Bronchoscopy with BAL (culture, cytology, polymerase chain reaction) and bronchial biopsy specimens did not reveal abnormalities. There was no evidence of infection following blood and sputum cultures and serologic screening. Autoimmune screening revealed antinuclear antibody positivity (1/160, negative Farr assay, negative extractable nuclear antigens, including Ro/SSA and La/SSB antibodies), and low complement factors (C3, 0.60 g/L [normal range, 0.79-1.52 g/L]; C4, 0.03 g/L [normal range, 0.16-0.38 g/L]). Tests for antineutrophil cytoplasmic and antiglomerular basement membrane antibodies, rheumatic factor, and cryoglobulin level were negative. Kininase II was within normal levels, and no paraprotein was identified in urine or blood. A lip biopsy specimen and Schirmer test results were negative.