Inverse relationship between patient peripheral blood CD34+ cell counts and collection efficiency for CD34+ cells in two automated leukapheresis systems

BACKGROUND: The purpose of this study was to analyze the CD34 cell collecti on efficiency (CE) of automated leukapheresis protocols of two blood cell s eparators (Spectra, COBE [AutoPBSC protocol] and AS104, Fresenius [PBSC-Lym , protocol]) for peripheral blood progenitor cell (PBPC) harvest in patient s with malignant diseases. STUDY DESIGN AND METHODS: PBPCs were collected by the Spectra AutoPBSC prot ocol in 95 patients (123 collections) and the AS104 PBSC-Lym protocol in 87 patients (115 harvests). Patients underwent a median of one (range, 1-4) c onventional-volume apheresis procedure of 10.8 L (9.0-13.9) to obtain a tar get cell dose of greater than or equal to2.5 x 10(6) CD34+ cells per kg. RESULTS: The median overall CD34 CE was significantly better on the AS104 t han on the Spectra: 55.8 percent versus 42.4 percent (p = 0.000). This was also true below (59.2% vs. 50.1%; p = 0.022) and above (51.2% vs. 41.3%; p = 0.001) the preleukapheresis threshold of 40 CD34+ cells per muL needed to collect a single-apheresis autograft. However, at greater than or equal to 40 circulating CD34+ cells per muL, both cell separators achieved the targ et of greater than or equal to2.5 x 10(6) CD34+ cells per kg. The CD34 CE d ropped significantly, from 59.2 percent at < 40 cells per muL to 51.2 perce nt at greater than or equal to 40 cells per muL on the AS104 (p = 0.017) an d from 50.1 percent to 41.3 percent on the Spectra (p = 0.033). CONCLUSION: Whereas the CD34 CE was significantly different with the AS104 and the Spectra, the CD34 CE of both machines correlated inversely with per ipheral blood CD34+ cell counts, showing a significant decline with increas ing numbers of circulating CD34+ cells. Nevertheless, at greater than or eq ual to 40 preapheresis CD34+ cells per muL, sufficient hematopoietic autogr afts of greater than or equal to2.5 x 10(6) CD34+ cells per kg were harvest ed by a single conventional-volume (11 L) leukapheresis on both cell separa tors.