BTG3 and Pulmonary hemorrhage: Multiple investigations to identify the systemic causes of pulmonary hemorrhage were performed, including ANA, double-stranded DNA antibody, rheumatoid factor quantitative index (RF QI), endomysial antibody, c-ANCA, P-ANCA, antiphospholipid immunoglobulin M (APL IgM), anti-GBM IgG, and anti-tissue transglutaminase (anti-tTG) IgA, which were all negative.