Evaluation of hematopoietic progenitors in hematopoietic progenitor cell transplants. CD34+dose effect in marrow recovery. Retrospective analysis in 38 patients

Our main goal was to evaluate the CD34+ dose in patients undergoing haemoto poietic stem cell-transplantation and its results in terms of recovery of n eutrophile and platelet counts, transfusion requirements, days of fever, an tibiotic requirements and length of hospital stay. We studied 38 consecutiv e patients with haematological malignancies transplanted at our Department, from Feb. 96 through Sept. 98. The CD34+ cell quantification technique was standardized, using a modification of the ISAGHE 96 protocol. Patients wer e sorted into three groups according to the CD34+ count administered: a) be tween 3 and 5 x 10(6) cells/kg; b) between 5 and 10 x 10(6) cells/kg; c) >1 0 x 10(6) CD34+ cells/kg. As a secondary end point, results were assessed a ccording to the number of aphereses required to arrive at the target count of CD34+, separating those patients that required only 1 or 2 aphereses ver sus those requiring 3 or more. Finally, an analysis was made of the results of transplantation comparing the different sources of stem cells (PBSC ver sus PBSC + B.M.). The best results were obtained in the group with cells be tween 3 and 5 x 10(6) CD34+. No statistically significant advantages were f ound in the group with cells over 5. The supra-optimal dose of more 10 x 10 (6) would yield no additional beneficial results, while they can imply a gr eater infusion of residual tumor cells. The number of aphereses had no impa ct on engraftment. Results obtained with PBSC transplants were better than those with BM+PBSC in terms of neutrophile and platelet recovery. The numbe r of CD34+ cells remains the main element in stem cell transplantation to e valuate the haematopoietic recorery after engraft-ment. Minimum and optimum yields remain unclear. Centers should establish their own optimal dose bas ed on local methodologies and outcomes, maximizing costs and benefits.