Efficacy of stem cell mobilization and cell yield-engraftment relations in autologous hematopoietic stem cell transplantation

Objectives: Hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for advanced hematological malignencies, and it also permits the administration of higher doses of chemotherapy to overcome tumor cell resistance. Mobilization is the iatrogenic augmentation of haematopoietic stem cell recirculation that occurs at low levels in steady state. G-CSF, chemotherapy and plerixafor are the most common used agents for mobilization. Mobilized patients underwent apheresis and the products collected by apheresis are cryopreserved. Then cryopreserved CD34+ stem cells are re-infused after conditioning regimen. Expected transient hematopoietic failure is compansated by supportive care. In this study, our aim is to evaluate patiens? data which acquired from our newly established haematopoietic stem cell transplantation unit in all processes and to compare them with published data. Materials and Methods: Between August 2010 and May 2013, 167 patients who had indication for autologous HSCT had referred to Şişli Florence Nightingale Hospital HSCT Unit, which is affiliated with Istanbul Bilim University Faculty of Medicine are accepted for this retrospective study. Patients? data are analyzed according to demographic features, received chemotherapies, mobilization, apheresis and stem cell transplantation characteristics. Results: Totally 31 Hodgkin lymphoma, 55 non-Hodgkin lymphoma and 81 multiple myeloma patients (F/M: 57/110) were included in this study. Mobilization with G-CSF as a single agent resulted optimal CD34+ cell yield for 121 patients. After any type of mobilization regimen median count for pCD34+ cells obtained was 18.0/?l. pCD34+ cell yield correlated with body mass index, but not with age, disease and previous treatment types. There is a close correlation between pCD34+ cell count and collected CD34+ cells in all types of mobilization regimens as G-CSF, chemotherapy and plerixafor (relatively; p<0.001, p=0.002 ve p=0.001). Median yield of 3,3 x 106/kg CD34+ cells/kg was collected with range of 33,9 ? 0,2 x106/kg in total apheresis sessions. An inverse correlation between apheresis sessions number and count of CD34+ cells is obtained. Succesful ASCT is achieved in 144 patients. Mobilization failure encountered only in 9 patients, although all types of mobilization regimen were applied. Median values of both neutrophil and platelet engraftment time for all patients determined as day 11. There is a close inverse correlation between neutrophil and platelet recovery with total CD34+ cell content collected. (p<0.0001). Conclusion: Mobilization is achieved in almost all multiple myeloma patients and most of lymphoma patients with only G-CSF based regimen in our cohort. Half of patients not mobilizated with G-CSF can be mobilizied with chemotherapy and plerixafor as second or third line regimen. Succes of mobilization is found associated with previous chemotherapy cycles but not associated with body weight and indices or age. Engraftment time is shortened with infused amount of CD34+ cell yield. Other mechanical processes like cryopreservation reduce CD34+ cell yield in product.