The Telegraph reports on a new finding in the biochemistry of human longevity: "White blood cells fend off infection - in effect delaying death - so [researchers] investigated longevity by taking samples of white blood cells from 45 men and women aged between 75 and 90 who all had parents born in Sicily between 1900 and 1908. Twenty-five of the donors had one parent who had reached 100 and one who had died of old age before reaching average life expectancy for Italians - which is 67 for men and 72 for women. The remaining 20 donors served as controls having lost both parents before they reached average life expectancy ... Our main finding was the increase in naive B-cells in individuals who had centenarian parents ... Unlike mature B-cells - which are primed to attack foes the body has seen before - naive B-cells are ready and waiting to attack microbes not previously encountered." You'll recall that depletion of naive T-cells is a strong component of immune system aging. As naive cells diminish, the ability to mount a response to new challenges also diminishes.