RECURRENT ABORTIONS AND LYMPHOCYTE TRANSFUSIONS

Normal pregnancies depend on successful implantation of the placenta i n the uterus. The trophoblast which forms the ultimate interface betwe en the fetal and maternal tissue seems to lack the foreign (allo) anti gens (namely HLA/TLX) required to induce immunological rejection react ions in the mother. It was previously believed that the trophoblast ex pressed paternal allo antigens and that successful pregnancies were de pendent on so called 'kind' (non-cytotoxic or non-complement binding) blocking antibodies in order to protect the fetal unit from maternal c ytotoxic T-cells and -antibodies. Blocking antibodies attached to pate rnal antigens on the trophoblast were assumed to prevent maternal cyto toxic T cell and cytotoxic antibodies from recognising the trophoblast as foreign tissue. On this assumption it was reasoned that transfusio ns of paternal HLA-expressing lymphocytes would increase maternal anti paternal HLA (TLX) blocking antibodies and thus be beneficial to women who experienced multiple miscarriages. There is, however, no scientif ic evidence for a specific immune response after lymphocyte transfusio ns that fulfil this function. Immunological tests, as for example mixe d lymphocyte culture (MLC), on peripheral blood lymphocytes do not see m to reflect the local immune state in the uterus, either in the pregn ant or the non-pregnant state. Since the trophoblast forms the ultimat e interface between fetal and maternal tissue, its structure, secretio ns, and interaction with the decidua must be of definite importance fo r implantation of the blastocyst and growth of the embryo.