Research On The Role Of Pathological Indicators In The Evaluation Of Prognosis Of IgA Nephropathy

ObjectiveThe Oxford Classification of the pathology of IgA nephropathy (IgAN) is identified as the most prognostic importance with four histological variables (MEST score) but hasn’t included the crescents as the predictive pathological parameter. However, the predictive value of cellular crescents in IgAN is controversial. Our objective is to validate these findings’ predictive power and to study correlations between pathological lesions and clinical presentation and to assess the potential predictive value of cellular crescents in our cohort of IgAN with crescentic formation.MethodsWe have93patients who were diagnosed primary IgAN with cellular crescents during January2004to December2009in our kidney disease center with a follow-up time more than12months. We observed the correlation between the pathological and clinical parameters at the time of renal biopsy in this cohort. According to the Oxford Classification, pathological parameters included mesangial hypercellularity score (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), tubular atrophy/interstitial fibrosis (T). We also included the cellular crescents and the percentage of crescents which was abbreviated as C. The clinical parameters included daily proteinuria, serum creatinine (Scr), eGFR (eMDRD) and mean arterial pressure (MAP) at the time of renal biopsy. We also collected the treatment modalities during follow up, including steroids/immunosuppressants, ACEI/ARB and dipyridamole. Renal outcome was defined AeGFR (eGFR at biopsy minus eGFR at last follow-up), slope of eGFR (ΔeGFR/years) and renal end point (doubling of serum creatinine, or>50%reduction in initial eGFR, or end stage renal disease).ResultsMedian length of follow-up was47months (range12-111).14%of the patients reached the renal end point. E, T and C were all associated with proteinuria at the time of biopsy. M and T were all associated with MAP and proteinuria at the time of biopsy. E was associated with MAP, proteinuria and slope of eGFR at the time of biopsy. Patients with endocapillary hypercellularity and higher proteinuria(≥1.0g/d) were more likely to receive immumosuppressive treatment. Kaplan-Meier analysis showed significant prognostic significance for M, E, and T lesions,but not S and C. By univariate analysis, renal end point was associated with presence of endocapillary hypercellularity and tubular atrophy/interstitial fibrosis. By multivariate analysis, we observed that endocapillary hypercellularity and tubular atrophy/interstitial fibrosis, as well as daily proteinuria, but not the cellular crescents, have independent value in predicting renal outcome. ConclusionThe mesangial hypercellularity, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis are valid in predicting a poor outcome in our cohort of IgAN patients.The endocapillary hypercellularity and tubular atrophy/interstitial fibrosis have independent value in predicting renal outcome. The cellular crescents has strong relationship with clinical manifestation, whereas no predictive value of cellular crescents for renal outcome was observed in the present cohort of IgAN.