Pyridoxine supplementation: Effect on lymphocyte responses in elderly persons

Abstract

The effect of pyridoxine supplementation on lymphocyte responsiveness was invesigated in 15 persons aged 65-81 y. Eleven subjects received 50 mg/d pyridoxine HCl (PN). Four subjects received a placebo. Lymphocyte proliferation to T and B cell mitogens, lymphocyte subpopulations with monoclonal antibodies, and plasma pyridoxal 5'-phosphate (PLP) were measured before and after 1 and 2 mo of supplementation. After 1 and 2 mo plasma PLP levels increased by 195 ± 88 nM and 201 ± 84 nM, respectively, in subjects receiving PN. With PN supplementation, lymphocyte proliferation increased significantly in response to phytohemagglutinin (p<0.001), pokeweed mitogen (p<0.01), and Staphylococcus aureus (Cowain I) (p<0.05). For PN-treated subjects with low presupplement plasma PLP levels, lymphocyte blastogenesis also increased significantly (p<0.01) in response to concanavlin A. Percentages of T3+ and T4+ but not T8+ cells increased significantly (p<0.05) in PN-treated subjects. These results suggest that improving vitamin B-6 status is important in stimulating immuno competence in the elderly.