A 67-year-old man with diabetes mellitus, chronic cystitis and hematuria was given 2 units of packed red blood cells because of severe iron-deficiency anemia (hemoglobin 54 g/L). Although he was pale, a physical examination on admission revealed normal vital signs. Following the transfusion, the patient was feeling well, and his vital signs were unchanged. Forty minutes after the second unit of red blood cells was transfused, the patient experienced a sudden onset of dyspnea, tachypnea (34 breaths/min), cyanosis, fever, profuse diaphoresis and hypoxemia (oxygen saturation < 75%). The patient's blood pressure was 150/80 mm Hg, and his temperature was 38.7°C. His breath sounds were markedly decreased, and chest auscultation revealed bilateral diffuse crackles. There were no signs of volume overload, and his jugular venous pressure was normal. An electrocardiogram appeared normal, and the test results for troponin and kidney function were within the normal range. A chest radiograph showed coarse alveolar infiltrates and a normal cardiac silhouette (Figure 1), which is the radiographic hallmark of noncardiogenic pulmonary edema. A CT scan showed diffuse edema and inflammatory consolidation of both lungs (Figure 2). The patient remained unstable, with a urine output of 250 mL in the 5-hour period after diuretics were administered; nitroglycerin and steroids were given, and mechanical ventilation was started. Fluid was not aspirated from the patient's lungs when his trachea was intubated. The patient's condition slowly improved, and he achieved a full recovery over the next 6 days. Blood transaminase levels peaked on the second day (alanine transaminase 1123 U/L; aspartate transaminase 875 U/L) and returned to normal on the fourth day; bilirubin levels remained normal. Six days later, both a chest radiograph and a CT scan showed the patient's lungs to be clear. The plasma from the 2 donors and the recipient was not assayed for anti-human leukocyte antigen (HLA) or anti-leukocyte antibodies. HLA typing of the recipient was not performed.