title: The Oxford classification of IgA nephropathy: pathology definitions, correlations, and reproducibility.
abstract: Pathological classifications in current use for the assessment of glomerular disease have been typically opinion-based and built on the expert assumptions of renal pathologists about lesions historically thought to be relevant to prognosis. Here we develop a unique approach for the pathological classification of a glomerular disease, IgA nephropathy, in which renal pathologists first undertook extensive iterative work to define pathologic variables with acceptable inter-observer reproducibility. Where groups of such features closely correlated, variables were further selected on the basis of least susceptibility to sampling error and ease of scoring in routine practice. This process identified six pathologic variables that could then be used to interrogate prognostic significance independent of the clinical data in IgA nephropathy (described in the accompanying article). These variables were (1) mesangial cellularity score; percentage of glomeruli showing (2) segmental sclerosis, (3) endocapillary hypercellularity, or (4) cellular/fibrocellular crescents; (5) percentage of interstitial fibrosis/tubular atrophy; and finally (6) arteriosclerosis score. Results for interobserver reproducibility of individual pathological features are likely applicable to other glomerulonephritides, but it is not known if the correlations between variables depend on the specific type of glomerular pathobiology. Variables identified in this study withstood rigorous pathology review and statistical testing and we recommend that they become a necessary part of pathology reports for IgA nephropathy. Our methodology, translating a strong evidence-based dataset into a working format, is a model for developing classifications of other types of renal disease.
authors: Department of Cellular Pathology, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK. ian.roberts@orh.nhs.uk
authors: Ian S D
authors: IS
authors: Roberts
authors: H Terence
authors: HT
authors: Cook
authors: Stéphan
authors: S
authors: Troyanov
authors: Charles E
authors: CE
authors: Alpers
authors: Alessandro
authors: A
authors: Amore
authors: Jonathan
authors: J
authors: Barratt
authors: Francois
authors: F
authors: Berthoux
authors: Stephen
authors: S
authors: Bonsib
authors: Jan A
authors: JA
authors: Bruijn
authors: Daniel C
authors: DC
authors: Cattran
authors: Rosanna
authors: R
authors: Coppo
authors: Vivette
authors: V
authors: D'Agati
authors: Giuseppe
authors: G
authors: D'Amico
authors: Steven
authors: S
authors: Emancipator
authors: Francesco
authors: F
authors: Emma
authors: John
authors: J
authors: Feehally
authors: Franco
authors: F
authors: Ferrario
authors: Fernando C
authors: FC
authors: Fervenza
authors: Sandrine
authors: S
authors: Florquin
authors: Agnes
authors: A
authors: Fogo
authors: Colin C
authors: CC
authors: Geddes
authors: Hermann-Josef
authors: HJ
authors: Groene
authors: Mark
authors: M
authors: Haas
authors: Andrew M
authors: AM
authors: Herzenberg
authors: Prue A
authors: PA
authors: Hill
authors: Ronald J
authors: RJ
authors: Hogg
authors: Stephen I
authors: SI
authors: Hsu
authors: J Charles
authors: JC
authors: Jennette
authors: Kensuke
authors: K
authors: Joh
authors: Bruce A
authors: BA
authors: Julian
authors: Tetsuya
authors: T
authors: Kawamura
authors: Fernand M
authors: FM
authors: Lai
authors: Lei-Shi
authors: LS
authors: Li
authors: Philip K T
authors: PK
authors: Li
authors: Zhi-Hong
authors: ZH
authors: Liu
authors: Bruce
authors: B
authors: Mackinnon
authors: Sergio
authors: S
authors: Mezzano
authors: F Paolo
authors: FP
authors: Schena
authors: Yasuhiko
authors: Y
authors: Tomino
authors: Patrick D
authors: PD
authors: Walker
authors: Haiyan
authors: H
authors: Wang
authors: Jan J
authors: JJ
authors: Weening
authors: Nori
authors: N
authors: Yoshikawa
authors: Hong
authors: H
authors: Zhang
mesh_terms: D001706:Biopsy; D005922:Glomerulonephritis, IGA / Q000145:classification* / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D050527:Mesangial Cells / Q000473:pathology; D009336:Necrosis; D015203:Reproducibility of Results