Transfuse Neonates with Cord Blood-Derived Red Blood Cells: A Feasibility Study to Assess Allogeneic Cord Blood Unit Fractionation and Validation

Abstract 275

Newborns are currently transfused with RBCs from adults, which mainly contain adult hemoglobin (HbA). HbA has a lower affinity for oxygen than fetal hemoglobin: therefore adult red cell transfusion could be responsible for increased oxygen increasing the risk of the “oxygen radicals disease of the newborn”. Autologous umbilical cord blood has been suggested as the only alternative source of blood for newborn transfusions. Previous studies, however, demonstrated that autologous cord blood transfusions in newborns are not sufficient to entirely cover the early neonatal blood requests. We reported the preliminary results of our study carried out to assess the feasibility of an allogeneic cord blood (ACB) transfusion program for prematures in terms of preparation and yield of valid ACB red blood cell (RBC) units. ACB units collected at the Cord Blood Bank but not suitable for processing and storage for allogeneic transplant cord blood were evaluated. Eligible criteria for cord blood collection were: more than 37 weeks of gestation, absence of mother's infection or fever 24 hours before the delivery, no stain of the amniotic fluid. ACB units eligible for our study contained more than 60 mL of cord blood, with no clots or hemolysis. We prepared buffy coat–depleted ACB RC units by automated separation (Compomat G4®, Fresenius HemoCare, Germany) in a processing set (Compoflex®). Suspension in SAG-mannitol and post-storage filtration was performed to obtain a leukocyte-depleted red cell unit. Resuspended units were stored for fourteen days after manipulation (2–6°C). Cultures for bacterial contamination were performed immediately after manipulation and after 14 days; biochemical determination (LDH, glucose, lactate, potassium, chloride, sodium, pH and pO₂) were performed the day of fractionation (=0) and after 7 and 14 days of storage. Biochemical data were also compared to the same parameters obtained from adult red blood cell concentrates. We collected 76 ACB units. Thirty-three were discharged for insufficient volume or clots. The median collection volume of the 43 remaining units was 92.3 (± 18.3) ml. After fractionation, 43 ACB RC units were obtained with a median volume of 31.2 (± 8.2) ml and a median hematocrit of 59 ± 2%. Microbial contamination was absent in all units after manipulation and after 14 days; viral tests carried out on mother's blood at the time of cord blood collection were negative. Biochemical parameters maintained rather well up to 14 days of storage, but less resistant than adult red cells. Our data highlight that ACB is a promising source of RBC for transfusion in preterm infants. Besides the reduction of waste of not validated ACB units collected in the Cord Blood Bank, transfusional utilization of ACB RBC can overcome several problems of autologous cord blood transfusion: insufficient volumes is less frequent in ACB from term newborns and the incidence of clots, which is one of the more frequent cause of ineligibility of cord blood units, is substantially reduced when collection is performed by trained staff, in term neonates and using adequate blood shakers. Microbial contamination is prevented by adopting the strict eligibility criteria and the adequate aseptic collection technique adopted in the Cord Blood Bank. In conclusion, the preparation of transfusionally valid RCs from ACB is possible and convenient. Clinical studies are needed to evaluate the efficacy and safety of this new transfusion practice.