Umbilical cord blood transplantation using non-myeloablative conditioning: the Mexican experience

Twenty-eight children and adults underwent transplantation with allogeneic umbilical cord blood cells (UCB) using a non-ablative conditioning regimen; there were 15 males and 13 females. Seven patients were grafted because a non-malignant condition and 21 for a malignant disease. The median age was 8 years (range 4 months-72 years). Ten UCB were obtained from Mexican cord bloods banks, five cords were from compatible siblings and the remaining 13 cords were obtained from abroad. Median time to recover >0.5 x 10(9)/l granulocytes was 24 days (range 8-32 days), whereas median time to recover >20 x 10(9)/l platelets was 26 days (range 12-50 days). Twelve recipients never engrafted and recovered subsequently endogenous hematopoiesis. The non-engraftment rate was significantly higher in patients allografted for benign conditions (71%) than in those allografted for malignant conditions (28%). The median overall post-transplant survival (SV) was 33 months and the 73-months overall SV was 39%. The cumulative incidence of grade II-IV acute GVHD and grade III-IV GVHD for the entire cohort of patients were 14 and 7%, respectively. Additional studies are needed to define if non-myeloablative conditioning is preferable over conventional conditioning in the case of UCB allografting.