 CMV is a virus that can also cause serious infections in patients with suppressed immune systems. It usually affects the lungs and can cause a very serious pneumonia, but it can also affect the intestinal tract, the liver and the eyes. Approximately 23 of normal people harbor this virus in their body. In healthy people CMV rarely causes any problems because the immune system can keep it under control. If the subject andor the subjects donor are positive for CMV, she is at risk of developing CMV disease while hisher immune system is weak post transplant. 