To study the efficacy of hematopoietic stem cell transplant in children with umbilical cord blood 6 children received transplant in our hospital within these 3 years.

Except for one patient suffered from acute severe aplastic anemia (SAA). All others had relapsed leukemia. Among them, 3 were relapsed ALL and another 2 were relapsed AML. The average age was 55 months (range, 38 months to 7 years old) and average weight was 17.8 kg (range, 13.5 ~28 kg) in this group. Only a 7 years old ALL-CR3 patient was conditioned with fraction total body irradiation, all the others were conditioned with non radiation regimen. Patients with ALL conditioned with Busulfan 16 mg + Cyclophosphomide 120 mg + VP1640 mg and patients with AML received Busulfan 16 mg + Cyclophosphomide 200 mg. Fludarabine 30 mg/m 2 × 5day +CTX 60 mg/kg × 2 day was chosen as the conditioning regimen for our SAA-I patient. 1 patient did not use ATG because the donor was matched related sibling, all the others received 6–30 mg/kg. day × 5 day ATG(Fresennius S). Only CSA was used for prophylaxis GVHD in this group.

Two cord blood provided from Shanghai and Beijing cord blood bank separately and another 4 were from Guangzhou cord blood bank. The average total neuclear cell count was 10×107/kg (6.5~13×107/kg) and CD34+ cell was 0.81×106/kg (0.2~1.47×107/kg). 5 patients had hematopoitic reconstitution with the average time for absolute neutrophil over 0.1×109/L and 0.5×109/L 16 days (range, 14~19day) and 17days (range, 14~20day) respectively. The average time for transfusion independent platelet count recovered over 20×109/L, 50×109/L was 33.3 days (range, 27~39 days) and 49.3days (range, 48~51days) separately. 4 patients had grade II GVHD after transplantation. All patients infected with CMV and one died from CMV pneumonia on day +43, another one had encephalitis on day +124 and treated with anti-epilepsy drug till now. The average time for follow up was 29 months (13–41 months) in this group. One patient suffered from grade III hemorrhagic cystitis on day +60 and resolved on day +100 after being treated with hydration, alkalization and anti-virus drugs. One patient suffered from a great deal of hemorrhagic pericardial effusion on day +172, because of no response after several times of pericardial puncture, dissection of pericardium was received on day +182 and recovered since then. Another patient received transfusion with autologous back-up peripheral blood stem cells on day +40 because of graft failure confirmed by DNA chimerism study on day +34. This patient died of leukemia relapse on day +73. 4 patients have kept on disease free survival till now.

These results further demonstrate umbilical cord blood transplant is a therapeutic option for children with very poor-prognosis leukemia and who lack an HLA-identical sibling or matched unrelated donor. But the decision of transplant for SAA patient with cord blood should be considered carefully.

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