<prompt> Answer this question truthfullyWhat is pauci-immune glomerulonephritis and how is it related to RPGN?  <response>: <reason> Pauci-immune glomerulonephritis is a type of glomerulonephritis, which is a group of diseases that affect the glomeruli, the tiny blood vessels in the kidneys that filter waste products from the blood. It is called pauci-immune because there is little or no immune complex deposition in the glomeruli. This means that there is no immunofluorescence pattern seen in renal biopsy samples. Pauci-immune glomerulonephritis is often associated with rapidly progressive glomerulonephritis RPGN, a severe form of kidney disease that can lead to kidney failure if left untreated. 