Her CBC count and complete metabolic panel findings were normal except for a mild leukocytosis level of 14,000/mL. Her chest radiograph (Fig 1) and CT chest scan (Fig 2) are shown. Her erythrocyte sedimentation rate, C-reactive protein level, and autoimmune panel (antinuclear antibody [ANA], antineutrophil cytoplasmic antibody, double-stranded DNA [dsDNA], antitopoisomerase, Sjögren antibodies, rheumatoid factor, cyclic citrullinated peptide, smooth muscle, ribonucleoprotein, and histidyl tRNA synthetase) results were all normal. She tested negative for hepatitis and HIV. C1 esterase-inhibitor level was normal. Her α1-antitrypsin genotype was normal. Her complement levels were low, with a C3 level of 42 mg/dL (normal, 90-180 mg/dL), C4 level of 9 mg/dL (normal, 15-46 mg/dL), and C1q level < 3.6 mg/dL (normal, 5.0-8.6 mg/dL). Pulmonary function tests (PFTs) showed a very severe obstructive pattern (FEV1, 29%) with significant reduction in diffusion capacity of lung for carbon monoxide (6% corrected for hemoglobin). Echocardiogram findings were unremarkable except for mildly elevated right ventricular systolic pressure (35-40 mm Hg).