Factors predicting engraftment of autologous blood stem cells: CD34(+) subsets inferior to the total CD34(+) cell dose

Data were analyzed on 178 consecutive patients (median age 43 years) who un derwent autologous blood stem cell transplantation (ABSCT) at a single inst itution to determine if CD34(+) subsets (CD34(+)38(-), CD34(+)33(-), CD34()33(+), CD34(+)41(+)) or various clinical factors affect hematopoietic engr aftment independent of the total CD34(+) cell dose/kg, Using Cox proportion al hazards models, the factors independently associated with rapid neutroph il engraftment were higher CD34(+) dosenig, use of G-CSF post-ABSCT, and co nditioning regimen (single-agent melphalan +/- TBI slower). Factors indepen dently associated with rapid platelet engraftment were higher CD34(+) cell dose/kg, higher ratio of CD34(+)33(-)/total CD34(+) cells infused, conditio ning regimen (mitoxantrone, vinblastine, cyclophosphamide faster), and no C D34(+) cell selection of the autograft, The CD34+ cell selection process se emed to deplete CD34(+)41(+) cells to a greater extent than total CD34(+) c ells which may explain our observation that it resulted in slower platelet engraftment. In conclusion, the total CD34(+) dose/kg was a better predicto r of hematopoietic engraftment following ABSCT than the dose of any CD34(+) subset. Platelet engraftment, however, was also influenced by the ratio of CD34(+)33(-)/total CD34(+) cells for unmanipulated autografts, and possibl y by the CD34(+)41(+) dose for autografts manipulated by CD34(+) selection, The use of CD34(+) subsets requires further investigation in predicting en graftment of autografts which undergo ex vivo manipulation.