Changes of human decidual natural killer cells cocultured with YFP-Toxoplasma gondii: implications for abnormal pregnancy

Objective: To investigate the changes of human decidual natural killer (dNK) cells cocultured with Toxoplasma gondii in vitro and to infer implications on pregnancy. Design: Case-control study. Setting: College and hospital. Patient(s): Decidual tissue was obtained from 85 patients undergoing voluntary abortion during the first trimester of gestation (6–12 weeks). Intervention(s): None. Main Outcome Measure(s): The dNK cells were isolated and infected with YFP-Toxoplasma gondii. Cells were observed by fluorescence and confocal microscopy. The CD56brightCD16−/CD56dimCD16+ dNK ratio, expression of KIR2DL4, ILT-2, and NKG2D on dNK cells were analyzed by flow cytometry and the cytotoxic activity of infected dNK cells were evaluated. Result(s): The CD56dimCD16+/CD56brightCD16− dNK ratio was significantly elevated at 12, 24, and 48 hours after YFP-T. gondii infection. Expression of KIR2DL4, ILT-2, and NKG2D were increased after infection, but NKG2D were significantly higher than those of KIR2DL4 and ILT-2. Both the CD56dimCD16+/CD56brightCD16− dNK ratio and NKG2D expression were correlated with dNK cytotoxic activity. Conclusion(s): Enhanced dNK cytotoxicity due to increased CD16 and NKG2D expression may contribute to abnormal pregnancy outcomes observed with maternal infection with T. gondii. [ABSTRACT FROM AUTHOR]