Purified blood stem cells improve success of bone marrow transplants in mice, study shows

Aug 02, 2010

Researchers at the Stanford University School of Medicine have challenged decades of accepted wisdom about bone marrow transplantation with a new study showing that mice receiving purified blood stem cells are less prone to complications than mice receiving stem cells plus purified T cells.

The study, led by Judith Shizuru, MD, PhD, associate professor of medicine, will be published online Aug. 2 in the .

has long been a powerful therapy in combating cancer and other disorders, but it also involves serious risks that make physicians wary. Patients getting bone marrow transplants must first be given powerful drugs or radiation treatments that wipe out their own bone marrow and , leaving them vulnerable to life-threatening infections.

The patient's supply of blood and immune is then replenished by bone marrow from a donor, but this bone marrow also contains mature immune cells called T cells that can see the patient's tissues as immunologically foreign. T cells that react against patient tissues cause a disorder called graft versus host disease, or GVHD, which can severely damage the patient's body.

Conventional wisdom among transplantation specialists has been that the should contain some T cells from the donor. Although the presence of mature donor T cells is known to cause GVHD, it is generally believed that these T cells can help protect the patient from infectious disease and fight cancer until the transplanted stem cells can mature into a new immune system. It is also thought that the presence of mature T cells decreases the chance that the patient will reject the graft.

"People think that T cells are a necessary evil because they help with engraftment and immune reconstitution," Shizuru said. For these reasons, patients are not given pure blood-forming stem cells as part of current therapy.

The new research by Shizuru, lead author, and research associate Antonia Mueller, MD, and their colleagues calls into question those assumptions. When they compared mice given pure stem cells with mice given a mixture of stem cells and mature T cells, they found that the mice given pure stem cells were better at forming new blood cells and faster in regenerating lymphoid tissues. T cells from the donor seemed to work against the grafted stem cells and inhibit their maturation into mature immune cells. Furthermore, Shizuru said follow-up studies showed that the donor's T cells did not help eradicate pathogens.

The current research expands on work done by Shizuru last year, in which she and her colleagues compared the effectiveness of purified stem cells with unmanipulated bone marrow cells containing low levels of T cells.

In the new study, Shizuru and her colleagues took a more precise look at the action of the mature by comparing how well both groups of mice were able to regenerate bone marrow, blood and lymphoid tissues in the early post-transplant period (within one week) up through one year after transplantation.

Although the work was done in mice, Shizuru believes the results will be medically pertinent. "In our studies we tried to replicate the human system, and I believe what we have found is applicable to humans," she said.

Explore further: US scientists make embryonic stem cells from adult skin

Related Stories

Molecule dictates how stem cells travel

Jan 14, 2006

U.S. researchers have defined a molecule that dictates how blood stem cells travel to the bone marrow and establish blood and immune cell production.

Stem cell breakthrough: Bone marrow cells are the answer

Jan 28, 2010

Using cells from mice, scientists from Iowa and Iran have discovered a new strategy for making embryonic stem cell transplants less likely to be rejected by a recipient's immune system. This strategy, described in a new research ...

Protein key to control, growth of blood cells

Aug 13, 2008

New research sheds light on the biological events by which stem cells in the bone marrow develop into the broad variety of cells that circulate in the blood. The findings may help improve the success of bone marrow transplants ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

Apr 18, 2014

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.