Problem: Uterine NK cells have a unique phenotype compared with blood NK cell subsets, yet little is known about how NK cells function as a part of the innate immune cell network in the female reproductive tract.
Method of study: The expression of key receptors and function of uterine NK cells in response to cytokines, sex hormones, and pathogen associated molecular patterns (PAMPs) was analyzed. This article summarizes recent findings on the biology and function of NK cells in the female reproductive tract.
Results: Uterine NK cells express Toll-like receptors and respond to cytokines and PAMPs under specific conditions. Evidence indicates that NK cells play an important role in the reorganization of blood vessels during pregnancy.
Conclusions: Human uterine NK cells are a major population of leukocytes in the endometrium and play an important role as a component of host defense and in successful reproduction.