Review Question - QID 108496

A 32-year-old man presents to the emergency room with difficulty breathing and reports that he has had a productive cough for a few days. He has not had any fevers. He has no recent travel, has never smoked, and does not report any recent chills, weight-loss or night-sweats. He is married and monogamous, and denies any history of drug use. He notes that the color of his urine "does not look normal". On physical exam, his temperature is 98.8°F (37.1°C), blood pressure is 127/84 mmHg, respirations are 21/min, and pulse is 105/min. His pulmonary exam is remarkable for bilateral rales, and the tissues he is coughing into are covered in blood-tinged sputum. Chest radiograph shows bilateral infiltrates. His creatinine is 3.4 mg/dL, and urinalysis is positive for red blood cells.

Renal biopsy reveals crescentic glomerulonephritis, and the photograph provided (see Figure A) shows the result of the immunofluorescence study. The patient is then treated with emergency plasmapheresis. Which of the following diseases is most similar in pathophysiology to the patient's disorder?