Long-term cryopreservation of human stem cells

Area of Science:

• Hematology
• Oncology
• Transplantation

Background:

• Successful autologous bone marrow transplantation relies on stem cell viability post-cryopreservation.
• Limited data exists on the impact of cryopreservation duration on human stem cell function.

Purpose of the Study:

• To evaluate the effect of prolonged cryopreservation duration on stem cell engraftment in leukemia patients.
• To assess the feasibility of using long-term cryopreserved stem cells for transplantation.

Main Methods:

• Retrospective review of engraftment data from 33 leukemia patients receiving stem cells cryopreserved for ≥2 years.
• Analysis of cryopreservation methods (liquid nitrogen, programmed freezer, ≤-140°C) in 18 patients.
• Median cryopreservation duration of 2.8 years (range 2-11 years).

Main Results:

• 94% of evaluable patients achieved adequate granulocyte counts.
• 74% achieved platelet counts >50 x 10(9)/l, and 69% achieved >100 x 10(9)/l.
• Engraftment occurred even after cryopreservation up to 11 years.

Conclusions:

• Human stem cells remain capable of engraftment after cryopreservation for up to 11 years.
• Prolonged storage of stem cells is feasible for transplantation.
• Cryopreserved stem cells can be utilized in patients harvested before pelvic irradiation or alkylating agent therapy.