[Expression of CD160 in natural killer (NK) cells from patients with active tuberculosis and its relationship with...

Objective To investigate the relationship between the CD160 expression and anti-tuberculosis immunity. Methods Fluorescence quantitative real-time PCR was used to detect the expression of CD160 in peripheral blood mononuclear cells (PBMCs). Flow cytometry was used to analyze the expression of CD160 on main subtypes of PBMCs, such as T cells, B cells, NK cells and monocytes. The relationship among CD160 and perforin, granzyme B, granulysin, CD69, CD107 and IFN-γ in NK cells was analyzed by flow cytometry. Results CD160 mRNAs in the PBMCs from patients with active tuberculosis was significantly down-regulated, and the levels of CD160 expression in Mycobacterium tuberculosis (MTB)-positive patients was significantly lower than in MTB-negative patients. The expression of CD160 on B cells and monocytes was lower in patients with active tuberculosis as compared with normal controls, while no significant difference was observed on CD3⁺ T cells. NK cells from patients with active tuberculosis had significantly lower CD160 expression than those from normal controls. In vitro culture with MTB antigens led to down-regulated expression of CD160 on NK cells. The activation marker CD69 on NK in patients with active tuberculosis was significantly lower than that in normal controls. The expression of perforin, granzyme B, granulysin, CD69 and CD107 in CD160⁺ NK cells was significantly higher than that of CD160^- NK cells. However, the expression of IFN-γ in CD160⁺ NK cells was significantly lower than that of CD160^- NK cells. Conclusion The mRNA and protein expression of CD160 was significantly down-regulated in patients with active tuberculosis. CD160 promotes the activation and degranulation of NK cells associated with tuberculosis antigens, but suppresses the expression of IFN-γ of NK cells. CD160 may become a new target for the diagnosis and treatment of tuberculosis.