Effects of cyanocobalamin on immunity in patients with pernicious anemia

Med Princ Pract. 2008;17(2):131-5. doi: 10.1159/000112967. Epub 2008 Feb 19.


Objective: The aim of the study was to evaluate the role of vitamin B(12) in patients with pernicious anemia.

Materials and methods: This study was conducted prospectively at the Turgut Ozal Medical Center, Department of Hematology, between April and November 2002. Absolute numbers and ratio of the surface antigens of T and B lymphocyte subgroups, CD4/CD8 ratio were calculated in order to evaluate changes in leukocyte and lymphocyte numbers; natural killer (NK) cell count, serum C3, C4, and levels of immunoglobulins G, A, and M were also measured to evaluate vitamin B(12) effect on immunity. Values obtained before treatment with cyanocobalamin were compared with those found during peak reticulocyte count.

Results: In vitamin B(12)-deficient patients, absolute numbers of CD4+ and especially CD8+ lymphocytes were found to be decreased; CD4/CD8 ratio increased, and NK cell activity was depressed. After cyanocobalamin treatment, absolute numbers and percentage of lymphocyte subgroups were elevated. Increased CD4/CD8 ratio and depressed NK cell activity were restored and levels of C3, C4, and immunoglobulins were elevated.

Conclusion: These findings suggest that vitamin B(12) has important immunomodulatory effects on cellular immunity, and abnormalities in the immune system in pernicious anemia are restored by vitamin B(12) replacement therapy.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anemia, Pernicious / drug therapy*
  • Anemia, Pernicious / immunology*
  • CD4-CD8 Ratio
  • Complement System Proteins / drug effects
  • Complement System Proteins / metabolism
  • Female
  • Humans
  • Immunity / drug effects*
  • Immunoglobulins / drug effects
  • Immunoglobulins / metabolism
  • Lymphocyte Subsets / drug effects
  • Lymphocyte Subsets / metabolism
  • Male
  • Middle Aged
  • Prospective Studies
  • Vitamin B 12 / pharmacology*


  • Immunoglobulins
  • Complement System Proteins
  • Vitamin B 12