Problems with blood stem cells, a type of stem cell in your bone marrow that gives rise to various kinds of blood cells, can sometimes result in blood cancer as well as genetic and autoimmune diseases.
It is because of this that researchers have looked towards blood stem cell transplants, which involves replacing a person’s defective blood stem cells with healthy ones take from either a donor or the patient themselves.
However, before this can be done, the existing population of defective stem cells must be eradicated in order to allow the transplanted blood stem cells to properly anchor themselves into the bone marrow. Current options for this include full-body radiation or chemotherapy, but these approaches are extremely toxic.
But what if there was a way to selectively target these blood stem cells in order to make the transplants much safer?
An article published in Nature highlights the advancements made in the field of blood stem cell transplantation, some of which is work that is funded by yours truly.
One of the approaches highlighted involves the work that we funded related to Forty Seven and an antibody created that inhibits a protein called CD47.
The article discusses how Forty Seven tested two antibodies in monkeys. One antibody blocks the activity of a molecule called c-Kit, which is found on blood stem cells. The other is the antibody that blocks CD47, which is found on some immune cells. Inhibiting CD47 allows those immune cells to sweep up the stem cells that were targeted by the c-Kit antibody, thereby boosting its effectiveness. In early tests, the two antibodies used together reduced the number of blood stem cells in bone marrow. The next step for this team is to demonstrate that the treatment clears out the old supply of stem cells well enough to allow transplanted cells to flourish.
You can read more about the CD47 antibody in a previous blog post.
Another notable segment of this article is the CIRM funded trial that is being conducted by Dr. Judith Shizuru at Stanford University. This clinical trial also uses an antibody that targets c-Kit found on blood stem cells.
The purpose of this trial is to wipe out the problematic blood stem cells in infants with X-linked Severe combined immunodeficiency (SCID), a rare fatal genetic disorder that leaves infants without a functional immune system, in order to introduce properly functioning blood stem cells. Dr. Shizuru and her team found that transplanted blood stem cells, in this case from donors who did not have the disease, successfully took hold in the bone marrow of four out of six of the babies.
You can read more about Dr. Shizuru’s work in a previous blog post as well.