Gender differences in PAX and PAX-GRP samples

The use of peripheral blood mononuclear cells (PBMC) for transcriptome analysis has already been proven valuable for assessing disease-associated and drug response related gene signatures. While these proof-of-principle studies have been critically important, the instability of RNA within PBMC prohibits their use in large scale multi-center trials for which samples have to be transported for a prolonged time prior RNA isolation. Therefore, a prerequisite for transcriptome analysis of peripheral blood in clinical trials will be a standardized and valid method to immediately stabilize the RNA profile after blood withdrawal. We demonstrate that the globin mRNA reduction method results in significantly improved data quality of stabilized RNA samples resulting in low intra-group variance and a detection rate of expressed genes similar to PBMC. More important, even small differences in gene expression such as observed between females and males were detected and sufficient to predict gender in whole blood samples. Keywords: biological replicates Whole blood was drawn from 7 female and 7 male subjects into PAXgeneTM blood collection tubes. After isolation of total RNA, a subset of each RNA sample was subjected to a globin reduction protocol (GRP) Microarray analysis was performed from PAX and GRP samples using Affymetrix U133A arrays. Gene expression profiles of females and males were compared in the PAX and the GRP group.