Oxford Classification of IgA nephropathy 2016: an update from the IgA Nephropathy Classification Working Group

• Published in: Kidney international Vol. 91; no. 5; pp. 1014 - 1021
• Main Authors: Trimarchi, Hernán, Barratt, Jonathan, Cattran, Daniel C., Cook, H. Terence, Coppo, Rosanna, Haas, Mark, Liu, Zhi-Hong, Roberts, Ian S.D., Yuzawa, Yukio, Zhang, Hong, Feehally, John, Alpers, Charles E., Asunis, Ana María, Barbour, Sean, Becker, Jan U., Ding, Jie, Espino, Gabriella, Ferrario, Franco, Fogo, Agnes, Hladunewich, Michelle, Joh, Kensuke, Katafuchi, Ritsuko, Lv, Jicheng, Matsuzaki, Keiichi, Nakanishi, Koichi, Pani, Antonello, Perera, Ran, Perkowska-Ptasinska, Agnieszka, Reich, Heather, Shima, Yuko, Soares, Maria Fernanda, Suzuki, Yusuke, Takahashi, Katsuo, Troyanov, Stéphan, Verhave, Jacobien C., Wang, Suxia, Weening, Jan, Wyatt, Robert, Yoshikawa, Nori, Zeng, Caihong
• Format: Journal Article
• Language: English
• Published: United States 01.05.2017
• Subjects: Atrophy; Biopsy; Fibrosis; Glomerular Filtration Rate; Glomerulonephritis, IGA - classification; Glomerulonephritis, IGA - drug therapy; Glomerulonephritis, IGA - immunology; Glomerulonephritis, IGA - pathology; Glomerulosclerosis, Focal Segmental - classification; Glomerulosclerosis, Focal Segmental - drug therapy; Glomerulosclerosis, Focal Segmental - immunology; Glomerulosclerosis, Focal Segmental - pathology; Humans; Immunosuppressive Agents - therapeutic use; Kidney Glomerulus - blood supply; Kidney Glomerulus - cytology; Kidney Glomerulus - immunology; Kidney Glomerulus - pathology; Kidney Tubules - cytology; Kidney Tubules - immunology; Kidney Tubules - pathology; Mesangial Cells - pathology; Proteinuria; Risk Assessment; Sclerosis; Treatment Outcome; chronic kidney disease; IgA nephropathy; glomerulonephritis; proteinuria
• ISSN: 0085-2538; 1523-1755; 1523-1755
• DOI: 10.1016/j.kint.2017.02.003

Since the Oxford Classification of IgA nephropathy (IgAN) was published in 2009, MEST scores have been increasingly used in clinical practice. Further retrospective cohort studies have confirmed that in biopsy specimens with a minimum of 8 glomeruli, mesangial hypercellularity (M), segmental sclerosis (S), and interstitial fibrosis/tubular atrophy (T) lesions predict clinical outcome. In a larger, more broadly based cohort than in the original Oxford study, crescents (C) are predictive of outcome, and we now recommend that C be added to the MEST score, and biopsy reporting should provide a MEST-C score. Inconsistencies in the reporting of M and endocapillary cellularity (E) lesions have been reported, so a web-based educational tool to assist pathologists has been developed. A large study showed E lesions are predictive of outcome in children and adults, but only in those without immunosuppression. A review of S lesions suggests there may be clinical utility in the subclassification of segmental sclerosis, identifying those cases with evidence of podocyte damage. It has now been shown that combining the MEST score with clinical data at biopsy provides the same predictive power as monitoring clinical data for 2 years; this requires further evaluation to assess earlier effective treatment intervention. The IgAN Classification Working Group has established a well-characterized dataset from a large cohort of adults and children with IgAN that will provide a substrate for further studies to refine risk prediction and clinical utility, including the MEST-C score and other factors.