Automated separation of cord blood units in top and bottom bags using the Compomat G4 P. SOLVES, V. MIRABET, F. CARBONELL- UBEROS, M. A. SOLER, R. ROIG Umbilical Cord Blood Bank, Valencia Transfusion Centre, Valencia, Spain Summary Cord blood (CB) has become a real alternative source of haematopoietic stem cells for bone marrow reconstitution in a variety of malignant disorders. As a response to this increasing activity, CB banks have been developed to guarantee the quality of processed CB units. Volume reduction of CB units maximizes storage space and also has other advantages. The aim of this study was to develop a program for the volume reduction of CB in the Compomat G4 device. We also compared two different top and bottom systems for CB fractionation (Compomat G4 and Optipress II). We empirically designed three different programs for volume reduction of CB with Compomat G4: two for final BC volume of 41 ml (CB1 and CB2) and the other one for buffy coat (BC) volume of 25 ml (CB3). Significantly worse recoveries were achieved for CB processed with program CB3. A RBC depletion of ‡50%, ‡60% and ‡70% were achieved for 67%, 39% and 9% of all units respectively. When comparing Compomat G4 and Optipress II, total nucleated cell recovery was similar for both methods, while lymphocytes recovery was significantly better for Optipress II. Keywords Cord blood, volume reduction, top and bottom Introduction Since 1988 when human umbilical cord blood (CB)- derived stem cells were transplanted for the first time as an alternative to marrow or circulating blood-derived pro- genitor cells (Gluckman et al., 1989), umbilical CB trans- plantation has been performed in more than 4000 patients worldwide (Ballen, 2005). In fact, CB has become a real alternative source of haematopoietic stem cells for bone marrow reconstitution in a variety of genetic, haemato- logical and oncological disorders. As a response to this increasing activity, CB banks have been developed to guarantee the quality of processed CB units (Stanworth et al., 2001). One of the major problems with long-term CB banking is the required storage space. Red blood cell (RBC) depletion of CB not only maximizes storage space, but also has other advantages like the reduction of the potential side-effects of dimethylsulfoxide (DMSO) and the reduction of side-effects of ABO-mismatched or haemolysed red blood cells in the unfractionated infusates (Oliveira et al., 2004). Various methods have been employed for the CB volume reduction purpose. To date, most CB banks have used the method developed by the New York Blood Centre consist- ing of hydroxyethylstarch (HES) sedimentation of RBC (Rubinstein et al., 1994; Adorno et al., 1998). To stan- dardize the process and improve cell recovery, other approaches with automated or semi-automated systems have also been developed (Armitage et al., 1999; Zingsem et al., 2003). Our CB bank performs the volume reduction of CB by top and bottom methodology with the Optipress II machine. It is a semi-automated system that allows good cell recoveries. However, the transfusion centre with which our bank is integrated decided to change to Compomat G4 fractionation machines, so we had to do the same. The Compomat G4 is a fully automated machine for the separation of centrifuged whole blood into compo- nents in transfusion centres. The Compomat G4 has been developed to process double, triple and quadruple blood bags systems (Loos, 1986). The principle is that two electronically directed presses can variably express blood Received 14 November 2005; accepted for publication 6 March 2006 Correspondence: Pilar Solves, Valencia Transfusion Centre, Avda del Cid 65-A, 46014 Valencia, Spain. Tel.: 00 34 96 386 81 42; Fax: 00 34 96 350 24 69; E-mail: solves_pil@gva.es Clin. Lab. Haem. doi: 10.1111/j.1365-2257.2006.00778.x 2006, 28, 202–207 Ó 2006 The Authors Journal compilation Ó 2006 Blackwell Publishing Ltd 202