On behalf of the Working Group of the International IgA Nephropathy Network & Renal Pathology Society

The new Oxford Classification of the Pathology of IgA nephro- pathy originated from an international collaborative effort of the Working Group of the International IgA Nephropathy Network & Renal Pathology Society. It provides a new common language to categorizing glomerular and tubulo-interstitial lesions in IgA nep- hropathy having a proved effect on progression. Although retrospective in design and requiring future prospective validation, the Oxford collaboration defined and scored four pathologic parameters having an influence on outcome (independently of clinical information at renal biopsy or during follow-up); including mesangial (M) and endoca- pillary (E) proliferation (hypercellularity), glomerulosclerosis (S) and tubular atrophy and interstitial fibrosis (T). The scheme will likely become known as the OXFORD- MEST scoring system.