Immunoregulatory Effects of the Active Form of Vitamin D (Calcitriol), Individually and in Combination with Curcumin, on Peripheral Blood Mononuclear Cells (PBMCs) of Multiple Sclerosis (MS) Patients.

OBJECTIVES Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease affecting the central nervous system. Immune cell subsets, notably T helper (Th) 17 and Th1, exert important roles in MS pathogenesis. Whereas, Treg cells modulate the disease process. Calcitriol, the active form of vitamin D, and curcumin, a bioactive compound derived from turmeric, play immunomodulatory effects relevant to autoimmune disorders, including MS. The objective of this study is to investigate the effects of calcitriol and Curcumin on Peripheral blood mononuclear cells (PBMCs) of individuals with MS. METHODS PBMCs from twenty MS patients were isolated, cultured, and exposed to 0.004 μg/mL of calcitriol and 10 μg/mL of curcumin. The cells underwent treatment with singular or combined doses of these components to assess potential cumulative or synergistic immunomod-ulatory effects. Following treatment, the expression levels of genes and the cellular population of Treg, Th1 and Th17 were evaluated using Real-time PCR and flow cytometry. RESULTS Treatment with curcumin and calcitriol led to a significant reduction in the expression levels of inflammatory cytokines and transcription factors related to Th1 and Th17 cells, includ-ing IFN-γ, T-bet, IL-17, and RORC. Furthermore, the frequency of these cells decreased follow-ing treatment. Additionally, curcumin and calcitriol treatment resulted in a significant upregu-lation of the FOXP3 gene expression and an increase in the frequency of Treg cells. CONCLUSION This study demonstrates that curcumin and calcitriol can effectively modulate the inflammatory processes intrinsic to MS by mitigating the expression of inflammatory cytokines by Th1 and Th17 cells while concurrently enhancing the regulatory role of Treg cells. Moreover, the combined treatment of curcumin and calcitriol did not yield superior outcomes compared to single-dosing strategies.