Comparing Platelet Loss in 2 Common Apheresis Machines for Collecting Autologous Peripheral Blood Stem Cells (PBSC).

Chemotherapy together with G-CSF is commonly used to mobilize patients prior to leukapheresis (LP) of PBSC for autologous transplantation. For many patients, peripheral blood platelet counts (PLT) were below 75,000/μl when LP was initiated. Minimizing PLT loss is an important consideration, especially for these patients. The aim of this retrospective analysis is to compare PLT loss during LP for autologous PBSC in two common apheresis machines (Baxter Amicus and Cobe Spectra). Between August 2004 and May 2005, 57 autologous PBSC products were collected from 28 adult patients (weight > 40 kg) with results (mean ± SD) summarized in Table 1. LP were collected using automated procedures and 3 times blood volume was processed. Collection efficiencies (EFF) were calculated as total cells (CD34+ or PLT) in product divided by the circulating count prior to LP times processed volume. Statistical significance was determined by unpaired Student’s t-test. There were no significant differences (p > 0.1) (NS) in patient age, weight, CD34+ cell count (data not shown) and PLT count prior to LP. There were also no differences in the proportion and the total CD34+ cells in the PBSC products collected by either machines. While both devices collected CD34+ cells with similar EFF (data not shown), the Amicus PBSC products have a trend (p = 0.08 and 0.07 when all LP or only those initiated with PLT count below 75,000/μl, respectively)towards a smaller volume (VOL) and contained significantly (p < 0.05) fewer PLT than those collected by Spectra. The PLT EFF was also significantly lower with Amicus, indicating a smaller PLT loss. The same findings were observed whether all LP or only those LP initiated with low PLT counts (< 75, 000/μl) were considered. Our results showed that lower PLT loss is achieved with Amicus during autologous PBSC collection. The machine would be more appropriate for collecting patients with low PLT counts.