October 24, 2004
SickKids researchers explain why incompatible blood type heart transplants are possible in infants
TORONTO — Researchers at The Hospital for Sick Children (SickKids) have illustrated the mechanisms that allow for successful infant heart transplants with major blood type (ABO) incompatibility. This discovery opens the door for the development of a means to induce incompatible transplantation tolerance in older patients. This research is reported in the November 2004 issue of the scientific journal Nature Medicine (available online October 24, 2004).
“By studying the immunological development of infants who have undergone ABO incompatible heart transplants, we discovered that the immune system of these infants is able to reprogram itself to consider foreign blood group antigens the way it considers self antigens,” said Dr. Lori West, the study’s principal investigator, a SickKids scientist and cardiologist, and an associate professor of Paediatrics at the University of Toronto.
“The next stage of this research is to develop a tool that will allow us to intentionally induce immune system tolerance so that ABO incompatible heart transplants will be possible in older patients,” said Dr. West. “We will also investigate whether an infant’s immune system can tolerate the more complex HLA, or transplantation, antigens from a foreign source, as it is these transplantation antigens that render immunosuppressant drugs necessary for transplant patients.”
The concept of neonatal tolerance, which is the ability of the immature immune system of a newborn to be induced to tolerate foreign antigens, was first demonstrated in a mouse model more than 50 years ago. The research from Dr. West’s group showed for first time that what was observed in a mouse model is the same in humans.
ABO-incompatible heart transplants were pioneered at The Hospital for Sick Children in the mid 1990s, and since then 20 have taken place at SickKids and 48 worldwide.
“Despite all the advances in heart transplantation research, there is still a critical shortage of organs. It is important that families discuss organ donation,” added Dr. West.
Other members of the research team included Dr. Xiaohu Fan, the study’s lead author, Andrew Ang, Dr. Stacey Pollock-BarZiv, Dr. Anne Dipchand, and Dr. Gregory Wilson, all from SickKids, Dr. Phillip Ruiz from the University of Miami School of Medicine, and Dr. Jeffrey Platt from the Mayo Clinic.
This research was supported by the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, and SickKids Foundation.
The Hospital for Sick Children, affiliated with the University of Toronto, is Canada’s most research-intensive hospital and the largest centre dedicated to improving children’s health in the country. Its mission is to provide the best in family-centred, compassionate care, to lead in scientific and clinical advancement, and to prepare the next generation of leaders in child health.
For more information, please contact:
Public Affairs
The Hospital for Sick Children
555 University Avenue
Suite 1742, Public Affairs, First floor Atrium
Toronto,
ON
M5G 1X8
Canada
Phone: 416-813-5058
Fax: 416-813-5328