Affiliations: Division of Viral and Rickettsial Diseases, National
Center for Infectious Diseases, Centers for Disease Control and Prevention,
Atlanta, GA 30333, USA
Note: [] Adrress for correspondence: Suzanne D. Vernon, Ph.D., Centers
for Disease Control and Prevention, Mail Stop A-15, 1600 Clifton Road, Atlanta,
GA 30333, Tel.: +1 404 639 1338; Fax: +1 404 639 2779; E-mail: svernon@cdc.gov
Abstract: Peripheral blood is representative of many systemic processes and is
an ideal sample for expression profiling of diseases that have no known or
accessible lesion. Peripheral blood is a complex mixture of cell types and some
differences in peripheral blood gene expression may reflect the timing of
sample collection rather than an underlying disease process. For this reason,
it is important to assess study design factors that may cause variability in
gene expression not related to what is being analyzed. Variation in the gene
expression of circulating peripheral blood mononuclear cells (PBMCs) from three
healthy volunteers sampled three times one day each week for one month was
examined for 1,176 genes printed on filter arrays. Less than 1% of the genes
showed any variation in expression that was related to the time of collection,
and none of the changes were noted in more than one individual. These results
suggest that observed variation was due to experimental variability.
