Pre-transplantation vitamin D deficiency increases acute graft-versus-host disease after hematopoietic stem cell transplantation in thalassemia major patients.

Background: Although there are many studies on the role of vitamin D deficiency (VDD) in hematopoetic stem cell transplantation (HSCT), outcomes have often reported conflicting results because of the heterogeneity of the patients in the studies.

Methods: We investigated the association between VDD prior to HSCT and outcomes after HSCT in a relatively homogenous group of patients with thalassemia major (TM) who received identical treatment for TM before transplantation, and the same conditioning regimen and GVHD prophylaxis during and after transplantation. All patients, including the patients with normal vitamin D levels received 400 to 800 IU per day of vitamin D for the first 6 months after HSCT.

Results: Pre-HSCT VDD increased the frequency of aGVHD after transplantation, particularly in HSCTs performed with PBSC for the stem cell source. Pre-transplant low vitamin D levels had no association with transplant outcomes such as engraftment, viral infections, alloimmunization, chronic GvHD, total days of hospitalization, and success in terms of transfusion independence.

Conclusions: Low vitamin D levels before HSCT carry a significant risk for aGVHD. All patients with TM should be screened for VDD before HSCT, and every effort should be made to supplement vitamin D before the transplant in VDD patients.