[Mechanisms of immune tolerance in physiological pregnancy].

Evidence for possible mechanisms providing maternal immune system tolerance to fetoplacental structure during physiological pregnancy is presented. Conditions forming systemic and peripheral tolerance are considered. Major regulatory cell and molecules are defined that are directly involved in tolerance realization to fetal antigens. In addition, processes of T-lymphocyte extra-thymic differentiation and apoptosis-inducing placental ligands are examined as essential mechanisms maintaining tolerance.