Pre-mobilization platelet count predicts stem cell yield during mobilization in patients with multiple myeloma

Background Autologous hematopoietic stem cell(HSC)transplantation remains the recommended treatment for eligible patients with multiple myeloma(MM).Increasing the number of transplanted CD34^(+)cells shorten the time to hematopoietic reconstitution and increases the overall survival of patients.With the harvest of a sufficient CD34^(+)cell number being crucial,this study aimed to predict the factors that affect stem cell collection.Methods We conducted a retrospective study of 110 patients who were newly diagnosed with MM and underwent autologous HSC collection at Beijing Jishuitan Hospital between March 2016 and July 2022.Multiple factors were analyzed using the Mann-Whitney U tests for between-group comparisons.Differences were considered statistically significant at P<0.05.Results We found that patient age affected stem cell collection significantly;for patients younger than 55 years,the number of CD34^(+)cells harvested may be≥2×10^(6)/L,is unlikely to reach 5×10^(6)/L.Platelet count at initial mobilization was a predictor of the number of CD34^(+)cells collected.Collection may fail when the platelet count at initial mobilization is below 17×10^(9)/L and may be excellent when it is higher than 199×10^(9)/L.Conclusions This finding could guide us to predict the approximate number of CD34^(+)cells collected in advance during autologous transplant mobilization for MM and to decide in advance whether to apply plerixafor to improve the number of HSCs collected.