Natural killer cells in hepatitis C: Current progress

Table 1 Controversies over phenotype and function of natural killer cells in chronic hepatitis C virus infection

Phenotype/function	Ref. reported increase	Ref. reported decrease	Ref. reported no change
Activation marker
CD69	[34]		[88]
Activating receptor
NKG2D	[34]	[68]
NKG2C	[77]
NKp46	[77,88,89]	[80]
NKp30	[88]	[80]
NKp44	[77]
Inhibitory receptor
KIR3DL1		[34]
NKG2A	[78-80]
KLRG1	[90]
Cytotoxicity
Degranulation	[34,77]	[68,80,89]	[78]
TRAIL expression	[77]	[89]
Immunostimulating cytokine
IFN-γ	[78]	[34,68]	[77,88]
Immunosuppressive cytokine
IL-10	[88]

IL: Interleukin; IFN: Interferon; NKG2D: Natural killer group 2D; TRAIL: Factor-related apoptosis inducing ligand; KLRG1: Killer cell lectin-like receptor subfamily G member 1.