Lupus nephritis (LN) is defined as a glomerular immune complex disease that occurs in patients who meet American College of Rheumatology criteria for diagnosis of systemic lupus erythematosus (SLE). SLE is a systemic autoimmune disease, most commonly involving the skin, kidneys, joints, heart, and serosal surfaces. Women are affected more than men (9:1), and SLE is more common in African Americans. Onset usually is from teenage years to the third decade of life, but SLE may manifest at any age. Kidney involvement is a major cause of morbidity and the most common cause of death in SLE patients.