Cytokine production by CD16^-CD56^bright natural killer cells in the human early pregnancy decidua

Using a cell sorter, CD16^-CD56^bright natural killer (NK) cells were sorted from decidual mononuclear cells at an early stage of pregnancy. These cells were examined by the reverse transcrlptase-polymerase chain reaction (RT-PCR) method for their expression of mRNA coding for the following 12 cytokines: IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colonystimulating factor (M-CSF), tumor necrosis factor-α (TNF-α), interferond-γ (IFN-γ), and leukemia inhibitory factor (LIF). Although mRNA coding for every cytokine was detected in decidual mononuclear cells, mRNAs coding for only G-CSF, GM-CSF, M-CSF, TNF-α, IFN-γ, and LIF were detected In CD16^-CD56^bright NK cells. Also, the supernatant of CD16^-CD56^bright NK cell cultures was found to contain G-CSF, GM-CSF, M-CSF, TNF-α, IFN-γ, and LIF. These findings indicate that CD16^-CD56^bright NK cells produce many different cytokines and that these cytokines may play an important role in a successful pregnancy.