Peripheral blood mononuclear cells (PBMCs) were prepared from heparinized blood samples by centrifugation using density gradients (Lymphoprep; Axis-Shield, Oslo, Norway). Total RNA was first extracted from PBMCs (Isogen RNA isolation kit; Nippon Gene, Tokyo, Japan) and purified (RNeasy Mini Kit; Qiagen, Tokyo, Japan). Total RNA was analyzed (2100 Bioanalyzer; Agilent Technologies, Santa Clara, CA) and UV spectrophotometry was used to check quality. Total RNA (1 μg) was taken, and biotin-labeled cRNA was synthesized (MessageAmp II-Biotin Enhanced Kit; Ambion, Austin, TX). The biotin-labeled cRNA was fragmented and hybridized (CodeLink Human Whole Genome Bioarray; Applied Microarrays, Tempe, AZ) for 18 hours (300 rpm shaker) at 37°C. The hybridized slides were washed and incubated with streptavidin-Alexa Fluor 647 (GE Health Care Bio-Science; Piscataway, NJ) for 30 minutes at 25°C, to label the cRNA, and washed again. The slides were scanned with a laser-based detection system (GenePix 4000B; Molecular Devices, Sunnyvale, CA).