110: Validation study of mononuclear cell recovery using the AXP™ AutoXpress™ Platform

Abstract

BACKGROUND: The AXP AutoXpress Platform has been developed for automatically processing cord blood stem cells before cryopreservation. The platform consists of a microprocessor-controlled device, docking station, functionally closed sterile disposable bag set and supporting XpressTRAK™ software. Cord blood is sterilely transferred to the bag set and centrifuged in the device at high and low speeds. During the high speed spin, the cells separate into layers according to density and during the low speed spin the device transfers the red blood cells (RBC) into the RBC bag, mononuclear cells (MNC) into the freezing bag and retains the plasma in the processing/plasma bag. The MNC volume in the freezing bag is operator selected and achieved with an analytical balance built into the AXP device. After being mixed with 5 ml cryoprotectant, the 25 ml MNC solution in the freezing bag can be directly frozen at a controlled rate and stored in the robotic BioArchive® System. STUDY DESIGN: The validation study was designed and performed to determine the efficiency of MNC recovery with and without addition of 20% HES before processing. High speed centrifugation was 1400xg for 20 minutes and low speed spin 80xg for 10 or 20 min. Human peripheral blood was used in the study to serve as a surrogate for cord blood. Blood volumes investigated were 60, 120 and 170 ml. In addition to MNC recovery, other parameters such as WBC recovery, red cell reduction, hematocrit, final volume in the freezing bag, and cell mass balance in the freezing, RBC and processing bags were also measured. RESULTS: Results are presented as the mean ± S.D. for MNC recovery value. The following table summarizes MNC cell recovery from human peripheral blood in the freezing bag with 60, 120 and 170 ml of initial blood volume in the presence or absence of 20% HES.Tabled 1NLow speed centrifugeVolumes (mL)MNC recovery (%)HES addition1280xg, 20min6091.5 ± 4.820% HES1280xg, 20min17092.3 ± 5.420% HES880xg, 10min6096.0 ± 6.020% HES880xg, 10min17098.7 ± 5.420% HES880xg, 10min6098 ± 5no HES880xg, 10min12092 ± 14no HES880xg, 10min17078 ± 15no HES Open table in a new tab CONCLUSION: The AXP AutoXpress Platform consistently yields MNC recovery greater than 90% with processing blood volume at 60 and 120 ml without HES addition. Adding 20% HES remarkably enhances average MNC recovery to greater than 90% when blood volume processed is 170 ml. The results from this study demonstrate that the AXP AutoXpress Platform can achieve automated volume reduction of blood with high efficiency of MNC recovery.