Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS).The most important reason for the limited success obtained in the treatment and prevention so far is most likely related to the limited knowledge about its cause and pathogenesis of MS.One of the recent proposed mechanism for autoimmunity base of MS is Th1/Th2 implance of as well as other inflammatory and anti-inflammatory T cell such as Th17 and Treg and their releasing cytokines. Therefore the control of cytokine production may become potential therapeutic targets and modulation of the Th1/Th2 balance may provide a new pharmacological tool to treat this disease. Vitamin A (VA) or VA-like analogs known as retinoids, are potent hormonal modifiers of type 1 or type 2 responses but a definitive description of their mechanism(s) of action is lacking. high level dietary vitamin A enhances Th2 cytokine production and IgA responses, and is likely to decrease Th1 cytokine production. Retinoic acid inhibits IL 12 production in activated macrophages, and RA pretreatment of macrophages reduces IFNγ production and increases IL4 production in antigen primed CD4 T cells. Supplemental treatment with vitamin A or retinoic acid (RA) decreases IFNγ and increases IL5, IL10, and IL4 production. Thus, vitamin A deficiency biases the immune response in a Th1 direction, whereas high level dietary vitamin A may bias the response in a Th2 direction.
