Encouraging Outcome of Using Sibling HLA-Matched Fresh Cord Blood for Children β-Thalassemia Major Transplantation

Background: Hematopoietic stem cell transplantation(HSCT) is currently the only curative treatment for thalassemia major (TM). Cord blood (CB) from a sibling has different characteristics from marrow and has potential advantages and disadvantages as a stem cell source.

Methods: We conducted a retrospective study of fresh cord blood transplantation (F-CBT) from the matched human leukocyte antigen (HLA)-identical sibling donors in 35 children (median age at transplantation: 4 years, range:1-7 years) with β-TM from June 2010 to December 2016. The conditioning protocol included intravenous busulfan, cyclophosphamide, fludarabine, and thiotepa.

Results:The median collected CB volume was 130ml (range: 79-209ml). The median infused total nucleated cell (TNC) dose was 9.38×10⁷/kg (range: 2.73-18.91×10⁷/kg). One patient had graft failure (GF) on +30day after F-CBT and one patient died from respiratory and heart failure that developed from a pulmonary infection. Of the 33 patients who had a successful engraftment, two patients developed grade II~III acute graft-versus-host disease(GVHD); and one with grade I extensive chronic GVHD was observed during the long-term follow-up period. The median time to neutrophil recovery was +27 days (range: +14 to +49days). The platelet and hemoglobin engraftment times were +33 days (range: +19 to +73 days) and +26 days (range: +11 to +74 days), respectively. All the patients were followed up by December 31, 2017; the median follow-up time was 45 months, and the estimated 5-year overall survival (OS) and TM-free survival (TFS) of F-CBT were 97.1% and 94.2%, respectively.

Conclusions: F-CBT from a matched HLA-identical sibling donor is an effective treatment option for β-TM in children with less GVHD.