ENGRAFTMENT KINETICS AND LONG-TERM STABILITY OF HEMATOPOIESIS FOLLOWING AUTOGRAFTING OF PERIPHERAL-BLOOD STEM-CELLS

Background. We analyzed short-term and sustained hematopoietic reconst itution after high-dose therapy with peripheral blood stem cell (PBSC) support in patients with various malignant disorders. Methods. Fifty- six patients, all with malignant hematologic disorders, were autograft ed between 1989 and 1994 using PBSC (47 pts) or PBSC + bone marrow (BM ) cells (9 pts). PBSC were collected after mobilization with chemother apy+/-hematopoietic growth factors (GF). Results. All patients engraft ed > 0.5 x 10(9)/L polymorphonuclear cells (PMN) and > 50.0 x 10(9)/L Plt at a median of 12 (8-32) and 13 (9-365) days, respectively. Thirty -nine patients were evaluable for long-term graft performance, and the ir hematologic values at 30 and 100 days, at 6 months and at 1, 2, 3, 4 and 5 years were retrospectively analyzed. Steady counts were record ed over the years. None of the patients had late graft failure. Conclu sions. PBSC given after high-dose chemotherapy ensure a fast hematolog ic recovery with stable graft performance up to five years after autog raft. Though this is not definitive proof of the presence of uncommitt ed stem cells in the PBSC population, it gives further support to the idea that PBSC are as safe as bone marrow for long-term engraftment. A delayed or incomplete recovery of platelets may occur with low PBSC c ounts or when disease relapse occurs rapidly after autograft.