Background: A wide variety of systemic lesions have been seen in patients with autoimmune pancreatitis. The pulmonary involvement of autoimmune pancreatitis was analysed to clarify the clinicopathological features of pulmonary lesions in comparison with pulmonary sarcoidosis.
Materials and methods: Nineteen patients had autoimmune pancreatitis and eight had pulmonary sarcoidosis. The symptoms, laboratory data, chest computed tomography, Gallium-67 scintigraphy, pulmonary function testing and bronchoscopy findings, including the histological IgG4-immunostaining and IgG subclasses in the bronchoalveolar lavage in autoimmune pancreatitis, were collected to compare them with pulmonary sarcoidosis.
Results: The serum total protein, IgG and IgG4 levels were found to be significantly elevated in comparison with pulmonary sarcoidosis. In autoimmune pancreatitis, 17 patients showed bilateral hilar lymphadenopathy, while eight showed pulmonary nodules on chest computed tomography. Eighteen of 19 patients on Gallium-67 scintigraphy showed accumulation spots in either the hilar or mediastinal lymph nodes. Six patients with pulmonary nodules demonstrated accumulation spots in the corresponding lesions on chest computed tomography. All eight patients with pulmonary sarcoidosis showed accumulation spots in either the hilar or mediastinal lymph nodes. Bronchoalveolar lavage IgG4 in autoimmune pancreatitis showed a significant increase in comparison with pulmonary sarcoidosis. The histological findings obtained by a transbronchial lung biopsy showed the infiltration of lymphocytes and plasma cells in the thickened interstitum and alveoli with IgG4-positive plasma cell infiltration in patients with autoimmune pancreatitis.
Conclusion: IgG4 in the bronchoalveolar lavage was seen at remarkably increased levels and IgG4-positive plasma cells were identified in the pulmonary lesions of patients with autoimmune pancreatitis.