Table 1.

Comparison of commonly used allogeneic NK cell sources

NK cell source	Advantages	Limitations	Status of CAR NK cell immunotherapy programme
Cord blood	Easily collected and highly amplified in vivo	Heterogeneous with poor genetic modification	Reported [31]
Pluripotent stem cells	High proliferation capacity, homogeneous cell population, ability to cryopreserve UCBs	Immature phenotype, only modified to fulfill ADCC role	Reported [32]
Peripheral blood	Mature phenotype, highly cytotoxic	Requires in vivo amplification and is not readily obtained	Unreported
NK cell line	Homogeneous cell population, can give multiple doses, easy to expand, easy to genetically modify	Lack of certain receptors, no ADCC effect, limited number of generations amplified in vivo	Unreported