No pregnant woman wants to hear that her developing baby has a life-threatening genetic disease. Historically, women carrying babies with alpha thalassemia major, a type of hereditary anemia, faced the difficult choice between terminating a pregnancy or continuing on despite nearly assured fetal death. Now, researchers at UCSF have reported another option: in utero blood transfusion, or IUT. In this procedure, healthy red blood cells are infused into the fetus, which can reverse the effects of ATM and increase the chance of survival.
Fetal hemoglobin – a protein with two alpha and two gamma subunits – is the main oxygen supplier in utero. Patients with ATM lack alpha subunits. As a result, their hemoglobin holds oxygen so tightly that it cannot be released into developing tissues. While a lack of oxygen is harmful at any age, the effects in utero are particularly severe – depriving a developing brain of oxygen, for example, can cause devastating neurologic injury.
Repeated bouts of IUT, however, can deliver a continual supply of normal red blood cells. This provides developing tissues the oxygen needed to grow and gives the fetus a chance to survive until birth, when postnatal therapy can be started. Despite IUT’s promise, its risks and benefits for the treatment of fetal ATM aren’t widely reported.
To better understand these issues, the researchers looked at 20 fetuses with ATM that underwent IUT. They found that the transfusions maintained appropriate levels of hemoglobin in all cases. Although most births were pre-term, all associated complications were effectively managed, and most patients showed normal brain development. Approximately half the group had minor anatomic abnormalities, but none were life threatening. In contrast to these encouraging results, few fetuses have been reported to survive without in utero therapy.
Perhaps most importantly: keeping a fetus alive until birth provided a chance to cure ATM. Some patients who received postnatal stem cell transplantation, a procedure that helps the body produce its own healthy blood cells, required no further transfusions. Based on these results, the researchers have started a clinical trial that provides stem cell transplantation concurrently with IUT.
These findings show how important it is to give families prenatally diagnosed with ATM the option of IUT, which may just offer a new chance at life.