Differentially expressed genes by age in stimulated PBMC.

<p>After 4 hours incubation of PBMC with or without a cocktail of IFNα, LPS, CD3+CD28, and anti-IgM+IgG, RNA was extracted and used for gene expression microarray analysis (Agilent, 4x44K, 2-color). Subjects <60 y and > = 80 y were randomly divided into a training set (53 subjects) and validation set (38 subjects). 4114 genes were identified in the training set as differentially expressed in the older vs. younger subset. (A) Differentially expressed genes are ordered by decreasing fold change between older and younger groups in the training set (left panel). A similar segregation is seen in the validation group (right panel). In these panels, expression values are represented as log2 expression(stimulated/unstimulated). (B) Display of 64 immune-related genes from the 4114 gene signature. In these panels, expression values are represented as fold change compared to the mean level of each gene in the young group. While many genes were associated with age, no gene signature was found to be specifically associated with CMV or sex (data not shown).