Predictors of high yield and purity of CD34(+) cell-selected PBPC, collected from patients with multiple myeloma

Background Wide ranges in cell recovery and purity may be observed followin g CD34(+) cell selection of mobilized HPC components. Characteristics of th e mobilized HPC, associated with isolation of a high CD34(+) cell yield and purity following cell selection, have yet to be defined. Methods Cell numbers and purities were determined before and after 56 CD34( +) cell-selection procedures, performed using the CellPro Ceprate SC system from April 1997 to February 1998. HPC were collected from 28 patients with multiple myeloma, following cyclophosphamide (60 mg/kg) and G-CSF (10 mu g /kg) mobilization. Results. A median of 47.9% (range 1.5-109.6%) CD34(+) cells were recovered ill the enriched (ENR) fraction. A linear correlation existed between total CD34(+) cells in the ENR fraction and total CD34(+) cells in the START fra ction (R2 = 0.93); there was a log-arithmic correlation between CD34 ENR fr action purity and START fraction purity (R2 = 0.73). A START CD34(+) cell p urity > 0.42% improved purity in the ENR fraction. A median of one (range o ne to nine) procedure was required to isolate 2 x 10(6) CD34(+) cells/kg. T hree patients pretreated with alkylating agents failed to mobilize adequate numbers of HPC. Discussion Isolation of highly purified CD34(+) cell-selected components us ing the Ceprate SC system is dependent on the CD34(+) purity of the leukaph eresis component collected. Mobilization regimens should be used to maximiz e CD34(+) cell purity in stem cell autografts if CD34(+) cell selection is to be performed. Similar strategies should be used to evaluate other cell-s election devices as they become available.