title: Effects of methylcobalamin (vitamin B12) on in vitro cytokine production of peripheral blood mononuclear cells.
abstract: Recently in Japan, one form of vitamin B12, methylcobalamin also known as methyl B12, has attracted the attention of physicians as a therapy for patients with rheumatoid arthritis. However, its immunological actions in vivo are still unknown. In this study, we induced the in vitro production of such cytokines as interleukin-6 (IL-6), interferon-gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) by adding various mitogens (phytohemagglutinin:PHA, concanavalin A: ConA, or pokeweed mitogen:PWM) as well as recombinant interleukin-2, and we investigated the effects of methyl B12 (final concentration, 8-8,000 ng/ml) on the production of these cytokines by peripheral mononuclear cells. As compared to the controls, IL-6 production induced by PHA and ConA on Day 4 of the culture was suppressed by an average 60-70% when methyl B12 (80-8,000 ng/ml) was added to the medium. IFN-gamma production decreased dose-dependently with methyl B12, i.e., it decreased to 46% of the control when this production was induced by rIL-2, and decreased to 56-66% when it was induced by mitogens. The effect of methyl B12 on IL-1 beta production on Day I of the culture was small. These findings indicate that methyl B12 suppresses mainly the cytokine production of T lymphocytes. Such suppressive effects as shown in the in vitro situation are expected to be expressed also in vivo in patients with rheumatoid arthritis, especially at articulation lesion sites.
authors.affiliation: Department of Laboratory Medicine, Mie University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamashiki
authors.forename: A
authors.initials: A
authors.lastname: Nishimura
authors.forename: Y
authors.initials: Y
authors.lastname: Kosaka
mesh_terms: D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D007375:Interleukin-1 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000276:immunology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D007376:Interleukin-2; D015850:Interleukin-6; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D003208:Concanavalin A; D007371:Interferon-gamma; C019476:mecobalamin; D014805:Vitamin B 12