Feasibility of cord blood collection for autologous cell therapy applications in extremely preterm infants

Abstract

Background aims: Umbilical cord blood (UCB)-derived cells show strong promise as a treatment for neonatal brain injury in pre-clinical models and early-phase clinical trials. Feasibility of UCB collection and autologous administration is reported for term infants, but data are limited for preterm infants. Here the authors assessed the feasibility of UCB-derived cell collection for autologous use in extremely preterm infants born at less than 28 weeks, a population with a high incidence of brain injury and subsequent neurodisability. Methods: In a prospective study at a tertiary hospital in Melbourne, Australia, UCB was collected from infants born at less than 28 weeks and processed to obtain total nucleated cells (TNCs), CD34+ cells, mononuclear cells and cell viability via fluorescence-activated cell sorting prior to cryopreservation. Feasibility was pre-defined as volume adequate for cryopreservation (>9 mL UCB collected) and >25 × 106 TNCs/kg retrieved. Results: Thirty-eight infants (21 male, 17 female) were included in the study. Twenty-four (63.1%) were delivered via cesarean section, 30 (78.9%) received delayed cord clamping before collection and 11 (28.9%) were a multiple birth. Median (interquartile range [IQR]) gestational age was 26.0 weeks (24.5–27.5) and mean (standard deviation) birth weight was 761.5 g (221.5). Median (IQR) UCB volume collected was 19.1 mL/kg (10.5–23.5), median (IQR) TNC count was 105.2 × 106/kg (57.4–174.4), median (IQR) CD34+ cell count was 1.5 × 106/kg (0.6–2.1) and median (IQR) cell viability pre-cryopreservation was 95% (92.1–96.0). Feasibility of collection volume and cell count suitable for cell cryopreservation was achieved in 27 (71%) and 28 (73.6%) infants, respectively. Conclusions: UCB-derived cell collection adequate for cryopreservation and subsequent autologous reinfusion was achieved in 70% of extremely preterm infants. Extremely preterm UCB demonstrated a higher CD34+:TNC ratio compared with published full-term values. Recruitment to demonstrate safety of UCB cell administration in extremely premature infants is ongoing in the CORD-SAFE study (trial registration no. ACTRN12619001637134).