Being the patient's own cells, they would be at no risk of immune rejection.

Second, transplant experts expect to face other problems involving immune rejection, although less daunting ones.

Similar to organ transplantation, gene therapy has been plagued by the problem of immune rejection.

A major roadblock to grafting these new organs into patients would be immune rejection, the body's attack on tissues recognized as foreign.

But, experts say, scientists must figure out a way to overcome the problem of immune rejection before using stem cells as treatment.

A major challenge facing survival of islet cells is immune rejection.

The cells would be derived in many cases from the patient's own bone marrow and thus present no problem of immune rejection.

The treated cells would then be returned to the patient without danger of immune rejection.

These would be taken from the patient's body so as to avoid problems of immune rejection.

Treating patients with cells derived from their own stem cells would avoid any problems of immune rejection.