In utero transplantation is a new technology that may provide non-toxic treatment for
congenital disorders. However, a decade of research on in utero transplantation has
demonstrated a low degree of chimerism and tolerance in small and large animal models as
well as in human beings. We hypothesized that if large numbers of purified stem
cells/progenitors were injected, a higher degree of tolerance would be induced. We have
performed a 2-year experiment designed to study chimerism and tolerance after in utero …