“…The uterine decidua is not an immunologically privileged site; allografts are rejected promptly if the mother is alloimmunized, and allografts at nonuterine sites are recognized and rejected in unprimed females (reviewed in Clark, 1991). By contrast, pregnant mothers, whether human or murine, do not reject gestating semi-allogeneic or completely allogeneic (foreign) embryos, even if pre-immunized against the alloantigens of the father (Wegmann et al, 1979). Further, a pregnant female can make an immune response to the foreign MHC and minor non-MHC antigens of her fetus, but anti-MHC antibodies are not harmful, unlike antibodies to blood group antigens such as Rh, which can cross trophoblast and attach to the baby's Rh-positive erythrocytes, and sensitized maternal T cells do not cause pathological conditions either (Lissauer et al, 2012).…”