A 53-year-old male smoker, unemployed with no occupational exposure, is admitted with progressive shoness of breath. He has been unwell for some time and has received multiple courses of antibiotics for "bronchitis." During the prior 4 mo, he has not had any medical follow-up. On exam, he is afebrile but looks ill. Lung exams reveal diffuse rhonchi and crackles with no localizing signs. ABGs on room air show PaO2 of 68 mm Hg with mild compensated respiratory alkalosis. Sputum for AFB is negative. CXR is shown.Associated with this diagnosis is