  
Higher donor CD3+ cell count improves allogeneic transplant engraftment
Last Updated: 2001-01-24 9:15:31 EST (Reuters Health)
WESTPORT, CT (Reuters Health) - A higher number of donor CD3+ cells improves engraftment after allogeneic transplantation of CD34+ selected cells (allo-PBT/CD34+) from HLA-identical siblings, according to a report in the January 15th issue of Blood.
T-cell depletion of donor inoculum significantly reduces the incidence and severity of graft-versus-host disease (GVHD), but also results in a high rate of graft failure, the authors explain. Few studies have analyzed the factors contributing to graft failure in this setting.
Dr. Alvaro Urbano-Ispizua from the University of Barcelona in Spain and colleagues analyzed the effect of various factors in 257 allo-PBT/CD34+ transplants on the incidence of graft failure.
Twenty-four patients (9%) developed graft failure at a median of 65 days posttransplant, the authors report. The failure rate was about 18 times higher among patients receiving a T-cell dose in the graft below 0.2 million cells per kg than among those receiving larger T-cell doses.
Most significantly, the probability of graft failure increased progressively as the number of CD3+ cells in the graft decreased, from 2.1% with more than 0.37 million cells per kg to 18.5% with fewer than 0.07 million cells per kg, the researchers note.
Patients with chronic myelogenous leukemia who were conditioned with busulfan also faced a significantly higher probability of graft failure, according to the investigators.
Fifteen of 24 retransplanted patients died, 12 from severe pancytopenia and 3 from GVHD, the report indicates.
"Taking these results into account," the researchers write, "we are considering fixing the quantity of CD3+ cells in the graft at 0.3 million/kg for HLA-identical sibling allo-PBT/CD34+, adding to the positive fraction the necessary number of CD3+ cells to reach this quantity, and maintaining the use of cyclosporine as GVHD posttransplant prophylaxis."
The authors also advise "that in patients with chronic myelogenous leukemia receiving 0.2 million/kg or less CD3+ cells, total body irradiation should be preferred to busulfan-based regimens."
Blood 2001;97:383-387.
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