RESUMO
The aim of the study was to evaluate the role of vitamin B12 in patients with pernicious anemia. This study was conducted prospectively at the Turgut ?zal 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. 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. 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