Cryopreservation of Stem Cells Using Human Serum Albumin and Autologus Plasma as Cryoprotectants: Its Clinical Impact Mohandoss Murugesan1, Chandran K Nair2 Transfusion Medicine1, Clinical Hematology2, Malabar Cancer Centre, Thalassery, Kannur Dt., Kerala (An autonomous center under Govt. of Kerala) Background Cryopreservation of stem cells in autologous hematopoietic stem cell transplantation (HSCT) was performed to maintain their cell viability and recovery during storage. Commonly followed practice was to dilute cryoprotectant DMSO with Human serum albumin (HSA) for achieving optimal concentration. Autologous Plasma (AP) is less expensive and ready availability makes it an easy alternative for HSA in preparing cryoprotective solutions. Aim: To study the process of using human serum albumin and autologous plasma as diluents for DMSO in autologous transplantation and to compare the impact of both cryoprotective solutions on hematopoietic engraftment Methods: Retrospective study, involving 15 autologous HSCT patients, who underwent cryopreservation. Two study groups The 15% cryoprotectants added in equal volume to the PBSC product to yield a final concentration of 7.5 %. Quantification of CD34+ cells: by flow cytometry using FC500 (Ishage protocol) Volume Reduction (VR): All the product were centrifuged at x5000g and supernatant plasma separated. In AP group, the plasma was used for dilution of DMSO. Engraftment Interval: Hematopoietic reconstitution in two groups studied. Transfusion Support: data retrieved Group I (n=7 patients) DMSO diluted by human serum albumin Group II (n=8 patients)DMSO diluted by autologous plasma (harvested during leukapheresis & volume reduction of final product) Volume of HSA/AP required = F * 85/100 Volume of DMSO required = F * 15/100 Results: 6/15 patients underwent stem cell infusion and taken for analysis Patient characteristic 5% HSA Auto Plasma Male /Female 7/0 5/3 Age 32 (14-50) 47 (19-62) Diagnosis MM HD NHL Others 3 1 2 5 CD34+cells (x106/kg) 7.2 (2.1-12) 4.4 (2.9-9.2) Viability % 86 90 Product volume 5% HSA Auto Plasma Before VR 278 ±48 314 ±74 After 170 ±66 193 ±42 Median Tx 5% HSA Auto Plasma PRBC 5 (0-5) 3 (1-5) PLT tx events (2-3) 6 (2-7) Median Engraftment Days (Range) 5% HSA Auto Plasma WBC> 1x109/L 9 (9-10) 11 (9-16) ANC > 0.5x109/L 3 consecutive days PLT>20x109/L without tx 15 (13-25) 27 (12-28) Discussion & Conclusion Smagur et.al, had shown HSA can be replaced by AP without negative impact on cell recovery and clonogenic potential. This study supports that the autologous plasma can be a easier & cheaper alternative to HSA in cryopreservation of HSCs. We refrain from drawing any conclusions from this study due to the insufficient sample and further studies are being carried out. References: Smagur A, Mitrus I, Ciomber A et al. Comparison of the cryoprotective solutions based on human albumin vs. autologus plasma: its effect on cell recovery, clonogenic potential of peripheral blood hematopoietic progenitor cells and engraftment after autologous transplantation. Vox Sanguinis (2015) 108, 417–424