A stem cell transplant can save the life of anyone suffering from blood cancer. But the treatment carries risks. In up to every second patient, the new immune cells attack the patient's own body after transplantation. Researchers at the Fraunhofer Institute for Cell Therapy and Immunology (IZI) in Leipzig have now developed a method to prevent this dangerous side effect.
In stem cell transplantation, patients with leukemia or other types of blood cancer receive healthy cells from a donor. First, the diseased blood cells are destroyed. The donated stem cells then settle in the body and form new, functional blood cells. The problem with this is that the transplanted immune cells sometimes recognize the recipient's tissue as foreign and fight it. Doctors call this reaction graft-versus-host disease, or GvHD for short. Up to 50 percent of all transplants lead to such rejection reactions.
Targeted intervention instead of inhibiting medication
So far, doctors have tried to suppress the rejection with medication that weakens the entire immune system. This has disadvantages. Patients become more susceptible to infections. In addition, the risk of the cancer returning increases.
The Fraunhofer IZI is pursuing a different approach. The scientists treat the donor cells with special antibodies before transferring them. These antibodies block a specific molecule on the surface of the immune cells, the CD4 molecule. This slows down precisely those cells that would trigger the rejection reaction. The rest of the immune system remains active and can continue to fight pathogens.
Successful tests in the laboratory
The researchers have tested their method in experimental laboratory trials. A single treatment of the donor cells prior to transplantation was sufficient to reduce the rejection reaction over the entire observation period. "The results suggest that this approach can effectively reduce the risk of acute GvHD and therefore has the potential to improve the chances of therapy for patients," explains Prof. Stephan Fricke, who led the study. However, the final evaluation must be carried out in clinical trials.
The Leipzig scientists are now preparing their method for initial tests on patients. A so-called phase I/II study will show whether the approach also works and is safe in humans. The research results were published in the scientific journal BLOOD.
The original publication can be found here.
