Long-term results of placental blood allografting using reduced-intensity conditioning: multicenter experience in a developing country.

BACKGROUND

Placental blood (PLB) hematopoietic stem cell transplantation has recently been explored in an increasing number of patients; the best conditioning regimen has not been established.

MATERIAL AND

METHODS

In an eight-year period, 66 consecutive patients, both children and adults (40 males and 26 females), were grafted with allogeneic placental blood cells using a reduced-intensity conditioning regimen: 23 patients were grafted because of a non-malignant condition and 43 patients for a malignant disease. The median age was 7 years (range 5 months to 72 years).

RESULTS

Median time to recover >0.5×10(9)/l granulocytes was 19 days, whereas median time to recover >20×10(9)/l platelets was 23 days. Thirty-eight individuals failed to engraft and they either recovered endogenous hematopoiesis or died. Patients have been followed for periods ranging from 0.5 to 66 months, median 9 months. The median overall post-transplant survival (OS) was 22 months and the 36-month OS was 32%; it was significantly better for individuals grafted with 6/6 matched cords (45%). The cumulative incidences of grade II-IV acute graft-versus-host disease (GVHD) and grade III-IV acute GVHD for the patients who engrafted were 33 and 10%, respectively.

DISCUSSION: The low engraftment rate should be improved by selecting better cord blood units; additional studies are needed to define if non-myeloablative conditioning is preferable over conventional conditioning.