lupus nephritis 1. classification A 27-year-old Caucasian woman with a 10-year history of systemic lupus erythematosus (SLE) but no previous history of renal disease presents with new onset of hematuria and proteinuria. Laboratory evaluation reveals a serum creatinine level of 0.5 mg/dl, 24-hour urine protein of 2.9 g, serum albumin of 2.8 g/dl, white blood cell count of 2.4 109/L, hematocrit of 36.8%, and platelet count of 127 109/L. Serologic evaluation reveals an anti-nuclear antibody (ANA) titer of 1:1280, an anti-DNA antibody of 500 IU/ml, depressed C3 and C4 complement levels, a positive IgG anti-cardiolipin antibody, and a negative lupus anticoagulant. Examination of the urine sediment discloses four to 10 red blood cells per high-power field, no significant white blood cells, and no cellular casts. Previous manifestations of SLE included pericarditis, alopecia, a malar rash, and arthralgias. Physical examination reveals a BP of 122/76, an erythematous facial rash, and no edema. Medications include methylprednisolone 6 mg/day and plaquenil 200 mg/ day. The kidneys measure 12.1 and 11.5 cm in length by ultrasound. Renal biopsy is performed. What is the BEST diagnosis? A. Lupus nephritis (LN) class V B. LN class IV-S C. LN class IV-S and V D. LN class IV-G E. LN class IV-G and V