Total RNA was isolated from freshly purified PBMC stored in Trizol according to the manufacturer's instructions (Invitrogen) prior to reverse-transcription using a T7 oligo dT (24 (link)) primer and Superscript II (Invitrogen). Second-strand cDNA synthesis was obtained with RNase H, E. coli DNA polymerase I, and DNA ligase (Invitrogen). cDNA was blunt-ended with T4 DNA polymerase (Invitrogen) and purified using the QIAQuick PCR purification Kit™ (Qiagen, Germantown, MD). Labeling was performed using the ENZO BioArray™ HighYield™ RNA Transcript Kit (Affymetrix) according to the manufacturer's instructions. After purification, labeled cRNA was quantified by OD, and the quality was assessed on a Bioanalyzer (Agilent, Santa Clara, CA). Fragmented cRNA with hybridization controls and Oligo B2 from Affymetrix were hybridized on Affymetrix U133 Plus 2.0 Genechips for 18 hours followed by washing and staining on Affymetrix Fluidic 400. The arrays were scanned using the Affymetrix GeneChip Scanner 3000. Array images were analyzed using Affymetrix Gene Chip Operating System (GCOS) software using the MAS5 algorithm. The MAS5 algorithm (6 (link)) computes an adjusted signal level for each probe set to estimate expression of the target mRNA of that probe set. Values were normalized for each probe set across all arrays in the dataset.