Comparison of the Feasibility of Adult Allogeneic Umbilical Cord Blood Transplantation between the Myeloablative Conditioning Regimen and the Non Myeloablative One.

Aim: To make clear the feasibility of non-myeloablative conditioning on the adult allogeneic umbilical cord blood transplantation, we compared the result between patients receiving the myeloablative (conventional) transplantation (CT) and the reduced intensity stem cell transplantation (RIST) in point of the engraftment, and the incidence of GVHD. Patients’

characteristics and Methods: Patients were admitted to our hospitals to receive umbilical cord blood transplantation during May 1999 to May 2004. CT group (n=23): Median age was 33 years. Diagnoses were included AML (n=9), ALL(n=7), NHL(n=4), MDS(n=2), CML(n=1). Preparative conditioning regimens were; TBI/Ara-C/CY (n=16), TBI/VP-16/CY (n=4), TBI/CY (n=3). GVHD prophylaxis was; Cyclosporine A (CsA) (n=11), CsA with short term Methotrexate (MTX) (n=10), Tacrolimus with short term MTX (n=2). The transplanted median cell number was 2.40 x 10^7/kg. HLA disparities were; 1AMM (n=5), 2AMM (n=18), 3AMM (n=3). RIST group (n=13): Median age was 54 years. Diagnoses were; AML (n=3), NHL (n=5), HD (n=2), ATL (n=1), CLL (n=1), CMMoL(n=1). Preparative conditioning regimens were; Flu/ L-PAM (n=4), TBI/ Flu/ L-PAM (n=1), TBI/ Flu/ CY (n=3), TBI/ Flu (n=1), TBI/ Flu/ BU (n=4). GVHD prophylaxis was; CsA (n=5), CsA with MMF (n=7), Tacrolimus (n=1). The transplanted median cell number was 2.49 x 10^7/kg. HLA disparities were; identical (n=3), 1AMM (n=2), 2AMM (n=6), 3AMM (n=2).

Result: The rate of engraftment failure including conditioning failure, and autologous recovery was 14.8 %in CT and 38.1%in RIST, respectively. The median duration of the engraftment of neutrophils in CT and RIST were 24 days and 19 days, respectively. Patients with Grade II-IV acute GVHD were 15 (65.2%) in CT and 8 (61.5%) in RIST, respectively. The incidence of Grade III-IVacute GvHD was 7 ( 30.4%) and 5(38.4%), respectively.

Conclusion: Engraftment in RIST was achieved earlier than CT, however the incidence of engraftment failure was increased in RIST. There were no significant differences on the incidence of acute GVHD between two groups. Further observations, especially long-term disease-free survival are seemed to be very interesting to ascertain RIST on adult umbilical cord blood transplantation.