Renal Vasculopathy And Tubulointerstitial Lesions In Lupus Nephritis Classified By The2003International Society Of Nephrology And Renal Pathology Society Classification

Objective This study assessed the renal vascular changes and clinical significance inChinese patients with lupus nephritis based on the2003International Society ofNephrology/Renal Pathology Society classification system. Methods （1）The renal biopsyspecimens of patients with lupus nephritis were examined by direct immunofluorescence,light microscopy and electron microscopy techniques;(2) To study immune complexdeposited in renal vessels roundly, immunofluorescence staining was performed using rabbitanti-human IgG, IgA, IgM, C1q, C3c, C4d and fibrin on formalin-fixed paraffin-embededtissue;(3) The observers classified and scored the biopsies separately, blinded to patients’ dataand scores of others. Renal histopathological data of patients were re-classified according tothe2003ISN/RPS classification;(4) According to Appel et al，renal vascular lesions in lupusnephritis were re-evaluated as following：vascular immune complex deposits, atherosclerosis,thrombotic microangiopathy, noninflammatory necrotizing vasculopathy and true renalvasculitis. Renal vascular lesions were semi-quantitative scored and the associations betweenrenal vascular changes and clinical, laboratory and pathological characteristics and outcomeswere further assessed in the large cohort. Results （1）Among341patients with renalbiopsy-proven lupus nephritis in Peking University First Hospital,280patients (82.1%) withrenal vascular lesions:254with vascular immune complex deposits (74.5%),82withatherosclerosis (24.0%),60with thrombotic microangiopathy (17.6%),13withnoninflammatory necrotizing vasculopathy (3.8%) and2with true renal vasculitis (0.6%).105 patients (37.5%) presented with more than two types of vascular lesions.（2）The ratios ofhypertension, anemia, hematuria and acute renal failure were highest in thromboticmicroangiopathy group (P<0.001, P<0.001, P=0.006, P<0.001, respectively). The values ofurine protein, serum creatinine and the scores of SLEDAI were highest in thromboticmicroangiopathy group (P=0.032, P<0.001, P<0.001, respectively). The thromboticmicroangiopathy group had the poorest renal outcome.（3）The vascular immune complexdeposits and thrombotic microangiopathy were risk factors for renal outcome in lupusnephritis by log-rank test. In multivariate Cox hazard analysis, the total pathologicalchronicity indices, including renal vascular scores, was identified as independent risk factorsfor renal outcome.(HR:2.321,95%CI:1.231-4.377, P=0.009) Conclusions Renal vascularlesions were common in lupus nephritis and correlated closely with clinical disease activityand renal outcome. The classification in lupus nephritis with detailed descriptions of the renalvascular lesions might be helpful in predicting renal outcome. Objective This study analyzed the tubulointerstitial lesions in patients with lupusnephritis within the different classes and subclasses of the2003ISN/RPS system. Methods（1）The renal biopsy specimens of patients with lupus nephritis were examined by directimmunofluorescence, light microscopy and electron microscopy techniques;（2） Theobservers classified and scored the biopsies separately, blinded to patients’ data. Renalhistopathological data of patients were re-classified according to the ISN/RPS2003classification;（3）Pathological parameters of the glomerular and tubulointerstitial lesions inlupus nephritis such as activity indices and chronicity indices were re-evaluated using therevised Austin’s semi-quantitative scoring system. The tubulointerstitial lesions were furtherassessed among patients with different classes and subclasses on the basis of the2003ISN/RPS classification. Results （1）Among313patients from five centers in northern Chinawith lupus nephritis, interstitial inflammatory cell infiltration, tubular atrophy, and interstitialfibrosis were severe in170patients with class IV, moderate in55with class III, and mild in19with class II and in69with class V disease, each with significance.（2）The severity oftubulointerstitial lesions in classes IV-segmental and III was similar, whereas the score ofinterstitial inflammatory cell infiltration in patients with subclass IV-global was significantlyhigher than that in those with subclass IV-segmental.（3）Interstitial fibrosis and tubularatrophy were each significantly more prominent in patients with both active and chroniclesions than in those with active lesions alone.（4）In multivariate Cox hazard analysis of tubulointerstitial lesions, indices of interstitial infiltration, tubular atrophy, and interstitialfibrosis were confirmed as significant independent risk factors for renal outcome.Conclusions The2003ISN/RPS classification system of lupus nephritis, based on glomerularlesions, could also reflect related tubulointerstitial lesions. Hence, we suggest that the extentof tubulointerstitial lesions may be helpful in predicting renal outcome in patients with lupusnephritis.