (NCT04578639). We analyzed serum sampled before treatment and after 3, 6, 12 and 18 months for immunoglobulin γ (IgG) against Epstein-Barr nuclear antigen 1 (EBNA1) and Epstein-Barr viral capsid antigen (VCA). We analyzed antibodies to cytomegalovirus (CMV) and total IgG in serum, as controls for viral and overall humoral immunity. The risk allele, HLA-DRB1*15:01, and the protective allele, HLA-A*02:01, were determined in all participants. In addition, polymerase chain reaction (PCR) for circulating EBV-DNA was performed in the first 156 samples drawn. The associations between time on B cell-depletion therapy and serum anti-EBV antibody levels were estimated using linear mixed-effects models. Results A total of 290 serum samples from 99 patients were available for analysis. After 6, 12 and 18 months, the EBNA1 IgG levels decreased by 12.7 % (95 % CI -18.8 to -6.60, p < 0.001), 12.1 % (95 % CI -19.8 to -3.7, p = 0.006) and 14.6 % (95 % CI to -25.3 to -2.4, p = 0.02) respectively, compared to baseline level. Carriers of the HLA-DRB1*15:01 allele had higher EBNA1 IgG levels at baseline (p = 0.02). The VCA IgG levels significantly increased by 13.7 % (95 % CI 9.4 to 18.1, p < 0.001) after 3 months, compared to baseline, and persisted at this level throughout the follow-up. CMV IgG levels decreased, but to a lesser extent than the decrease of EBNA1 IgG, and total IgG levels decreased during therapy. Circulating EBV-DNA was found in only three of 156 samples from 64 patients. Conclusions EBNA1 IgG levels decreased, while VCA IgG levels increased, during B cell depletion therapy. This supports the hypothesis that the mechanism of action for B cell depletion therapy might be mediated by effects on EBV infection, which, in turn, mitigate immune cross-reactivity and disease perpetuation.publishedVersio

Identification of Human NK17/NK1 Cells

Background: Natural killer (NK) cells have both cytolytic and immunoregulatory functions. We recently described that these cells release the inflammatory cytokines IL-17 and IFN-c. However, the precise identity of the NK cell subset(s) that secrete these cytokines is not known. Methodology/Principal Findings: To isolate the cells secreting IL-17 and IFN-c, we took advantage of the findings that Th17/Th1 cells express chemokine receptors. Therefore, CD56 + NK cells were stained with antibodies against various chemokine receptors and intracellularly with antibodies toward IL-17 and IFN-c. Consequently, we identified previously unrecognized subset of NK cells generated from normal human peripheral blood after activation with IL-2 but not PMA plus ionomycin. The cells are characterized by the expression of CD56 + and CCR4 +, produce IL-17 and IFN-c and are consequently named NK17/NK1 cells. They also express CD161, NKp30, NKp44, NKp46, NKG2D, CD158, CCL22, IL-2Rb and the common c chain but not CD127 or IL-23R. Further, they possess T-bet and RORct transcription factors. Antibodies to IL-1b, IL-6, IL-21, or TGF-b1 do not inhibit IL-2-induced generation of NK17/NK1 cells, suggesting that IL-2 has the capacity to polarize these cells. Notably, NK17/NK1 cells are abundant in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) without activation, and are generated from the peripheral blood of these patients after activation with IL-2

Month of birth and risk of multiple sclerosis: confounding and adjustments

A month of birth effect on multiple sclerosis (MS) risk has been reported from different countries. Recent critics have suggested that this finding is caused by confounding and that adequately adjusting for year and place of birth would markedly reduce this effect. All inhabitants in Norway are registered in the Norwegian Population Registry (Statistics Norway), making this an ideal area for performing adjusted analyses. Using the entire Norwegian population born between 1930 and 1979 (n = 2,899,260), we calculated the excess between observed and expected number of births for each month for 6649 Norwegian MS patients, 5711 mothers, 5247 fathers, and 8956 unaffected siblings. The analyses were adjusted for year of birth and place of birth according to the 19 counties in Norway. An unadjusted analysis revealed 13% fewer MS births than expected in February (P = 0.0015; Bonferroni corrected P = 0.018), 10% more in April (P = 0.0083; Bonferroni corrected P = 0.0996) and 15% more in December (P = 0.00058; Bonferroni corrected P = 0.007). Adjustments for both year and place of birth significantly altered our results for February and December, but even after these adjustments there were still 10% more MS births than expected in April (P = 0.00796; Bonferroni corrected P = 0.096). MS patients had a higher incidence of April births than their siblings (Fisher-exact test; P = 0.011), mothers (Fisher-exact test; P = 0.004), and fathers (Fisher-exact test; P = 0.011) without MS. Adjustments for confounding significantly affected our results. However, even after adjustments, there appears to be a persistent higher than expected frequency of April births in the MS population. © 2014 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association

Abuse and revictimization in adulthood in multiple sclerosis: a cross-sectional study during pregnancy

Background: Knowledge concerning exposure to abuse in adulthood and in pregnancy in people with multiple sclerosis (MS) is sparse. Objective: To determine the occurrence of adult abuse and abuse in relation to pregnancy in women with MS and their risk of revictimization (repeated abuse as adults after childhood abuse). Methods: This cross-sectional study comprised pregnant women from the Norwegian Mother, Father and Child Cohort study. Information on abuse was acquired through self-completed questionnaires. We used logistic regression to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results: We identified 106 women with MS at enrollment through linkage with national health registries. The reference group consisted of 77,278 women without MS. Twenty-seven women (26%) with MS reported any adult abuse compared to 15,491 women (20%) without MS, aOR 1.33 (0.85–2.09). Twenty-two (21%) women with MS reported systematic emotional abuse compared to 13% without MS, aOR 1.75 (1.08–2.83). Ten women (10%) with MS reported sexual abuse, compared to 6% without MS, aOR 1.72 (0.89–3.33). More women with MS reported rape as an adult, aOR 2.37 (1.02–5.49). Women with MS had higher risk of revictimization as adults, after childhood abuse, aOR 2.23 (1.22–4.10). The risk of abuse during pregnancy or 6 months preceding pregnancy was similar between the groups. Conclusions: Women with MS had increased occurrence of systematic emotional abuse, rape, and revictimization as adults, compared to women without MS.publishedVersio

Alpha-tocopherol and MRI outcomes in multiple sclerosis - association and prediction

Objective: Alpha-tocopherol is the main vitamin E compound in humans, and has important antioxidative and immunomodulatory properties. The aim of this study was to study alpha-tocopherol concentrations and their relationship to disease activity in Norwegian multiple sclerosis (MS) patients. Methods: Prospective cohort study in 88 relapsing-remitting MS (RRMS) patients, originally included in a randomised placebo-controlled trial of omega-3 fatty acids (the OFAMS study), before and during treatment with interferon beta. The patients were followed for two years with repeated 12 magnetic resonance imaging (MRI) scans and nine serum measurements of alpha-tocopherol. Results: During interferon beta (IFNB) treatment, each 10 µmol/L increase in alpha-tocopherol reduced the odds (CI 95%) for simultaneous new T2 lesions by 36.8 (0.5–59.8) %, p = 0.048, and for combined unique activity by 35.4 (1.6–57.7) %, p = 0.042, in a hierarchical regression model. These associations were not significant prior to IFNB treatment, and were not noticeably changed by gender, age, body mass index, HLA-DRB1*15, treatment group, compliance, or the concentrations of 25-hydroxyvitamin D, retinol, neutralising antibodies against IFNB, or the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. The corresponding odds for having new T1 gadolinium enhancing lesions two months later was reduced by 65.4 (16.5–85.7) %, p = 0.019, and for new T2 lesions by 61.0 (12.4–82.6) %, p = 0.023. Conclusion: During treatment with IFNB, increasing serum concentrations of alpha-tocopherol were associated with reduced odds for simultaneous and subsequent MRI disease activity in RRMS patients.publishedVersio

Inflammation markers in multiple sclerosis: CXCL16 reflects and may also predict disease activity

Background: Serum markers of inflammation are candidate biomarkers in multiple sclerosis (MS). ω-3 fatty acids are suggested to have anti-inflammatory properties that might be beneficial in MS. We aimed to explore the relationship between serum levels of inflammation markers and MRI activity in patients with relapsing remitting MS, as well as the effect of ω-3 fatty acids on these markers. Methods: We performed a prospective cohort study in 85 relapsing remitting MS patients who participated in a randomized clinical trial of ω-3 fatty acids versus placebo (the OFAMS study). During a period of 24 months 12 repeated magnetic resonance imaging (MRI) scans and nine serum samples were obtained. We measured 10 inflammation markers, including general down-stream markers of inflammation, specific markers of up-stream inflammatory pathways, endothelial action, and matrix regulation. Results: After Bonferroni correction, increasing serum levels of CXCL16 and osteoprotegerin were associated with low odds ratio for simultaneous MRI activity, whereas a positive association was observed for matrix metalloproteinase (MMP) 9. CXCL16 were also associated with low MRI activity the next month, but this was not significant after Bonferroni correction. In agreement with previously reported MRI and clinical results, ω-3 fatty acid treatment did not induce any change in the inflammation markers. Conclusions: Serum levels of CXCL16, MMP-9, and osteoprotegerin reflect disease activity in MS, but are not affected by ω-3 fatty acid treatment. CXCL16 could be a novel biomarker and potential predictor of disease activity in MS.© 2013 Holmøy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited