Figure 1

Study concept. (A) Total RNA of each of the first 24 samples had been extracted following three different total RNA purification methods A, B, and C. Method A: lysis of the mononuclear cells, followed by lysate homogenization (to reduce viscosity caused by high-molecular-weight cellular components and cell debris) using a biopolymer shredding system in a microcentrifuge spin-column format (QIAshredder, Qiagen) followed by total RNA purification (RNeasy Mini Kit, Qiagen). Method B: TRIzol RNA isolation (Invitrogen). Method C: TRIzol RNA isolation (Invitrogen) followed by an RNeasy purification step (RNeasy Mini Kit, Qiagen). The RNA purification step combines the selective binding properties of a silica-based membrane with the speed of microspin technology. It allows only RNA longer than 200 bases to bind to the silica membrane, providing an enriching for mRNA since nucleotides shorter than 200 nucleotides are selectively excluded. (B) For each of three additional samples, nine aliquots of mononuclear cells had been collected. Total RNA has been processed for each aliquot following one of the three methods and for each method three independent technical replicates were performed (A,A,A, B,B,B, C,C,C).