[Umbilical cord blood transplantation (UCBT) in thalassemia children]

To evaluate the efficacy of allo-UCBT in thalassemia children.

Five patients with beta-thalassemia major (genotypes were homozygote of beta41-42, beta654 and double heterozygosities of beta41-42/beta654, beta41-42/-28, beta654/-28, respectively) were treated by allo-UCBT. The median age was 3 year and ten month old (31/2 - 7 2/12). Four donor-recipient pairs were HLA-identical and one 1 locus mismatch. The patients received a median UCB nucleated cells (NC) of 5.5 x 10(7)/kg body weight [range (4.7 - 7.7) x 10(7)/kg] and CD(34)(+)CD(38)(-) cells 2.8 x 10(5)/kg [range (0.6 - 4.5) x 10(5)/kg] and CFU-GM 1.09 x 10(5)/kg [range (0.24 - 230.00) x 10(5)/kg]. The conditioning regimen consisted ofbusalphan 16 - 20 mg/kg, cyclophosphamide 180 - 200 mg/kg, horse antithymocyte globulin (ATG) 90 mg/kg or rabbit anti-lymphocyte globulin (ALG) 25 mg/kg and melphalan of 90 mg/m(2) was added to four cases. Cyclosporine A (CsA) alone was administered in 3 cases, and a combination of CsA and methotrexate in the other 2 cases.

Four cases were engrafted, but one rejected and recurred thalassemia state at day 60 past UCBT. One case had autologous reconstitution. The reconstitutions were found in all patients with neutrophils 0.5 x 10(9)/L at day 19 (14 - 22), platelets > 20 x 10(9)/L at day 37 (21 - 63). Two cases developed grade I and II acute GVHD respectively. None developed chronic GVHD. Three patients survived disease-freely (survival with ex-thalassemia state). The median follow-up was 18 months, the probability of survival was 100%.

Allo-UCBT could reconstitute hematopoiesis with low frequency and mild grade of GVHD. It is an effective treatment for thalassemia.