Pb2449: effect of mobilization methods on cd34+ and total nucleated cell count and their relation with engraftment in autologous hematopoietic stem cell transplantation

Topic: 22. Stem cell transplantation - Clinical Background: The choice of mobilization regimen is important for the quality of the product, as well as for reaching the target CD34 cell dose. Engraftment time varies according to the quality of the product and the mobilization method used. In stem cell collection, the source may be through the bone marrow or peripheral blood. There are various mobilization methods, the most commonly used being granulocyte colony stimulating factor (GCSF) alone, chemotherapy or GCSF combined with plerixafor. Aims: We aimed to compare stem cell collection methods in terms of product quality and engraftment time. Methods: A total of 227 autologous stem cell transplant patients were included in our study. Patients were diagnosed with multiple myeloma (56%), non hodgkin lymphoma (29%) and hodgkin lymphoma (13%). Mobilization regimen were categorized into three groups; mobilized with 1) GCSF only, 2) GCSF & plerixafor and 3) mobilized with chemotherapy. Multiple myeloma patients in the chemotherapy arm received cyclophosphamide, and patients in the lymphoma group received DHAP or ICE regimens. Mann Whitney U test statistical testing was performed on pairewise comparions of medians on CD34, TNC (total nucleated cell), TMNC (total mononuclear cell) numbers and duration of platelet and neutrophil engraftment among independent groups of regimen, age and gender. A p value of 0.05 was considered statistically significant. All analyses were carried out using ‘ SPSS Statistics V.26’ statistical software. Results: In the analysis of the number of CD34 positive cells between the 3 groups, a significant difference was found in the chemotherapy arm compared to the GCSF arm and GCSF&plerixafor arm (p=0.001). In addition, the number of TNC and TMNC was determined at least in the chemotherapy group (p=0.000). There was no statistically significant difference between the use of GCSF alone and GCSF and plerixafor in terms of platelet engraftment times (p=0.254), while there was a statistically significant difference at the 95% confidence level when the chemotherapy group was compared with the GCSF alone and GCSF with plerixafor group (p=0.017 and 0.001, respectively). A high dose of CD34(+) cells is associated with faster platelet engraftment (P =0.01) but not with neutrophil engraftment (P=0.875) It was observed that there was a positive relationship between uncategorized age and the number of TNC and the duration of neutrophil engraftment (p=0.018 and p=0.021 respectively). A positive correlation was found between TNC count and in the group above 50 years of age (p=0.022), among the categorized age groups (under 50 years of age and above). Summary/Conclusion: In our study, the highest CD34+ cell count, the lowest TNC count, and the fastest platelet engraftment were observed in the mobilization group with chemotherapy. In patients over 50 years of age, a prolonged neutrophil engraftment and an increase in the number of TNC were detected. In addition to obtaining CD34 positive cells, product quality, TNC amount, age are the factors that affect the engraftment. This is important in terms of its association with complications such as length of hospital stay, bleeding or infection risk. Keywords: Autologous hematopoietic stem cell transplantation, CD34+ cells