A medical team at La Paz hospital in Madrid has reported a significant advance in organ transplantation, claiming to have effectively resolved the longstanding challenge of organ rejection. The group has successfully performed what they describe as lifelong transplants using a novel "double graft" technique that integrates donor organs with a personalized infusion of the donor’s stem cells.
The approach aims to retrain the recipient’s immune system to accept the transplanted organ as part of the body, thereby minimizing or potentially eliminating the need for lifelong immunosuppressant drugs. These medications, while essential in current transplant care, carry serious risks including increased vulnerability to infections, kidney damage, and cancer.
The technique was applied to two patients with complex medical histories involving multiple prior graft failures. Yassine, 21, who had undergone several unsuccessful intestinal and multiorgan transplants before age 15, and Nora, 55, who received several kidney transplants over nearly three decades—all of which were rejected—both underwent the procedure at La Paz. Six years later, Yassine requires only minimal doses of a single immunosuppressant, while Nora remains on a reduced regimen with no signs of organ rejection. Both patients report good health and have expressed gratitude for the opportunity to participate in the experimental treatment.
The procedure, developed under the OneTransplant4Life project by oncologist Antonio Pérez-Martínez and transplant surgeon Francisco Hernández Oliveros, involves harvesting haematopoietic stem cells from the donor’s bone marrow or blood. In the laboratory, these cells are processed to remove naïve T lymphocytes—white blood cells that could attack healthy recipient tissue—while preserving memory cells that protect against infection. When administered post-transplant, this cell infusion induces a state known as transient mixed chimerism, wherein the recipient’s and donor’s immune systems coexist temporarily, promoting tolerance of the graft.
Beatriz Domínguez-Gil, director of the Spanish National Transplant Organisation, which supported the initiative, described the results as promising and indicated that the technique could transform transplant medicine if outcomes are confirmed in larger clinical trials. The organisation has authorized a phase one trial involving ten additional patients to assess safety, with plans for a subsequent phase two trial to evaluate treatment efficacy and the potential to discontinue immunosuppressive drugs.
The development builds on decades of international research into immune tolerance but seeks to extend its benefits by reducing rejection risks across multiple organs simultaneously, including transplants from deceased donors lacking genetic compatibility.
Pérez-Martínez, motivated in part by personal experience after losing his father to complications related to immunosuppression following a liver transplant, said the ultimate aim is to make this approach widely available. The team has since performed two more procedures using the method, maintaining chimerism for over six months in these cases. However, Domínguez-Gil emphasized that broad implementation will require careful, incremental steps, rigorous safety monitoring, and substantial logistical coordination in organ retrieval.
“This has only just begun,” Domínguez-Gil said, underscoring the need for further research before the technique can become standard practice. Meanwhile, Pérez-Martínez remains hopeful that the innovation will eventually become routine, offering transplant recipients improved longevity and quality of life.