In vitro functions of natural killer cells in peripheral blood of patients with severe aplastic anemia

Abstract

To observe the in vitro killing functions of natural killer (NK) cells for K562 cells in peripheral blood of severe aplastic anemia (SAA) patients and explore the role of NK cells in the immunological pathogenesis of SAA. NK cells (CD3(-)CD56(+)CD16(+)) as effector cells were sorted from peripheral blood mononuclear cells (PBMNC) of 12 SAA patients and 10 normal controls by magnetic activated cell sorting system (MACS)from June 2013 to August 2014. K562 cells as target cells were co-cultured with the effector cells (1: 1, 1: 5, 1: 10). Using Annexin V and PI double staining markers, the apoptotic rate of K562 cells were measured by flow cytometry after culturing. The apoptotic rate of K562 cells in SAA patients was (10.30% ± 6.08%) according to the ratio of effector-target (1: 1). And it was significantly higher than that in normal controls (6.30% ± 3.46%) (P < 0.05). The apoptotic rate of K562 cells in SAA patients were 10.30% ± 6.08%, 16.47% ± 8.29% and 25.45% ± 9.88% respectively according to the ratio of effector-target(1: 1, 5: 1, 10: 1). The higher ratio of effector-target, the higher apoptotic rate of K562 cells. There were statistic differences among three groups (P < 0.05). There are enhanced in vitro functions of NK cells in peripheral blood of SAA patients NK cells may play an important role in abnormal immune tolerance mechanisms of SAA patients.