A 47-year-old white woman came to the clinic complaining of dyspnea on exertion for the past few weeks. She had a cough with scanty whitish expectoration during the first week of her illness. She had rheumatoid arthritis (RA) for 34 years, and had been treated with corticosteroids, methotrexate, infliximab, and etanercept. Her condition had been stabilized for the past 5 years. Her medical history included thalassemia, gastroesophageal reflux disease, hypertension, hysterectomy, and bilateral knee replacements. Her medications included lisinopril and prednisone, 10 mg/d. Family history was not significant. The patient did not smoke and had not been exposed to any organic or inorganic dusts and fumes.