Outcome of Umbilical Cord Blood Transplantation in 51 Patients with Hematologic Malignancies.

Umbilical cord blood transplantation (UCBT) has recently emerged as a curative approach for patients with hematologic malignancies who lack a suitable HLA-matched donor. We report the outcome of UCBT for 51 hematologic malignancies from a single hospital in Southeast China.

Fifty-one cases of UCBT for hematologic malignancies at Anhui Provincial Hospital from March 2000 to May 2009 were retrospectively characterized, including 20 cases of acute lymphoblastic leukemia (ALL), 12 acute myeloid leukemia (AML), 12 chronic myeloid leukemia (CML) (accelerated phase 5, blast crisis 4), 2 mixed acute leukemia(MIX-AL),4 myelodysplastic syndrome (MDS), and one case of non-Hodgkin lymphoma (NHL). Double UCB grafts were used for 27 patients, while single UCB graft was used for 24 patients. All but one UCB grafts were from unrelated donors. The median cell doses infused were 4.37×10⁷TNC/kg (range, 2.41?16.24), 2.96×10⁵ CD34/kg (range, 0.67?29.28) in single UCBT or 4.44×10⁷TNC/kg (range, 2.76?7.70), 2.67×10⁵ CD34/kg (range, 0.8?9.35) in double UCBT. Myeloablative conditioning was given to 46 patients and nonmyeloablative regimen was given to 5 patients according to the standard protocols. Myeloablative regimen consisted of fractionated total body irradiation (TBI) 1,200 cGy, cyclophosphamide 120 mg/kg, cytarabine 8g/m² (n=26) or of modified BUCY2 consisting of busulfan 16mg/kg orally or 12.8 mg/kg intravenously, cyclophosphamide 120 mg/kg, and rabbit antithymocyte globulin (ATG, Fresenius, Germany) 7.5mg/kg (n=20). Reduced intensity conditioning consisted of fludarabine 160 mg/m², BU6.4m/kg, ATG 7.5mg/kg and TBI 3Gy. All patients were given a combination of cyclosporin A (CsA) and mycophenolate mofetil (MMF) for graft-versus-host disease (GVHD) prophylaxis.

Of the 51 patients, 34 had advanced stage of disease. The patients' age ranged from 3 to 48 years (median 19 yr) and the body weight ranged from 15 to 84 kg (median 53 kg), respectively. Although one patient with advance-staged chronic myeloid leukemia (CML) died 16 days after UCBT and 6 patients showed primary graft failure, 44 of the 50 patients (88%) achieved engraftment, with neutrophil recovery (≥0.5×10⁹/L) occurring at a median of 19 days (range, 12-39) and platelet recovery (≥20×10⁹/L) occurring at a median of 34 days (range, 21-73), respectively. All of the 44 patients gained complete donor chimerism by PCR analysis of short tandem repeat (STR) sequences on whole blood or bone marrow from day 7 to day 100 after transplantation. Half of the patients (22/44, 50%) developed acute GVHD with 19 cases of grade I/II disease (43.2%) and 3 cases of grade III disease (6.8%). Only five patients (16.1%) developed chronic GVHD, with 2 in skin, 1 in intestinal, 1 in liver, and 1 patient with refractory chronic GVHD with thrombocytopenia. Three patients had relapse (2 year relapse rate of 5.9%) with one in central nervous system, who achieved remission after intrathecal injection of chemotherapy regimen.,one with CML blast crisis achieved remission after oral imatinib,and the third died of relapsed disease. The median follow-up duration of surviving patients was 19 months (range, 3-113) with a 2 year overall survival rate of 54.5%. A total of 20 patients died during the study, with a 2 year transplant related mortality rate of 37.3%. The most common cause of death was severe infection (12) due to bacteria, fungi and/or viruses, and other causes included acute GVHD (1), disease progression (1), veno-occlusive disease of the liver (1), sudden cardiac death (1), cerebral hemorrhage (1), fulminant viral hepatitis (1), early rejection (1),and systemic failure (1).

UCBT could be safely and effectively used for patients with hematologic malignancies. The use of double UCB as a strategy extends the availability of transplantation. Prevention and control of infection are essential for long-term survival after UCBT.

No relevant conflicts of interest to declare.