The allogeneic transplant of haematopoietic cell is the only treatment option for many malignant blood diseases. Unfortunately, the progression free survival and the quality of life of transplanted patients is limited due to the development of graft-versus-host-disease (GVHD).~The development of new prophylaxis strategies of GVHD based in the use of immunomodulator agents (allowing the generation of an immunotolerance state and avoiding the use of immunosuppression) is essential.~The GVHD is due to the cytotoxic effect of the donor lymphocytes T against healthy organs and tissues of the receptor. Calcineurin inhibitor combined with methotrexate or antibodies anti-lymphocytes T are used as standard prophylaxis. This type of antibodies has demonstrated efficacy to reduce GVHD, but have not increased survival due to increasing the risk of relapses and serious post-transplant infections.~Due to its interactions with VDR (vitamin D receptor) present in immune system cells, vitamin D is able to inhibit the activation of dendritic cells and the proliferation and production of cytokines by lymphocytes T. Based on this effect, the peri- and post- transplant administration of vitamin D might decrease the risk of GVHD in allogeneic transplanted patients, subsequently decreasing the immunosuppressant treatment requirements and improving the prognosis of those patients.
The purpose of this study is to determine whether vitamin D is effective in the prevention of graft-versus-host-disease after completion of allogeneic transplant.