AUTHOR=Cho Eun Bin , Shin Jong Hwa , Kwon Soonwook , Kim Juhyeon , Seok Jin Myoung , Kim Byoung Joon , Min Ju-Hong 

TITLE=Effects of Vitamin D and Dexamethasone on Lymphocyte Proportions and Their Associations With Serum Concentrations of 25-Hydroxyvitamin D3In Vitro in Patients With Multiple Sclerosis or Neuromyelitis Optica Spectrum Disorder

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.677041

DOI=10.3389/fimmu.2021.677041

ISSN=1664-3224

ABSTRACT=<sec><title>Background</title><p>Clear associations have been found between vitamin D deficiency and several autoimmune diseases including multiple sclerosis (MS). However, the benefits of vitamin D supplementation on disease management remain a matter of debate.</p></sec><sec><title>Objective and Methods</title><p>Patients with MS (<italic>N</italic>=12) and neuromyelitis optica spectrum disorder (NMOSD; <italic>N</italic>=12) were enrolled along with 15 healthy controls. Changes in lymphocyte subset proportions during stimulation of their peripheral blood mononuclear cells (PBMCs) with the active form of vitamin D, 1,25-dihydroxyvitamin D<sub>3</sub> (1,25(OH)<sub>2</sub>D<sub>3</sub>), and correlations with serum concentrations of the vitamin D precursor 25-hydroxyvitamin D<sub>3</sub> (serum 25(OH)D<sub>3</sub>) were explored. The impact of 1,25(OH)<sub>2</sub>D<sub>3</sub> stimulation on the expression of vitamin-D-responsive genes in immune cells was also investigated.</p></sec><sec><title>Results</title><p>In both MS and NMOSD, stimulation of PBMCs with 1,25(OH)<sub>2</sub>D<sub>3</sub> followed by steroid suppressed the proliferation of total lymphocytes and T cells. The ratio of CD19<sup>+</sup>CD27<sup>+</sup> memory B cells (Bmem) to all B cells after stimulation with 1,25(OH)<sub>2</sub>D<sub>3</sub> was negatively correlated with serum 25(OH)D<sub>3</sub> in MS (Spearman’s <italic>ρ</italic>=–0.594, <italic>p</italic>=0.042), but positively correlated in NMOSD (Pearson’s <italic>r</italic> = 0.739, <italic>p</italic>=0.006). However, there was no relationship between the ratio of Bmem to CD19<sup>+</sup>CD24<sup>+</sup>CD38<sup>+</sup> regulatory B cells and serum 25(OH)D<sub>3</sub> in either MS or NMOSD. In addition, the level of 1,25(OH)<sub>2</sub>D<sub>3</sub>-induced <italic>CYP24A1</italic> mRNA expression in PBMCs was significantly and negatively correlated with serum 25(OH)D<sub>3</sub> (for ΔC<sub>T</sub>, <italic>r</italic>=0.744, <italic>p</italic>=0.014) in MS.</p></sec><sec><title>Conclusion</title><p>These findings suggest a beneficial impact of stimulation of PBMCs with vitamin D followed by steroid on the T-cell population. The association between patient serum 25(OH)D<sub>3</sub> and the proportion of Bmem under immune-cell stimulation differed between MS and NMOSD. Further investigations are warranted with larger patient populations.</p></sec>