Impact of Vitamin D Supplementation on Immune Functions: Study in Subjects Aged Over 65 Years Vaccinated Against Influenza

The main objective is to assess the variation in plasma levels of cathelicidin before and after influenza vaccination. All bibliographic data suggests that supplementation vitamin D in the elderly often deficient in this vitamin may have a double interest: * By induction of cathelicidin, assist in anti-infective response in particular to the influenza virus * The normalization of vitamin D status, promote the return to an appropriate immune response limiting excess inflammation and improving capacity to respond. The entire project will collect new information on the merits of the use of vitamin D in aging. A better knowledge of mechanisms involved and the impact of aging on them is a necessary prerequisite the definition of a new strategy using this drug in the elderly particularly fragile in order to improve its autonomy. This definition seems a sociological interest obvious economic knowing the current aging population and its impact future of our health system.