| 1. |
- Grut, Viktor, et al.
(författare)
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Cytomegalovirus seropositivity is associated with reduced risk of multiple sclerosis : a presymptomatic case-control study
- 2021
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Ingår i: European Journal of Neurology. - : Blackwell Publishing. - 1351-5101 .- 1468-1331. ; 28:9, s. 3072-3079
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: 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, we sought to increase the understanding of CMV in MS aetiology.METHODS: We performed a nested case-control study with presymptomatically collected blood samples identified through cross-linkage 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 intervals (CI) for CMV seropositivity as 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 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: CMV 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.
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| 2. |
- Grut, Viktor, 1980-
(författare)
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Exposures associated with multiple sclerosis development : presymptomatic case-control studies
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Multiple sclerosis (MS) is a chronic immune-mediated disease affecting the central nervous system. The current view is that MS is caused by a complex interplay of several environmental factors, eliciting an immune reaction in genetically susceptible individuals. Most previous studies of MS aetiology were retrospective, conferring the risk of reverse causation or recall bias. Few studies have been performed on data collected before the onset of the disease. The objective of this project was to identify risk factors for MS by analysing markers of exposure in samples collected before the clinical onset of MS.Method: A series of nested case-control studies were performed by cross-linking Swedish MS registries with Swedish biobanks, thereby identifying serum or plasma samples from up to 837 cases who later developed MS. For each case, up to two matched controls were selected. The following environmental risk factors were assessed: Antibodies against herpesviruses Epstein-Barr virus (EBV), Human herpesvirus 6A (HHV-6A) and Cytomegalovirus (CMV); Free Vitamin D3 Index and Vitamin D Binding Protein (DBP); and C-reactive Protein (CRP). Early signs of neural injury were assessed by measuring the concentration of neurofilament light chain in serum (sNfL). The associations between the environmental factors and future development of MS were analysed with conditional logistic regression, calculating odds ratios (OR) with 95% confidence intervals (CI). Interactions were analysed on the multiplicative and additive scales. The temporal relation of HHV-6A serostatus and axonal injury was analysed with locally estimated scatterplot smoothing regression.Results: Serological evidence of CMV infection was associated with a lower risk of MS development (OR = 0.70, 95% CI 0.56–0.88). Antagonistic interactions were observed between serological signs of CMV, HHV-6A, and EBV infection. Antibodies against HHV-6A were associated with a higher level of sNfL. In MS cases, increasing levels of HHV-6A antibodies were detected several years before increasing sNfL. Among young individuals, high levels of Free Vitamin D3 Index were associated with a lower MS risk (OR = 0.37, 95% CI 0.15–0.91). In older individuals, high levels of DBP were associated with a lower risk of developing MS (OR = 0.36, 95% CI 0.15–0.85). Elevated levels of CRP were not associated with MS risk.Conclusions: These results strengthen the evidence for HHV-6A and EBV in MS aetiology. They also support the hypothesis that CMV infection and a high level of free Vitamin D3 during childhood and adolescence are associated with a lower risk of MS later in life.
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| 3. |
- Grut, Viktor, et al.
(författare)
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Free vitamin D3 index and vitamin D-binding protein in multiple sclerosis : A presymptomatic case-control study
- 2022
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Ingår i: European Journal of Neurology. - : John Wiley & Sons. - 1351-5101 .- 1468-1331. ; 29:8, s. 2335-2342
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Grut, Viktor, et al.
(författare)
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Human herpesvirus 6A and axonal injury before the clinical onset of multiple sclerosis
- 2024
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 147:1, s. 177-185
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Grut, Viktor, et al.
(författare)
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National cohort study showed that infants with Down's syndrome faced a high risk of hospitalisation for the respiratory syncytial virus
- 2017
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Ingår i: Acta Paediatrica. - : John Wiley & Sons. - 0803-5253 .- 1651-2227. ; 106:9, s. 1519-1524
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The respiratory syncytial virus (RSV) is a leading cause of hospitalisation in infants. We investigated this risk in children with Down's syndrome under two years of age, adjusted for other known risk factors. Methods: This national, retrospective 1: 2 matched cohort study comprised all Swedish children born with Down's from 2006 to 2011, who were each randomly matched to two controls without Down's. Data on RSV hospitalisation and risk factors for RSV were obtained from national registers. The risk of RSV hospitalisation was assessed using multivariable Cox regression with pairwise stratification. Results: The study comprised 814 children with Down's and 1628 controls. We found that 82 children with Down's (10.1%) and 22 controls (1.4%) were hospitalised for RSV. The hazard ratio for children with Down's was 4.00 (95% confidence interval 1.58-10.13) for up to one year of age and 6.60 (95% CI: 2.83-15.38) for up to two years of age, adjusted for other risk factors. During the second year of life, RSV hospitalisation continued for children with Down's, while it was minimal for the controls. Conclusion: Children with Down's faced a high risk of RSV hospitalisation, which continued beyond the first year of age.
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| 6. |
- Grut, Viktor, et al.
(författare)
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Systemic inflammation and risk of multiple sclerosis – A presymptomatic case-control study
- 2022
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Ingår i: Multiple Sclerosis Journal - Experimental, Translational and Clinical. - : SAGE Publications. - 2055-2173. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Jons, Daniel, et al.
(författare)
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Epstein-Barr virus seroreactivity, putative autoimmunity and axonal injury in pre-symptomatic multiple sclerosis
- 2023
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Ingår i: Multiple Sclerosis Journal. - : Sage Publications. - 1352-4585 .- 1477-0970. ; 29:Suppl. 3, s. 39-40
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Multiple sclerosis (MS) and presymptomatic axonal injury appears to develop only after an Epstein-Barr virus (EBV) infection. Anoctamin2 (ANO2), a chloride channel expressed in glial cells and neurons, was identified as a possible MS autoantigen. We here examine serum neurofilament (sNfL), a comprehensive EBV seroreactivity and antibodies against ANO2 in pre-symptomatic MS.Objectives/Aims: To study whether the appearance of EBV seroreactivity in the pre-symptomatic phase of MS precedes cumulating MS-induced neuroaxonal damage and whether it is associated with an incipient autoreactivity against a reported MS autoantigen (ANO2).Methods: We performed a case-control study with presymptomatic serum samples identified through cross-linkage of the Swedish MS register and Swedish biobanks. We assayed serum antibodies against EBV nuclear antigen 1 (EBNA1), viral capsid antigen p18 (VCAp18), EBV glycoprotein 350 (gp350), anoctamin 2 (ANO2), and serum neurofilament light (sNfL) in 669 pre-MS cases and matched controls.Results: EBNA1 seroreactivity increased in the pre-MS group from 20–15 years before MS onset, followed by gp350 seroreactivity (p=0.001–0.002, 15–10 years before onset). This appeared before the elevation of sNfL in EBV seropositive pre-MS cases (p=8⋅10-5, 10–5 years before onset). No significant sNfL increase was observed in the EBV seronegative group (p=0.95). Pre-MS cases with the highest sNfL levels cumulated in the EBV seropositive group (p=0.038). ANO2 seropositivity appeared virtually only in the EBNA1 seropositive group, in 16.7 % of EBNA1 seropositive pre-MS samples and in 10.0 % of corresponding controls (p=0.001). Combined EBNA1 and ANO2 seropositivity showed a higher association with subsequent MS than EBNA1 independent of ANO2 (p=0.002–0.028). In the EBNA1 seropositive stratum, ANO2 seropositivity was associated with 26% higher sNfL.Conclusion: In presymptomatic MS an antibody response against EBV, associated with ANO2 autoimmunity, was detectable before elevated sNfL, which cumulated in the EBV seropositive group. ANO2 seropositivity was associated with higher sNfL. An increase in ANO2 seroreactivity did not appear until after EBV seroconversion, limited to a subgroup of the EBV seropositive stratum. Thus, this specific cross-reaction could contribute to MS pathogenesis in a subgroup. This further implicates EBV in the pathogenesis of MS.
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| 8. |
- Jons, Daniel, et al.
(författare)
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Seroreactivity against lytic, latent and possible cross-reactive EBV antigens appears on average 10 years before MS induced preclinical neuroaxonal damage
- 2023
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Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ Publishing Group Ltd. - 1468-330X .- 0022-3050.
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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