Quality controls of cord blood units according to JACIE standards are highly predictive in unrelated cord blood transplant

Cord Blood Units (CBU) are increasingly used for allogeneic stem cell transplant and their selection is meanly done accord- ing to value of pre-freezing cell dose and HLA compatibility. According to JACIE standard, the quality controls (QC) for evaluating the efficiency of CBU before the recruitment include viability and CFU tests. Objectives: Aim of our study was to evaluate the sensibility of QC, performed on pilot vial/fragment before CBU formal recruitment, as cell dose, clonogenic test and viability in order to define the predictive parameters for the graft. Methods: We retrospectively analyzed 48 unrelated Cord Blood Transplant (CBT) performed with 52 CBU (4 double trans- plants) at Rome Transplant Network (RTN) from September 2005 to September 2008. Patients underwent unrelated CBT for malignant (n=45) or non malignant diseases (n=3) either in 1st/2nd complete remission (n=18/11) or in advanced disease (n=19). Median patient age and body weight were 20.4 years (0.6–60) and 50.5 kg (4 -96), respectively. The CBU were HLA matched in 4 cases and mismatched for 1 (n=12) or 2 HLA loci (n=36) in 48 cases. According to RTN policy, CBU selec- tion was based on the following pre-freezing parameters: NC dose > 2.5 x 107/kg, HLA compatibility >4/6 loci, CD34+cells >1x105/kg, CFU-GM >1x104/kg and AB0 matching. In order to confirm the reproducibility of pre-freezing data, the cell recov- ery in terms of NC, CD34+, clonogenic assay and viability was required after thawing of an aliquot before the CBU formal recruitment for transplant. Results Our analysis has shown a significant relationship between the QC performed on a thawed fragment and the val- ues both pre-freezing and at infusion of CBU, in terms of NC (p<0.01), CD34 (p<0.01) and CFU-GM (p<0.05), whereas no significant correlation has been found for viability. The median time between CBU freezing and thawing was 5.2 years (0.26- 9.04) and did not affect the NC, CD34+ and CFU-GM recovery. The viability of CBU at infusion significantly correlates with the speed of engraftment for PLTS (p=0.005). Conclusions: From this study we can draw the following prelimi- nary conclusions: 1) QC in terms of cell dose recovery and clonogenic assay are predictive for the values at infusion and reflect the safety of cryopreservation procedure; 2) the viability of cells at infusion is related to the speed of PLTS engraftment; 3) CD 34+ and CFU-GM results of QC, performed on a thawed fragment, may replace pre-freezing missing data.