The Application Of Oxford Classification In Clinico-pathological Analysis In IgA Nephropathy With Crescents

ObjectiveThe purpose of the present study is to verify the clinic-pathological significance of Oxford Classification in IgA nephropathy with crescents in Chinese population. The relationship between cellular crescents and clinical parameters and its predictive value for renal outcome was also analyzed.MethodsCohort 1 composed of 236 patients of primary IgA nephropathy with cellular crescents formation who underwent renal biopsy during January 2004 to December 2009 in our kidney disease center were enrolled in the study. We observed the correlation between the pathological features and clinical features at the time of renal biopsy in this cohort, retrospectively. According to the Oxford Classification, pathological features included mesangial hypercellularity score(M), endocapillary hypercellularity(E), segmental glomerulosclerosis(S), tubular atrophy/interstitial fibrosis(T). We also included the cellular crescents formation and the percentage of crescents was abbreviated as C. The clinical features included daily proteinuria, serum creatinine (Scr), Egfr (MDRD) and mean arterial pressure (MAP) at the time of renal biopsy. The cut-off value of the percentage of cellular crescents was derived from ROC analysis.93 patients of the corhort 1 who were followed more than 12 months were chosen to establish cohort 2 and the correlation between clinico-pathological features with the renal outcome were observed. Renal outcome was defined AeGFR(eGFR at biopsy-eGFR at last follow-up), eGFR rapid decline (renal function decline>0.13 ml/min/1.73 m2/month) and renal end point(>30%reduction in initial eGFR, ESRD or sustained requirement of renal replacement therapy). We also collected and studied the therapy regimen during follow up, including steroids/immunosuppressants, ACEI/ARB and dipyridamole.ResultsIn cohort l, M, E, S, T and C were strongly associated with proteinuria at the time of biopsy. M, E, T and C were strongly associated with Scr and eGFR at the time of biopsy. M, E and T were strongly associated with MAP at the time of biopsy. Patients with endocapillary hypercellularity, cellular crescents and higher proteinuria(≥1.0g/d) were more likely to receive immumosuppressive treatment. Patients with tubular atrophy/interstitial fibrosis were more likely to be treated with ACEI/ARB drugs. In cohort 2, M, E and T were evidently associated with AeGFR and eGFR rapid decline. E, T and lower eGFR(<90ml/min) at biopsy were strongly associated with renal end point. By univariate analysis, eGFR rapid decline was significantly associated with mesangial hypercellularity, presence of endocapillary hypercellularity and tubular atrophy/interstitial fibrosis. Renal end point was significantly associated with presence of endocapillary hypercellularity and tubular atrophy/interstitial fibrosis and four clinical parameters at biopsy. By multivariate analysis, we observed that mesangial hypercellularity, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis, as well as daily proteinuria have independent value in predicting renal outcome.ConclusionIn the present cohort of crescentic IgA nephropathy it was confirmed that the four pathological parameters of Oxford Classification have strong relationship with the clinical indicators. The mesangial hypercellularity score, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis, as well as daily proteinuria have independent value in predicting renal outcome. The pathology variable of cellular crescents has strong relationship with clinical indicators of IgA nephropathy. Whereas no predictive value of cellular crescents for renal outcome was observed in these patients.