Optimization of the Spectra Optia for Leukapheresis of Very Small Subjects

• Published in: Blood 2014-12, Vol.124 (21), p.3857-3857
• Main Authors: Donahue, Robert E., Metzger, Mark E., Bonifacino, Aylin C., Parker, Drew M., Leitman, Susan F., Cullis, Herb, Lienesch, Maura
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V124.21.3857.3857

▪ Leukapheresis procedures in very small volume subjects require procedure modifications related to anticoagulant, venous access, and volume. Historically, we accomplished this procedure in 4-5 kg rhesus macaques using a modified CS3000Plus cell separator, but this instrument is no longer available. The Spectra Optia apheresis system and its mononuclear cell (MNC) collection set were evaluated to develop leukapheresis procedures for such subjects. Five rhesus macaques, weight 7-9 kg, blood volume 60 mL/kg, were studied. They pre-donated 100-120 mL of autologous blood (25-30 mL/wk x 4 wks). Aspirin 81 mg was given daily for 3 days prior to 5 of 8 procedures. AMD3100 1 mg/kg SQ 2-3 hours prior to leukapheresis was given as a mobilizing agent. Autologous blood was pooled, diluted 1:1 with saline, and washed to remove citrate and plasma. The Optia was primed first with saline, and then with a customized albumin option in which 30-35 mL of the 40-50 mL of packed RBCs were pumped into the disposable apheresis kit at 10 mL/min. The albumin option shortens procedure ramp-up time. A closed circuit was created between the return line and the packed RBC bag and the flow rate increased to 40 mL/min until 400 mL was processed. To minimize citrate toxicity and avoid volume overload, animals received heparin 50 U/kg bolus IV followed by an ACDA solution containing heparin 5U/mL at an inlet:AC ratio of 25:1. A Collection Preference (CP) setting of 20 was selected using the automatic interface management mode. In the last procedure a semi-automatic mode was utilized so that collection deeper than CP of 20 was possible. Procedures were terminated at 120 min. Animals were anesthetized and catheters placed in the saphenous and cephalic as draw and return lines. Blood counts, chemistries, and ionized calcium (iCa) levels were monitored every 30 min. The elutriation chamber, which concentrates MNCs and allows platelets to return to the donor, was filled 1-2 times per procedure resulting in a product volume of 17-34 mL. A total of eight leukapheresis procedures were performed. Inlet flow rates were typically 10.5 mL/min. In one animal, an inlet rate of 12.0 mL/min was achieved; however, at 120 minutes severe citrate toxicity developed with bradycardia and an iCa level of 0.62 mmol/L, requiring IV calcium gluconate. Excluding this case, a mean(SD) baseline iCa value of 1.17(0.2) dropped to 0.84(0.03) mmol/L at120 min. Mean hematocrit (HCT) decreased from 40.4(1.7)% to a nadir of