Blood Stem Cells Induce Tolerance for Transplanted Organs

Peripheral blood stem cell transplantation, used for patients with certain cancers, now shows promise as a way to induce drug-free tolerance of a transplanted organ, according to researchers at the University of Pittsburgh (PA, USA).

Three days after receiving a kidney donated by her brother, a transplant recipient at the university's Thomas E. Starzl Transplantation Institute received an infusion of her brother's immune system cells taken from blood he had donated earlier. The procedure took less than 20 minutes and both donor and recipient were discharged five days later.
The recipient's transplanted kidney is functioning well, with no complications from the stem cell infusion. The doctors say it will be several months before they can determine whether she can be weaned of immunosuppressive drugs.

Surgeons at the university have been evaluating the long-term benefits of giving transplant recipients unmodified donor bone marrow infusions as a means to enhance chimerism. As with these transplants, the aim of the new treatment is to boost the level of chimerism, in the hope that tolerance is more likely to follow and the patient can be successfully weaned off immunosuppressive drugs.

"Unlike liver transplant patients, very few kidney recipients have been able to be safely weaned off immunosuppression,” noted Ron Shapiro, M.D., professor of surgery at the Starzl Transplantation Institute. "We think this is because the kidney contains fewer of the types of cells that are immunoprotective.”




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