A 30-year-old woman manifested fatigue and high fever. She was diagnosed with antiphospholipid antibodies positive-systemic lupus erythematosus (SLE), but she had never demonstrated any serious organ involvements including nephritis and thrombosis, and had never received immunosuppressants. Physical examination demonstrated costovertebral tenderness and pyuria, and she was treated with cefaclor for uncomplicated pyelonephritis. After ten days, she visited our emergency room with the same manifestations and was improved equally by cefaclor.
