PTX3 and lupus nephritis: The mean optical density of PTX3 in tubulointerstitium of lupus nephritis was 0.46 ± 0.28 and correlated positively with total renal activity indices score (r = 0.372, P = 0.021), interstitial inflammation (r = 0.369, P = 0.010), and interstitial fibrosis (r = 0.326, P = 0.038) in lupus nephritis group, respectively.