Allogeneic transplantation of G-CSF mobilized peripheral blood stem cells from unrelated donors: a retrospective analysis.

Background and Objectives. Allogeneic peripheral blood stem cell transplant ation (PBSCT) from matched siblings has lead to clinical results comparable to those of standard bone marrow transplantation (BMT). We report the outc ome of 79 patients transplanted with PBSC from unrelated donors. Design and Methods. In 61 cases PBSC were used for primary transplantation whereas 18 patients were treated for relapse or graft-failure. In 35 patien ts receiving primary transplants, T-cell depletion (TCD) using CD34 positiv e selection of PBSC with or without additional T-cell depletion had been pe rformed to reduce the risk of graft-versus-host-disease (GvHD). Results. The rate of primary graft-failure was higher (20%) in the TCD grou p than in that receiving unmanipulated grafts (UM) (5%, p=0.007). Patients with standard risk (n=34) receiving first transplants had a significantly b etter overall (60.4% vs. 24%, p=0.02) and disease-free survival (57.2% vs. 22.3%, p=0.006) compared to a high risk group of patients (n=21). There wer e no differences in the speed of neutrophil and platelet engraftment betwee n TCD and UM transplants. As expected, the cumulative risk for acute GvHD g rade Il.-IV was significantly higher in the patients who had received UM gr afts (71.8% vs. 38.1%, p=0.005). Although a trend towards a better survival rate was observed after TCD transplantation (52.2%) compared to the UM gro up (38.1%), this difference was not statistically significant. The probabil ity of relapse was significantly higher in patients after UM transplants (3 8.8% vs. 8.4%). This apparent paradox is explained by the higher number of high-risk patients in this group (p=0.03). Multivariable analysis of diseas e-free survival revealed risk category (p=0.02) and use of ATG (p=0.03) to be of significant impact. AII patients (n=6) with non-malignant diseases ar e alive with full donor chimerism. Interpretation and Conclusions. These data show that PBSC from unrelated do nors can be transplanted either unmanipulated or CD34 selected. Prospective studies comparing BMT with PBSCT from unrelated donors are needed in defin ed disease categories. (C)2000 Ferrata Storti Foundation.