The Effect of Vitamin a Supplementation on Disease Progression, Cytokine Levels and Gene Expression in Multiple Sclerotic Patients: Study Protocol For a Randomized Controlled Trial - Harrirchian, Mohammad Hassan; Mohammadzadeh Honarvar, Niyaz; Koohdani, Fariba; Bitarafan, Sama; Siassi, Fereydoon; Jafarirad, Sima; Abdolahi, Mina; Salehi, Eisa; Saharian, Mohammad Ali; Rouystaee, Homa; Eshraghian, Mohammad Reza; Saboor-Yarghi, Ali Akbar (Acta Medica Iranica)