Stem cells could let kidney recipients skip rejection drugs

Date: Wednesday Mar. 7, 2012 1:03 PM PT

Researchers in the U.S. say they may have found a way to allow kidney patients to ditch the powerful immune suppressing drugs that they need to take for life to prevent organ rejection.

The key lies in borrowing some stem cells from the donor's bone marrow. The cells are then engineered to "trick" the immune system of the recipient into thinking the new organ is an original part of the body.

"Essentially, it tricks the donor and recipient's immune system to accept each other," study author Dr. Suzanne Ildstad, a professor of Transplantation Research from the University of Louisville, told CTV News.

Transplant recipients usually are forced to take multiple immune-suppressing pills for life to prevent their own immune systems from rejecting the new organ. Kidney recipient Susan McKenzie tells CTV she takes eight pills a day. The pills not onlycome with a host of toxic side effects that boost her risk of heart disease and cancer, they interfere with her daily life.

"The really difficult part of it is that your immune sysytem is suppressed so you catch everything that is going around," she says.

"Your susceptibility to illness and infection is a big problem and of course, if you do get ill or have an infection ,you do have a risk of your kidney rejecting."

This new approach uses a special mix of bone marrow cells including blood-producing stem cells, and another type of cell named "facilitating cells. They also filter out certain cells that can cause a life-threatening disorder named "graft-versus-host disease."

The transplant recipients must then undergo radiation and chemotherapy to suppress their own immune system and allow it to accept the donated stem cells.

So far, teams from Northwestern Medicine and University of Louisville have tested the treatment on eight kidney transplant recipients. Two and a half years later, five of the patients have now been taken off immune-suppressing medication, the researchers reported Wednesday in the journal Science Translational Medicine.

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Stem cells could let kidney recipients skip rejection drugs