Nat. Rev. Nephrol. doi:10.1038/nrneph.2015.208 Figure 2 A comparison of duodenal histology in IgA nephropathy (IgAN) and coeliac disease Figure 2 | A comparison of duodenal histology in IgA nephropathy (IgAN) and coeliac disease. a | A duodenal biopsy sample from a patient with IgAN shows normal mucosa. b | By contrast, the duodenum of the patient with coeliac disease has subtotal atrophy, with elongated crypts and reduced villous length (Marsh class 3b). Periodic-acid–Schiff staining. Scale bars, 500 μm. Images courtesy of Peter Boor, Department of Pathology, University of Aachen, Germany. Floege, J. & Feehally, J. (2015) The mucosa–kidney axis in IgA nephropathy Nat. Rev. Nephrol. doi:10.1038/nrneph.2015.208