Fig. 5

Representative matched pairs of patients. A, B A 63-year-old male with fibrotic bird-related hypersensitivity pneumonitis was treated with prednisolone from baseline until the end of the follow-up period at 60 months. At baseline, the patient’s %FVC was 57.9%, his annual %FVC decline before treatment was 26.1%, and his BAL lymphocyte count was 29%. At the 1-year follow-up, the change in %FVC from baseline was + 15.9%. A reduction in the extent of GGA with minimal fibrotic progression was observed on HRCT after one year. The total scores for the HRCT findings (baseline to the 1-year follow-up) were as follows: GGA (22 to 14), consolidation (2 to 0), reticulation (12 to 13), traction bronchiectasis (6 to 8), honeycombing (13 to 14), and mosaic attenuation (2 to 0). C, D A 66-year-old male with fibrotic bird-related hypersensitivity pneumonitis did not undergo treatment with corticosteroids and died at 17 months. At baseline, his %FVC was 46.6%, and his annual FVC decline until the date of diagnosis was 4.7%. At the 1-year follow-up, the change in %FVC from baseline was − 12.3%. Severe fibrotic progression was observed on HRCT. The total scores for the HRCT findings were as follows: GGA (11 to 18), consolidation (5 to 6), reticulation (16 to 19), traction bronchiectasis (10 to 15), honeycombing (14 to 19), and mosaic attenuation (0 to 0). BAL bronchoalveolar lavage; %FVC percent forced vital capacity; GGA ground glass attenuation; HP hypersensitivity pneumonitis; HRCT high-resolution computed tomography