Toll-like receptors in female reproductive tract and their menstrual cycle dependent expression

Rapid innate immune defences against infection usually involve the recognition of invading pathogens by specific pattern recognition receptors recently attributed to the family of Toll-like receptors (TLR). TLRs constitute a major part of innate immune system, and have been characterised in different tissues and organs. Reports from our laboratory and others have demonstrated the existence of TLRs in the female reproductive tract, yet TLRs have not been explored completely in this system. There is little known about variation in TLR expression during the menstrual cycle and the effects that sex hormones may have on their expression and function. Here, we review recent information regarding the existence of TLRs in the female reproductive tract, their function in the maintenance of innate immune system in this tract and their potential role in pregnancy.