Diagnosis and Oxford classification

The diagnosis of IgAN performed by 3 nephrologists and a renal pathologist by confirming mesangial proliferative glomerulonephritis in light microscopy, mesangial IgA deposition by immunofluorescence, and electron-dense deposits in the mesangial area by electron microscopy³⁸. The following pathological scoring systems were employed, including MEST scores by Oxford classification³⁹, presence of crescent formation (cellular/fibrocellular/fibrous) & tuft adhesion, glomeruli with global sclerosis (%), and IFTA (10% increments). There was very good agreement among 3 nephrologists’ scores in the percentage of IFTA (weighted κ value⁴⁰: 0.92). The Oxford classification excludes cases with fewer than 8 glomeruli from analysis³⁹. In this investigation, 9 patients (7 ≥ glomeruli ≥ 4) were included and the Oxford classification was performed by the consensus of 3 nephrologists.