Amyloidosis can occur in association with a series of other processes, including connective tissue disease; amyloid deposition has been found in rheumatoid arthritis, dermatomyositis, scleroderma, and periarteritis nodosum. But among the many cases published only four authors describe systemic lupus erythematosus (SLE) and amyloidosis (1-4). We report a case of association of SLE and amyloidosis in a patient in whom radiologic and serologic findings compatible with ankylosing spondylitis were discovered.Case report. JFR, a 62-year-old white woman, was admitted to the hospital with acute pyelonephritis. Her history was not significant except for isolated episodes of noninflammatory arthralgia of the large joints with morning stiffness for the last 25 years, occasional Raynaud's syndrome of both hands, and more recently, mild congestive heart failure. Physical examination on admission revealed mild congestive heart failure and tenderness on deep pressure in both costovertebral areas; blood-pressure was 130/70 mm Hg, pulse 85 and regular, temperature 38.4OC; chest x-ray film showed basal platelike atelectasis, diaphragmatic elevation, and a widened left costophrenic angle. Hemoglobin was 6.5 gm/ 100 ml; there was anisopoikilocytosis; WBC was 10,100; differential showed 3 1% stab neutrophils; sedimentation rate was 83 mm/hour; serum iron was 18 pg/ 100 ml and iron-binding saturation 13%. BUN was 49 mg/100 ml, creatinine 2.1 mg/100 ml with an endogenous creatinine clearance of 23.6 ml/minute; urine sediment showed 50 leukocytes and 5 erythrocytes per high power field. Electrolytes, fasting blood sugar, SGOT, SGPT, LDH, lipids, bilirubin, coagulation tests, ECG, barium meal and enema, and an intravenous pyelogram were normal. Serum protein electrophoresis showed a broad-based increase in the gammaglobulin (22 gm/ liter) and a decrease in the albumin (21 gm/liter) region; immunoglobulin A and M were normal, but IgG was 2560 mg/100 ml (normal: 600-1500 mg/100 ml); proteinuria oscillated between 1960 and 7530 mg/liter. Blood and urine cultures were positive for E coli and treatment with trimethoprine-sulfametoxazole was begun. A bone marrow examination showed a decreased red cell series, 1% sideroblasts, and decreased reticuloendothelial iron; a search for occult bleeding from the gastrointestinal tract was slightly positive once and negative on two occasions; we were unable to explain further the cause of this iron deficient anemia. Antinuclear antibodies were positive at 1/2000 and exhibited a speckled pattern; anti-DNA antibodies were positive at 1 /200 (by radioimmunoassay); rheumatoid factor, cryoglobulins, and the LE-cell phenomenon were positive; syphilis serologic tests, cryofibrinogen, Coombs test, and antimuscle antibodies were negative; serum complement was reduced to a C'3 of 32 mg/100 ml (normal: 80-140), C'4 of 8 mg/100 ml (normal 20-50) and CH50 of 100 units (normal: 400-700). A kidney biopsy revealed by optic microscopy extensive renal amyloidosis and lesions suggestive of necrotizing arteritis; glomerula...