Outcome of first or second transplantation using unrelated umbilical cord blood without ATG conditioning regimen for pediatric bone marrow failure disorders.

BACKGROUND: Unrelated umbilical cord blood transplantation (UCBT) for bone marrow failure (BMF) disorders using conditioning regimens without Anti-Thymocyte Globulin (ATG) has been used as an alternative transplantation for emerging patients without matched-sibling donors. Experience with this transplant modality in children is limited, especially as a secondary treatment for transplant failure patients. PROCEDURE: We retrospectively reviewed 17 consecutive bone marrow failure patients who underwent unrelated umbilical cord blood transplantation in our center and received conditioning regimens of Total Body Irradiation (TBI) or Busulfan (BU) + Fludarabine (FLU) + Cyclophosphamide (CY). RESULTS: Among the 17 BMF patients, 15 patients were treated with first cord blood transplantation and another 2 with secondary cord blood transplantation because of graft failure after first haploidentical stem cell transplantation at days +38 and +82. All patients engrafted with a median donor cell chimerism of 50 % at days +7 (range, 16 %-99.95 %) and finally rose to 100 % at days +30. Median time to neutrophil engraftment was 19 days (range, 12-30) and time to platelet engraftment was 32 days (range, 18-61). Pre-engraftment syndrome (PES) was found in 16 patients (94.11 %, 16/17). Cumulative incidence of grades II to IV acute GVHD was 58.8 % (95 % CI: 32.7-84.9 %), and 17.6 % (95 % CI: 2.6-37.9 %) of patients developed chronic GVHD. The 3-year overall survival (OS) and failure-free survival (FFS) rates were 92.86 ± 6.88 %. CONCLUSION: UCBT is an effective alternative treatment for bone marrow failure pediatric patients. TBI/BU + FLU + CY regimen ensure a high engraftment rate for unrelated umbilical cord blood transplantation, which overcomes the difficulty of graft failure. Secondary salvage use of cord blood transplantation may still be useful for patients who have failed after other transplantation.

Unrelated Umbilical Cord Blood Transplant for Children with ß-Thalassemia Major.

Beta thalassemia major, one of the most prevalent hemoglobinopathy throughout the word, can be cured by allogenic stem cell transplantation (SCT) (Bone Marrow Transplant 36:971-975, 2005). Many patients, however, lack a suitably matched related sibling donor. Unrelated umbilical cord blood (UCB) can be used as an alternative stem cell source for these patients. This report describes SCT for nine children with beta-thalassemia major using partially HLA-matched unrelated UCB. Conditioning included oral busulfan 16 mg/kg (day -10 to -7), cyclophosphamide (Cy) 200 mg/kg (day -5 to -2), fludarabine 90 mg/kg (day -13 to -11), and antithymocyte globulin (rabbit) 7.5 mg/kg (day -3 to -1). The infused cell dose was 10.71 × 10(7)/kg total nucleated cells (TNC) (range 6.5-17 × 10(7)/kg TNC). The patients ranged in age from 1.5 to 7 years, in weight from 10.5 to 17 kg. A second transplant with two unrelated cord blood units was attempted in two patients who had primary graft failure. The retransplant recipients were preconditioned with i.v Cy 120 mg/kg (day -3 to -2). Five of the nine patients engrafted promptly with 50-100 % donor chimerism (56 %). They engrafted at a median of 17 days (range 12-19). One patient is transfusion free for 36 months; a second patient is transfusion free for 18 months and a third is transfusion free for 9 months. There was no transplant related mortality. Four of the nine children had autologous recovery without engraftment. Primary graft rejection is the major complication. Post transplant complications were mild hepatic veno-occlusive disease, acute GVHD grade II, and CMV interstitial pneumonia. The chronic GVHD was limited and could be controlled by Methylprednisolone combined with Mycophenolate. The lack of a marrow donor registry in India makes UCBT from related and unrelated donors a good alternative. Transplant should be delayed until the child is at least 18 months of age. The dose of UCB stem cells is the most important factor for engraftment. UCB has the advantages of rapid availability and low risk of severe GVHD despite donor-recipient HLA disparity (Transplant Proc 37:2667-2669, 2005). We demonstrate the feasibility of this procedure in the setting of a developing country.