After the double transplant from her sister, the patient had normal kidney function with no sign of graft-versus-host disease. While she received cyclosporine right after the transplant, the immunosuppressant was tapered off and discontinued on the 73rd day after the procedures. Two post-transplant donor-white-blood-cell infusions were also given in an attempt to suppress her myeloma, which remains at a nearly undetectable level at this time.
Thomas Spitzer, MD, director of the MGH Bone Marrow Transplant Program and lead author of the Transplantation paper, says, "The great results we've seen in this patient - who probably would not have survived without these transplants - raises the possibility that other patients with blood-cell cancers and kidney failure may be successfully treated with the same approach."
The researchers are particularly intrigued by the fact that, while the effect of mixed chimerism - no conflict between the donor and recipient immune systems - continues in this patient, the actual chimeric state seems to be disappearing. In fact, donor cells can no longer be found in the recipient's marrow. "This kind of transient chimerism had been observed in the preclinical studies we have performed in monkeys, and we need to understand better the mechanism behind this phenomenon," says David Sachs, MD, director of the TBRC and a study coauthor. "One theory is that the donor kidney itself helps the recipients' body maintain a state of tolerance."
The animal studies that first achieved mixed chimerism were conducted in Sachs's TBRC laboratory, and the concept of applying the chimeric effect to blood-cell cancers was developed by TBRC researcher Megan Sykes, MD, another study coauthor. The procedures and their application to both transplant tolerance and cancer treatment have been licensed to BioTransplant Incorporated (Nasdaq:BTRN).
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Contact: Susan McGreevey
smcgreevey@partners.org
617-724-2764
Massachusetts General Hospital
25-Aug-1999