Assessment of Leukocytes and Hematopoietic Stem Cells in Umbilical Cord Blood

Abstract

Background: Umbilical cord blood is an important alternative source of hematopoietic stem cells and functionally active leukocytes, widely applied in modern transplantation and cellular medicine. Preservation of their viability depends on collection conditions and pre-cryopreservation storage duration.

Methods: Samples of cord blood obtained during physiological deliveries were analyzed. Multicolor flow cytometry was used for vital fluorescent staining, absolute quantification of CD34+ progenitors, and apoptosis assessment. Colony-forming capacity (CFU-GM, CFU-E) was evaluated by semi-solid agar culture.

Results: Transport and storage of cord blood at 18–22°C within the first 24 hours ensured maximal leukocyte viability and stem cell proliferative activity. Extending the interval to cryopreservation beyond 36 hours resulted in a significant decline in viable CD34+ cells and increased early apoptosis.

Conclusion: Time and strict temperature control during pre-laboratory processing are critical for maintaining the survival potential of cord blood transplants. The findings support the need for standardized collection protocols to ensure high-quality cell grafts for subsequent cryopreservation.