Longitudinal study of gene expression in healthy individuals

The gene expression profile of blood drawn from healthy individuals was studied over a period of six months, at five time points. The gene expression profiles appeared to be constant over one month and to slightly vary over three months. A small proportion of genes were found to be differentially regulated according to gender. Differential gene regulation by age (in subjects 25–55 years of age versus subjects > 55 years of age) was not observed. Healthy subjects were enrolled at a single site, their health status was determined by medical history, physical examination, and standard laboratory test values. Venous blood was drawn in the morning, from fasted subjects at five time points (Day1, Day14, Day28, Day 90 and Day 180). Blood was collected into PAXgene tubes (Becton-Dickinson Diagnostics; Hombrechtikon, Switzerland).