Problem: The paradigm of local suppression necessary to understand the survival of the fetal allograft is often compared with the host-tumor relationship.
Methods: We investigated two components of local immune suppression: placenta-induced immunosuppression, which is mediated at least in part by a soluble factor of low molecular weight that can induce anergy in lymphocytes, and interleukin-10 (IL-10).
Results: We show that enhancement of IL-10 production in the decidua and placenta after alloimmunization requires the presence of Asialo GM1+ cells. Placenta-induced immunosuppression is linked with defects in phosphorylation of some components of the T cell receptor.
Conclusion: NK cells could be in fact regulatory cells pushing maternal immune response toward a Th2 profile, beneficial for fetal survival, or toward a Th1 type of immune response, which acts in synergy. Modulation of TcR may represent a new mechanism for maternal-fetal tolerance.