The possible role of the Jak/STAT pathway in lymphocytes at the fetomaternal interface.

Pregnancy is accompanied by a Th2-prone immune modulation, which is a major puzzle piece among maternofetal tolerance-promoting factors. A large number of cytokines is physiologically or pathologically present in the decidua and is potentially able to act on lymphocytes and NK cells, which express a variety of respective receptors. Intracellular signals from these receptors are to a major part transduced via the Janus kinases (JAK) and signal transducers and activators of a transcription (STAT) system, which consists of at least 4 different kinases and 7 STATs plus several subtypes and splicing variants. A network of suppressors of cytokine signaling (SOCS) controls their balance. The interactions of all these intracellular factors and cross-linking with further signaling systems seem to be crucial for the maintenance of a maternal cytokine profile which promotes the tolerance of the fetus.