circletimessquare writes "The spleen doesn't get much respect. Those undergoing a splenectomy seem to be able to carry on without any consequences. However, some studies have suggested an enhanced risk of early death for those who have undergone splenectomies. Now researchers have discovered why: the spleen apparently serves as a vast reservoir for monocytes, the largest of the white blood cells, the wrecking crew of the immune system. After major trauma, such as a heart attack, the monocytes are disgorged into the blood stream and immediately get to work repairing the damage. '"The parallel in military terms is a standing army," said Matthias Nahrendorf, an author of the report. "You don't want to have to recruit an entire fighting force from the ground up every time you need it."'"