Effects of methylcobalamin (vitamin B12) on in vitro cytokine production of peripheral blood mononuclear cells

J Clin Lab Immunol. 1992;37(4):173-82.


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.

MeSH terms

  • Arthritis, Rheumatoid / drug therapy
  • Arthritis, Rheumatoid / immunology
  • Concanavalin A / pharmacology
  • Cytokines / biosynthesis*
  • Humans
  • In Vitro Techniques
  • Interferon-gamma / biosynthesis
  • Interleukin-1 / biosynthesis
  • Interleukin-2 / pharmacology
  • Interleukin-6 / biosynthesis
  • Leukocytes, Mononuclear / drug effects*
  • Leukocytes, Mononuclear / immunology
  • Phytohemagglutinins / pharmacology
  • Pokeweed Mitogens / pharmacology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • Vitamin B 12 / analogs & derivatives*
  • Vitamin B 12 / pharmacology


  • Cytokines
  • Interleukin-1
  • Interleukin-2
  • Interleukin-6
  • Phytohemagglutinins
  • Pokeweed Mitogens
  • Concanavalin A
  • Interferon-gamma
  • mecobalamin
  • Vitamin B 12