Table 1.

Major human NK cell subsets

NK Cell Subset	Characteristics &Functions	References
CD56bright	Robust cytokine production (IFNγ, TNFα, GM-CSF, IL-10, IL-13)	[25, 30]
	Regulatory, immunomodulatory role	[25, 71]
	↓ with age	[85–87]
	Major subset in CSF	[34]
CD56dim	High cytotoxic capacity	[30, 32]
	↑ perforin, granzymes, cytolytic granules	[31]
	↑ with age	[87]
	Major population in circulation (> 90%)	[25]
CD56–	↑ in chronic viral infections	[27–29]
	↓ cytotoxic capacity	[28]
	↓ cytokine production	[28]

↑: Increased; ↓: Decreased.