MPO and interstitial nephritis: The average sCr, 24hUP, urinary RBCs, hemoglobin, and MPO tilter were 251.0 ± 115.8 and 306.8 ± 77.1 μmol/L (P = 0.709), 0.28 ± 0.08 and 1.31 ± 0.67 g/24 h (P = 0.184), 19.7 ± 17.4 and 244.5 ± 62.3/μL (P = 0.014), 108.7 ± 20.6 and 101.5 ± 8.1 g/L (P = 0.770), and 154.1 ± 59.5 and 210.2 ± 13.3 AU/mL (P = 0.447) in AAV-associated interstitial nephritis without glomerulonephritis and the control group, respectively.