¹Division of Pediatric Blood and Marrow Transplantation, Texas Transplant Institute and Methodist Children's Hospital, San Antonio, TX, USA

Correspondence: Dr KW Chan, Division of Pediatric Blood and Marrow Transplantation, Texas Transplant Institute, 7711 Louis Pasteur Drive, Suite 708, San Antonio, TX 78229, USA. E-mail: kawah.chan@mhshealth.com

Received 2 April 2008; Revised 4 June 2008; Accepted 6 June 2008; Published online 11 August 2008.

Abstract

Early results of unrelated cord blood transplantation (UCBT) for severe aplastic anemia (SAA) were poor with a high rate of engraftment failure. This was attributed to the combination of lower graft cell dose and intact host immune system. We performed UCBT in nine children (median age 9 years) with refractory SAA using increasingly immunosuppressive preparative regimens. The time from diagnosis to UCBT was 3.4–20 months (median age 7.2 years), with all children having failed at least one course of immunosuppression. Donor/recipient HLA matching was six of six (n=1), five of six (n=2) and four of six (n=6). The median nucleated cell dose infused was 5.7 10⁷ cells/kg (range 3.5–20 10⁷ cells/kg). Six patients were engrafted after the first UCBT. Two of the three patients without hematopoietic reconstitution were engrafted after a second UCBT. All children receiving 120 mg/kg of CY in the preparative regimen were engrafted. The median time to myeloid engraftment was 25 (17–59 days) days. Acute GVHD developed in two, and chronic GVHD in five patients. Five patients developed EBV viremia post transplant (lymphoproliferative disorder in three patients). At a median follow-up of 34 months, seven patients are alive and transfusion-independent. UCBT is a feasible treatment strategy for children with refractory SAA lacking a well-matched adult donor.