A foetus with a severe immune deficiency has benefited from in utero hematopoietic stem-cell transplantation. The operation took place in July 2015, following a risk of mother-to-child transmission of toxoplasmosis. This parasite-transmitted disease "can have major consequences on a foetus’s cerebral development", especially in a foetus without T cells.
The operation was carried out with the cooperation of teams from Necker-Enfants Malades Hospital, the Foetal Medicine Department at Trousseau Hospital, the French National Institute of Health and Medical Research (INSERM), the Imagine Institute, the University of Paris Descartes and Sorbonne University.
The injected transplant was made possible thanks to a donation from the foetus’s sister, whose immune system was compatible. The transplant is a mixture of hematopoietic stem cells to "restore normal long-term development of the immune system", and mature T cells "capable of defending the foetus quickly against infection by the parasite". The foetus received the transplant via the umbilical vein, under ultrasound guidance. The pregnancy then progressed normally and the child was born at full term. The child is now three years old, in good health, and has never been hospitalized or received any therapeutic treatment.
This transplant is usually performed just after birth. Due to the fragility of the young transplant recipients, it is followed by several trying weeks of hospitalization in an extremely protected environment. The procedure "enabled the foetus to heal during pregnancy". This transplant therefore opens up "new therapeutic prospects" for foetuses with severe immunodeficiency, "when there is a compatible donor" and when "there is a proven risk of infection during pregnancy".