Autologous hematopoietic stem cell transplantation in multiple myeloma and lymphoma: an analysis of factors influencing stem cell collection and hematological recovery.

Autologous stem cell transplantation is standard treatment for newly diagnosed younger patients with multiple myeloma and for relapsed or refractory Hodgkin or non-Hodgkin lymphoma. Patient characteristics influencing the yield from stem cell collection and time from transplant to platelet recovery were retrospectively analyzed in 630 consecutive patients, attempting to define adequate amounts of CD34+ cells to collect and reinfuse; 509/630 patients (81%) mobilized the requested CD34+ cell number. Factors influencing the harvest yield were age (P < 0.001) and gender, where 85% of men and 78% of women (P < 0.02) attained the requested stem cell amount. Time to platelet recovery was significantly faster for multiple myeloma patients compared to all other diagnoses (14.6 days compared to 19.8, P < 0.0001). Multiple myeloma patients were older than lymphoma patients but received stem cell transplant up-front as opposed to second line therapy for other patient groups. Multivariate analysis revealed that the most important factor influencing platelet recovery was diagnosis, followed by the amount of reinfused CD34+ cells (P < 0.001, P < 0.05). Blood group O+ had the fastest platelet recovery, whereas blood group A harvested the highest cell amounts. In conclusion, we demonstrate a significant importance of the number of reinfused CD34+ cells on the time to platelet recovery.