XDH and acute respiratory distress syndrome: Increased serum XOR activity was observed (Fig. 3) in the combined group of all patients (54.5 ± 57.1 mU/mL; or log-transformed: 1.6 ± 0.4; n = 143), sepsis-only patients (43.8 ± 27.9 mU/mL; or log-transformed: 1.5 ± 0.3; n = 68) or sepsis with ARDS (73.4 ± 64.9 mU/mL; or 1.6 ± 0.4; n = 75) as compared to the controls (20.9 ± 12.4 mU/mL, or 1.3 ± 0.2; n = 31) (P = 1.96 × 10− 13, P < 0.0002 and P < 0.0001, respectively).