Validation of long-term handling and storage conditions for hematopoietic stem cell products for autologous transplants

Abstract

Hematopoietic stem cells (HPSCs) are multipotent stem cells that can differentiate into lymphoid and myeloid progenitors, giving rise to white blood cells (WBCs), red blood cells (RBCs), and platelets. HPSCs are a widely used treatment for many hematological non-malignant and malignant disorders. HPSCs can be used in the fresh or cryopreserved state for future use. Fresh HPSCs are typically stored at 2-6°C for up to 72 hours and are primarily used for allogeneic transplants or autologous transplants in myeloma and lymphoma patients. However, in some cases of autologous donations, HPSC transplantation is delayed more than three days after collection. In such situations, the cells are thawed after short-term preservation, resulting in a 35% cell viability loss. This study aimed to investigate the quality of HPSCs products after long-term storage exceeding 72 hours. The quality of HPSCs products was assessed by measuring viable CD34+ cell count, the total number of nucleated cells (TNC), and HPSCs recovery after different storage intervals of up to 120 hours in hypothermal storage. The mean total cell viability decreased by 2.18% within 72 hours and 7.4% within 120 hours, while mean CD34+ cell recovery was 92.61 % at 72 hours and 83.83 % at 120 hours in hypothermal storage. The mean TNC recovery was 89.93% at 72 hours and 76.18 % at 120 hours. All products were free from bacterial contamination for up to 120 hours under hypothermal storage conditions.

Keywords: HPSCs; cryopreservation; hematopoietic stem cells; hypothermic storage; stem cells; validation.