Determining factors for the outcome of peripheral blood progenitor cells harvests

This is a pilot retrospective study to investigate the factors that may affect the collection of peripheral blood progenitor cells (PBPC). Sixty-nine PBPC harvests in 18 cancer patients (median age 39.5; 8 males and 10 females) were performed during marrow recovery after chemotherapy and hematopoietic growth factors. Median number of nucleated cells (MNC) collected were 13.3 (range 2.3-44.5) x 10 9 per session. Median CFU-GM was 362 colonies (range 63-1,720) per 500,000 MNC. Neither sex, body weight, diagnosis, nor the number of days into leukapheresis was significantly associated with MNC and CFU-GM. Older patients tend to have higher CFU-GM in the PBPC harvests (P =.0437). Higher WBC on the day of harvest is significantly associated with higher yield of MNC after leukapheresis (P <.0001). Patients without any evidence of disease have significantly higher yield of MNC than those having local/distant metastases with or without marrow involvement (P =.0302 and.0446). For patients with metastatic disease, those with bone marrow involvement tend to have higher CFU-GM than those without bone marrow involvement although the difference is not statistically significant (P =.0559). Those patients who have received only one, or three and more chemotherapy regimens have a higher yield of MNC than those who have only two previous chemotherapy regimens (P =.036 and.0324). The mechanism of PBPC mobilization is also discussed. In view of the limited patient number in this study, the results should be confirmed by larger studies.