In utero transplantation of haemopoietic stem cells

In utero haematopoietic stem cell transplantation is a potentially valuable therapeutic approach that strives to take advantage of biological opportunities for cellular transplantation that exist in the early gestational fetus. However, with the exception of severe combined immunodeficiency, clinical application has been limited by minimal or no engraftment, suggesting the presence of significant barriers to engraftment within the fetal environnment. Research directed toward elucidating these barriers is progressing, and there is hope that the barriers to engraftment can be overcome in the near future. In the meantime, there are a limited number of specific disorders that are biologically favourable and may be amenable to treatment by this approach using conventional techniques. In the future, strategies that improve the competitive capacity of donor cells or the use of pre-natal transplantation to induce donor-specific tolerance followed by post-natal non-myeloablative enhancement of donor chimerism may allow broad clinical application of this approach.