D.1. Vitamin D and the Immune System - J Investig Med:
Cynthia Aranow, MD[Investigator] Feinstein Institute for Medic.Research, Manhasset, N.Y. 2011 August ; 59(6): 881–886.
It is now clear that vitamin D has important roles in addition to its classic effects on calcium and bone homeostasis. As the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen presenting cells) and these immunologic cells are all are capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic milieu. Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as an increased susceptibility to infection. As immune cells in autoimmune diseases are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D deficient individuals with autoimmune disease may extend beyond the effects on bone and calcium homeostasis.
D.2. Vitamin D’s Effect on Immune Function- Nutrients:
Pieter-Jan Martens, Conny Gysemans, Annemieke Verstuyf, and Chantal Mathieu* 2020 May; 12(5): 1248.
Ever since its discovery by Windhaus, the importance of the active metabolite of vitamin D (1,25-dihydroxyvitamin D3; 1,25-(OH)2D3) has been ever expanding. In this review, the attention is shifted towards the importance of the extra-skeletal effects of vitamin D, with special emphasis on the immune system. The first hint of the significant role of vitamin D on the immune system was made by the discovery of the presence of the vitamin D receptor on almost all cells of the immune system. In vitro, the overwhelming effect of supra-physiological doses of vitamin D on the individual components of the immune system is very clear. Despite these promising pre-clinical results, the translation of the in vitro observations to solid clinical effects has mostly failed. Nevertheless, the evidence of a link between vitamin D deficiency and adverse outcomes is overwhelming and clearly points towards avoidance of vitamin D deficiency especially in early life.
D.3. The Immunologic Profile of Vitamin D and Its Role in Different Immune-Mediated Diseases:
An Expert Opinion by Sandro Giannini, Andrea Giust, Salvatore Minisola, Nicola Napoli Giovanni Passeri, Maurizio Rossini and Luigi Sinigaglia- Nutrients 2022, 14(3), 473
Historically, vitamin D is recognized as an essential component for the maintenance of the musculoskeletal system. The immunomodulatory role of vitamin D in health and disease has gained much interest in recent years due to the many pathologies that share underlying immunological features where vitamin D has been shown to exert a potential role. Evidence from pre-clinical studies show that vitamin D elicits biological effects on both the innate and adaptive immune systems. Furthermore, in vivo studies have shown that administration of vitamin D can lead to changes in or the development of a range of immune-related diseases. This encourages the hypothesis that data derived from clinical and epidemiological studies connect vitamin D with the incidence and severity of many immune-mediated disorders such as rheumatoid arthritis, diabetes, and infectious diseases. Since some other immune-mediated diseases share similar features to that of viral infection such as COVID-19, in this review, we examined these other areas and the role of vitamin D in these diseases.