Supernatants of cell cultures were harvested 3, 6, 9, 12, 18, 24, 30, 36 and 48 hours after stimulation and stored at -80 °C until used and thawed only once. IFNγ, TNFα, IL-1 and IL-6 were determined using an ELISA from Bender Systems (Vienna, Austria), IL-1RA and IL-8 by an ELISA from R&D Systems (Wiesbaden-Nordenstadt, Germany), and TGFβ 1 using an ELISA as previously described [57]. Quantification of IL-2 as an indicator for the bioactivity of IL-1 was done as previously described [46]. Samples were diluted in the same buffer as that used for the standards. All cytokines were quantified using an ELISA plate reader (Anthos Labotec, Salzburg, Austria or Microplate Reader, BioRad). Cytokine amounts were all within the range of the standard curve. Only stimulation of PBMC observed in donors showing no spontaneous cytokine release was included in the statistics.