ABSTRACT
Objective To explore the cell frequency , phenotypes and in vitro cytotoxic effects of circulating CD56+T cells in the patients with chronic HCV infection .Methods Peripheral blood mononu-clear cells (PBMCs) were isolated from 33 patients with HCV chronic infection and 21 healthy subjects. Multi-color flow cytometry was used to analyze cell frequency , expressions of activating receptors ( NKG2C, CD16 and NKp46) and inhibitory receptors (NKG2A and CD158a) on CD56+T cells.The functional mark-er for cytotoxic effects (CD107a) on circulating CD56+T cells and their cytokines expression (IFN-γand TNF-α) with or without stimulation of K 562 human Leukemia cell line were also analyzed .Then the correla-tions among the expressing levels of CD 107 a, IFN-γand TNF-αwere investigated .Results The frequency of CD56+T cells in periphery lymphocytes were significantly decreased in the patients with chronic HCV in -fection as compared with that in healthy controls ( P=0.018 ).The expressions of activating receptors (NKG2C, CD16 and NKp46) on CD56+T cells from HCV infected patients were decreased (P=0.015 for NKG2C, P=0.036 for CD16 and P=0.001 for NKp46), while there was no significant change in the ex-pressions of inhibitory receptors (P>0.05 for both CD158a and NKG2A).The concentrations of IFN-γand TNF-αsecreted by CD56+T cells in the patients with chronic HCV infection were significantly decreased with or without K562 stimulation (P0.05). The expressions of CD107a, IFN-γand TNF-αwere closely related under the stimulation of K562(r>0.80, P<0.0001).Conclusion The frequency of CD56+T cells was reduced in patients with chronic HCV infec-tion.Moreover, cytotoxic effects and cytokines production mediated by CD 56+T cells were also significantly impaired, indicating that the dysfunction of circulating CD 56+T cells might be associated with the persist-ence of chronic HCV infection .