Facilitating cells in tolerance induction for kidney transplantation.

Purpose Of Review: To describe the clinical outcomes and science behind a CD8/TCR facilitating cell-based hematopoietic stem cell transplant approach (termed FCRx) to induce tolerance to renal allografts without graft-versus-host disease (GVHD) and avoidance of long-term immunosuppressant drugs in living donor kidney transplant recipients.

Recent Findings: Successful solid organ transplantation currently requires the life-long use of medications to suppress the immune system to prevent transplant rejection. Drug-based immunosuppression significantly increases the risk of infection and cancer, as well as being very costly. Development of new therapies to minimize or eliminate entirely the need for antirejection drugs is of great interest to the transplant community. Therapeutic cell transfer for the control of the human immune system represents a compelling approach to reduce or eliminate the need for antirejection drugs.

Summary: Establishment of durable hematopoietic macrochimerism under nonmyeloablative conditioning is achievable in mismatched recipients using facilitating cells and stem cells obtained from donor mobilized peripheral blood mononuclear cells. Persistently chimeric recipients developed donor-specific tolerance and were weaned off of immunosuppressive drugs over 12 months. They maintained stable renal function without development of acute or chronic GVHD.