Cutting Edge: Human CD49e- NK Cells Are Tissue Resident in the Liver.

Most knowledge on NK cells is based on studies of what are now known as conventional NK cells in the mouse spleen or human peripheral blood. However, recent studies in mice indicate the presence of tissue-resident NK cells in certain organs, such as the liver, that display different markers and transcription factor dependencies as compared with conventional NK cells. In this study, we provide evidence from cytometry by time-of-flight analysis and humanized mice indicating that human CD49e- NK cells are tissue resident in the liver. Thus, these studies indicate that tissue-resident NK cells are evolutionarily conserved in humans and mice, providing a foundation to explore their role in human disease.