Specially engineered 'young' immune cells could help to reverse the effects of aging and the damage to brain cells caused by diseases such as Alzheimer's , according to a new study in mice. In their natural state, these immune cells are known as mononuclear phagocytes , and they flow around the body, cleaning up waste. As we get older, however, these immune-cell cleaners get a bit sloppy , clearing away less cellular debris and triggering more inflammation than before. Inflammation and protein