Blood-sample processing for the study of age-dependent gene expression in peripheral blood mononuclear cells.

Although most new biogerontological studies seeking to identify longevity candidate genes and factors involved in successful human aging are population based, and likely to involve the collection of blood from extremely old individuals, to our knowledge no unified protocols have yet been published to describe a methodology permitting the simultaneous generation of different kinds of biological specimens derived from a single source of a very small volume of peripheral blood. Here we describe a method permitting the simultaneous generation of plasma, RNA, DNA, protein, fixed lymphocytes, and frozen blood aliquots from a single 10- to 30-ml blood sample obtained from donors of any age (10-102 years old), and we show that the quality and quantity of DNA, RNA, protein, and fixed lymphocytes obtained do not vary significantly with age. As is frequently observed, the older individuals have higher plasma proportions.