IL6 and pyelonephritis: Serum IL-6 was 67.5 ± 75.4 pg/ml (mean ± standard deviation [SD]) in the pyelonephritis group, 12.1 ± 15.0 pg/ml in the lower UTI group and 1.6 to 2.8 pg/ml in the healthy controls, P < 0.001.