Immuno-suppressive regimens of glucocorticoids combined with cytotoxic drugs, particularly cyclophosphamide, are effective for the treatment of severe lupus nephritis. However, cyclophosphamide has serious side effects, such as bone marrow suppression, gonadal toxicity, hemorrhagic cystitis and cancer. Mycophenolate mofetil (MM), a cytotoxic agent selective for lymphocytes, compares favorably with cyclophosphamide in terms of side effects.