Oxford MEST classification in Iranian patients with IgA nephropathy, with regards to extracapillary proliferation; a single center experience

Abstract

Introduction: IgA nephropathy is the most common glomerulonephritis in the world. Objectives: In this study we aimed to find the relationship between morphological lesions of Oxford classification for IgA nephropathy with clinical findings and some laboratory data. Patients and Methods: All kidney biopsy conducted from 2009 to 2019 conducted in medical centers and were sent to a reference laboratory in Isfahan. All kidney biopsies included two samples for immunofluorescence and light microscopy. After definitive diagnosis of IgAN (IgA nephropathy), the slides were examined to classify the disease based on the Oxford-MEST (M; mesangial hypercellularity, E; endocapillary hypercellularity, S; segmental glomerulosclerosis, and T; tubular atrophy/interstitial fibrosis and also C; crescent) classification. Results: Our study on 238 biopsy proven IgA nephropathy patients showed that 78 patients (32.8%) were male. Mean ± SD of age individuals was 38.00 ±13.68 years. The mean± SD of serum creatinine level was 1.42 ± 0.79 mg/dL and the mean ± SD of proteinuria was 1780.94 ± 1168.75 mg/d. Our study showed no significant association between M, E and S variables with patients’ age. However, a statistically significant relationship between T variable and patients’ age (P=0.028) was detected. Furthermore, morphologic variables of M, E and S were not significantly associated with proteinuria while T variable was positively associated with the quantity of proteinuria (P=0.021). Conclusion: The association of tubular atrophy/interstitial fibrosis (T variable) with quantity of proteinuria showed significance of interstitial lesion on the prognosis IgA nephropathy.