High Percentage of Regulatory T Cells before and after Vitamin B12 Treatment in Patients with Pernicious Anemia

Introduction: In some previous studies, vitamin B12 treatment showed immunomodulatory effects and restored the immunological abnormalities in patients with pernicious anemia (PA). In the present study, peripheral blood T cell subsets, including regulatory T cells (Tregs), were examined before and after vitamin B12 treatment in PA patients. Patients and Methods: The percentages of CD4, CD8, Th1, Th2 and Tregs were examined in 23 PA patients before vitamin B12 treatment, in 23 other PA patients after vitamin B12 treatment and in 28 healthy controls. Results: The mean percentage of CD8+ T cells was significantly higher in the control group (23.0%; 95% CI, 20.4-25.6%) than in the pre- (16.0%; 95% CI, 12.1-20.0%) and posttreatment groups (15.2%; 95% CI, 11.8-18.6%; p regs in the pre- (6.29%; 95% CI, 5.04-7.54%) and posttreatment groups (7.77%; 95% CI, 6.34-9.20%) compared with the control group (4.18%; 95% CI, 3.92-4.47%; p Conclusions: The percentage of Tregs was significantly higher in PA patients than in normal subjects, and this high Treg percentage was not different before and after vitamin B12 treatment. Other immunological alterations also did not recover after vitamin B12 treatment, so that these immunological changes appear to be the cause of PA and are not induced by vitamin B12 deficiency.