Transplanted cells can turn on patients

clipped from www.gulfnews.com Bone marrow transplants are one of cancer care's striking successes, but they have a dark side: The transplanted cells can turn on patients, attacking their skin and organs The potentially deadly side effect with the unwieldy name of graft-versus-host disease, or GVHD, strikes several thousand each year Many times, GVHD is mild or moderate, causing skin rashes or blistering, vomiting, liver or lung damage. But one of every five cases is life-threatening A particularly dangerous form ravages the stomach and intestines, causing unremitting vomiting and diarrhoea When someone receives a transplanted organ, the big fear is that their own immune system will attack the new "foreign" tissue. GVHD is the opposite problem. It occurs when patients receive donated bone marrow or the stem cells that produce it, pieces of someone else's immune system. Sometimes the donor's T cells, whose job is to hunt foreign invaders, become super-aggressive and attack the recipient's body