Letter regarding article by Tomic et al, "transcriptomic and proteomic patterns of systemic inflammation in on-pump and off-pump coronary artery bypass grafting".

To the Editor: We read with interest the article by Tomic and colleagues1 that sought to compare gene expression patterns from leukocytes and protein levels of inflammatory mediators after cardiac surgery. This involved isolation of RNA from blood collected in PaxGene tubes (Qiagen, Valencia, Calif). All subsequent interpretation of gene expression results refers to transcripts isolated from either peripheral blood mononuclear cells (PBMCs) or leukocytes. …