Radboud eight years ago because of general fatigue, arthralgias, myalgias, facial rash, and a fever (38.1 C). Her general physician had prescribed salicylates and later nonsteroidal anti-inflammatory drugs, which partially relieved the symptoms. Several years before, systemic lupus eiythematosus (SLE) had been diagnosed in one of her sisters who had had similar complaints. Physical examination of this healthy-looking, white female revealed a typical butterfly rash on the face but no further skin abnormalities. Her blood pressure was 140/70 mm Hg supine and standing, and the pulse rate was 76 beats/mm and regular. She had no signs of anemia or edema. Oral and genital ulcers were absent as was lymphadenopathy. None of the joints showed signs of synovial swelling. Auscultation did not reveal a pleural or a pericardial rub but did disclose a systolic murmur, grade JI/VI, at the left fourth intercostal space and the apex. These findings suggested mitral valve insufficiency, which was confirmed on echocardiography. Further physical examination was unremarkable. Laboratory examination revealed a sedimentation rate of 106 mm/br; urea, 5.6 mmol/liter; creatinine, 91 mol/liter (1.0 mg/dl); and serum albumin, 29 g/liter. A 24-hour urine collection contained 1.29 g of protein. The urinary sediment contained 5—10 polymorphic erythrocytes/high-powered field and numerous hyaline and red blood cell casts. The hemoglobin was 6.1 mmol/liter; leukocytes, 3.0>< 109/liter; and thrombo-cytes, 222 X 109/liter. The LDH value was elevated to 372 U/liter. Liver function tests all were normal. An antiglobulin test was strongly positive, both with an anti-IgG and an anti-complement antiserum. Serologic examination showed a strongly positive homogenous ANA, with a positive Crithidia luciliae test indicating the presence of anti-dsDNA antibodies. The Farr assay was strongly positive, with 5000 U/mI. The C3 and C4 levels