Fetal therapy: ethical, legal and medical considerations

Gestational Age and Cell Viability Determine the Effect of Frozen Storage on Human Fetal Hematopoietic Progenitor Cell Preparations

“…The developing fetus represents a 'privileged' environment; devoid of immune capability it is able to accept donor tissue without the sequelae of transplant-associated rejection phenomena evident in postnatal life [4], However, in order to exploit this immu nological naivete for in utero transplantation, it is imperative that donor cells are intro duced while hepatic erythropoiesis is proceed ing, before myelopoiesis and lymphoid devel opment become established. With chorionic villus sampling for prenatal diagnosis per formed at around 12 weeks [5], there is a win dow of opportunity for in utero transplanta tion of donor hematopoietic cells which we have calculated at between 12 and 14 weeks [1]. Further, we have demonstrated that lym phoid development occurs in the liver at around 15 weeks and that migration of hema topoietic cells to seed the spleen and bone marrow is also occurring at around this time [1], although the bone marrow is not thought to contribute to hematopoiesis until postnatal life [6], Thus, the opportunity for in utero therapeutic intervention for a serious hemo globinopathy is limited to around a 2-week period within the first trimester.…”