Perinatal fetal-cell and gene therapy.

Several inherited diseases can now be treated using postnatal or prenatal, in utero, transplantation of stem cells from the human fetal liver. Twenty-four patients with severe immunodeficiency diseases have been treated in infancy and three at the fetal stage, in our institution. We have also treated similarly 34 patients with inborn errors of metabolism or hemoglobinopathies. A total of 64% of all patients are alive with either full cure of their initial disease or at least significant benefit from the treatment. Immunological reconstitution can develop despite full mismatch between the stem cell donor and the recipient patient. Tolerance is acquired both towards donor and host antigens. Gene therapy is starting its development in some infants with an immunodeficiency related to a known gene defect and, in the future, it may be used in fetuses, immediately after the prenatal diagnosis of the gene abnormality.