Graft-versus-host disease (GvHD) is a complication that can occur after a stem cell transplant. GvHD occurs when infection-fighting cells from the donor recognize the patient's body as being different or foreign. These infection-fighting cells then attack tissues in the patient's body just as if they were attacking an infection. GvHD is often treated with steroids, though this does not always work. GvHD is a serious condition with a high death rate so researchers are constantly evaluating new ways to treat it or reduce the symptoms.

European researchers conducted a study to see if a certain type of stem cell, infused into patients with GvHD that are not responding to treatment, would be effective. Patients were treated with mesenchymal stem cells, that are specific types of stems cells that are collected from the bone marrow of a donor. These stem cells are thought to help suppress the donor's immune cells and reduce the risk of GvHD.

The researcher found that 68 percent of the patients responded, children having slightly better results. They concluded that treatment with mesenchymal stem cells appears to effectively treat recurrent GvHD that would otherwise have been fatal in a majority of patients.