Validation of the Oxford classification for pediatric IgA nephropathy

Abstract

Objective To assess the validity of the Oxford classification for pediatric patients with primary IgA nephropathy (IgAN) and to analyze the correlations between clinical characteristics at time of biopsy and the Oxford classification,which identified four definitive histological features:mesangial hypereellularity,endocapillary proliferation,segmental sclerosis and tubular atrophy/interstitial fibrosis.Methods Clinical and pathological characteristics of 35 children with primary IgAN were analyzed.The scoring sheet was based on the Oxford classification of IgAN,and four pathological variables,namely mesangial hypercellularity (M),endocapillary proliferation (E),segmental sclerosis (S),and tubular atrophy/interstitial fibrosis (T) were assessed.A total of 35 children with IgAN were grouped according to the scores(M,E,S,T):the M0 and M1 group,E0 and E1 group,S0 and S1 group,T0 and T1/T2 group.These groups were compared in terms of estimated glomeralar filtration rate (eGFR),mean artery pressure (MAP) and proteinuria at time of biopsy.Results We found that the Oxford classification was significantly negatively correlated with eGFR (Pearson's correlation coefficient r =-0.48).However,the Oxford classification was shown to be positively associated with initial proteinuria per day(Pearson's correlation coefficient r =0.35).The M,E,S,T scores were strongly associated with proteinuria at biopsy (P ＜ 0.05),and the lesion S was not correlated with eGFR (P ＞ 0.05).The lesion T was significantly associated with eGFR (P =0.001) and MAP (P =0.03) at biopsy.Conclusion We confirmed that the Oxford classification of IgA nephropathy was valid for children.In addition,our study indicated that the four histological lesions M,E,S and T were significantly associated with clinical features. Key words: IgA nephropathy;  Oxford classification;  Children