Systemic lupus erythematosus nephritis characterized by active or inactive diffuse, segmental endo- or extracapillary glomerulonephritis that involves 50% or more of all glomeruli. (Weening, Jan J. et al. (2004). The Classification of Glomerulonephritis in Systemic Lupus Erythematosus Revisited. Journal of the American Society of Nephrology 15(2), 241-50.) [from NCI]