Immune suppression and Th1/Th2 balance in pregnancy revisited: a (very) personal tribute to Tom Wegmann.

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.