G-CSF-Mobilized Peripheral Blood Mononuclear Cells: An Alternative Cellular Source for CAR Therapy

Lymphocyte collection by apheresis for CAR-T production usually does not include mobilized blood using Granulocyte Colony Stimulating Factor (G-CSF) due to the widespread knowledge that it causes a decrease in the number and functionality of lymphocytes. However, it is used for stem cell transplant, which is a common treatment for hematological malignancies. The growing demand for CAR therapies (CAR-T and NK-CAR), both in research and clinic, makes necessary to evaluate whether mobilized PBSC products may be potential candidates for use in such therapies. This review collects recent work that experimentally verifies the role and functionality of T and NK lymphocytes, and the generation of CAR-T, from apheresis after G-CSF mobilization. As discussed, T cells do not vary significantly in their phenotype, the ratio of CD4+ and CD8+ remains constant and the different sub-populations remain stable. In addition, its expansion and proliferation rate are invariant regardless mobilization with G-CSF, as well as the secretion of proinflammatory cytokines and the cytotoxic ability. Therefore, cells mobilized before apheresis are postulated as a new alternative source of T cells for adoptive therapies that will serve to alleviate high demand, increase availability, and take advantage of the substantial number of existing cryopreserved products.