Two CIRM supported studies highlighted in Nature as promising approaches for blood disorders

Blood stem cells (blue) are cleared from the bone marrow (purple) before new stem cells can be transplanted.Credit: Dennis Kunkel Microscopy/SPL

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.

CIRM-funded therapy helps “bubble babies” lead a normal life

Ja’Ceon Golden; ‘cured” of SCID

At CIRM we are very cautious about using the “c” word. Saying someone has been “cured” is a powerful statement but one that loses its meaning when over used or used inappropriately. However, in the case of a new study from U.C. San Francisco and St. Jude Children’s Research Hospital in Memphis, saying “cure” is not just accurate, it’s a celebration of something that would have seemed impossible just a few years ago.

The research focuses on children with a specific form of Severe Combined Immunodeficiency (SCID) called X-Linked SCID. It’s also known as “bubble baby” disease because children born with this condition lack a functioning immune system, so even a simple infection could be fatal and in the past they were kept inside sterile plastic bubbles to protect them.

In this study, published in the New England Journal of Medicine, researchers took blood stem cells from the child and, in the lab, genetically re-engineered them to correct the defective gene, and then infused them back into the child. Over time they multiplied and created a new blood supply, one free of the defect, which helped repair the immune system.

In a news release Dr. Ewelina Mamcarz, the lead author of the study, announced that ten children have been treated with this method.

“These patients are toddlers now, who are responding to vaccinations and have immune systems to make all immune cells they need for protection from infections as they explore the world and live normal lives. This is a first for patients with SCID-X1.”

The ten children were treated at both St. Jude and at UCSF and CIRM funded the UCSF arm of the clinical trial.

The story, not surprisingly, got a lot of attention in the media including this fine piece by CNN.

Oh, and by the way we are also funding three other clinical trials targeting different forms of SCID. One with UCLA’s Don Kohn,  one with Stanford’s Judy Shizuru, and one with UCSF’s Mort Cowan