It works by interfering with the growth of T-lymphocytes. These specialized white blood cells are one of the main instigators of the rejection process. While suppressing these cells to help prevent rejection, Imuran also can suppress all blood cells, including white cells, red cells, and platelets. White blood cells are the part of the immune system that surveys the body for foreign invaders, such as bacteria, viruses, and, of course, transplanted organs. When these foreign materials are found, the immune system swings into action, alerting cells to fight and kill the invaders.
Immunosuppressants slow down the white blood cells and interfere with the rejection process.
The body then allows the new organ to remain - but sometimes viruses and bacteria remain or enter the body also, resulting in infection. That's why you and your transplant team must always be on the lookout for infection. Sometimes cancer cells also can grow. In fact, most immunosuppressive drugs, including Imuran, can make you more susceptible to infection and malignancy. Imuran is used to help prevent rejection, not to treat it.