190-P: EVALUATION OF CELL ISOLATION METHODS FOR FLOW CROSSMATCH OF DECEASED SOLID ORGAN TRANSPLANTATION

Aim Crossmatch (XM) for deceased solid organ transplant is a critical and challenging process due to limited cold ischemia time, the need for adequate cell yield and purity of cell isolation, and the process must be quick. In this study we evaluated different cell separation methods to select the most efficient one for clinical transplant crossmatch. Methods Lymphocytes were isolated following lab procedure and/or manufacturer instructions (STEMCELL Technologies Inc.) using Ficoll, RosetteSep, RosetteSep with SepMate Tube, EasySep magnetic selections. Flow T and B cell crossmatches were performed following lab procedure. Results The purity, yield, and average time spent isolating lymphocytes from PB samples obtained from 6 volunteers are given in the following table ( Table 1 ). Conclusions EasySep custom positive selection delivered excellent yield and purity; however, the cells showed strong background binding in the flow XM, making them unacceptable for use in the flow XM. The Ficoll method gave the highest yield with the lowest purity, which may require additional centrifugations to remove red cells, platelets and granulocyte, thus adding time for isolation. Many lymphocytes were lost during the separation using the RosetteSep and RosetteSep with SepMate Tube. However, the methods offer excellent cell purity and no additional separation is needed. Overall, the use of RosetteSep with SepMate tubes could be a practical method for routine lymphocyte isolation for deceased solid organ transplantation.