A form of glomerluponephritis occuring in some people with systemic lupus erythematosus, although it may also be renally limited. May be characterized by hematuria, proteinuria, or both, with or without associated hypertension. Can lead to a progressive or fulminant course resulting in renal failure. May present as the progressive or fulminant course resulting in renal failure. May also present as the nephrotic syndrome in some people; renal biopsies in these people are classified by the World Health Organization criteria and by activity and chronicity. Biopsy findings take the forms of: no apparent disease (WHO class I), mesangial proliferation (WHO class II), focal proliferative lesions (WHO class III), diffuse proliferative lesions (WHO class IV), membranous lesions (WHO class V), or end stage lesions (WHO class VI).