Serum TNF-α, IL-6 and IL-8 Measurements The venous blood samples were added into centrifuge tubes not containing anticoagulant for measuring serum TNF-α, IL-6 and IL-8 levels. Samples were centrifuged at 3000 rpm, 4 °C for 15 minutes and the resultant serum samples were stored at -80 °C. Samples taken for measuring serum TNF-, IL-6 and IL-8 levels were analyzed with ELISA method using Human TNF-α ELISA, Human IL-6 ELISA, Human IL-8/NAP-1 ELISA kits (Bender MedSystems, Vienna, Austria). Absorbance was read at 450 nm. Results were expressed as pg/ml.