A 21-year-old woman presents with a 3-month history of malaise, joint pain, weight loss, and sporadic fever. The patient appears agitated. Her temperature is 38degC (101degF). Other physical findings include malar rash, erythematous pink plaques with telangiectatic vessels, oral ulcers, and non blanching purpuric papules on her legs. Laboratory studies show elevated levels of blood urea nitrogen and creatinine. Antibodies directed to which of the following antigens would be expected in the serum of this patient?

Systemic lupus erythematosus (SLE) is an autoimmune, inflammatory disease that may involve almost any organ but characteristically affects the kidneys, joints, serous membranes, and skin. Autoantibodies are formed against a variety of self-antigens. The most impoant diagnostic autoantibodies are those against nuclear antigens:-- Antibody to double-stranded DNA A soluble nuclear antigen complex that is pa of the spliceosome and is termed Sm (Smith) antigen. High titers of these two autoantibodies (termed antinuclear antibodies) are nearly pathognomonic for SLE. -Antibodies to rheumatoid factor (choice D) are seen in patients with rheumatoid ahritis. -Antineutrophil cytoplasmic antibodies (choices A and C) are seen in patients with small vessel vasculitis (e.g., Wegener granulomatosis). Diagnosis: Systemic lupus erythematosus