IFNB1 and relapsing-remitting multiple sclerosis: Noteworthy is a study that evaluated the in vivo immunomodulatory effect of single and combined treatment with all-trans-retinoic acid (ATRA) and docosahexaenoic acid (DHA), on peripheral blood mononuclear cells (PBMC) in patients with RRMS who were also receiving interferon beta (IFN-β) [47].