The nature of genetic and environmental susceptibility to multiple sclerosis

Cancer and multiple sclerosis: 2023 recommendations from the French Multiple Sclerosis Society

BACKGROUND

Epidemiological data reveal that 45% of persons with multiple sclerosis (PwMS) in France are more than 50 years. This population more than 50 is more susceptible to cancer, and this risk may be increased by frequent use of immunosuppressive drugs. Consequently, concerns have arisen about the potential increased risk of cancer in PwMS and how patients should be screened and managed in terms of cancer risk.

OBJECTIVE

To develop evidence-based recommendations to manage the coexistence of cancer and multiple sclerosis (MS).

METHODS

The French Group for Recommendations in MS collected articles from PubMed and university databases covering the period January 1975 through June 2022. The RAND/UCLA method was employed to achieve formal consensus. MS experts comprehensively reviewed the full-text articles and developed the initial recommendations. A group of multidisciplinary health care specialists then validated the final proposal.

RESULTS

Five key questions were addressed, encompassing various topics such as cancer screening before or after initiating a disease-modifying therapy (DMT), appropriate management of MS in the context of cancer, recommended follow-up for cancer in patients receiving a DMT, and the potential reintroduction of a DMT after initial cancer treatment. A strong consensus was reached for all 31 recommendations.

CONCLUSION

These recommendations propose a strategic approach to managing cancer risk in PwMS.

Multiple Sclerosis Onset before and after COVID-19 Vaccination: Can HLA Haplotype Be Determinant?

A few cases of multiple sclerosis (MS) onset after COVID-19 vaccination have been reported, although the evidence is insufficient to establish causality. The aim of this study is to compare cases of newly diagnosed relapsing-remitting MS before and after the outbreak of the COVID-19 pandemic and the impact of COVID-19 vaccination. Potential environmental and genetic predisposing factors were also investigated, as well as clinical patterns. This is a single-centre retrospective cohort study including all patients who presented with relapsing-remitting MS onset between January 2018 and July 2022. Data on COVID-19 vaccination administration, dose, and type were collected. HLA-DRB1 genotyping was performed in three subgroups. A total of 266 patients received a new diagnosis of relapsing-remitting MS in our centre, 143 before the COVID-19 pandemic (until and including March 2020), and 123 during the COVID-19 era (from April 2020). The mean number of new MS onset cases per year was not different before and during the COVID-19 era and neither were baseline patients' characteristics, type of onset, clinical recovery, or radiological patterns. Fourteen (11.4%) patients who subsequently received a new diagnosis of MS had a history of COVID-19 vaccination within one month before symptoms onset. Patients' characteristics, type of onset, clinical recovery, and radiological patterns did not differ from those of patients with non-vaccine-related new diagnoses of MS. The allele frequencies of HLA-DRB1*15 were 17.6% and 22.2% in patients with non-vaccine-related disease onset before and during the COVID-19 era, respectively, while no case of HLA-DRB1*15 was identified among patients with a new diagnosis of MS post-COVID-19 vaccine. In contrast, HLA-DRB1*08+ or HLA-DRB1*10+ MS patients were present only in this subgroup. Although a causal link between COVID-19 vaccination and relapsing-remitting MS cannot be detected, it is interesting to note and speculate about the peculiarities and heterogeneities underlying disease mechanisms of MS, where the interactions of genetics and the environment could be crucial also for the follow-up and the evaluation of therapeutic options.

Efficacy and Safety of Ponesimod Compared with Teriflunomide in Female Patients with Relapsing Multiple Sclerosis: Findings from the Pivotal OPTIMUM Study

Background: Multiple sclerosis (MS) is threefold more prevalent in women than men. However, sex-specific efficacy analysis for MS disease-modifying therapies is not typically performed. Methods: Post hoc analyses of data from female patients enrolled in the phase 3, double-blind OPTIMUM study of relapsing MS were carried out. Eligible adults were randomized to ponesimod 20 mg or teriflunomide 14 mg once daily for up to 108 weeks. The primary endpoint was annualized relapse rate (ARR); secondary endpoints included change in symptom domain of Fatigue Symptom and Impact Questionnaire-Relapsing Multiple Sclerosis (FSIQ-RMS) at week 108, number of combined unique active lesions (CUALs) per year on magnetic resonance imaging, and time to 12- and 24-week confirmed disability accumulation (CDA). Results: A total of 735 female patients (581 of childbearing potential) were randomized to ponesimod (n = 363, 49.4%) or teriflunomide (n = 372, 50.6%). Relative risk reduction in the ARR for ponesimod versus teriflunomide was 33.1% (mean, 0.192 vs. 0.286, respectively; p < 0.002). Mean difference in FSIQ-RMS for ponesimod versus teriflunomide was -4.34 (0.12 vs. 4.46; p = 0.002); rate ratio in CUALs per year, 0.601 (1.45 vs. 2.41; p < 0.0001), and hazard ratio for time to 12- and 24-week CDA risk estimates, 0.83 (10.7% vs. 12.9%; p = 0.38) and 0.91 (8.8% vs. 9.7%; p = 0.69), respectively. Incidence of treatment-emergent adverse events was similar between treatment groups (89.0% and 90.1%). Conclusions: Analyses demonstrate the efficacy and safety of ponesimod, versus active comparator, for women with relapsing MS, supporting data-informed decision-making for women with MS. Clinical Trial Registration Number: NCT02425644.

Seasonality and clinical characteristics of MS in an equatorial country

BACKGROUND

Month and season of birth have been associated with risk of multiple sclerosis (MS), but there is relatively little evidence regarding their influence on the timing and severity of disease at onset.

OBJECTIVE

To assess whether month and season of birth influence the age and phenotype at onset of MS as well as its severity in a cohort of Colombian patients.

METHODS

This study is an analysis on MS cases only, drawn from a previously published case-control study. MS cases confirmed with current diagnostic criteria cared for at least once in our center were included. We assessed the influence of the month and season of birth in the age at MS onset, MS severity score, and age-related MS severity score using multiple and pairwise comparisons. Age at onset was also studied using Kaplan-Meier survival estimates compared with the log-rank test. The likelihood of progressive MS onset was evaluated with OR estimated from logistic regression models adjusted for age at onset and sex.

RESULTS

668 MS cases were included. No significant differences were found in the age at MS onset according to month of birth or season of birth. Neither month of birth nor season of birth conferred significant differences in MS severity score or age-related MS severity score. No significant association was found between month (ORs ranging from 0.62 to 3.11, none significant) or season of birth (OR 0.91; 95 %CI: 0.46-1.84) with primary progressive MS.

CONCLUSION

The month or season of birth do not appear to influence the age onset and phenotype of MS in our country.

Multiple sclerosis in Morocco: Epidemiological, clinical, and therapeutic profile

OBJECTIVE

This study aims to describe the clinical, therapeutic, and epidemiological profiles of MS patients in Morocco.

METHODS

This descriptive study involved 170 patients representing four Morocco regions. We collected the data using an electronic survey.

RESULTS

The results show female dominance in patients with MS. Besides, most patients present with relapsing-remitting MS (RRMS). The main clinical symptoms reported by patients are fatigue, cognitive issues, spasticity, bowel or bladder complaints, and visual issues. Furthermore, the findings show that almost half of the patients use Interferon bêta-1a and azathioprine as disease-modifying therapies; 60.5 % use traditional and complementary medicine, of which 30.6 % use cupping, 30 % recite the Holy Quran, and 28.2 % use apitherapy. The findings show that there is a statistically significant relationship between specific MS factors such as professional activity (p = 0.0071), degree of satisfaction with treatment (p = 0.005), stress (p = 0.014), and the frequency of relapses.

CONCLUSIONS

In addition to DMT, patients also use traditional and complementary medicine. There is also a relationship between some epidemiological characteristics and the frequency of relapses in patients with MS.

Expression of CD40 and CD192 in Classical Monocytes in Multiple Sclerosis Patients Assessed with Transcranial Magnetic Stimulation

Expression of CD40 and CD192 markers in different monocyte subpopulations has been reported to be altered in people with MS (pwMS). Also, functional connectivity of the corticospinal motor system pathway alterations has been proved by transcranial magnetic stimulation (TMS). The study objective was to investigate the expression of CD40 and CD192 in classical (CD14++CD16-), intermediate CD14++CD16+ and non-classical (CD14+CD16++) blood monocyte subpopulations in pwMS, undergoing neurophysiological TMS assessment of the corticospinal tract integrity by recording motor-evoked potentials (MEPs). Radiological examination on lesion detection with MRI was performed for 23 patients with relapsing-remitting MS treated with teriflunomide. Then, immunological analysis was conducted on peripheral blood samples collected from the patients and 10 healthy controls (HC). The blood samples were incubated with anti-human CD14, CD16, CD40 and CD192 antibodies. Next, pwMS underwent neurological testing of functional disability (EDSS) and TMS assessment with recording MEPs from upper and lower extremity muscles. The results show that in comparison to HC subjects, both pwMS with normal and altered MEP findings (prolonged MEP latency or absent MEP response) had significantly decreased surface receptor expression measured (MFIs) of CD192 and increased CD40 MFI in classical monocytes, and significantly increased percentages of classical and total monocytes positive for CD40. Knowing CD40's pro-inflammatory action, and CD192 as a molecule that enables the passing of monocytes into the brain, decreased CD192 in classical monocytes could represent a beneficial anti-inflammatory parameter.

Decision trees to evaluate the risk of developing multiple sclerosis

Introduction

Multiple sclerosis (MS) is a persistent neurological condition impacting the central nervous system (CNS). The precise cause of multiple sclerosis is still uncertain; however, it is thought to arise from a blend of genetic and environmental factors. MS diagnosis includes assessing medical history, conducting neurological exams, performing magnetic resonance imaging (MRI) scans, and analyzing cerebrospinal fluid. While there is currently no cure for MS, numerous treatments exist to address symptoms, decelerate disease progression, and enhance the quality of life for individuals with MS.

Methods

This paper introduces a novel machine learning (ML) algorithm utilizing decision trees to address a key objective: creating a predictive tool for assessing the likelihood of MS development. It achieves this by combining prevalent demographic risk factors, specifically gender, with crucial immunogenetic risk markers, such as the alleles responsible for human leukocyte antigen (HLA) class I molecules and the killer immunoglobulin-like receptors (KIR) genes responsible for natural killer lymphocyte receptors.

Results

The study included 619 healthy controls and 299 patients affected by MS, all of whom originated from Sardinia. The gender feature has been disregarded due to its substantial bias in influencing the classification outcomes. By solely considering immunogenetic risk markers, the algorithm demonstrates an ability to accurately identify 73.24% of MS patients and 66.07% of individuals without the disease.

Discussion

Given its notable performance, this system has the potential to support clinicians in monitoring the relatives of MS patients and identifying individuals who are at an increased risk of developing the disease.

Multiple sclerosis: Exploring the limits and implications of genetic and environmental susceptibility

OBJECTIVE

To explore and describe the basis and implications of genetic and environmental susceptibility to multiple sclerosis (MS) using the Canadian population-based data.

BACKGROUND

Certain parameters of MS-epidemiology are directly observable (e.g., the recurrence-risk of MS in siblings and twins, the proportion of women among MS patients, the population-prevalence of MS, and the time-dependent changes in the sex-ratio). By contrast, other parameters can only be inferred from the observed parameters (e.g., the proportion of the population that is "genetically susceptible", the proportion of women among susceptible individuals, the probability that a susceptible individual will experience an environment "sufficient" to cause MS, and if they do, the probability that they will develop the disease).

DESIGN/METHODS

The "genetically susceptible" subset (G) of the population (Z) is defined to include everyone with any non-zero life-time chance of developing MS under some environmental conditions. The value for each observed and non-observed epidemiological parameter is assigned a "plausible" range. Using both a Cross-sectional Model and a Longitudinal Model, together with established parameter relationships, we explore, iteratively, trillions of potential parameter combinations and determine those combinations (i.e., solutions) that fall within the acceptable range for both the observed and non-observed parameters.

RESULTS

Both Models and all analyses intersect and converge to demonstrate that probability of genetic-susceptibitly, P(G), is limited to only a fraction of the population {i.e., P(G) ≤ 0.52)} and an even smaller fraction of women {i.e., P(G│F) < 0.32)}. Consequently, most individuals (particularly women) have no chance whatsoever of developing MS, regardless of their environmental exposure. However, for any susceptible individual to develop MS, requires that they also experience a "sufficient" environment. We use the Canadian data to derive, separately, the exponential response-curves for men and women that relate the increasing likelihood of developing MS to an increasing probability that a susceptible individual experiences an environment "sufficient" to cause MS. As the probability of a "sufficient" exposure increases, we define, separately, the limiting probability of developing MS in men (c) and women (d). These Canadian data strongly suggest that: (c < d ≤ 1). If so, this observation establishes both that there must be a "truly" random factor involved in MS pathogenesis and that it is this difference, rather than any difference in genetic or environmental factors, which primarily accounts for the penetrance difference between women and men.

CONCLUSIONS

The development of MS (in an individual) requires both that they have an appropriate genotype (which is uncommon in the population) and that they have an environmental exposure "sufficient" to cause MS given their genotype. Nevertheless, the two principal findings of this study are that: P(G) ≤ 0.52)} and: (c < d ≤ 1). Threfore, even when the necessary genetic and environmental factors, "sufficient" for MS pathogenesis, co-occur for an individual, they still may or may not develop MS. Consequently, disease pathogenesis, even in this circumstance, seems to involve an important element of chance. Moreover, the conclusion that the macroscopic process of disease development for MS includes a "truly" random element, if replicated (either for MS or for other complex diseases), provides empiric evidence that our universe is non-deterministic.

Relationship between medical history and multiple sclerosis: A-case-control study

This project sought to explore the potential association between medical history and the development of multiple sclerosis (MS) by conducting a retrospective study. This population-based case-control study included 200 MS cases and 2 control groups of 200 patients and healthy individuals each. Data was collected through face-to-face interviews, medical file reviews, and an electronic checklist. Multivariable analysis was used to calculate odds ratios and 95% confidence intervals to estimate the risk of each medical history on MS occurrences. Of 600 participants, 381 (63.5%) individuals were female. The mean age of the participants was 36.5 ± 11.9 years. The adjusted risks of MS were 4.40; 95% CI: 1.73 to 11.1 for measles and 4.75; 95% CI: 2.05 to 11 for amoxicillin consumption. The adjusted MS odds for autoimmune disease including 4.63; 95% CI: 0.35 to 60.6 for psoriasis and 7.15; 95% CI: 1.87 to 27.2 for myasthenia gravis. On the other hand, the calculated adjusted odds of MS occurrence were 0.14; 95% CI: 0.03 to 0.69 for seizure and 0.17; 95% CI: 0.02 to 1.49 for epilepsy. This study suggested that individuals with autoimmune diseases should be monitored more closely, as they may be at an increased risk of developing other autoimmune conditions, particularly MS.

Potentially toxic elements in the brains of people with multiple sclerosis

Potentially toxic elements such as lead and aluminium have been proposed to play a role in the pathogenesis of multiple sclerosis (MS), since their neurotoxic mechanisms mimic many of the pathogenetic processes in MS. We therefore examined the distribution of several potentially toxic elements in the autopsied brains of people with and without MS, using two methods of elemental bio-imaging. Toxicants detected in the locus ceruleus were used as indicators of past exposures. Autometallography of paraffin sections from multiple brain regions of 21 MS patients and 109 controls detected inorganic mercury, silver, or bismuth in many locus ceruleus neurons of both groups, and in widespread blood vessels, oligodendrocytes, astrocytes, and neurons of four MS patients and one control. Laser ablation-inductively coupled plasma-mass spectrometry imaging of pons paraffin sections from all MS patients and 12 controls showed that combinations of iron, silver, lead, aluminium, mercury, nickel, and bismuth were present more often in the locus ceruleus of MS patients and were located predominantly in white matter tracts. Based on these results, we propose that metal toxicants in locus ceruleus neurons weaken the blood-brain barrier, enabling multiple interacting toxicants to pass through blood vessels and enter astrocytes and oligodendroglia, leading to demyelination.

Assessment of Motor Evoked Potentials in Multiple Sclerosis

Transcranial magnetic stimulation (TMS) is a noninvasive technique mainly used for the assessment of corticospinal tract integrity and excitability of the primary motor cortices. Motor evoked potentials (MEPs) play a pivotal role in TMS studies. TMS clinical guidelines, concerning the use and interpretation of MEPs in diagnosing and monitoring corticospinal tract integrity in people with multiple sclerosis (pwMS), were established almost ten years ago and refer mainly to the use of TMS implementation; this comprises the magnetic stimulator connected to a standard EMG unit, with the positioning of the coil performed by using the external landmarks on the head. The aim of the present work was to conduct a narrative literature review on the MEP assessment and outcome measures in clinical and research settings, assessed by TMS Methodological characteristics of different TMS system implementations (TMS without navigation, line-navigated TMS and e-field-navigated TMS); these were discussed in the context of mapping the corticospinal tract integrity in MS. An MEP assessment of two case reports, by using an e-field-navigated TMS, was presented; the results of the correspondence between the e-field-navigated TMS with MRI, and the EDSS classifications were presented. Practical and technical guiding principles for the improvement of TMS studies in MEP assessment for MS are discussed, suggesting the use of e-field TMS assessment in the sense that it can improve the accuracy of corticospinal tract integrity testing by providing a more objective correspondence of the neurophysiological (e-field-navigated TMS) and clinical (Expanded Disability Status Scale-EDSS) classifications.

High prevalence of low-allele-fraction somatic mutations in STAT3 in peripheral blood CD8+ cells in multiple sclerosis patients and controls

Somatic mutations have a central role in cancer, but there are also a few rare autoimmune diseases in which somatic mutations play a major role. We have recently shown that nonsynonymous somatic mutations with low allele fractions are preferentially detectable in CD8+ cells and that the STAT3 gene is a promising target for screening. Here, we analyzed somatic mutations in the STAT3 SH2 domain in peripheral blood CD8+ cells in a set of 94 multiple sclerosis (MS) patients and 99 matched controls. PCR amplicons targeting the exons 20 and 21 of STAT3 were prepared and sequenced using the Illumina MiSeq instrument with 2x300bp reads. We designed a novel variant calling method, optimized for large number of samples, high sequencing depth (>25,000x) and small target genomic area. Overall, we discovered 64 STAT3 somatic mutations in the 193 donors, of which 63 were non-synonymous and 77% have been previously reported in cancer or lymphoproliferative disease. The overall median variant allele fraction was 0.065% (range 0.007-1.2%), without significant difference between MS and controls (p = 0.82). There were 26 (28%) MS patients vs. 24 (24%) controls with mutations (p = 0.62). Two or more mutations were found in 9 MS patients vs. 2 controls (p = 0.03, pcorr = 0.12). Carriership of mutations associated with older age and lower neutrophil counts. These results demonstrate that STAT3 SH2 domain is a hotspot for somatic mutations in CD8+ cells with a prevalence of 26% among the participants. There were no significant differences in the mutation prevalences between MS patients and controls. Further research is needed to elucidate the role of antigenic stimuli in the expansion of the mutant clones. Furthermore, the high discovered prevalence of STAT3 somatic mutations makes it feasible to analyze these mutations directly in tissue-infiltrating CD8+ cells in autoimmune diseases.

Whole Exome Sequencing in Multi-Incident Families Identifies Novel Candidate Genes for Multiple Sclerosis

Multiple sclerosis (MS) is a degenerative disease of the central nervous system in which auto-immunity-induced demyelination occurs. MS is thought to be caused by a complex interplay of environmental and genetic risk factors. While most genetic studies have focused on identifying common genetic variants for MS through genome-wide association studies, the objective of the present study was to identify rare genetic variants contributing to MS susceptibility. We used whole exome sequencing (WES) followed by co-segregation analyses in nine multi-incident families with two to four affected individuals. WES was performed in 31 family members with and without MS. After applying a suite of selection criteria, co-segregation analyses for a number of rare variants selected from the WES results were performed, adding 24 family members. This approach resulted in 12 exonic rare variants that showed acceptable co-segregation with MS within the nine families, implicating the genes MBP, PLK1, MECP2, MTMR7, TOX3, CPT1A, SORCS1, TRIM66, ITPR3, TTC28, CACNA1F, and PRAM1. Of these, three genes (MBP, MECP2, and CPT1A) have been previously reported as carrying MS-related rare variants. Six additional genes (MTMR7, TOX3, SORCS1, ITPR3, TTC28, and PRAM1) have also been implicated in MS through common genetic variants. The proteins encoded by all twelve genes containing rare variants interact in a molecular framework that points to biological processes involved in (de-/re-)myelination and auto-immunity. Our approach provides clues to possible molecular mechanisms underlying MS that should be studied further in cellular and/or animal models.

Symptom-Level Disability Status Assessed with an Electronic Unsupervised Patient-Reported Expanded Disability Status Scale (ePR-EDSS) in Multiple Sclerosis Patients-The Example of Croatia

The present study aimed to apply an electronic, unsupervised patient-reported Expanded Disability Status Scale (ePR-EDSS) to investigate disability severity in people with multiple sclerosis (pwMS) as a case study in Croatia in 2021, including demographic and comorbidity characteristics and multiple sclerosis (MS) disease-related factors. The cross-sectional study was conducted as an online survey from 4 October 2021 to 31 December 2021. Symptom-level disability status was assessed with ePR-EDSS for MS capturing MS-related disability across the spectrum of severity.The study enrolled 147 pwMS patients, of which 84% were women. The mean age ± standard deviation in the sample was 41.1 ± 11.3, and the mean disease duration was 8.5 ± 7.4 years, with a median EDSS score of 3.0 (range, 0−8). The distribution of the participants according to clinical forms of MS was as follows: 71% had relapsing-remitting MS, 13% had primary progressive MS, 4% had secondary progressive PMS, and 12% did not provide information on their MS type. Twenty-nine point two percent (29.2%) of the participants had comorbidities in addition to MS. EDSS scores indicate significant differences with regard to age (t = −3.51, p < 0.001), gender (χ2 = 8.04, p < 0.01), and immunomodulatory drug use (χ2 = 5.89, p < 0.05). An ePR-EDSS analysis of disability symptoms showed a significant difference in symptoms with regard to strength, sensation, coordination, vision, fatigue, mobility, and overall wellness among MS types. Participants with PPMS and SPMS were older on average, had higher EDSS, and had more pronounced symptoms of disability measured with ePR-EDSS compared to those with RRMS. Application of ePR-EDSS shows it to be a reliable eHealth tool for clinical assessment of pwMS disability status, and future studies should correlate it with standard self-report scales capturing MS symptoms such as fatigue, depression, anxiety, and stress.

Risk Factors from Pregnancy to Adulthood in Multiple Sclerosis Outcome

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Predicting Multiple Sclerosis: Challenges and Opportunities

Determining effective means of preventing Multiple Sclerosis (MS) relies on testing preventive strategies in trial populations. However, because of the low incidence of MS, demonstrating that a preventive measure has benefit requires either very large trial populations or an enriched population with a higher disease incidence. Risk scores which incorporate genetic and environmental data could be used, in principle, to identify high-risk individuals for enrolment in preventive trials. Here we discuss the concepts of developing predictive scores for identifying individuals at high risk of MS. We discuss the empirical efforts to do so using real cohorts, and some of the challenges-both theoretical and practical-limiting this work. We argue that such scores could offer a means of risk stratification for preventive trial design, but are unlikely to ever constitute a clinically-helpful approach to predicting MS for an individual.

Exosomes with FOXP3 from gene-modified dendritic cells ameliorate the development of EAE by regulating the balance of Th/Treg

Objective: To investigate the efficiency and potential mechanisms of exosomes from dendritic cells (DCs) transfected with Forkhead box protein P3 (FOXP3) in the development of experimental autoimmune encephalomyelitis (EAE). Method: Mouse bone marrow-derived immature DCs were loaded with adenovirus carrying FOXP3 gene, and exosomes were generated. Then the exosomes with FOXP3 (FOXP3-EXOs) were co-cultured with CD4+T cell in vitro to evaluate their potential on CD4+T cell proliferation and differentiation, and injected into EAE mice to assess their effects on the development of EAE. Result: FOXP3-EXOs were effective to inhibit the CD4⁺T cell proliferation and the production of Interferon gamma (IFN-γ), interleukin (IL)-6, and IL-17, while they promoted the production of IL-10 in vitro. Moreover, FOXP3-EXOs treatment significantly decreased the neurological scores, reduced the infiltration of inflammatory cells into the spinal cord, and decreased demyelination in comparison to saline and Con-EXOs treated EAE mice. Moreover, the FOXP3-EXOs treatment resulted in obvious increases in the levels of regulatory T (Treg) cells and IL-10, whereas levels of T helper 1 (Th1) cells, Th17 cells, IFN-γ, IL-6, and IL-17 decreased significantly in the splenocyte culture of EAE mice. Conclusion: The present study preliminarily investigated the effects and potential mechanisms of FOXP3-EXOs in EAE and revealed that the FOXP3-EXOs could inhibit the production of Th1 and Th17 cells and promote the production of Treg cells as well as ameliorate the development of EAE. The neuroprotective effects of FOXP3-EXOs on EAE are likely due to the regulation of Th/Treg balance.

What Can We Learn from Sex Differences in MS?

Multiple sclerosis (MS) is the major acquired central nervous system disease of young adults. It is a female predominant disease. Multiple aspects of MS are influenced by sex-based differences. This has become an important area of research and study. It teaches us how the impact of sex on a disease can lead to new insights, guidelines, management, and treatments.

Genetic susceptibility to multiple sclerosis in African Americans

Objective

To explore the nature of genetic-susceptibility to multiple sclerosis (MS) in African-Americans.

Background

Recently, the number of genetic-associations with MS has exploded although the MS-associations of specific haplotypes within the major histocompatibility complex (MHC) have been known for decades. For example, the haplotypes HLA-DRB1*15:01~HLA-DQB1*06:02, and HLA-DRB1*03:01~ HLA-DQB1*02:01 have odds ratios (ORs) for an MS-association orders of magnitude stronger than many of these newly-discovered associations. Nevertheless, all these haplotypes are part of much larger conserved extended haplotypes (CEHs), which span both the Class I and Class II MHC regions. African-Americans are at greater risk of developing MS compared to a native Africans but at lesser risk compared to Europeans. It is the purpose of this manuscript to explore the relationship between MS-susceptibility and the CEH make-up of our African-American cohort.

Design/methods

The African-American (AA) cohort consisted of 1,305 patients with MS and 1,155 controls, who self-identified as being African-American. For comparison, we used the 18,492 controls and 11,144 MS-cases from the predominantly European Wellcome Trust Case Control Consortium (WTCCC) and the 28,557 phased native Africans from the multinational “Be the Match” registry. The WTCCC and the African-Americans were phased at each of five HLA loci (HLA-A, HLA-C, HLA-B, HLA-DRB1 and HLA-DQB1) and the at 11 SNPs (10 of which were in non-coding regions) surrounding the Class II region of the DRB1 gene using previously-published probabilistic phasing algorithms.

Results

Of the 32 most frequent CEHs, 18 (56%) occurred either more frequently or exclusively in Africans) whereas 9 (28%) occurred more frequently or exclusively in Europeans. The remaining 5 CEHs occurred in neither control group although, likely, these were African in origin. Eight of these CEHs carried the DRB1*15:03~DQB1*06:02~a36 haplotype and three carried the DRB1*15:01~DQB1*06:02~a1 haplotype. In African Americans, a single-copy of the European CEH (03:01_07:02_07:02_15:01_06:02_a1) was associated with considerable MS-risk (OR = 3.30; p = 0.0001)–similar to that observed in the WTCCC (OR = 3.25; p<10⁻¹⁶⁸). By contrast, the MS-risk for the European CEH (02:01_07:02_07:02_15:01_06:02_a1) was less (OR = 1.49; ns)–again, similar to the WTCCC (OR = 2.2; p<10⁻³⁸). Moreover, four African haplotypes were “protective” relative to a neutral reference, to three European CEHs, and also to the five other African CEHs.

Conclusions

The common CEHs in African Americans are divisible into those that are either African or European in origin, which are derived without modification from their source population. European CEHs, linked to MS-risk, in general, had similar impacts in African-Americans as they did in Europeans. By contrast, African CEHs had mixed MS-risks. For a few, the MS-risk exceeded that in a neutral-reference group whereas, for many others, these CEHs were “protective”–perhaps providing a partial rationale for the lower MS-risk in African-Americans compared to European-Americans.

Genetic susceptibility to multiple sclerosis: interactions between conserved extended haplotypes of the MHC and other susceptibility regions

Background

To study the accumulation of MS-risk resulting from different combinations of MS-associated conserved-extended-haplotypes (CEHs) of the MHC and three non-MHC “risk-haplotypes” nearby genes EOMES, ZFP36L1, and CLEC16A. Many haplotypes are MS-associated despite having population-frequencies exceeding the percentage of genetically-susceptible individuals. The basis of this frequency-disparity requires explanation.

Methods

The SNP-data from the WTCCC was phased at the MHC and three non-MHC susceptibility-regions. CEHs at the MHC were classified into five haplotype-groups: (HLA-DRB1*15:01 ~ DQB1*06:02 ~ a1)-containing (H +); extended-risk (ER); all-protective (AP); neutral (0); and the single-CEH (c1). MS-associations for different “risk-combinations” at the MHC and other non-MHC “risk-loci” and the appropriateness of additive and multiplicative risk-accumulation models were assessed.

Results

Different combinations of “risk-haplotypes” produce a final MS-risk closer to additive rather than multiplicative risk-models but neither model was consistent. Thus, (H +)-haplotypes had greater impact when combined with (0)-haplotypes than with (H +)-haplotypes, whereas, (H +)-haplotypes had greater impact when combined with a (c1)-haplotypes than with (0)-haplotypes. Similarly, risk-genotypes (0,H +), (c1,H +), (H + ,H +) and (0,c1) were additive with risks from non-MHC risk-loci, whereas risk-genotypes (ER,H +) and (AP,c1) were unaffected.

Conclusions

Genetic-susceptibility to MS is essential for MS to develop but actually developing MS depends heavily upon both an individual’s particular combination of “risk-haplotypes” and how these loci interact.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01018-6.