doi:10.1155/2012/195956 Review Article

Copyright © 2012 Xavier Camous et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. NK cells exhibit the highest cytotoxic capacity within the immune system. Alteration of their number or functionality may have a deep impact on overall immunity. This is of particular relevance in aging where the elderly population becomes more susceptible to infection, cancer, autoimmune diseases, and neurodegenerative diseases amongst others. As the fraction of elderly increases worldwide, it becomes urgent to better understand the aging of the immune system to prevent and cure the elderly population. For this, a better understanding of the function and phenotype of the different immune cells and their subsets is necessary. We review here NK cell functions and phenotype in healthy aging as well as in various age-associated diseases. 1. Cellular Senescence Aging, at the whole organism scale, is a very complex process, involving many different mechanisms. Studying the normal senescence process is also complex as we are permanently surrounded by pathogens, have different lifestyle habits, and exposed to different levels of stress which all influence the senescence process. Senescence biology really started in 196