Stem Cell Agency Board Invests in Therapy Targeting Deadly Blood Cancers

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Dr. Ezra Cohen, photo courtesy UCSD

Hematologic malignancies are cancers that affect the blood, bone marrow and lymph nodes and include different forms of leukemia and lymphoma. Current treatments can be effective, but in those patients that do not respond, there are few treatment options. Today, the governing Board of the California Institute for Regenerative Medicine (CIRM) approved investing $4.1 million in a therapy aimed at helping patients who have failed standard therapy.

Dr. Ezra Cohen, at the University of California San Diego, and Oncternal Therapeutics are targeting a protein called ROR1 that is found in B cell malignancies, such as leukemias and lymphomas, and solid tumors such as breast, lung and colon. They are using a molecule called a chimeric antigen receptor (CAR) that can enable a patient’s own T cells, an important part of the immune system, to target and kill their cancer cells. These cells are derived from a related approach with an antibody therapy that targets ROR1-binding medication called Cirmtuzumab, also created with CIRM support. This CAR-T product is designed to recognize and kill cancer stem cells that express ROR1.

This is a late-stage preclinical project so the goal is to show they can produce enough high-quality cells to treat patients, as well as complete other regulatory measures needed for them to apply to the US Food and Drug Administration (FDA) for permission to test the therapy in a clinical trial in people.

If given the go-ahead by the FDA the therapy will target patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and acute lymphoblastic leukemia (ALL).  

“CAR-T cell therapies represent a transformational advance in the treatment of hematologic malignancies,” says Dr. Maria T. Millan, CIRM’s President and CEO. “This approach addresses the need to develop new therapies for patients whose cancers are resistant to standard chemotherapies, who have few therapeutic options and a very poor chance or recovery.”

A new approach to a deadly childhood cancer

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Cancers of the blood, bone marrow and lymph nodes (also called hematologic malignancies) are the most common form of cancer in children and young adults. Current treatments can be effective but can also pose life-threatening health risks to the child. Now researchers at Stanford have developed a new approach and the Board of the California Institute for Regenerative Medicine (CIRM) voted to support that approach in a clinical trial.

The Board approved investing $11,996,634 in the study, which is the Stem Cell Agency’s 76th clinical trial.

The current standard of care for cancers such as acute leukemias and lymphomas is chemotherapy and a bone marrow (also called HSCT) transplant. However, without a perfectly matched donor the risk of the patient’s body rejecting the transplant is higher. Patients may also be at greater risk of graft vs host disease (GVHD), where the donor cells attack the patient’s body. In severe cases GVHD can be life-threatening.

Dr. Maria Grazia Roncarlo: Photo courtesy Stanford

Dr. Maria Grazia Roncarolo and her team at Stanford will test an immunotherapy cell approach using a therapy that is enriched with specialized immune cells called type 1 regulatory T (Tr1) cells. These cells will be infused into the patient following the bone marrow transplant. Both the Tr1 cells and the bone marrow will come from the same donor. The hope is this will help provide the patient’s immune system with these regulatory cells to combat life-threatening graft versus host disease and increase the success of treatment and bone marrow (HSCT) transplant.

“Every year around 500 children receive stem cell transplants in California, and while many children do well, too many experiences a rejection of the transplant or a relapse of the cancer,” says Dr. Maria T. Millan, President and CEO of CIRM. “Finding an improved therapy for these children means a shorter stay in the hospital, less risk of the need for a second transplant, and a greater quality of life for the child and the whole family.”

The CIRM Board has previously approved funding for 12 other clinical trials targeting cancers of the blood. You can read about them here.

Inspiring new documentary about stem cell research

Poster for the documentary “Ending Disease”

2020 has been, to say the very least, a difficult and challenging year for all of us. But while the focus of the world has, understandably, been on the coronavirus there was also some really promising advances in stem cell research. Those advances are captured in a great new documentary called Ending Disease.

The documentary is by Emmy award-winning filmmaker Joe Gantz. In it he follows ten people who are facing life-threatening or life-changing diseases and injuries and who turn to pioneering stem cell therapies for help.

It’s an inspiring documentary, one that reminds you of the real need for new treatments and the tremendous hope and promise of stem cell therapies. Here’s a look at a trailer for Ending Disease.

You can see an exclusive screening of Ending Disease on Friday, January 8th, 2021 at 5:00pm PST.

After the livestream, there will be a live Q&A session where former members of the successful Proposition 14 campaign team – which refunded CIRM with an additional $5.5 billion – will be joined by CIRM’s President and CEO Dr. Maria Millan, talking about what lies ahead for CIRM and the future of stem cell research.

To purchase a ticket, click here. It only costs $12 and 50% of the ticket sales proceeds will go to Americans for Cures to help them continue to advocate for the advancement of stem cell research, and more importantly, for the patients and families to whom stem cell research provides so much hope.

If you need any extra persuading that it’s something you should definitely put on our calendar, here’s a letter from the film maker Joe Gantz.

I am the director of the documentary Ending Disease: The Stem Cell, Anti-Cancer T-Cell, & Antibody Revolution In Medicine, a film that will help inform people about the progress that’s been made in this field and how people with their lives on the line are now able to benefit from these new regenerative therapies. 

I was granted unprecedented access to ten of the first generation of clinical trials using stem cell and regenerative medicine to treat and cure many of the most devastating diseases and conditions including: brain cancer, breast cancer, leukemia and lymphoma, HIV, repairing a broken spinal cord, retinitis pigmentosa and SCID. The results are truly inspiring.

This is personal for me.  After spending four years making this documentary, I was diagnosed with bladder cancer. Upon diagnosis, I immediately felt the same desperation as millions of families who are in search of a medical breakthrough. I understood, on a personal level, what the patients we followed in the film all knew: when you are diagnosed with a disease, there is a narrow window of time in which you can effectively seek a life-saving treatment or cure. If treatment becomes available outside of that window, then it is too late. However, Ending Disease shows that with continued support for regenerative medicine, we can create a near future in which one-time cures and highly mitigating therapies are available to patients for a whole host of diseases.

Best regards,

Joe

Partners in health

From left to right: Heather Dahlenburg, Jan Nolta, Jeannine Logan White, Sheng Yang
From left to right: Heather Dahlenburg, staff research associate; Jan Nolta, director of the Stem Cell Program; Jeannine Logan White, advanced cell therapy project manager; Sheng Yang, graduate student, Bridges Program, Humboldt State University, October 18, 2019. (AJ Cheline/UC Davis)

At CIRM we are modest enough to know that we can’t do everything by ourselves. To succeed we need partners. And in UC Davis we have a terrific partner. The work they do in advancing stem cell research is exciting and really promising. But it’s not just the science that makes them so special. It’s also their compassion and commitment to caring for patients.

What follows is an excerpt from an article by Lisa Howard on the work they do at UC Davis. When you read it you’ll see why we are honored to be a part of this research.

Gene therapy research at UC Davis

UC Davis’ commitment to stem cell and gene therapy research dates back more than a decade.

In 2010, with major support from the California Institute for Regenerative Medicine (CIRM), UC Davis launched the UC Davis Institute for Regenerative Cures, which includes research facilities as well as a Good Manufacturing Practice (GMP) facility.

In 2016, led by Fred Meyers, a professor in the School of Medicine, UC Davis launched the Center for Precision Medicine and Data Sciences, bringing together innovations such as genomics and biomedical data sciences to create individualized treatments for patients.

Last year, the university launched the Gene Therapy Center, part of the IMPACT Center program.

Led by Jan Nolta, a professor of cell biology and human anatomy and the director of the UC Davis Institute for Regenerative Cures, the new center leverages UC Davis’ network of expert researchers, facilities and equipment to establish a center of excellence aimed at developing lifelong cures for diseases.

Nolta began her career at the University of Southern California working with Donald B. Kohn on a cure for bubble baby disease, a condition in which babies are born without an immune system. The blood stem cell gene therapy has cured more than 50 babies to date.

Work at the UC Davis Gene Therapy Center targets disorders that potentially can be treated through gene replacement, editing or augmentation.

“The sectors that make up the core of our center stretch out across campus,” said Nolta. “We work with the MIND Institute a lot. We work with the bioengineering and genetics departments, and with the Cancer Center and the Center for Precision Medicine and Data Sciences.”

A recent UC Davis stem cell study shows a potential breakthrough for healing diabetic foot ulcers with a bioengineered scaffold made up of human mesenchymal stem cells (MSCs). Another recent study revealed that blocking an enzyme linked with inflammation enables stem cells to repair damaged heart tissue. A cell gene therapy study demonstrated restored enzyme activity in Tay-Sachs disease affected cells in humanized mouse models.

Several cell and gene therapies have progressed to the point that ongoing clinical trials are being conducted at UC Davis for diseases, including sickle-cell anemia, retinopathy, muscle injury, dysphasia, advanced cancer, and Duchenne muscular dystrophy, among others.

“Some promising and exciting research right now at the Gene Therapy Center comes from work with hematopoietic stem cells and with viral vector delivery,” said Nolta.

Hematopoietic stem cells give rise to other blood cells. A multi-institutional Phase I clinical trial using hematopoietic stem cells to treat HIV-lymphoma patients is currently underway at UC Davis.

.Joseph Anderson

Joseph Anderson

“We are genetically engineering a patient’s own blood stem cells with genes that block HIV infection,” said Joseph Anderson, an associate professor in the UC Davis Department of Internal Medicine. The clinical trial is a collaboration with Mehrdad Abedi, the lead principal investigator.

“When the patients receive the modified stem cells, any new immune system cell, like T-cell or macrophage, that is derived from one of these stem cells, will contain the HIV-resistant genes and block further infection,” said Anderson.

He explained that an added benefit with the unique therapy is that it contains an additional gene that “tags” the stem cells. “We are able to purify the HIV-resistant cells prior to transplantation, thus enriching for a more protective cell population.

Kyle David Fink

Kyle David Fink

Kyle David Fink, an assistant professor of neurology at UC Davis, is affiliated with the Stem Cell Program and Institute for Regenerative Cures. His lab is focused on leveraging institutional expertise to bring curative therapies to rare, genetically linked neurological disorders.

“We are developing novel therapeutics targeted to the underlying genetic condition for diseases such as CDKL5 deficiency disorder, Angelman, Jordan and Rett syndromes, and Juvenile Huntington’s disease,” said Fink.

The lab is developing therapies to target the underlying genetic condition using DNA-binding domains to modify gene expression in therapeutically relevant ways. They are also creating novel delivery platforms to allow these therapeutics to reach their intended target: the brain.

“The hope is that these highly innovative methods will speed up the progress of bringing therapies to these rare neurodegenerative disease communities,” said Fink.Jasmine Carter, a graduate research assistant at the UC Davis Stem Cell Program.

Jasmine Carter, a graduate research assistant at the UC Davis Stem Cell Program, October 18, 2019. (AJ Cheline/UC Davis)

Developing potential lifetime cures

Among Nolta’s concerns is how expensive gene therapy treatments can be.

“Some of the therapies cost half a million dollars and that’s simply not available to everyone. If you are someone with no insurance or someone on Medicare, which reimburses about 65 percent, it’s harder for you to get these life-saving therapies,” said Nolta.

To help address that for cancer patients at UC Davis, Nolta has set up a team known as the “CAR T Team.”

Chimeric antigen receptor (CAR) T-cell therapy is a type of immunotherapy in which a patient’s own immune cells are reprogrammed to attack a specific protein found in cancer cells.

“We can develop our own homegrown CAR T-cells,” said Nolta. “We can use our own good manufacturing facility to genetically engineer treatments specifically for our UC Davis patients.”

Although safely developing stem cell treatments can be painfully slow for patients and their families hoping for cures, Nolta sees progress every day. She envisions a time when gene therapy treatments are no longer considered experimental and doctors will simply be able to prescribe them to their patients.

“And the beauty of the therapy is that it can work for the lifetime of a patient,” said Nolta.

Stem cell progress and promise in fighting leukemia

Computer illustration of a cancerous white blood cell in leukemia.

There is nothing you can do to prevent or reduce your risk of leukemia. That’s not a very reassuring statement considering that this year alone almost 62,000 Americans will be diagnosed with leukemia; almost 23,000 will die from the disease. That’s why CIRM is funding four clinical trials targeting leukemia, hoping to develop new approaches to treat, and even cure it.

That’s also why our next special Facebook Live “Ask the Stem Cell Team” event is focused on this issue. Join us on Thursday, August 29th from 1pm to 2pm PDT to hear a discussion about the progress in, and promise of, stem cell research for leukemia.

We have two great panelists joining us:

Dr. Crystal Mackall, has many titles including serving as the Founding Director of the Stanford Center for Cancer Cell Therapy.  She is using an innovative approach called a Chimeric Antigen Receptor (CAR) T Cell Therapy. This works by isolating a patient’s own T cells (a type of immune cell) and then genetically engineering them to recognize a protein on the surface of cancer cells, triggering their destruction. This is now being tested in a clinical trial funded by CIRM.

Natasha Fooman. To describe Natasha as a patient advocate would not do justice to her experience and expertise in fighting blood cancer and advocating on behalf of those battling the disease. For her work she has twice been named “Woman of the Year” by the Leukemia and Lymphoma Society. In 2011 she was diagnosed with a form of lymphoma that was affecting her brain. Over the years, she would battle lymphoma three times and undergo chemotherapy, radiation and eventually a bone marrow transplant. Today she is cancer free and is a key part of a CIRM team fighting blood cancer.

We hope you’ll join us to learn about the progress being made using stem cells to combat blood cancers, the challenges ahead but also the promising signs that we are advancing the field.

We also hope you’ll take an active role by posting questions on Facebook during the event, or sending us questions ahead of time to info@cirm.ca.gov. We will do our best to address as many as we can.

Here’s the link to the event, feel free to share this with anyone you think might be interested in joining us for Facebook Live “Ask the Stem Cell Team about Leukemia”

How a see-through fish could one day lead to substitutes for bone marrow transplants

Human blood stem cells

For years researchers have struggled to create human blood stem cells in the lab. They have done it several times with animal models, but the human kind? Well, that’s proved a bit trickier. Now a CIRM-funded team at UC San Diego (UCSD) think they have cracked the code. And that would be great news for anyone who may ever need a bone marrow transplant.

Why are blood stem cells important? Well, they help create our red and white blood cells and platelets, critical elements in carrying oxygen to all our organs and fighting infections. They have also become one of the most important weapons we have to combat deadly diseases like leukemia and lymphoma. Unfortunately, today we depend on finding a perfect or near-perfect match to make bone marrow transplants as safe and effective as possible and without a perfect match many patients miss out. That’s why this news is so exciting.

Researchers at UCSD found that the process of creating new blood stem cells depends on the action of three molecules, not two as was previously thought.

Zebrafish

Here’s where it gets a bit complicated but stick with me. The team worked with zebrafish, which use the same method to create blood stem cells as people do but also have the advantage of being translucent, so you can watch what’s going on inside them as it happens.  They noticed that a molecule called Wnt9a touches down on a receptor called Fzd9b and brings along with it something called the epidermal growth factor receptor (EGFR). It’s the interaction of these three together that turns a stem cell into a blood cell.

In a news release, Stephanie Grainger, the first author of the study published in Nature Cell Biology, said this discovery could help lead to new ways to grow the cells in the lab.

“Previous attempts to develop blood stem cells in a laboratory dish have failed, and that may be in part because they didn’t take the interaction between EGFR and Wnt into account.”

If this new approach helps the team generate blood stem cells in the lab these could be used to create off-the-shelf blood stem cells, instead of bone marrow transplants, to treat people battling leukemia and/or lymphoma.

CIRM is also funding a number of other projects, several in clinical trials, that involve the use of blood stem cells. Those include treatments for: Beta Thalassemia; blood cancer; HIV/AIDS; and Severe Combined Immunodeficiency among others.

Stem Cell Agency Board Approves 50th Clinical Trial

2018-12-13 01.18.50Rich Lajara

Rich Lajara, the first patient treated in a CIRM-funded clinical trial

May 4th, 2011 marked a landmark moment for the California Institute for Regenerative Medicine (CIRM). On that day the Stem Cell Agency’s Board voted to invest in its first ever clinical trial, which was also the first clinical trial to use cells derived from embryonic stem cells. Today the Stem Cell Agency reached another landmark, with the Board voting to approve its 50th clinical trial.

“We have come a long way in the past seven and a half years, helping advance the field from its early days to a much more mature space today, one capable of producing new treatments and even cures,” says Jonathan Thomas, JD, PhD, Chair of the CIRM Board. “But we feel that in many ways we are just getting started, and we intend funding as many additional clinical trials as we can for as long as we can.”

angiocrinelogo

The project approved today awards almost $6.2 million to Angiocrine Bioscience Inc. to see if genetically engineered cells, derived from cord blood, can help alleviate or accelerate recovery from the toxic side effects of chemotherapy for people undergoing treatment for lymphoma and other aggressive cancers of the blood or lymph system.

“This is a project that CIRM has supported from an earlier stage of research, highlighting our commitment to moving the most promising research out of the lab and into people,” says Maria T. Millan, MD, President & CEO of CIRM. “Lymphoma is the most common blood cancer and the 6th most commonly diagnosed cancer in California. Despite advances in therapy many patients still suffer severe complications from the chemotherapy, so any treatment that can reduce those complications can not only improve quality of life but also, we hope, improve long term health outcomes for patients.”

The first clinical trial CIRM funded was with Geron, targeting spinal cord injury. While Geron halted the trial for business reasons (and returned the money, with interest) the mantle was later picked up by Asterias Biotherapeutics, which has now treated 25 patients with no serious side effects and some encouraging results.

Rich Lajara was part of the Geron trial, the first patient ever treated in a CIRM-funded clinical trial. He came to the CIRM Board meeting to tell his story saying when he was injured “I knew immediately I was paralyzed. I thought this was the end, little did I know this was just the beginning. I call it being in the wrong place at the right time.”

When he learned about the Geron clinical trial he asked how many people had been treated with stem cells. “Close to none” he was told. Nonetheless he went ahead with it. He says he has never regretted that decision, knowing it helped inform the research that has since helped others.

Since that first trial the Stem Cell Agency has funded a wide range of projects targeting heart disease and stroke, cancer, diabetes, HIV/AIDS and several rare diseases. You can see the full list on the Clinical Trials Dashboard page on our website.

Rich ended by saying: “CIRM has proven how much can be achieved if we invest in cutting-edge medical research. As most of you here probably know, CIRM’s funding from Proposition 71 is about to run out. If I had just one message I wanted people to leave with today it would be this, I will do everything I can to make sure the agency gets refunded and I hope that all of you will join me in that fight. I’m excited for the world of stem cells, particularly in California and can’t wait to see what’s on the horizon.”

lubinbert-mug

The CIRM Board also took time today to honor Dr. Bert Lubin, who is stepping down after serving almost eight years on the Board.

When he joined the Board in February, 2011 Dr. Lubin said: “I hope to use my position on this committee to advocate for stem cell research that translates into benefits for children and adults, not only in California but throughout the world.”

Over the years he certainly lived up to that goal. As a CIRM Board member he has supported research for a broad range of unmet medical needs, and specifically for curative treatments for children born with a rare life-threatening conditions such as Sickle Cell Disease and Severe Combined Immunodeficiency (SCID) as well as  treatments to help people battling vision destroying diseases.

As the President & CEO of Children’s Hospital Oakland (now UCSF Benioff Children’s Hospital Oakland) Dr. Lubin was a leader in helping advance research into new treatments for sickle cell disease and addressing health disparities in diseases such as asthma, diabetes and obesity.

Senator Art Torres said he has known Dr. Lubin since the 1970’s and in all that time has been impressed by his devotion to patients, and his humility, and that all Californians should be grateful to him for his service, and his leadership.

Dr. Lubin said he was “Really grateful to be on the Board and I consider it an honor to be part of a group that benefits patients.”

He said he may be stepping down from the CIRM Board but that was all: “I am going to retire the word retirement. I think it’s a mistake to stop doing work that you find stimulating. I’m going to repurpose the rest of my life, and work to make sure the treatments we’ve helped develop are available to everyone. I am so proud to be part of this. I am stepping down, but I am devoted to doing all I can to ensure that you get the resources you need to sustain this work for the future.”

Mechanical forces are the key to speedy recovery after blood cancer treatment

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Mesenchymal stem cells grown on a surface with specialized mechanical properties. Image courtesy of Krystyn Van Vliet at MIT.

Blood cancers, such as leukemia and lymphoma, are projected to be responsible for 10% of all new cancer diagnoses this year. These types of cancers are often treated by killing the patient’s bone marrow (the site of blood cell manufacturing), with a treatment called irradiation. While effective for ridding the body of cancerous cells, this treatment also kills healthy blood cells. Therefore, for a time after the treatment, patients are particularly vulnerable to infections, because the cellular components of the immune system are down for the count.

Now scientists at MIT have devised a method to make blood cells regenerate faster and  minimize the window for opportunistic infections.

Using multipotent stem cells (stem cells that are able to become multiple cell types) grown on a new and specialized surface that mimics bone marrow, the investigators changed the stem cells into different types of blood cells. When transplanted into mice that had undergone irradiation, they found that the mice recovered much more quickly compared to mice given stem cells grown on a more traditional plastic surface that does not resemble bone marrow as well.

This finding, published in the journal Stem Cell Research and Therapy, is particularly revolutionary, because it is the first time researchers have observed that mechanical properties can affect how the cells differentiate and behave.

The lead author of the study attributes the decreased recovery time to the type of stem cell that was given to mice compared to what humans are normally given after irradiation. Humans are given a stem cell that is only able to become different types of blood cells. The mice in this study, however, were give a stem cell that can become many different types of cells such as muscle, bone and cartilage, suggesting that these cells somehow changed the bone marrow environment to promote a more efficient recovery. They attributed a large part of this phenomenon to a secreted protein call ostepontin, which has previously been describe in activating the cells of the immune system.

In a press release, Dr. Viola Vogel, a scientist not related to study, puts the significance of these findings in a larger context:

“Illustrating how mechanopriming of mesenchymal stem cells can be exploited to improve on hematopoietic recovery is of huge medical significance. It also sheds light onto how to utilize their approach to perhaps take advantage of other cell subpopulations for therapeutic applications in the future.”

Dr. Krystyn Van Vliet, explains the potential to expand these findings beyond the scope of just blood cancer treatment:

“You could imagine that by changing their culture environment, including their mechanical environment, MSCs could be used for administration to target several other diseases such as Parkinson’s disease, rheumatoid arthritis, and others.”

 

Stem Cell Agency Heads to Inland Empire for Free Patient Advocate Event

UCRiversidePatientAdvocateMtg_EventBrite copy

I am embarrassed to admit that I have never been to the Inland Empire in California, the area that extends from San Bernardino to Riverside counties.  That’s about to change. On Monday, April 16th CIRM is taking a road trip to UC Riverside, and we’re inviting you to join us.

We are holding a special, free, public event at UC Riverside to talk about the work that CIRM does and to highlight the progress being made in stem cell research. We have funded 45 clinical trials in a wide range of conditions from stroke and cancer, leukemia, lymphoma, vision loss, diabetes and sickle cell disease to name just a few. And will talk about how we plan on funding many more clinical trials in the years to come.

We’ll be joined by colleagues from both UC Riverside, and City of Hope, talking about the research they are doing from developing new imaging techniques to see what is happening inside the brain with diseases like Alzheimer’s, to using a patient’s own cells and immune system to attack deadly brain cancers.

It promises to be a fascinating event and of course we want to hear from you, our supporters, friends and patient advocates. We are leaving plenty of time for questions, so we can hear what’s on your mind.

So, join us at UC Riverside on Monday, April 16th from 12.30pm to 2pm. The doors open at 11am so you can enjoy a poster session (highlighting some of the research at UCR) and a light lunch before the event. Parking will be available on site.

Visit the Eventbrite page we have created for all the information you’ll need about the event, including a chance to RSVP and book your place.

The event is free so feel free to share this with anyone and everyone you think might be interested in joining us.

 

 

Surprise findings about bone marrow transplants could lead to more effective stem cell therapies

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Bone marrow transplant: Photo courtesy FierceBiotech

Some medical therapies have been around for so long that we naturally assume we understand how they work. That’s not always the case. Take aspirin for example. It’s been used for more than 4,000 years to treat pain and inflammation but it was only in the 1970’s that we really learned how it works.

The same is now true for bone marrow transplants. Thanks to some skilled research at the Fred Hutchinson Cancer Research Center in Seattle.

Bone marrow transplants have been used for decades to help treat deadly blood cancers such as leukemia and lymphoma. The first successful bone marrow transplant was in the late 1950’s, involving identical twins, one of whom had leukemia. Because the twins shared the same genetic make-up the transplant avoided potentially fatal problems like graft-vs-host-disease, where the transplanted cells attack the person getting them. It wasn’t until the 1970’s that doctors were able to perform transplants involving people who were not related or who did not share the same genetic make-up.

In a bone marrow or blood stem cell transplant, doctors use radiation or chemotherapy to destroy the bone marrow in a patient with, say, leukemia. Then cancer-free donor blood stem cells are transplanted into the patient to help create a new blood system, and rebuild their immune system.

Surprise findings

In the study, published in the journal Science Translational Medicine, the researchers were able to isolate a specific kind of stem cell that helps repair and rebuild the blood and immune system.

The team found that a small subset of blood stem cells, characterized by having one of three different kinds of protein on their surface – CD34 positive, CD45RA negative and CD90 positive – did all the work.

In a news release Dr. Hans-Peter Kiem, a senior author on the study, says some of their initial assumptions about how bone marrow transplants work were wrong:

“These findings came as a surprise; we had thought that there were multiple types of blood stem cells that take on different roles in rebuilding a blood and immune system. This population does it all.”

Tracking the cells

The team performed bone-marrow transplants on monkeys and then followed those animals over the next seven years, observing what happened as the donor cells grew and multiplied.

They tracked hundreds of thousands of cells in the blood and found that, even though the cells with those three proteins on the surface made up just five percent of the total blood supply, they were responsible for rebuilding the entire blood and immune system.

Study co-author Dr. Jennifer Adair said they saw evidence of this rebuilding within 10 days of the transplant:

“Our ability to track individual blood cells that developed after transplant was critical to demonstrating that these really are stem cells.”

Hope for the future

It’s an important finding because it could help researchers develop new ways of delivering bone marrow transplants that are both safer and more effective. Every year some 3,000 people die because they cannot find a matching donor. Knowing which stem cells are specifically responsible for an effective transplant could help researchers come up with ways to get around that problem.

Although this work was done in monkeys, the scientists say humans have similar kinds of stem cells that appear to act in the same way. Proving that’s the case will obviously be the next step in this research.