Sunlight exposure exerts immunomodulatory effects to reduce multiple sclerosis severity

Infiltration by monocytes of the central nervous system and its role in multiple sclerosis: reflections on therapeutic strategies

Mononuclear macrophage infiltration in the central nervous system is a prominent feature of neuroinflammation. Recent studies on the pathogenesis and progression of multiple sclerosis have highlighted the multiple roles of mononuclear macrophages in the neuroinflammatory process. Monocytes play a significant role in neuroinflammation, and managing neuroinflammation by manipulating peripheral monocytes stands out as an effective strategy for the treatment of multiple sclerosis, leading to improved patient outcomes. This review outlines the steps involved in the entry of myeloid monocytes into the central nervous system that are targets for effective intervention: the activation of bone marrow hematopoiesis, migration of monocytes in the blood, and penetration of the blood-brain barrier by monocytes. Finally, we summarize the different monocyte subpopulations and their effects on the central nervous system based on phenotypic differences. As activated microglia resemble monocyte-derived macrophages, it is important to accurately identify the role of monocyte-derived macrophages in disease. Depending on the roles played by monocyte-derived macrophages at different stages of the disease, several of these processes can be interrupted to limit neuroinflammation and improve patient prognosis. Here, we discuss possible strategies to target monocytes in neurological diseases, focusing on three key aspects of monocyte infiltration into the central nervous system, to provide new ideas for the treatment of neurodegenerative diseases.

Variation in ultraviolet-B (UV-B)-induced DNA damage repair mechanisms in plants and humans: an avenue for developing protection against skin photoaging

PURPOSE

The increasing amounts of ultraviolet-B (UV-B) light in our surroundings have sparked worries about the possible effects on humans and plants. The detrimental effects of heightened UV-B exposure on these two vital elements of terrestrial life are different due to their unique and concurrent nature. Understanding common vulnerabilities and distinctive adaptations of UV-B radiation by exploring the physiological and biochemical responses of plants and the effects on human health is of huge importance. The comparative effects of UV-B radiation on plants and animals, however, are poorly studied. This review sheds light on the sophisticated web of UV-B radiation effects by navigating the complex interaction between botanical and medical perspectives, drawing upon current findings.

CONCLUSION

By providing a comprehensive understanding of the complex effects of heightened UV-B radiation on plants and humans, this study summarizes relevant adaptation strategies to the heightened UV-B radiation stress, which offer new approaches for improving human cellular resilience to environmental stressors.

Trends in mortality due to multiple sclerosis in the United States: A retrospective analysis from 1999 to 2020

BACKGROUND

Multiple sclerosis (MS) is a neuroinflammatory condition with a prevalence of about 309.2 per 100,000 people in the United States. We aim to identify MS-related mortality trends in the USA from 1999 to 2020, stratified by age, sex, race, and geography, and its correlation with sunlight.

METHODS

Death certificates from the CDC-WONDER database were examined for adults aged ≥25 years. Crude rates (CR) and age-adjusted mortality rates (AAMRs) per 1,000,000 persons and annual percent change (APC) were calculated. We also retrieved data for daily sunlight from 1999 to 2011.

RESULTS

From 1999 to 2020, a total of 121,694 deaths occurred due to MS. The AAMR rose from 23.6 in 1999 to 29.7 in 2020 (APC 0.65), with a stable trend till 2018 (APC -0.22) followed by an abrupt increase towards 2020 (APC 9.27). Women had higher AAMR than men. Non-Hispanic (NH) Whites exhibited the highest AAMR (28.5), followed by NH Blacks (25.9), NH American Indians/Alaska Natives (9.6), Hispanics or Latino (6.8), and NH Asian or Pacific Islanders (1.9). AAMRs also varied substantially by region (Midwest: 32.4; Northeast: 26.9; West: 26.2; South: 19.4). States with the highest AAMRs were Montana, Wyoming, Colorado, and Oregon. The states with lower daily sunlight had higher AAMRs (r = -0.559, p = 0.000). AAMRs were comparable in urban (25) and rural (26.3) areas. Most deaths occurred in medical facilities (33.92 %) and nursing homes / long-term care (30.80 %), followed by home (27.79 %), and hospice (4.06 %). Adults ≥ 65 years depicted the highest mortality rates (CR 64.4) while adults aged 25 to 44 years showed the lowest rates (CR 4.6).

CONCLUSION

We found an overall stable trend in MS-related mortality rates in the US till 2018 with a sharp increase thereafter. We observed highest mortality among women and NH White adults, among residents of Midwest and Northeast regions, and among adults ≥ 65 years. Higher disease burden in recent years calls for devising timely policies focused on these high-risk populations.

Endogenous retroviruses in multiple sclerosis: A network-based etiopathogenic model

The present perspective article proposes an etiopathological model for multiple sclerosis pathogenesis and progression associated with the activation of human endogenous retroviruses. We reviewed preclinical, clinical, epidemiological, and evolutionary evidence indicating how the complex, multi-level interplay of genetic traits and environmental factors contributes to multiple sclerosis. We propose that endogenous retroviruses transactivation acts as a critical node in disease development. We also discuss the rationale for combined anti-retroviral therapy in multiple sclerosis as a disease-modifying therapeutic strategy. Finally, we propose that the immuno-pathogenic process triggered by endogenous retrovirus activation can be extended to aging and aging-related neurodegeneration. In this regard, endogenous retroviruses can be envisioned to act as epigenetic noise, favoring the proliferation of disorganized cellular subpopulations and accelerating system-specific "aging". Since inflammation and aging are two sides of the same coin (plastic dis-adaptation to external stimuli with system-specific degree of freedom), the two conditions may be epiphenomenal products of increased epigenomic entropy. Inflammation accelerates organ-specific aging, disrupting communication throughout critical systems of the body and producing symptoms. Overlapping neurological symptoms and syndromes may emerge from the activity of shared molecular networks that respond to endogenous retroviruses' reactivation.

Sunlight: Time for a Rethink?

UVR is a skin carcinogen, yet no studies link sun exposure to increased all-cause mortality. Epidemiological studies from the United Kingdom and Sweden link sun exposure with reduced all-cause, cardiovascular, and cancer mortality. Vitamin D synthesis is dependent on UVB exposure. Individuals with higher serum levels of vitamin D are healthier in many ways, yet multiple trials of oral vitamin D supplementation show little benefit. Growing evidence shows that sunlight has health benefits through vitamin D-independent pathways, such as photomobilization of nitric oxide from cutaneous stores with reduction in cardiovascular morbidity. Sunlight has important systemic health benefit as well as risks.

Association between sun exposure habits and disease progression in multiple sclerosis

BACKGROUND AND PURPOSE

Higher latitude has been associated with increased occurrence of multiple sclerosis (MS) and with more severe disease. The aim was to study the impact of sun exposure habits on MS disease progression and health-related quality of life.

METHODS

Patients from a population-based case-control study were categorized based on sun exposure habits at diagnosis and were followed up to 15 years post-diagnosis through the Swedish MS registry (n = 3314) with regard to changes in Expanded Disability Status Scale (EDSS). Linear mixed models were used to analyse long-term changes, while Cox regression models, with 95% confidence intervals, were used to investigate outcomes, including 24-week confirmed diasability worsening, EDSS3, EDSS4, and physical worsening as measured by the physical component of the Multiple Sclerosis Impact Scale 29.

RESULTS

Compared to average sun exposure (median value), low exposure to sunlight was associated with faster EDSS progression, increased risk of confirmed disability worsening (hazard ratio [HR] 1.48, 95% CI 1.21-1.81), increased risk of reaching EDSS 3 (HR 1.35, 95% CI 1.02-1.79), EDSS 4 (HR 1.47, 95% CI 1.01-2.20) and self-reported physical worsening (HR 1.27, 95% CI 1.00-1.62). Significant trends revealed a lower risk of unfavourable outcomes with increasing sun exposure.

CONCLUSIONS

Very low levels of sun exposure are associated with worse disease progression and health-related quality of life in patients with MS.

The impact of genetic variants related to vitamin D and autoimmunity: A systematic review

Over the past few years, there has been a notable increment in scientific literature aimed at unraveling the genetic foundations of vitamin D signaling and its implications for susceptibility to autoimmunity, however, most of them address isolated diseases. Here, we conducted a systematic review of genetic variants related to vitamin D and autoimmune diseases and we discussed the current landscape of susceptibility and outcomes. Of 65 studies analyzed, most variants cited are in vitamin D binding protein (VDBP; rs2282679 GC gene), 25-hydroxylase (rs10751657 CYP2R1), 1α-hydroxylase (rs10877012, CYP27B1) and the nuclear hormone receptor superfamily [FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) in VDR gene]. Therefore, our findings confirmed the associations of several genetic variants of vitamin D signaling with a broad spectrum of autoimmune diseases/traits. In addition, given the low number of papers found with functional analysis, further studies to elucidate the real effect that the variants exert on Vitamin D signaling are recommended.

Photo-neuro-immuno-endocrinology: How the ultraviolet radiation regulates the body, brain, and immune system

Ultraviolet radiation (UVR) is primarily recognized for its detrimental effects such as cancerogenesis, skin aging, eye damage, and autoimmune disorders. With exception of ultraviolet B (UVB) requirement in the production of vitamin D3, the positive role of UVR in modulation of homeostasis is underappreciated. Skin exposure to UVR triggers local responses secondary to the induction of chemical, hormonal, immune, and neural signals that are defined by the chromophores and extent of UVR penetration into skin compartments. These responses are not random and are coordinated by the cutaneous neuro-immuno-endocrine system, which counteracts the action of external stressors and accommodates local homeostasis to the changing environment. The UVR induces electrical, chemical, and biological signals to be sent to the brain, endocrine and immune systems, as well as other central organs, which in concert regulate body homeostasis. To achieve its central homeostatic goal, the UVR-induced signals are precisely computed locally with transmission through nerves or humoral signals release into the circulation to activate and/or modulate coordinating central centers or organs. Such modulatory effects will be dependent on UVA and UVB wavelengths. This leads to immunosuppression, the activation of brain and endocrine coordinating centers, and the modification of different organ functions. Therefore, it is imperative to understand the underlying mechanisms of UVR electromagnetic energy penetration deep into the body, with its impact on the brain and internal organs. Photo-neuro-immuno-endocrinology can offer novel therapeutic approaches in addiction and mood disorders; autoimmune, neurodegenerative, and chronic pain-generating disorders; or pathologies involving endocrine, cardiovascular, gastrointestinal, or reproductive systems.

Multiple sclerosis endophenotypes identified by high-dimensional blood signatures are associated with distinct disease trajectories

One of the biggest challenges in managing multiple sclerosis is the heterogeneity of clinical manifestations and progression trajectories. It still remains to be elucidated whether this heterogeneity is reflected by discrete immune signatures in the blood as a surrogate of disease pathophysiology. Accordingly, individualized treatment selection based on immunobiological principles is still not feasible. Using two independent multicentric longitudinal cohorts of patients with early multiple sclerosis (n = 309 discovery and n = 232 validation), we were able to identify three distinct peripheral blood immunological endophenotypes by a combination of high-dimensional flow cytometry and serum proteomics, followed by unsupervised clustering. Longitudinal clinical and paraclinical follow-up data collected for the cohorts revealed that these endophenotypes were associated with disease trajectories of inflammation versus early structural damage. Investigating the capacity of immunotherapies to normalize endophenotype-specific immune signatures revealed discrete effect sizes as illustrated by the limited effect of interferon-β on endophenotype 3-related immune signatures. Accordingly, patients who fell into endophenotype 3 subsequently treated with interferon-β exhibited higher disease progression and MRI activity over a 4-year follow-up compared with treatment with other therapies. We therefore propose that ascertaining a patient's blood immune signature before immunomodulatory treatment initiation may facilitate prediction of clinical disease trajectories and enable personalized treatment decisions based on pathobiological principles.

Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin

Ultraviolet (UV) radiation is ubiquitous in the environment, which has been classified as an established human carcinogen. As the largest and outermost organ of the body, direct exposure of skin to sunlight or UV radiation can result in sunburn, inflammation, photo-immunosuppression, photoaging and even skin cancers. To date, there are tactics to protect the skin by preventing UV radiation and reducing the amount of UV radiation to the skin. Nevertheless, deciphering the essential regulatory mechanisms may pave the way for therapeutic interventions against UV-induced skin disorders. Additionally, UV light is considered beneficial for specific skin-related conditions in medical UV therapy. Recent evidence indicates that the biological effects of UV exposure extend beyond the skin and include the treatment of inflammatory diseases, solid tumors and certain abnormal behaviors. This review mainly focuses on the effects of UV on the skin. Moreover, novel findings of the biological effects of UV in other organs and systems are also summarized. Nevertheless, the mechanisms through which UV affects the human organism remain to be fully elucidated to achieve a more comprehensive understanding of its biological effects.

Vitamin D as a Modulator of Neuroinflammation: Implications for Brain Health

Neuroinflammation represents a critical immune response within the brain, playing a pivotal role in defense against injury and infection. However, when this response becomes chronic, it can contribute to the development of various neurodegenerative and psychiatric disorders. This bibliographic review delves into the role of vitamin D in modulating neuroinflammation and its implications for brain health, particularly in the context of neurological and psychiatric disorders. While vitamin D is traditionally associated with calcium homeostasis and bone health, it also exerts immunomodulatory and neuroprotective effects within the central nervous system. Through comprehensive analysis of preclinical and clinical studies, we uncover how vitamin D, acting through its receptors in glial cells, may influence the production of proinflammatory cytokines and antioxidants, potentially mitigating the cascade of events leading to neuronal damage. Clinical research has identified vitamin D deficiency as a common thread in the increased risks of multiple sclerosis, Parkinson's disease, Alzheimer's, and depression, among others. Furthermore, preclinical models suggest vitamin D's regulatory capacity over inflammatory mediators, its protective role against neuronal apoptosis, and its contribution to neurogenesis and synaptic plasticity. These insights underscore the potential of vitamin D supplementation not only in slowing the progression of neurodegenerative diseases but also in improving the quality of life for patients suffering from psychiatric conditions. Future clinical studies are essential to validate these findings and further our understanding of vitamin D's capacity to prevent or alleviate symptoms, opening new avenues for therapeutic strategies against neuroinflammation-related pathologies. Neuroinflammation is a crucial immune response in the brain against injuries or infections, but its persistence can lead to diseases such as Alzheimer's, Parkinson's, multiple sclerosis, and depression. Cholecalciferol (Vitamin D3) emerges as a regulator of neuroinflammation, present in brain cells such as astrocytes and microglia, modulating immune function. Vitamin D's mechanisms of action include cytokine modulation and regulation of nuclear and mitochondrial genes. It adjusts inflammatory mediators and antioxidants, resulting in neuroprotective effects. Additionally, vitamin D impacts neurotransmitter synthesis and brain plasticity. This positions vitamin D as a potential adjunct in treating diseases like Alzheimer's and Parkinson's. Lastly, its role in intestinal microbiota and serotonin synthesis contributes to psychiatric disorders like schizophrenia and depression. Thus, vitamin D presents a novel therapeutic approach for neuroinflammatory, neurodegenerative, and neuropsychiatric diseases.

Linking Mechanisms of Vitamin D Signaling with Multiple Sclerosis

Environmental triggers often work via signal transduction cascades that modulate the epigenome and transcriptome of cell types involved in the disease process. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system being characterized by a combination of recurring inflammation, demyelination and progressive loss of axons. The mechanisms of MS onset are not fully understood and genetic variants may explain only some 20% of the disease susceptibility. From the environmental factors being involved in disease development low vitamin D levels have been shown to significantly contribute to MS susceptibility. The pro-hormone vitamin D3 acts via its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) as a high affinity ligand to the transcription factor VDR (vitamin D receptor) and is a potent modulator of the epigenome at thousands of genomic regions and the transcriptome of hundreds of genes. A major target tissue of the effects of 1,25(OH)2D3 and VDR are cells of innate and adaptive immunity, such as monocytes, dendritic cells as well as B and T cells. Vitamin D induces immunological tolerance in T cells and reduces inflammatory reactions of various types of immune cells, all of which are implicated in MS pathogenesis. The immunomodulatory effects of 1,25(OH)2D3 contribute to the prevention of MS. However, the strength of the responses to vitamin D3 supplementation is highly variegated between individuals. This review will relate mechanisms of individual's vitamin D responsiveness to MS susceptibility and discuss the prospect of vitamin D3 supplementation as a way to extinguish the autoimmunity in MS.

Factors associated with depressive mood at the onset of multiple sclerosis - an analysis of 781 patients of the German NationMS cohort

Background

Depression has a major impact on the disease burden of multiple sclerosis (MS). Analyses of overlapping MS and depression risk factors [smoking, vitamin D (25-OH-VD) and Epstein-Barr virus (EBV) infection] and sex, age, disease characteristics and neuroimaging features associated with depressive symptoms in early MS are scarce.

Objectives

To assess an association of MS risk factors with depressive symptoms within the German NationMS cohort.

Design

Cross-sectional analysis within a multicenter observational study.

Methods

Baseline data of n = 781 adults with newly diagnosed clinically isolated syndrome or relapsing-remitting MS qualified for analysis. Global and region-specific magnetic resonance imaging (MRI)-volumetry parameters were available for n = 327 patients. Association of demographic factors, MS characteristics and risk factors [sex, age, smoking, disease course, presence of current relapse, expanded disability status scale (EDSS) score, fatigue (fatigue scale motor cognition), 25-OH-VD serum concentration, EBV nuclear antigen-1 IgG (EBNA1-IgG) serum levels] and depressive symptoms (Beck Depression Inventory-II, BDI-II) was tested as a primary outcome by multivariable linear regression. Non-parametric correlation and group comparison were performed for associations of MRI parameters and depressive symptoms.

Results

Mean age was 34.3 years (95% confidence interval: 33.6-35.0). The female-to-male ratio was 2.3:1. At least minimal depressive symptoms (BDI-II > 8) were present in n = 256 (32.8%), 25-OH-VD deficiency (<20 ng/ml) in n = 398 (51.0%), n = 246 (31.5%) participants were smokers. Presence of current relapse [coefficient (c) = 1.48, p = 0.016], more severe fatigue (c = 0.26, p < 0.0001), lower 25-OH-VD (c = -0.03, p = 0.034) and smoking (c = 0.35, p = 0.008) were associated with higher BDI-II scores. Sex, age, disease course, EDSS, month of visit, EBNA1-IgG levels and brain volumes at baseline were not.

Conclusion

Depressive symptoms need to be assessed in early MS. Patients during relapse seem especially vulnerable to depressive symptoms. Contributing factors such as fatigue, vitamin D deficiency and smoking, could specifically be targeted in future interventions and should be investigated in prospective studies.

Triggering multiple sclerosis at conception and early gestation: The variation in ultraviolet radiation is as important as its intensity

Background and objectives

Medical science needs to further elucidate the role of ultraviolet radiation (UVR), geographic latitude, and the role of vitamin D in the autoimmune disease multiple sclerosis (MS). We separated several papers into categories out of the thousands published and used their conclusions to explore the relationship between UVR and MS.

Relevance

MS is increasing in incidence, particularly in women where MS is two to three times that in men and particularly severe in African Americans.

Methods

We collected UVR data at our observatory in Central Maine and calculated the average coefficient of variation (CVUVR) for each month for 15 years (2007-2021, inclusive).

Results

The month of conception (MOC) is more important than the month of birth (MOB) in explaining how UVR triggers the variable genetic predisposition to MS. We hypothesize that the rapidly increasing CVUVR is important in preventing an increase in the activity of the vitamin D receptor (VDR) from August to December, which then requires a higher intensity of UVR later in life to suppress the immune system, therefore predisposing to more MS.

Limitations

One observatory at about 44° latitude.

Conclusions

While variation in UVR is important at the MOC if UVR exceeds a threshold (e.g., if the sunspot number equals or is greater than 90, usually at a solar cycle MAX, or at elevations above approximately 3,000 feet above sea level), the MS mitigating vitamin D-VDR mechanism is overwhelmed and the genotoxic effects of higher-intensity UVR promote MS in those with a genetic predisposition.

What is new in this research

This paper offers a new concept in MS research.

High-dose vitamin D3 supplementation in relapsing-remitting multiple sclerosis: a randomised clinical trial

Background

Vitamin D insufficiency is associated with risk of multiple sclerosis (MS) relapse; whether supplementation influences prognosis is unknown. The Vitamin D to Ameliorate MS (VIDAMS) trial aimed to determine if high dose (5000 International Units (IU)/day) versus low dose (600 IU/day) vitamin D_3, added to daily glatiramer acetate (GA), reduced the risk of clinical relapse in people with established relapsing remitting MS (RRMS) over 96 weeks.

Methods

VIDAMS is a randomised, phase 3, double-blind, multi-centre, controlled trial conducted at sixteen neurology clinics in the United States. Participants with MAGNIMS 2010 RRMS, aged 18-50 years, with recent disease activity were eligible to enroll if they had an Expanded Disability Status Scale score ≤4.0; minimum serum 25-hydroxyvitamin D level of 15 ng/ml within 30 days of screening; and average ≤ 1000 IU supplemental vitamin D₃ daily in the 90 days prior to screening. Of 203 screened, 183 were eligible for the 30-day run-in to assess GA adherence, after which 172 were randomised 1:1 to low dose vitamin D₃ (LDVD) or high dose vitamin D₃ (HDVD), and were followed every 12 weeks for 96 weeks. The primary outcome was the proportion that experienced a confirmed relapse and analyses used Kaplan Meier and Cox proportional hazards models. 165 participants returned for ≥1 follow-up visit and were included in the primary and safety analyses; 140 completed a week 96 visit. This study was registered with ClinicalTrials.gov, NCT01490502.

Findings

Between March 22, 2012 and March 8, 2019, 172 participants were enrolled and randomised (83 LDVD, 89 HDVD) and differed at baseline only in gender and race: more males received HDVD (31%) than LDVD (16%), and fewer Black participants received HDVD (12%) than LDVD (22%). Among 165 participants with at least one follow-up visit, the proportion experiencing confirmed relapse did not differ between LDVD and HDVD [at 96 weeks: 32% vs. 34%, p = 0.60; hazard ratio (HR): 1.17 (0.67, 2.05), p = 0.57]. There was no hypercalcaemia. Three participants developed nephrolithiasis or ureterolithiasis (1 in the LDVD and 2 in the HDVD group). Two were possibly related to study drug; and one was presumed related to concomitant treatment with topiramate for migraine.

Interpretation

VIDAMS provides evidence that HDVD supplementation, added to GA, does not reduce the risk of clinical relapse in people with RRMS. Taken together with the null findings of previous trials, these results suggest that prescribing higher doses of vitamin D for purposes of modifying the RRMS course may not be beneficial.

Funding

This investigation was supported by a grant from the National Multiple Sclerosis Society (RG 4407A2/1). Teva Neuroscience, Inc. provided Copaxone (GA) for the duration of the trial.

The effects of exposure to solar radiation on human health

This assessment by the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol under the United Nations Environment Programme (UNEP) evaluates the effects of ultraviolet (UV) radiation on human health within the context of the Montreal Protocol and its Amendments. We assess work published since our last comprehensive assessment in 2018. Over the last four years gains have been made in knowledge of the links between sun exposure and health outcomes, mechanisms, and estimates of disease burden, including economic impacts. Of particular note, there is new information about the way in which exposure to UV radiation modulates the immune system, causing both harms and benefits for health. The burden of skin cancer remains high, with many lives lost to melanoma and many more people treated for keratinocyte cancer, but it has been estimated that the Montreal Protocol will prevent 11 million cases of melanoma and 432 million cases of keratinocyte cancer that would otherwise have occurred in the United States in people born between 1890 and 2100. While the incidence of skin cancer continues to rise, rates have stabilised in younger populations in some countries. Mortality has also plateaued, partly due to the use of systemic therapies for advanced disease. However, these therapies are very expensive, contributing to the extremely high economic burden of skin cancer, and emphasising the importance and comparative cost-effectiveness of prevention. Photodermatoses, inflammatory skin conditions induced by exposure to UV radiation, can have a marked detrimental impact on the quality of life of sufferers. More information is emerging about their potential link with commonly used drugs, particularly anti-hypertensives. The eyes are also harmed by over-exposure to UV radiation. The incidence of cataract and pterygium is continuing to rise, and there is now evidence of a link between intraocular melanoma and sun exposure. It has been estimated that the Montreal Protocol will prevent 63 million cases of cataract that would otherwise have occurred in the United States in people born between 1890 and 2100. Despite the clearly established harms, exposure to UV radiation also has benefits for human health. While the best recognised benefit is production of vitamin D, beneficial effects mediated by factors other than vitamin D are emerging. For both sun exposure and vitamin D, there is increasingly convincing evidence of a positive role in diseases related to immune function, including both autoimmune diseases and infection. With its influence on the intensity of UV radiation and global warming, the Montreal Protocol has, and will have, both direct and indirect effects on human health, potentially changing the balance of the risks and benefits of spending time outdoors.

Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis

Previous studies revealed a latitudinal gradient of multiple sclerosis (MS) prevalence, increasing by moving from the equator to the poles. The duration and quality of an individual's exposure to sunlight vary with latitude. Skin exposure to sunlight activates vitamin D synthesis, while light absence, as perceived by the eyes, activates melatonin synthesis in the pineal gland. Vitamin D or melatonin deficiency/insufficiency or overdose can occur at any latitude due to specific lifestyles and diets. Moving away from the equator, especially beyond 37°, decreases vitamin D while raising melatonin. Furthermore, melatonin synthesis increases in cold habitats like northern countries. Since melatonin's beneficial role was shown in MS, it is expected that northern countries whose individuals have higher endogenous melatonin should show a lower MS prevalence; however, these are ranked with the highest scores. In addition, countries like the United States and Canada have uncontrolled over-the-counter usage. In high latitudes, vitamin D deficiency and a higher MS prevalence persist even though vitamin D is typically compensated for by supplementation and not sunlight. Recently, we found that prolonged darkness increased MS melatonin levels, mimicking the long-term increase in northern countries. This caused a reduction in cortisol and increased infiltration, inflammation, and demyelination, which were all rescued by constant light therapy. In this review, we explain melatonin and vitamin D's possible roles in MS prevalence. The possible causes in northern countries are then discussed. Finally, we suggest strategies to treat MS by manipulating vitamin D and melatonin, preferably with sunlight or darkness, not supplements.

The Ah Receptor from Toxicity to Therapeutics: Report from the 5th AHR Meeting at Penn State University, USA, June 2022

The aryl hydrocarbon receptor (AHR) is a sensor of low-molecular-weight molecule signals that originate from environmental exposures, the microbiome, and host metabolism. Building upon initial studies examining anthropogenic chemical exposures, the list of AHR ligands of microbial, diet, and host metabolism origin continues to grow and has provided important clues as to the function of this enigmatic receptor. The AHR has now been shown to be directly involved in numerous biochemical pathways that influence host homeostasis, chronic disease development, and responses to toxic insults. As this field of study has continued to grow, it has become apparent that the AHR is an important novel target for cancer, metabolic diseases, skin conditions, and autoimmune disease. This meeting attempted to cover the scope of basic and applied research being performed to address possible applications of our basic knowledge of this receptor on therapeutic outcomes.

Seasonal Changes in Serum Metabolites in Multiple Sclerosis Relapse

Multiple sclerosis (MS) is a debilitating chronic disease of unknown etiology. There are limited treatment options due to an incomplete understanding of disease pathology. The disease is shown to have seasonal exacerbation of clinical symptoms. The mechanisms of such seasonal worsening of symptoms remains unknown. In this study, we applied targeted metabolomics analysis of serum samples using LC-MC/MC to determine seasonal changes in metabolites throughout the four seasons. We also analyzed seasonal serum cytokine alterations in patients with relapsed MS. For the first time, we can demonstrate seasonal changes in various metabolites in MS compared to the control. More metabolites were affected in MS in the fall season followed by spring, while summer MS was characterized by the smallest number of affected metabolites. Ceramides were activated in all seasons, suggesting their central role in the disease pathogenesis. Substantial changes in glucose metabolite levels were found in MS, indicating a potential shift to glycolysis. An increased serum level of quinolinic acid was demonstrated in winter MS. Histidine pathways were affected, suggesting their role in relapse of MS in the spring and fall. We also found that spring and fall seasons had a higher number of overlapping metabolites affected in MS. This could be explained by patients having a relapse of symptoms during these two seasons.

In Vivo Corneal Confocal Microscopy in Multiple Sclerosis: Can it Differentiate Disease Relapse in Multiple Sclerosis?

PURPOSE

This study aims to investigate the role of in vivo corneal confocal microscopy (IVCCM) in the detection of corneal inflammatory activity and subbasal nerve alterations in patients with multiple sclerosis (MS) and to further determine whether IVCCM can be used to detect (acute) disease relapse.

DESIGN

Prospective cross-sectional study, with a subgroup follow-up.

METHODS

This single-center study included 58 patients with MS (MS-Relapse group [n = 27] and MS-Remission group [n = 31]), and 30 age- and sex-matched healthy control subjects. Patients with a history of optic neuritis or trigeminal symptoms were excluded. Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and dendritic cell (DC) density were evaluated in all patients with MS and control subjects by IVCCM. Patients in the MS-Relapse group who were in remission for ≥6 months after the MS incident underwent a repeat IVCCM.

RESULTS

No statistical difference was observed between the MS-Relapse and MS-Remission groups regarding age, sex, MS duration, and the number of relapses (P > .05). Compared with healthy control subjects, all subbasal nerve parameters were significantly lower (CNFD: P < .001, CNFL: P < .001, CNBD: P < .001), and the DC density was significantly higher (P = .023) in patients with MS. However, no significant difference was observed between MS-Relapse and MS-Remission groups in terms of CNFD (mean [SE] difference -2.05 [1.69] fibers/mm² [95% confidence interval {CI} -1.32 to 5.43]; P < .227), CNFL (mean [SE] difference -1.10 [0.83] mm/mm² [95% CI -0.56 to 2.75]; P < .190), CNBD (mean [SE] difference -3.91 [2.48] branches/mm² [95% CI -1.05 to 8.87]; P < .120), and DC density (median [IQR], 59.38 [43.75-85.0] vs 75.0 [31.25-128.75]; P = .596). The repeat IVCCM in relapse patients (n = 16 [59.3%]) showed a significant increase in CNFD (P = .036) and CNBD (P = .018), but no change was observed in CNFL (P = .075) and DC density (P = .469).

CONCLUSION

Although increased inflammation and neurodegeneration can be demonstrated in patients with MS compared with healthy control subjects, a single time point evaluation of IVCCM does not seem to be sufficient to confirm the occurrence of relapse in patients with MS. However, IVCCM holds promise for demonstrating early neuroregeneration in patients with MS.

A Comprehensive Exploration of the Transcriptomic Landscape in Multiple Sclerosis: A Systematic Review

Multiple Sclerosis (MS) is, to date, an incurable disease of the nervous system characterized by demyelination. Several genetic mutations are associated with the disease but they are not able to explain all the diagnosticated cases. Thus, it is suggested that altered gene expression may play a role in human pathologies. In this review, we explored the role of the transcriptomic profile in MS to investigate the main altered biological processes and pathways involved in the disease. Herein, we focused our attention on RNA-seq methods that in recent years are producing a huge amount of data rapidly replacing microarrays, both with bulk and single-cells. The studies evidenced that different MS stages have specific molecular signatures and non-coding RNAs may play a key role in the disease. Sex-dependence was observed before and after treatments used to alleviate symptomatology activating different biological processes in a drug-dependent manner. New pathways, such as neddylation, were found deregulated in MS and inflammation was linked to neuron degeneration areas through spatial transcriptomics. It is evident that the use of RNA-seq in the study of complex pathologies, such as MS, is a valid strategy to shed light on new involved mechanisms.

Enhanced pathogenicity of Th17 cells due to natalizumab treatment: Implications for MS disease rebound

After natalizumab (NAT) cessation, some multiple sclerosis (MS) patients experience a severe disease rebound. The rebound pathophysiology is still unclear; however, it has been linked to interleukin-17-producing T-helper (Th17) cells. We demonstrate that during NAT treatment, MCAM+CCR6+Th17 cells gradually acquire a pathogenic profile, including proinflammatory cytokine production, pathogenic transcriptional signatures, brain endothelial barrier impairment, and oligodendrocyte damage via induction of apoptotic pathways. This is accompanied by an increase in Th17 cell frequencies in the cerebrospinal fluid of NAT-treated patients. Notably, Th17 cells derived from NAT-treated patients, who later developed a disease rebound upon treatment cessation, displayed a distinct transcriptional pathogenicity profile associated with altered migratory properties. Accordingly, increased brain infiltration of patient Th17 cells was illustrated in a humanized mouse model and brain histology from a rebound patient. Therefore, peripheral blood-accumulated MCAM+CCR6+Th17 cells might be involved in rebound pathophysiology, and monitoring of changes in Th17 cell pathogenicity in patients before/during NAT treatment cessation might enable rebound risk assessment in the future.

Epstein-Barr virus infection, B-cell dysfunction and other risk factors converge in gut-associated lymphoid tissue to drive the immunopathogenesis of multiple sclerosis: a hypothesis

Multiple sclerosis is associated with Epstein-Barr virus (EBV) infection, B-cell dysfunction, gut dysbiosis, and environmental and genetic risk factors, including female sex. A disease model incorporating all these factors remains elusive. Here, we hypothesise that EBV-infected memory B cells (MBCs) migrate to gut-associated lymphoid tissue (GALT) through EBV-induced expression of LPAM-1, where they are subsequently activated by gut microbes and/or their products resulting in EBV reactivation and compartmentalised anti-EBV immune responses. These responses involve marginal zone (MZ) B cells that activate CD4⁺ T-cell responses, via HLA-DRB1, which promote downstream B-cell differentiation towards CD11c⁺/T-bet⁺ MBCs, as well as conventional MBCs. Intrinsic expression of low-affinity B-cell receptors (BCRs) by MZ B cells and CD11c⁺/T-bet⁺ MBCs promotes polyreactive BCR/antibody responses against EBV proteins (e.g. EBNA-1) that cross-react with central nervous system (CNS) autoantigens (e.g. GlialCAM). EBV protein/autoantigen-specific CD11c⁺/T-bet⁺ MBCs migrate to the meningeal immune system and CNS, facilitated by their expression of CXCR3, and induce cytotoxic CD8⁺ T-cell responses against CNS autoantigens amplified by BAFF, released from EBV-infected MBCs. An increased abundance of circulating IgA⁺ MBCs, observed in MS patients, might also reflect GALT-derived immune responses, including disease-enhancing IgA antibody responses against EBV and gut microbiota-specific regulatory IgA⁺ plasma cells. Female sex increases MZ B-cell and CD11c⁺/T-bet⁺ MBC activity while environmental risk factors affect gut dysbiosis. Thus, EBV infection, B-cell dysfunction and other risk factors converge in GALT to generate aberrant B-cell responses that drive pathogenic T-cell responses in the CNS.

Full spectrum of vitamin D immunomodulation in multiple sclerosis: mechanisms and therapeutic implications

Vitamin D deficiency has been associated with the risk of multiple sclerosis, disease activity and progression. Results from in vitro experiments, animal models and analysis of human samples from randomized controlled trials provide comprehensive data illustrating the pleiotropic actions of Vitamin D on the immune system. They globally result in immunomodulation by decreasing differentiation of effector T and B cells while promoting regulatory subsets. Vitamin D also modulates innate immune cells such as macrophages, monocytes and dendritic cells, and acts at the level of the blood–brain barrier reducing immune cell trafficking. Vitamin D exerts additional activity within the central nervous system reducing microglial and astrocytic activation. The immunomodulatory role of Vitamin D detected in animal models of multiple sclerosis has suggested its potential therapeutic use for treating multiple sclerosis. In this review, we focus on recent published data describing the biological effects of Vitamin D in animal models of multiple sclerosis on immune cells, blood–brain barrier function, activation of glial cells and its potential neuroprotective effects. Based on the current knowledge, we also discuss optimization of therapeutic interventions with Vitamin D in patients with multiple sclerosis, as well as new technologies allowing in-depth analysis of immune cell regulations by vitamin D.

Predictors of progression from a first demyelinating event to clinically definite multiple sclerosis

Understanding the predictors of progression from a first to a second demyelinating event (and formerly, a diagnosis of clinically definite multiple sclerosis) is important clinically. Previous studies have focused on predictors within a single domain, e.g. radiological, lacking prospective data across multiple domains. We tested a comprehensive set of personal, environmental, neurological, MRI and genetic characteristics, considered together, as predictors of progression from a first demyelinating event to clinically definite multiple sclerosis. Participants were aged 18–59 years and had a first demyelinating event during the study recruitment period (1 November 2003–31 December 2006) for the Ausimmune Study (n = 216) and had follow-up data to 2–3 years post-initial interview. Detailed baseline data were available on a broad range of demographic and environmental factors, MRI, and genetic and viral studies. Follow-up data included confirmation of clinically definite multiple sclerosis (or not) and changes in environmental exposures during the follow-up period. We used multivariable logistic regression and Cox proportional hazards regression modelling to test predictors of, and time to, conversion to clinically definite multiple sclerosis. On review, one participant had an undiagnosed event prior to study recruitment and was excluded (n = 215). Data on progression to clinically definite multiple sclerosis were available for 91.2% (n = 196); 77% were diagnosed as clinically definite multiple sclerosis at follow-up. Mean (standard deviation) duration of follow-up was 2.7 (0.7) years. The set of predictors retained in the best predictive model for progression from a first demyelinating event to clinically definite multiple sclerosis were as follows: younger age at first demyelinating event [adjusted odds ratio (aOR) = 0.92, 95% confidence interval (CI) = 0.87–0.97, per additional year of age); being a smoker at baseline (versus not) (aOR = 2.55, 95% CI 0.85–7.69); lower sun exposure at age 6–18 years (aOR = 0.86, 95% CI 0.74–1.00, per 100 kJ/m² increment in ultraviolet radiation dose), presence (versus absence) of infratentorial lesions on baseline magnetic resonance imaging (aOR = 7.41, 95% CI 2.08–26.41); and single nucleotide polymorphisms in human leukocyte antigen (HLA)-B (rs2523393, aOR = 0.25, 95% CI 0.09–0.68, for any G versus A:A), TNFRSF1A (rs1800693, aOR = 5.82, 95% CI 2.10–16.12, for any C versus T:T), and a vitamin D-binding protein gene (rs7041, aOR = 3.76, 95% CI 1.41–9.99, for any A versus C:C). The final model explained 36% of the variance. Predictors of more rapid progression to clinically definite multiple sclerosis (Cox proportional hazards regression) were similar. Genetic and magnetic resonance imaging characteristics as well as demographic and environmental factors predicted progression, and more rapid progression, from a first demyelinating event to a second event and clinically definite multiple sclerosis.

Therapeutic Role of Vitamin D in Multiple Sclerosis: An Essentially Contested Concept

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the nervous system with incredibly intricate etiopathogenesis involving numerous genetic, epigenetic, and environmental risk factors. Major environmental risk factors include ultraviolet (UV) radiation, vitamin D, Epstein-Barr virus (EBV) infection, smoking, and high body mass index (BMI). Vitamin D, in particular, can be viewed as one piece of this puzzle, with various tabs and pockets, occupying a sequential site. In this article, we have briefly discussed the neuroimmunology of MS and the role of vitamin D in regulating immune responses. Various observational studies and clinical trials were reviewed and discussed according to stages of disease activity and course of the disease. The data reviewed in this article implied that serum vitamin D levels greatly influence the risk of developing MS and disease activity. Long-term follow-up studies indicated that low serum vitamin D levels correlate with worse disability outcomes. Since clinical trials did not provide significant evidence, the role of vitamin D in controlling disease activity remains unresolved. Larger clinical trials are needed to support the findings of observational studies and provide significant evidence in favour of vitamin D. 

Vitamin D as a Risk Factor for Multiple Sclerosis: Immunoregulatory or Neuroprotective?

Vitamin D insufficiency during childhood has been linked to the development of multiple sclerosis (MS), typically an adult-onset inflammatory demyelinating disease of the central nervous system (CNS). Since vitamin D was known to have immunoregulatory properties on both innate and adaptive immunity, it was hypothesized that low vitamin D resulted in aberrant immune responses and the development of MS. However, vitamin D receptors are present on many cell types, including neurons, oligodendrocytes, astrocytes and microglia, and vitamin D has profound effects on development and function of the CNS. This leads to the possibility that low vitamin D may alter the CNS in a manner that makes it vulnerable to inflammation and the development of MS. This review analysis the role of vitamin D in the immune and nervous system, and how vitamin D insufficiency in children may contribute to the development of MS.

Effects of Vitamin D and Body Mass Index on Disease Risk and Relapse Hazard in Multiple Sclerosis: A Mendelian Randomization Study

Background and Objectives

Decreased vitamin D levels and obesity are associated with an increased risk for multiple sclerosis (MS). However, whether they also affect the disease course after onset remains unclear. With larger data sets now available, we used Mendelian randomization (MR) to determine whether serum 25-hydroxyvitamin D (25OHD) and body mass index (BMI) are causally associated with MS risk and, moving beyond susceptibility toward heterogeneity, with relapse hazard.

Methods

We used genetic variants from 4 distinct genome-wide association studies (GWASs) for serum 25OHD in up to 416,247 individuals and for BMI from a GWAS in 681,275 individuals. Applying 2-sample MR, we examined associations of 25OHD and BMI with the risk of MS, with summary statistics from the International Multiple Sclerosis Genetics Consortium GWAS in 14,802 MS cases and 26,703 controls. In addition, we examined associations with relapse hazard, with data from our GWAS in 506 MS cases.

Results

A 1-SD increase in genetically predicted natural-log transformed 25OHD levels decreased odds of MS up to 28% (95% CI: 12%–40%, p = 0.001) and decreased hazard for a relapse occurring up to 43% (95% CI: 15%–61%, p = 0.006). A 1-SD increase in genetically predicted BMI, corresponding to roughly 5 kg/m², increased risk for MS with 30% (95% CI: 15%–47%, p = 3.76 × 10⁻⁵). On the contrary, we did not find evidence for a causal role of higher BMI with an increased hazard for occurrence of a relapse.

Discussion

This study supports causal effects of genetically predicted serum 25OHD concentrations and BMI on risk of MS. In contrast, serum 25OHD but not BMI is significantly associated with relapse hazard after onset. These findings might offer clinical implications for both prevention and treatment.

Association of Latitude and Exposure to Ultraviolet B Radiation With Severity of Multiple Sclerosis: An International Registry Study

BACKGROUND AND OBJECTIVES

The severity of multiple sclerosis (MS) varies widely among individuals. Understanding the determinants of this heterogeneity will help clinicians optimize the management of MS. The aim of this study was to investigate the association between latitude of residence, ultraviolet B radiation exposure (UVB) and the severity of MS.

METHODS

This observational study used the MSBase registry data. The included patients met the 2005 or 2010 McDonald diagnostic criteria for MS and had a minimum dataset recorded in the registry (date of birth, sex, clinic location, date of MS symptom onset, disease phenotype at baseline and censoring, and ≥1 EDSS [Expanded Disability Status Scale] score recorded). The latitude of each study center and cumulative annualized UVB dose at study center (calculated from NASA's Total Ozone Mapping Spectrometer) at ages 6 and 18 and the year of disability assessment were calculated. Disease severity was quantified with MS Severity Score (MSSS). Quadratic regression was used to model the associations between latitude, UVB and MSSS.

RESULTS

46,128 patients contributing 453,208 visits and a cumulative follow-up of 351,196 patient-years (70% women, mean age 39.2±12, resident between latitudes 19°35´ and 56°16´) were included in this study. Latitude showed a non-linear association with MS severity. In latitudes greater than 40°, more severe disease was associated with higher latitudes (β=0.08, 95%CI: 0.04 to 0.12). For example, this translates into a mean difference of 1.3 points of MSSS between patients living in Madrid and Copenhagen. No such association was observed in latitudes <40° (β=-0.02, 95% CI:-0.06 to 0.03). The overall disability accrual was faster in those with a lower level of estimated UVB exposure before the age of 6 (β=- 0.5, 95% CI: -0.6 to 0.4) and 18 years (β=- 0.6, 95%CI:-0.7 to 0.4), as well as with lower life-time UVB exposure at the time of disability assessment (β=-1.0, 95%CI:-1.1 to 0.9).

DISCUSSION

In temperate zones, MS severity is associated with latitude. This association is mainly, but not exclusively, driven by UVB exposure contributing to both MS susceptibility and severity.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2021

The Environmental Effects Assessment Panel of the Montreal Protocol under the United Nations Environment Programme evaluates effects on the environment and human health that arise from changes in the stratospheric ozone layer and concomitant variations in ultraviolet (UV) radiation at the Earth's surface. The current update is based on scientific advances that have accumulated since our last assessment (Photochem and Photobiol Sci 20(1):1-67, 2021). We also discuss how climate change affects stratospheric ozone depletion and ultraviolet radiation, and how stratospheric ozone depletion affects climate change. The resulting interlinking effects of stratospheric ozone depletion, UV radiation, and climate change are assessed in terms of air quality, carbon sinks, ecosystems, human health, and natural and synthetic materials. We further highlight potential impacts on the biosphere from extreme climate events that are occurring with increasing frequency as a consequence of climate change. These and other interactive effects are examined with respect to the benefits that the Montreal Protocol and its Amendments are providing to life on Earth by controlling the production of various substances that contribute to both stratospheric ozone depletion and climate change.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Low sun exposure acts synergistically with high Epstein-Barr nuclear antigen 1 (EBNA-1) antibody levels in multiple sclerosis etiology

BACKGROUND

Among multiple sclerosis (MS) patients, an association has been observed between low levels of vitamin D and high Epstein-Barr nuclear antigen 1 (EBNA-1) antibody levels. However, whether sun exposure/vitamin D moderates the role of Epstein-Barr virus (EBV) infection in MS etiology is unclear. We aimed to investigate potential synergistic effects between low sun exposure and elevated EBNA-1 antibody levels regarding MS risk.

METHODS

We used a population-based case-control study involving 2017 incident cases of MS and 2443 matched controls. We used logistic regression models to calculate the odds ratios of MS with 95% confidence intervals (CIs) in subjects with different sun exposure habits and EBNA-1 status. Potential interaction on the additive scale was evaluated by calculating the attributable proportion due to interaction (AP).

RESULTS

Low sun exposure acted synergistically with high EBNA-1 antibody levels (AP 0.2, 95% CI 0.03-0.3) in its association to increased MS risk. The interaction was present regardless of HLA-DRB1*15:01 status.

CONCLUSIONS

Low sun exposure may either directly, or indirectly by affecting vitamin D levels, synergistically reinforce pathogenic mechanisms, such as aspects of the adaptive immune response, related to MS risk conveyed by EBV infection.

Pathogenesis of autoimmune demyelination: from multiple sclerosis to neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease

Autoimmunity plays a significant role in the pathogenesis of demyelination. Multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein antibody‐associated disease (MOGAD) are now recognised as separate disease entities under the amalgam of human central nervous system demyelinating disorders. While these disorders share inherent similarities, investigations into their distinct clinical presentations and lesion pathologies have aided in differential diagnoses and understanding of disease pathogenesis. An interplay of various genetic and environmental factors contributes to each disease, many of which implicate an autoimmune response. The pivotal role of the adaptive immune system has been highlighted by the diagnostic autoantibodies in NMOSD and MOGAD, and the presence of autoreactive lymphocytes in MS lesions. While a number of autoantigens have been proposed in MS, recent emphasis on the contribution of B cells has shed new light on the well‐established understanding of T cell involvement in pathogenesis. This review aims to synthesise the clinical characteristics and pathological findings, discuss existing and emerging hypotheses regarding the aetiology of demyelination and evaluate recent pathogenicity studies involving T cells, B cells, and autoantibodies and their implications in human demyelination.

More Than Effects in Skin: Ultraviolet Radiation-Induced Changes in Immune Cells in Human Blood

Cells of the skin and circulation are in constant two-way communication. Following exposure of humans to sunlight or to phototherapy, there are alterations in the number, phenotype and function of circulating blood cells. In this review, only data obtained from human studies are considered, with changes induced by UV radiation (UVR) exposure described for phagocytic leukocytes and peripheral blood mononuclear cells plus their component T and B cells, natural killer cells and dendritic cells. These immune modulations illustrate the potential of UVR to have therapeutic effects beyond the skin, and that sunlight exposure is an important environmental influence on human health.

Vitamin D supplementation in multiple sclerosis: an expert opinion based on the review of current evidence

INTRODUCTION

Vitamin D has long been known for its immune-modulating effects, next to its function in calcium metabolism. As a consequence, poor vitamin D status has been associated with many diseases including multiple sclerosis (MS). Epidemiological studies suggest an association between a poor vitamin D status and development of MS and a poor vitamin D status is associated with more relapses and faster progression after patients are diagnosed with MS.

AREA’S COVERED

The aim of the authors was to review the role of vitamin D supplementation in the treatment of MS. Pubmed was used to review literature with a focus of vitamin D supplementation trials and meta-analyses in MS.

EXPERT OPINION

There is no solid evidence to support the application of vitamin D therapy, based on current available supplementation trials, although there are some promising results in the clinically isolated syndrome (CIS) patients and young MS patients early after initial diagnosis. The authors recommend further larger clinical trials with selected patient groups, preferable CIS patients and young patients at the time of diagnosis, using vitamin D₃ supplements to reach a 100 nmol/l level, to further investigate the effects of vitamin D supplementation in MS.

Seasonal fluctuations in serum levels of vitamin D in Japanese patients with multiple sclerosis

We explored the presence of seasonal fluctuations in serum vitamin D levels and potential relationship between vitamin D levels and disease severity or prognosis in patients with multiple sclerosis (MS) in northern Japan. Serum levels of 25(OH)D in spring were significantly lower than in summer and autumn, whereas no differences in 1,25(OH)₂D levels were demonstrated among four seasons. Seasonal fluctuations in 25(OH)D were demonstrated in patients with EDSS ≤3.5, but not in those with EDSS≥4.0. Negative correlations between 25(OH)D and EDSS or MSSS were found in each season. Seasonal fluctuations in 25(OH)D levels may be affected by physical disabilities.