June 4, 2019
International Society of Nephrology / Renal Pathology Society Classification of Lupus Nephritis
How do we classify lupus nephritis on a renal biopsy?
SLE patients with an active urinary sediment or proteinuria may undergo a kidney biopsy to evaluate for nephritis. The International Society of Nephrology (ISN) and Renal Pathology Society (RPS) created a lupus nephritis classification system based on morphologic findings on kidney biopsies. A simplified view of the classification algorithm is based on the sites of immune deposits within glomeruli. A flow-chart demonstrating that algorithm is shown below. Mesangial immune deposits can be present in all classes.
A summary in tabular format is shown below.
While a majority of SLE patients who undergo kidney biopsy for nephritic or nephrotic syndrome have lupus nephritis, other findings that could be identified on kidney biopsy in lupus patients include, but are not limited to focal and segmental glomerulosclerosis, pauci-immune crescentic glomerulonephritis, acute interstitial nephritis, arterionephrosclerosis, and other vascular lesions.