Vitamin D's hidden power: immune cell changes revealed in healthy volunteers

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * The patient must have given their free and informed consent and signed the consent form * The patient must be a member or beneficiary of a health insurance plan * Women of childbearing potential must have effective contraception during the study period. Effective contraception is defined by a low failure rate (less than 1% per year) when used correctly and consistently, such as implants, injectables, oral contraceptives, IUDs, abstinence, or partner vasectomy. A urine pregnancy test will be performed at inclusion. Exclusion Criteria: * The subject is participating in another therapeutic study, or is in a period of exclusion determined by a previous study * The subject is unable to express their consent * It is impossible to give the subject informed information * The patient is under safeguard of justice or state guardianship * Pregnant or breastfeeding * Infectious disease or vaccination within previous 3 months * Chronic psychiatric disease, or disease that, in the opinion of the investigator ,may put the patient at risk or affect compliance. * Chronic inflammatory or dysimmune disease or subject on immunomodulatory or immunosuppressive therapy (including corticosteroids) within the last 3 months. * Uncontrolled epilepsy. * Known vitamin D deficiency secondary to active or other digestive disease (celiac disease, IBD, gastrectomy or bypass, cirrhosis, short bowel syndrome, nephrotic syndrome, hyperthyroidism, hypoparathyroidism, cancer, granulomatous pathology, lymphoma, rickettsiosis). * History of hypercalcemia, osteopenia or osteoporosis, urinary lithiasis, heart rhythm disorders. * Pathology requiring a daily intake of more than 1 gram of Calcium. * Contraindication to vitamin D3 treatment as mentioned on the VIDAL documentation of UVEDOSE. * Treatment affecting vitamin D metabolism other than corticosteroids: anti-epileptic drugs \[phenobarbital, primidone, phenytoin\], rifampicin, isoniazid, ketoconazole, 5-FU and leucovorin, thiazide diuretic. * Active vitamin supplementation or dietary supplements rich in vitamin D. * Present or past neurological symptoms that may suggest an undiagnosed inflammatory neurological pathology.