IL6 and pyelonephritis: Gürgoze et al showed that at the time of presentation, median serum IL-6 was higher in the pyelonephritis group compared with the lower UTI group, 59 pg/ml (range 0–357.2) vs. 10 pg/ml (range 0–64), P < 0.001.19 This study was conducted in children less than one year of age.