The admission serum leptin mean values were nearly equal among patients in the different groups, they were 2.76 μg/l in non-SIRS, 2.94 μg/I in SIRS and 3.25 μg/l in septic patients, the second day levels significantly increased in septic and SIRS but not in non-SIRS patients, the mean value was 3.4 μg/l in non-SIRS compared to 30.5 μg/l in SIRS and 44.7 μg/I in septic patients (P = 0.005) (Table 2). This evidence concerns the gene LEP and systemic inflammatory response syndrome.