Stanford team prevents kidney transplant rejection without
Researchers at Stanford University Medical Center have
discovered a way to transplant kidneys without having the patient
remain on a lifelong course of immune-suppressing drugs in order to
prevent rejection. As an added bonus, the donor kidneys don't even
need to come from a relative -- a restriction that has severely
limited kidney availability to sick people in need.
"Transplantation is a life-saving procedure, but the price is the
lifelong use of immune-suppressing drugs," said Samuel Strober, MD,
professor of immunology and rheumatology at Stanford School of
Medicine and leader of the study. Strober noted that these powerful
drugs leave kidney recipients open to infection and increase the
risk of heart disease or cancer later in life.
Research results from four patients in the groundbreaking study
will be presented April 28 in Washington, DC, at the American
Transplant Congress by Maria Millan, MD, transplant surgeon at
Stanford Hospital & Clinics and assistant professor of surgery.
The work is also scheduled to be published in the journal
Transplantation May 15.
Organ rejection after transplantation occurs because the immune
system scans for foreign cells. If the immune system in the
transplant recipient weren't heavily suppressed, it would attack
cells in the transplanted organ, leading to rejection.
Strober said the study asks two questions: Can you get patients off
the drugs and, if so, for how long? "We feel we can answer yes to
the first question," Strober said, adding that so far, two of the
four patients in the study are completely free of drugs, with
another still tapering off.
This new approach to kidney transplantation began in the usual way,
with surgery followed by immune-suppressing drugs, which were
needed to prevent organ rejection while the team completed the next
After the transplant, the kidney recipient received multiple small
doses of radiation targeted to the immune system combined with a
drug to reduce the number of cells capable of an immune attack. The
team then injected blood stem cells from the kidney donor into the
recipient. The stem cells made their way to the recipient's bone
marrow where they produced new blood and immune cells that mixed
with those of the recipient. After this procedure, the recipient's
immune cells recognize the donor's organ as friend rather than
The Stanford team monitored the recipient's new hybrid immune
system looking for a mixture of cells from both the recipient and
the donor. These cells were tested in the laboratory and did not
attack cells taken from the donor. This told the team that the new
hybrid immune system would not mount an attack against the
transplanted organ. At this time, the team slowly weaned the
patient away from the immune-suppressive drugs.
Millan said this study represents the direction in which
transplantation will move in the future. In the past, the goal was
to have a transplanted organ function in the recipient. Doctors now
routinely achieve that goal, and are looking for ways to increase
the long-term survival of the transplanted organ while maintaining
the recipient's quality of life. "We've topped out on what we can
do with drugs," Millan said.
In addition to Strober and Millan, the team consisted of Richard
Hoppe, MD, the Henry S. Kaplan-Harry Lebeson professor of radiation
oncology; John Scandling, MD, professor of medicine (nephrology);
Oscar Salvatierra, professor of surgery and pediatrics; and Judith
Shizuru, MD, PhD, assistant professor of medicine (bone marrow