Jessica Hamzelou for New Scientist reports that work in mice hints at a way that allergies and other genetic-based diseases might be treated before birth. Typically, your body destroys any foreign material such as bacteria or donated organs (unless the immune system is suppressed). But this doesn’t seem to be the case in developing fetuses. Their immune system hasn’t formed fully, so in mice at least, when foreign cells are introduced, they are more likely to be accepted.
Now, researchers in France are using that developmental loop hole to prime the fetal immune system to tolerate certain foreign material that might help treat disease. Hamzelou writes:
In haemophilia, genetic mutations cause a lack of blood clotting proteins. The most common type is caused by a lack of coagulation factor VIII. People born with the disorder can be given injections of factor VIII, but the immune systems of about one-fifth of people with haemophilia develop antibodies that render the protein ineffective.
To see if priming in the womb would make any difference to this immune response, Lacroix-Desmazes's team attached parts of factor VIII to another protein that enabled it to cross the placenta between mother and fetus. The group then administered this to pregnant mice lacking factor VIII. Other similar pregnant mice received no treatment.
When the mice were born, the treated pups were able to tolerate further factor VII therapy: Their immune systems produced 80 percent less antibody agains the factor than control mice did.
The human immune system in the fetus and newborn are very different than that in mice, but the work is a first step. There could be many unknown problems that similar therapy could cause in humans. "We know precious little about the immune system of the human fetus and the human newborn," Mike McCune, of the University of California, San Francisco, told New Scientist. "The third trimester is a total black box of human fetal development, because we have no way to study it."
Allergies, type 1 diabetes and other autoimmune disorders all involve some genetic predisposition. If this treatment is safe, it might offer a way to replace altered proteins and genes that cause those disorders. The idea is worth investigating. As we understand even more about these genetic disorders, scientists are exploring all types of novel ways to diagnose and treat them.