Lupus nephritis (also known as SLE nephritis) is an inflammation of the kidneys caused by systemic lupus erythematosus (SLE), a disease of the autoimmune system. It is a type of glomerulonephritis in which the glomeruli become inflamed. As the result of SLE, the cause of glomerulonephritis is said to be secondary and has a different pattern and outcome from conditions with a primary cause originating in the kidney.