Genetic differences between primary progressive and relapsing-remitting multiple sclerosis: The impact of immune-related genes variability

A comparison of serum inflammatory parameters in progressive forms of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system. Primary progressive MS (PPMS) is diagnosed in approximately 10-15 % of MS patients. Disease-modifying therapies (DMT) are less effective in modifying the course of progressive types of MS. It seems that inflammatory processes differ in the MS subtypes.

OBJECTIVES

The objective of this study was to assess differences in the inflammatory parameters between PPMS and other courses of MS.

MATERIALS AND METHODS

A total of 84 subjects were included in the study. The study group was divided according to the course of MS into the following categories: PPMS (n = 24); SPMS-secondary progressive multiple sclerosis (n = 14); RRMS-relapsing-remitting multiple sclerosis (n = 46). PPMS patients were further divided into treated with ocrelizumab and treatment-naive groups. The concentrations of serum inflammatory parameters were evaluated.

RESULTS

PPMS and SPMS significantly differed in the serum levels of sCD30, gp130, sIL-6R alpha, osteopontin, pentraxin-3 and sTNF-R1. The serum concentrations of IFN-alpha2, IL-10, IL-20, IL-29 and osteopontin significantly differed between PPMS and RRMS. The serum levels of BAFF, IL-19, IL-20, pentraxin-3, s-TNF-R1 and s-TNF-R2 significantly differed between PPMS treated with ocrelizumab and treatment-naive.

CONCLUSION

Although inflammatory processes take part in the pathogenesis of all types of MS, they differ between MS courses. Serum inflammatory parameters seem to be promising biomarkers in helping to differentiate courses of MS, and in assessing reactions to DMT treatment. Further investigations on their usage are required.

Bacillus Calmette-Guerin vaccination and multiple sclerosis: a population-based birth cohort study in Quebec, Canada

BACKGROUND

The Bacillus Calmette-Guerin (BCG) vaccine could reduce the incidence of multiple sclerosis (MS) through immunomodulation. Previous studies, presenting some limitations, reported no association. We re-examined this association in a large cohort focusing on relapsing-remitting MS (RRMS).

METHODS

The cohort included 400,563 individuals, and was linked with the Quebec provincial BCG vaccination registry and administrative health data. Individuals were followed-up from 1983 to 2014 and then within period 1 (1983-1996) and period 2 (1997-2014), for the occurrence of MS. Incident MS cases were defined as those with ≥3 hospital or physician claims for MS. Subjects with ≥1 drug reimbursement for MS disease-modifying therapies were classified as RRMS. Cox proportional hazards regression was used to estimate hazard ratios (HR) over the follow-ups, adjusting for potential confounders. Possible effect modification due to sex was assessed.

RESULTS

A total of 178,335 (46%) individuals were BCG vaccinated. There were 274 (0.06%) incident MS cases identified in 1983-1996, and 1,433 (0.4%) in 1997-2014. No association was found with RRMS, either in period 1 (adjusted HRs= 0.96, 95% confidence interval: 0.63-1.45; 96 cases) or in period 2 (HRadj= 1.02, 0.85-1.23; 480 cases). The remaining MS cases, for whom the phenotype was unknown, were positively associated with BCG over the entire follow-up (HRadj= 1.25, 1.10-1.41; 1,131 cases) and in period 2 (HRadj=1.33, 1.17-1.52; 953 cases). No interaction with sex was found.

CONCLUSION

Findings suggest that BCG vaccination does not decrease the risk of RRMS, and that future studies should consider phenotypes of MS.

Effect of probiotics supplementation on disease progression, depression, general health, and anthropometric measurements in relapsing-remitting multiple sclerosis patients: A systematic review and meta-analysis of clinical trials

BACKGROUND

Probiotics may have a promising role in chronic autoinflammatory diseases. The current systematic review and meta-analysis investigated the effects of probiotics on disease progression, depression, general health, and anthropometric measurements in Relapsing-Remitting Multiple Sclerosis (RRMS) patients.

METHODS

The English literature search was performed using PubMed, Scopus, Web of Science, and the Central Cochrane Library through January 2021. Random effect models were used to synthesise quantitative data by STATA₁₄ .

RESULTS

From a total of 152 identified entries, four trials were included in quantitative synthesis (n = 213; 106 as intervention, 107 as control). An additional six studies with the same structure and different markers were also systematically reviewed. The pooled effect size showed that Expanded Disability Status Scale (EDSS) (WMD = -0.43; 95% CI = -0.65, -0.20; P < .001), Beck Depression Inventory-Ⅱ (BDI-Ⅱ) (WMD = -3.22; 95% CI = -4.38, -2.06; P < .001) and General Health Questionnaire (GHQ) (WMD = -4.37; 95% CI = -6.43, -2.31; P < .001) were improved following probiotics supplementation. However, body weight and body mass index did not statistically change.

CONCLUSION

Our findings revealed that probiotics supplementation can improve disease progression, suppress depression, and general health in MS patients; although, further investigations may be needed.

[The possibility of using multiple sclerosis-associated variants of the mitochondrial genome to predict the development of multiple sclerosis]

Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by autoimmune inflammation, demyelination, and neurodegeneration. MS is a complex disease that develops under the influence of environmental factors in genetically predisposed individuals. Currently, more than 200 genetic loci associated with MS have been identified by various methods. Some of them are located in the mitochondrial DNA. This paper collects data on mtDNA variants associated with MS in the Russian ethnic group, and shows the possibility of using this information to construct and refine models for predicting the development of MS.

The combined effect of nuclear and mitochondrial genomes on the risk of developing multiple sclerosis

Multiple sclerosis (MS) is a severe chronic CNS disease characterized by autoimmune inflammation, demyelination, and neurodegeneration. The interaction of mitochondrial and nuclear genomes is shown to be important in the formation of a predisposition to many diseases.

Objective: to analyze the association of MS with the carriage of biallelic combinations, including as components the polymorphisms of three genes of mitochondrial DNA (mtDNA) and those of 16 nuclear genes, the products of which are involved in the functioning of the immune system and may participate in the development of autoimmune inflammation in MS; and, if these combinations are identified, to determine the nature of an interaction between their components.

Patients and methods. The investigation enrolled 540 MS patients and 406 control group individuals; all were Russians. The mitochondrial genome was genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. APSampler software was used for multilocus association analysis. 

Results and discussion. The investigators identified five biallelic combinations that were associated with MS (p=0.0036–0.022) and possessed protective properties (odds ratio (OR) 0.67–0.75). The mitochondrial component of the identified combinations was the polymorphisms m.4580 (rs28357975), m.13368 (rs3899498), and m.13708 (rs28359178) mtDNA; the nuclear component was CXCR5 (rs523604), TNFRSF1A (rs1800693), and CD86 (rs2255214) gene polymorphisms. The interaction between the components of the identified combinations was additive.

Conclusion. The data obtained in the Russian population suggest that the combined contribution of the mitochondrial and nuclear genomes may affect the risk of developing MS.

IL7RA genetic variants differentially affect IL-7Rα expression and alternative splicing: a role in autoimmune and infectious diseases?

Interleukin-7 receptor α chain (IL-7Rα) single nucleotide polymorphisms (SNPs) are associated with susceptibility to immunopathologies like autoimmune and inflammatory diseases. The current hypothesis about underlying mechanisms is based on the regulation of IL-7 availability for self-reactive T cells by influencing the generation of a soluble (s)IL-7Rα variant. This assumption was mainly predicated on the well-defined IL7RA SNP rs6897932, which affects alternative splicing and causes aberrant generation of the sIL-7Rα variant with potential effects on the IL-7 serum reservoir. However, more recent studies shed light on novel functions of autoimmunity risk-associated IL7RA SNPs and characterized the largely neglected effect of rs6897932 on membrane (m)IL-7Rα expression. These findings as well as a described role of impaired mIL-7Rα expression and IL7RA SNP influence on chronic infectious diseases necessitates the reevaluation of previous findings on the role of IL7RA SNPs in immunopathology.

Primary progressive multiple sclerosis in a Russian cohort: relationship with gut bacterial diversity

Background

Gut microbiota has been increasingly acknowledged to shape significantly human health, contributing to various autoimmune diseases, both intestinal and non-intestinal, including multiple sclerosis (MS). Gut microbiota studies in patients with relapsing remitting MS strongly suggested its possible role in immunoregulation; however, the profile and potential of gut microbiota involvement in patients with primary progressive MS (PPMS) patients has received much less attention due to the rarity of this disease form. We compared the composition and structure of faecal bacterial assemblage using Illumina MiSeq sequencing of V3-V4 hypervariable region of 16S rRNA genes amplicons in patients with primary progressive MS and in the healthy controls.

Results

Over all samples 12 bacterial phyla were identified, containing 21 classes, 25 orders, 54 families, 174 genera and 1256 operational taxonomic units (OTUs). The Firmicutes phylum was found to be ultimately dominating both in OTUs richness (68% of the total bacterial OTU number) and in abundance (71% of the total number of sequence reads), followed by Bacteroidetes (12 and 16%, resp.) and Actinobacteria (7 and 6%, resp.). Summarily in all samples the number of dominant OTUs, i.e. OTUs with ≥1% relative abundance, was 13, representing much less taxonomic richness (three phyla, three classes, four orders, six families and twelve genera) as compared to the total list of identified OTUs and accounting for 30% of the sequence reads number in the healthy cohort and for 23% in the PPMS cohort. Human faecal bacterial diversity profiles were found to differ between PPMS and healthy cohorts at different taxonomic levels in minor or rare taxa. Marked PPMS-associated increase was found in the relative abundance of two dominant OTUs (Gemmiger sp. and an unclassified Ruminococcaceae). The MS-related differences were also found at the level of minor and rare OTUs (101 OTUs). These changes in OTUs’ abundance translated into increased bacterial assemblage diversity in patients.

Conclusion

The findings are important for constructing a more detailed global picture of the primary progressive MS-associated gut microbiota, contributing to better understanding of the disease pathogenesis.