Effect of vitamin C on immune reconstitution after bone marrow transplantation.

BACKGROUND Vitamin C is an essential nutrient for the adequate function and maturation of the immune system. In vitro studies show that the development, proliferation, and functioning of T cells requires vitamin C, especially for natural killer (NK) cells. Their deficiency during the acute phase post-transplantation could cause greater morbidity and mortality in these patients. A prospective clinical trial using high-dose vitamin C was performed to determine if vitamin C supplementation improves reconstitution of NK lymphocytes after hematopoietic stem cell transplantation (HSCT). MATERIALS AND METHODS We enrolled 24 patients who underwent autologous HSCT for multiple myeloma and lymphoma. Patients were randomized to receive standard treatment or standard treatment plus 20 g vitamin C once daily (1 - 10 days) and 500 mg twice daily (11 - 100 days) after transplantation. RESULTS NK and CD3+ lymphocytes showed an increase from days +30 to +100 only in the vitamin C-treated group. Patients in the vitamin C group had a lower frequency of infections. No severe adverse events were reported. CONCLUSION Our results suggest that high-dose vitamin C supplementation is an effective and safe therapeutic option to decrease the frequency of infections and enhance immune reconstitution after HSCT.