[Optimization of a haematopoietic stem cell freezing process using a qualification protocol applicable to a programmable freezer]. / Optimisation d'un processus de congélation des cellules souches hématopoïétique par l'application d'un protocole de qualification d'un congélateur programmable.

BACKGROUND: The freezing phase is a critical step of the freezing process of the hematopoietic stem cells. To standardize the decrease of the temperature, the use of a programmable freezer is recommended. There is no available protocol, neither to describe exactly the validation of a programmable freezer, nor to prove the performance of the freezing/thawing step of the grafts. METHOD: We describe a validation protocol with three phases: first a qualification of installation, then an operational qualification and finally, a qualification of performance. The validation is performed in tandem between the freezer which is routinely used (Nicool Plus) and a new one (Freezal). RESULTS: With this protocol, we demonstrate the efficacy of the freezing program and its ability to assure the quality of the grafts reinjected to the patients, particularly in terms of cellular efficiency on CD34+ hematopoietic stem cells. On these cells, we measured a significant increase of cellular efficiency (+10%) after freezing with the Freezal. CONCLUSION: Here, we propose a validation protocol which is able to qualify a programmable freezer. This protocol can optimize the capability of the freezer and is able to prove its performance.