Narrowband UVB Phototherapy for Clinically Isolated Syndrome: A Trial to Deliver the Benefits of Vitamin D and Other UVB-Induced Molecules

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.

Phototherapy for age-related brain diseases: Challenges, successes and future

Brain diseases present a significant obstacle to both global health and economic progress, owing to their elusive pathogenesis and the limited effectiveness of pharmaceutical interventions. Phototherapy has emerged as a promising non-invasive therapeutic modality for addressing age-related brain disorders, including stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), among others. This review examines the recent progressions in phototherapeutic interventions. Firstly, the article elucidates the various wavelengths of visible light that possess the capability to penetrate the skin and skull, as well as the pathways of light stimulation, encompassing the eyes, skin, veins, and skull. Secondly, it deliberates on the molecular mechanisms of visible light on photosensitive proteins, within the context of brain disorders and other molecular pathways of light modulation. Lastly, the practical application of phototherapy in diverse clinical neurological disorders is indicated. Additionally, this review presents novel approaches that combine phototherapy and pharmacological interventions. Moreover, it outlines the limitations of phototherapeutics and proposes innovative strategies to improve the treatment of cerebral disorders.

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.

Changes in serum neurofilament light chain levels following narrowband ultraviolet B phototherapy in clinically isolated syndrome

OBJECTIVE

To determine whether serum neurofilament light chain (sNfL) levels are suppressed in patients with the clinically isolated syndrome (CIS) following narrowband ultraviolet B phototherapy (UVB-PT).

METHODS

sNfL levels were measured using a sensitive single-molecule array assay at baseline and up to 12 months in 17 patients with CIS, 10 of whom received UVB-PT, and were compared with healthy control (HC) and early relapsing remitting multiple sclerosis (RRMS) group. sNfL levels were correlated with magnetic resonance imaging total lesion volume (LV) determined using icobrain version 4.4.1 and with clinical outcomes.

RESULTS

Baseline median sNfL levels were significantly higher in the CIS (20.6 pg/mL, interquartile range [IQR] 13.7-161.4) and RRMS groups (36.6 pg/ml [IQR] 16.2-212.2) than in HC (10.7 pg/ml [IQR] 4.9-21.5) (p = .012 and p = .0002, respectively), and were strongly correlated with T2 and T1 LV at 12 months (r = .800; p = .014 and r = .833; p = .008, respectively) in the CIS group. Analysis of changes in sNfL levels over time in the CIS group showed a significant cumulative suppressive effect of UVB-PT in the first 3 months (UVB-PT -10.6% vs non-UVB-PT +58.3%; p = .04) following which the levels in the two groups converged and continued to fall.

CONCLUSIONS

Our findings provide the basis for further studies to determine the utility of sNfL levels as a marker of neuro-axonal damage in CIS and early MS and for assessing the efficacy of new therapeutic interventions such as UVB-PT.

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.

A deep dive into UV-based phototherapy: Mechanisms of action and emerging molecular targets in inflammation and cancer

UV-based phototherapy (including psoralen plus UVA (PUVA), UVB and UVA1) has a long, successful history in the management of numerous cutaneous disorders. Photoresponsive diseases are etiologically diverse, but most involve disturbances in local (and occasionally systemic) inflammatory cells and/or abnormalities in keratinocytes that trigger inflammation. UV-based phototherapy works by regulating the inflammatory component and inducing apoptosis of pathogenic cells. This results in a fascinating and complex network of simultaneous events-immediate transcriptional changes in keratinocytes, immune cells, and pigment cells; the emergence of apoptotic bodies; and the trafficking of antigen-presenting cells in skin-that quickly transform the microenvironment of UV-exposed skin. Molecular elements in this system of UV recognition and response include chromophores, metabolic byproducts, innate immune receptors, neurotransmitters and mediators such as chemokines and cytokines, antimicrobial peptides, and platelet activating factor (PAF) and PAF-like molecules that simultaneously shape the immunomodulatory effects of UV and their interplay with the microbiota of the skin and beyond. Phototherapy's key effects-proapoptotic, immunomodulatory, antipruritic, antifibrotic, propigmentary, and pro-prebiotic-promote clinical improvement in various skin diseases such as psoriasis, atopic dermatitis (AD), graft-versus-host disease (GvHD), vitiligo, scleroderma, and cutaneous T-cell lymphoma (CTCL) as well as prevention of polymorphic light eruption (PLE). As understanding of phototherapy improves, new therapies (UV- and non-UV-based) are being developed that will modify regulatory T-cells (Treg), interact with (resident) memory T-cells and /or utilize agonists and antagonists as well as antibodies targeting soluble molecules such as cytokines and chemokines, transcription factors, and a variety of membrane-associated receptors.

Effects of UVR exposure on the gut microbiota of mice and humans

Many alterations to the skin microbiome by exposure to UV radiation (UVR) have been postulated and may contribute to the ability of UVR phototherapy to regulate skin inflammatory diseases. Very recently, an effect of sub-erythemal narrowband UVB radiation (311 nm) on the gut microbiome of healthy individuals was reported. The relative abundance of Firmicutes and Proteobacteria increased in faecal samples of those receiving three exposures to narrowband UVB radiation; the Bacteroidetes phyla were reduced by UVB. In mice chronically exposed to sub-erythemal broadband UVR, similar faecal changes in Firmicutes and Bacteroidetes have been reported. Murine studies have allowed a further dissection of the relative ability of UVR and dietary vitamin D to modulate the gut microbiome by analysis of relative bacterial abundance in mice with similar 25-hydroxy vitamin D levels obtained by UVR exposure or from their diet, respectively. The studies of mice recovering from colitis suggested that dietary vitamin D could stimulate greater faecal abundance of Rikenellaceae, whilst exposure to UVR was necessary for changes to the abundance of Lachnospiraceae and Desulfovibrionaceae. Both human and murine studies report that multiple exposures to sub-erythemal UVR can increase the diversity of the gut microbiome, which in turn may be beneficial to the health of the host.

Low sun exposure increases multiple sclerosis risk both directly and indirectly

Objective

We aimed to study (1) to what extent the influence of low sun exposure on multiple sclerosis (MS) risk is mediated by low vitamin D levels; (2) whether low sun exposure or vitamin D deficiency act synergistically with HLA-DRB1*15:01 and absence of HLA-A*02:01.

Methods

We used two population-based case–control studies (7069 cases, 6632 matched controls). Subjects with different HLA alleles, sun exposure habits and vitamin D status were compared regarding MS risk, by calculating odds ratios (OR) with 95% confidence intervals (CI) employing logistic regression. Mediation analysis was used to identify the potential mediation effect of vitamin D on the relationship between low sun exposure and MS risk.

Results

Low sun exposure increased MS risk directly as well as indirectly, by affecting vitamin D status. The direct effect, expressed as OR, was 1.26 (95% CI 1.04–1.45) and the indirect effect, mediated by vitamin D deficiency, was 1.10 (95% CI 1.02–1.23). Of the total effect, nearly 30% was mediated by vitamin D deficiency. There was a significant interaction between low sun exposure and vitamin D deficiency (attributable proportion due to interaction 0.3, 95% CI 0.04–0.5) accounting for about 12% of the total effect. Further, both factors interacted with HLA-DRB1*15:01 to increase MS risk.

Interpretation

Our findings indicate that low sun exposure acts both directly on MS risk as well as indirectly, by leading to low vitamin D levels. The protective effect of sun exposure thus seems to involve both vitamin D and non-vitamin D pathways, which is of relevance for prevention, in particular for those with a genetic susceptibility to MS.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09677-3) contains supplementary material, which is available to authorized users.

The challenges of developing and optimising an assay to measure 25-hydroxyvitamin D in saliva

Accurately detecting vitamin D deficiency (defined as concentration in blood of 25-hydroxyvitamin D (25(OH)D), <20 ng/mL) is important for both clinicians and researchers. Drawing blood may be difficult in some populations, such as infants and children. We thus explored the development of a method to measure 25(OH)D concentrations in saliva, using a liquid chromatography tandem mass spectrometry (LC-MS/MS) assay. Using 25(OH)D₃ standards spiked into synthetic saliva, we generated a standard curve with high correlation (r = 0.999, Pearson's); the intra-assay and inter-assay variation were ≤3.2% and ≤13.2% (CV%), respectively. Passive collection of saliva via drooling into glass or polypropylene tubes yielded higher levels of 25(OH)D₃ than chewing on a synthetic swab. Chewing gum for at least 4 min reduced saliva levels of 25(OH)D₃. Differences in the levels of 25(OH)D₃ in saliva between the passive drooling and stimulated swab-chewing methods were normalised by adjusting for measured levels of vitamin D binding protein in saliva. Freezing samples immediately, or after 24 h of refrigeration did not affect 25(OH)D₃ levels. When saliva levels of 25(OH)D₃ were averaged from samples collected daily for three consecutive days, for which an additional centrifugation step was performed after samples were defrosted (to remove mucin), there was a positive (but non-significant) correlation between 25(OH)D₃ levels in saliva and serum (r = 0.57, p = 0.24, Pearson's) with significant correlations (r ≥ 0.88, p < 0.05) observed after further adjusting for saliva flow rate. The time of day of the collection made little difference to 25(OH)D₃ levels measured in saliva. In conclusion, we have developed an LC-MS/MS assay that accurately measures saliva 25(OH)D₃ levels, which correlated with serum levels. However, for a measurement that correlates with serum 25(OH)D it may be necessary to average results from saliva collected on three consecutive days, and adjust for differences in saliva flow rate. This would increase costs, and combined with the processing requirements for samples, could limit the applicability of this assay to large cohort and field studies.

Short-term changes in frequencies of circulating leukocytes associated with narrowband UVB phototherapy in people with clinically isolated syndrome

Clinically isolated syndrome (CIS) is the earliest clinical episode in multiple sclerosis (MS). Low environmental exposure to UV radiation is implicated in risk of developing MS, and therefore, narrowband UVB phototherapy might delay progression to MS in people with CIS. Twenty individuals with CIS were recruited, and half were randomised to receive 24 sessions of narrowband UVB phototherapy over a period of 8 weeks. Here, the effects of narrowband UVB phototherapy on the frequencies of circulating immune cells and immunoglobulin levels after phototherapy are reported. Peripheral blood samples for all participants were collected at baseline, and 1, 2, 3, 6 and 12 months after enrolment. An extensive panel of leukocyte populations, including subsets of T cells, B cells, monocytes, dendritic cells, and natural killer cells were examined in phototherapy-treated and control participants, and immunoglobulin levels measured in serum. There were significant short-term increases in the frequency of naïve B cells, intermediate monocytes, and fraction III FoxP3+ T regulatory cells, and decreases in switched memory B cells and classical monocytes in phototherapy-treated individuals. Since B cells are increasingly targeted by MS therapies, the effects of narrowband UVB phototherapy in people with MS should be investigated further.

Vitamin D C3-epimer levels are proportionally higher with oral vitamin D supplementation compared to ultraviolet irradiation of skin in mice but not humans

A proportion of circulating 25-hydroxy vitamin D₃ (25(OH)D₃₎) undergoes epimerization to form C3-epi 25(OH)D₃ and C3-epi 1,25(OH)₂D₃. These epimers have less calcaemic activity than non-epimerized metabolites and are not differentiated by many immunoassays when reporting total 25(OH)D₃ levels. This study aimed to compare the effect of exposure to ultraviolet radiation (UVR) and oral vitamin D₃ supplementation on vitamin D C3-epimer levels. C57Bl/6 female mice were fed either vitamin D-sufficient (vitamin D₃ 2000 IU/kg) or -deficient diets (no vitamin D₃) for 4 weeks. Among the vitamin D-deficient group, the shaved backs of half were irradiated daily for 4 days with 1 kJ/m² UVR, followed by twice weekly irradiation for 4 weeks. Despite similar 25(OH)D₃ levels, the UV-irradiated group had a lower proportion of C3-epi 25(OH)D₃ at week 7 (p < 0.05) and week 9 (p < 0.01). C3-epimer concentrations and %C3-epi 25(OH)D₃ were also analysed in serum samples from two human clinical trials. These trials investigated the effect of high dose oral vitamin D₃ supplementation and narrowband UVB phototherapy, respectively. Serum 25(OH)D₃ and the %C3-epi 25(OH)D₃ levels measured at 12 months after oral vitamin D₃ supplementation were not significantly different to those measured at the time of maximal effect of phototherapy (2 months). Thus, the proportion of 25(OH)D₃ that undergoes epimerization is greater with oral vitamin D₃ supplementation than exposure to UVR in mice, but not in humans. This important difference between human and murine vitamin D metabolism warrants consideration when interpreting animal studies.

Exposure to Ultraviolet Radiation in the Modulation of Human Diseases

This review focuses primarily on the beneficial effects for human health of exposure to ultraviolet radiation (UVR). UVR stimulates anti-inflammatory and immunosuppressive pathways in skin that modulate psoriasis, atopic dermatitis, and vitiligo; suppresses cutaneous lesions of graft-versus-host disease; and regulates some infection and vaccination outcomes. While polymorphic light eruption and the cutaneous photosensitivity of systemic lupus erythematosus are triggered by UVR, polymorphic light eruption also frequently benefits from UVR-induced immunomodulation. For systemic diseases such as multiple sclerosis, type 1 diabetes, asthma, schizophrenia, autism, and cardiovascular disease, any positive consequences of UVR exposure are more speculative, but could occur through the actions of UVR-induced regulatory cells and mediators, including 1,25-dihydroxy vitamin D₃, interleukin-10, and nitric oxide. Reduced UVR exposure is a risk factor for the development of several inflammatory, allergic, and autoimmune conditions, including diseases initiated in early life. This suggests that UVR-induced molecules can regulate cell maturation in developing organs.

Tryptophan and arginine catabolic enzymes and regulatory cytokines in clinically isolated syndrome and multiple sclerosis

Objectives

Clinically isolated syndrome (CIS) is the earliest clinical episode in multiple sclerosis (MS). A study of circulating cells from patients with CIS may help us understand the transition to, and processes associated with, the development of MS.

Methods

As immune cell activity can be determined by flux through metabolic pathways, the mRNA expression of l‐tryptophan‐ and l‐arginine‐catabolising enzymes, indoleamine 2,3‐dioxygenase (IDO) 1 and IDO2 and arginase (ARG) 1 and ARG2, respectively, was compared between peripheral blood mononuclear cells (PBMCs) from healthy controls, and patients with CIS and definite MS. As one measure of cell function, cytokine mRNA levels were analysed directly ex vivo and in cells after culture for 4 h in the absence of regulatory factors in autologous serum.

Results

When measured directly ex vivo, the expression of IDO and ARG was greater in cells from patients with CIS and MS than cells from healthy controls. Although not linked to IDO and ARG expression, PBMCs from the CIS patients were characterised by low IL‐10 and TGFB mRNA levels and not by greater expression of proinflammatory cytokines. When the cells were cultured for 4 h without autologous serum, pro‐ and anti‐inflammatory cytokine mRNA levels positively correlated with IDO1 expression, and TGFB mRNA levels correlated with ARG1 expression.

Conclusion

Higher IDO and ARG expression in CIS and MS provides one sustained homeostatic mechanism to control MS‐associated inflammation. However, potent extrinsic mediators in serum may regulate immune cell function in CIS and associations between IDO, ARG and cytokine expression.

Does the environment influence multiple sclerosis pathogenesis via UVB light and/or induction of vitamin D?

Multiple sclerosis (MS) is a disease of presumed auto-immune origin. Long-standing observations such as the correlation between MS incidence and geographical latitude or the levels of Vitamin D (Vit D) in the serum have implicated the environmental factors UVB radiation and diet in the etiology of the disease. Clinical trials have been conducted and are currently underway to elucidate whether a Vit D enriched diet or treatment with UVB can influence MS incidence, -severity, and -progression, as well as the ideal time point for treatment. This review summarizes the current scientific knowledge to the environmental factors UVB-light and Vit D concerning the clinical aspects of MS in epidemiological studies and clinical trials.

A randomised, controlled clinical trial of narrowband UVB phototherapy for clinically isolated syndrome: The PhoCIS study

Background

The natural history of multiple sclerosis (MS) typically presents with the clinically isolated syndrome (CIS), an episode of neurological symptoms caused by central nervous system inflammation or demyelination that does not fulfil the diagnostic criteria for MS.

Objective

As preclinical studies have suggested that exposure to ultraviolet radiation (UVR) could regulate the development of MS, the Phototherapy for CIS (PhoCIS trial) was established to examine the effects of narrowband UVB phototherapy on patients with CIS, and their conversion to MS.

Methods

Of the 20 participants, half received 24 sessions of narrowband UVB exposure over eight weeks; participants in both arms were followed for 12 months. All participants were supplemented to 25-hydroxyvitamin D₃ levels of >80 nmol/l.

Results

By 12 months, 100% of those in the no phototherapy arm and 70% in the phototherapy arm had converted to MS, although this difference was not statistically significant.

Conclusion

This study provides a basis for further studies to determine if there are any benefits of the therapeutic effects of narrowband UVB radiation on MS progression.

MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics

Multiple sclerosis (MS) incidence and serum 25-hydroxyvitamin D (25OHD) levels vary by race/ethnicity. We examined the consistency of beneficial effects of 25OHD and/or sun exposure for MS risk across multiple racial/ethnic groups. We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267) from the membership of Kaiser Permanente Southern California into the MS Sunshine Study to simultaneously examine sun exposure and 25OHD, accounting for genetic ancestry and other factors. Higher lifetime ultraviolet radiation exposure (a rigorous measure of sun exposure) was associated with a lower risk of MS independent of serum 25OHD levels in blacks (adjusted OR = 0.53, 95% CI = 0.31-0.83; p = 0.007) and whites (OR = 0.68, 95% CI = 0.48-0.94; p = 0.020) with a similar magnitude of effect that did not reach statistical significance in Hispanics (OR = 0.66, 95% CI = 0.42-1.04; p = 0.071). Higher serum 25OHD levels were associated with a lower risk of MS only in whites. No association was found in Hispanics or blacks regardless of how 25OHD was modeled. Lifetime sun exposure appears to reduce the risk of MS regardless of race/ethnicity. In contrast, serum 25OHD levels are not associated with MS risk in blacks or Hispanics. Our findings challenge the biological plausibility of vitamin D deficiency as causal for MS and call into question the targeting of specific serum 25OHD levels to achieve health benefits, particularly in blacks and Hispanics.

Vitamin D-Binding Protein Polymorphisms, 25-Hydroxyvitamin D, Sunshine and Multiple Sclerosis

Blacks have different dominant polymorphisms in the vitamin D-binding protein (DBP) gene that result in higher bioavailable vitamin D than whites. This study tested whether the lack of association between 25-hydroxyvitamin D (25OHD) and multiple sclerosis (MS) risk in blacks and Hispanics is due to differences in these common polymorphisms (rs7041, rs4588). We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267) from Kaiser Permanente Southern California. AA is the dominant rs7041 genotype in blacks (70.0%) whereas C is the dominant allele in whites (79.0% AC/CC) and Hispanics (77.1%). Higher 25OHD levels were associated with a lower risk of MS in whites who carried at least one copy of the C allele but not AA carriers. No association was found in Hispanics or blacks regardless of genotype. Higher ultraviolet radiation exposure was associated with a lower risk of MS in blacks (OR = 0.06), Hispanics and whites who carried at least one copy of the C allele but not in others. Racial/ethnic variations in bioavailable vitamin D do not explain the lack of association between 25OHD and MS in blacks and Hispanics. These findings further challenge the biological plausibility of vitamin D deficiency as causal for MS.

Sun Exposure across the Life Course Significantly Modulates Early Multiple Sclerosis Clinical Course

Background

Low vitamin D and/or sun exposure have been associated with increased risk of multiple sclerosis (MS) onset. However, comparatively, few studies have prospectively examined associations between these factors and clinical course.

Objectives

To evaluate the association of sun exposure parameters and vitamin D levels with conversion to MS and relapse risk in a prospectively monitored cohort of 145 participants followed after a first demyelinating event up to 5-year review (AusLong Study).

Methods

Sun exposure prior to and after onset measured by annual questionnaire; ultraviolet radiation (UVR) "load" estimated by location of residence over the life course and ambient UVR levels. Serum 25-hydroxyvitamin D [25(OH)D] concentrations measured at baseline, 2/3-year, and 5-year review. MS conversion and relapse assessed by neurologist assessment and medical record review.

Results

Over two-thirds (69%) of those followed to 5-year review (100/145) converted to MS, with a total of 252 relapses. Higher pre-MS onset sun exposure was associated with reduced risk of MS conversion, with internal consistency between measures and dose-response relationships. Analogous associations were also seen with risk of relapse, albeit less strong. No consistent associations were observed between postonset sun exposure and clinical course, however. Notably, those who increased their sun exposure during follow-up had significantly reduced hazards of MS conversion and relapse. Serum 25(OH)D levels and vitamin D supplementation were not associated with conversion to MS or relapse hazard.

Conclusion

We found that preonset sun exposure was protective against subsequent conversion to MS and relapses. While consistent associations between postonset sun exposure or serum 25(OH)D level and clinical course were not evident, possibly masked by behavior change, those participants who markedly increased their sun exposure demonstrated a reduced MS conversion and relapse hazard, suggesting beneficial effects of sun exposure on clinical course.

Vitamin D in the prevention, prediction and treatment of neurodegenerative and neuroinflammatory diseases

Vitamin D research has gained increased attention in recent times due to its roles beyond bone health and calcium homeostasis, such as immunomodulation. In some parts of the brain and on immune cells, vitamin D hydroxylating enzymes and its receptors are located. Epidemiological evidence demonstrates that deficiency of Vitamin D is relevant for disease risk and course in multiple sclerosis (MS) and presumably also in neuromyelitis optica spectrum disorders (NMOSD), Parkinson's disease (PD), and Alzheimer's disease (AD). Although the exact mechanism underlying vitamin D effects in these diseases remains widely unexplored, human and animal studies continue to provide some hints. While the majority of vitamin D researchers so far speculate that vitamin D may be involved in disease pathogenesis, others could not show any association although none have reported that sufficient vitamin D worsens disease progression. The studies presented in this review suggest that whether vitamin D may have beneficial effects in disease course or not, may be dependent on factors such as ethnicity, gender, diet, vitamin D receptor (VDR) polymorphisms and sunlight exposure. We here review the possible role of vitamin D in the pathogenesis and disease course of MS, NMOSD, PD, and AD and potential therapeutic effects of vitamin D supplementation which may be relevant for predictive, preventive, and personalized medicine. We suggest areas to consider in vitamin D research for future studies and recommend the need to supplement patients with low vitamin D levels below 30 ng/ml to at least reach sufficient levels.

Evolving Identification of Blood Cells Associated with Clinically Isolated Syndrome: Importance of Time since Clinical Presentation and Diagnostic MRI

It is not clear how the profile of immune cells in peripheral blood differs between patients with clinically isolated syndrome (CIS) and healthy controls (HC). This study aimed to identify a CIS peripheral blood signature that may provide clues for potential immunomodulatory approaches early in disease. Peripheral blood mononuclear cells (PBMCs) were collected from 18 people with CIS, 19 HC and 13 individuals with other demyelinating conditions (ODC) including multiple sclerosis (MS). Individuals with CIS separated into two groups, namely those with early (≤14 days post-diagnostic magnetic resonance imaging (MRI); n = 6) and late (≥27 days; n = 12) blood sampling. Transitional B cells were increased in the blood of CIS patients independently of when blood was taken. However, there were two time-dependent effects found in the late CIS group relative to HC, including decreased CD56bright NK cells, which correlated significantly with time since MRI, and increased CD141+ myeloid dendritic cell (mDC2) frequencies. Higher CD1c+ B cells and lower non-classical monocyte frequencies were characteristic of more recent demyelinating disease activity (ODC and early CIS). Analysing cell populations by time since symptoms (subjective) and diagnostic MRI (objective) may contribute to understanding CIS.

Altered regulatory T-cell fractions and Helios expression in clinically isolated syndrome: clues to the development of multiple sclerosis

Development of multiple sclerosis (MS) is frequently preceded by an acute or subacute neurological disturbance referred to as clinically isolated syndrome (CIS). The specific immunological disturbances present in CIS remain underexamined. This study analysed peripheral blood mononuclear cells from n=18 treatment-naive individuals with recently diagnosed CIS (<120 days) for disturbances in the phenotype of T regulatory (Treg), follicular T regulatory (Tfr), T helper (Th), follicular T helper (Tfh) and B cells. Relative to healthy controls (n=19), CIS was associated with lower proportions of suppressive CD45RA⁺FoxP3^lo Treg and Tfr cells and greater proportions of non-suppressive CD45RA⁻FoxP3^lo and Th17-like Treg and Tfr. Lower Helios expression (maen fluorescent intensity) was measured across all Treg and Tfr fractions in the CIS group, suggesting less potent regulatory function. Greater frequencies of activated, efficient B-cell helper Tfh subsets and a trend for a higher proportion of IgD⁻CD27⁻ B cells was also detected in the CIS group, characteristics that were positively correlated with Treg and Tfr Helios expression. These results indicate that Treg and Tfr impairment is an early feature in MS.

The Multiple Sclerosis (MS) Genetic Risk Factors Indicate both Acquired and Innate Immune Cell Subsets Contribute to MS Pathogenesis and Identify Novel Therapeutic Opportunities

Multiple sclerosis (MS) is known to be a partially heritable autoimmune disease. The risk of developing MS increases from typically 1 in 1,000 in the normal population to 1 in 4 or so for identical twins where one twin is affected. Much of this heritability is now explained and is due almost entirely to genes affecting the immune response. The largest and first identified genetic risk factor is an allele from the MHC class II HLA-DRB1 gene, HLA-DRB1*15:01, which increases risk about threefold. The HLA-DRB1 gene is expressed in antigen-presenting cells, and its protein functions in presenting particular types of antigen to CD4 T cells. This discovery supported the development of the first successful immunomodulatory therapies: glatiramer acetate, which mimics the antigen presentation process, and interferon beta, which targets CD4 T cell activation. Over 200 genetic risk variants, all single nucleotide polymorphisms (SNPs), have now been described. The SNPs are located within, or close to, genes expressed predominantly in acquired and innate immune cell subsets, indicating that both contribute to MS pathogenesis. The risk alleles indicate variation in the regulation of gene expression, rather than protein variation, underpins genetic susceptibility. In this review, we discuss how the expression and function of the risk genes, as well as the effect on these of the risk SNPs, indicate specific acquired immune cell processes that are the target of current successful therapies, and also point to novel therapeutic approaches.