Destroying Chronic Infections
One main reason your immune system fails with age appears to be that chronic infections by the likes of cytomegalovirus (CMV) cause too many of your immune cells to be - uselessly - specialized. As noted in the New Scientist, researchers are looking into a possible way of clearing these infections from the body: they "studied an acute and chronic meningitis infection in mice, called lymphocytic choriomeningitis virus (LCMV). They discovered that mice with chronic infections had high levels of the inflammatory-damping chemical interleukin-10 (IL-10). When they gave mice with chronic LCMV a drug that blocks the inflammatory-calming action of IL-10, the inflammatory immune response was re-activated. Within a week the mice were healthier. In two weeks, they had cleared the virus completely." Now if this could be turned against CMV early in life, the immune system would look a lot better later on - but a method of cleaning out the uselessly specialized cells would be needed to help those suffering now.
Link: http://www.newscientist.com/article/dn10264-inflammation-turned-on-to-fight-killer-viruses.html