IL-6 mean values were nearly equal among groups and no significant differences were found between the admission values; mean IL-6 level was 7.4 pg/ml in non-SIRS, 8.5 pg/ml in SIRS and 9.6 pg/ml in septic patients, but on the second day there was a significant increase in the mean value in SIRS and septic patients: 275 pg/ml and 485 pg/ml respectively versus 21.4 pg/ml in non-SIRS patients (P = 0.004). This evidence concerns the gene IL6 and systemic inflammatory response syndrome.