Peripheral blood (2.5 ml) for all samples was collected with the PAXgene system (PreAnalytix GmbH, UK). PAXgene vials were chosen to prevent density gradient centrifugation, immortalization or in vitro cell culture artifacts changing mRNA profiles. PAXgene tubes were mixed gently and incubated at room temperature for two hours. After collection, tubes were frozen at −20°C for at least 24 hours followed by storage at −80°C. RNA was isolated using the PAXgene Blood RNA isolation kit (PreAnalytix GmbH, UK). RNA was quantified using the Nanodrop (Nanodrop Technologies, USA). Total RNA integrity was analyzed using an Agilent Bioanalyzer (Agilent Technologies, USA).
