Distinctive Pulmonary Histopathology With Increased IgG4-positive Plasma Cells in Patients With Autoimmune Pancreatitis

Autoimmune pancreatitis (AP) is one manifestation of a systemic, steroid-responsive disease with elevated serum IgG4 and characteristic histopathology, including increased IgG4-positive (+) plasma cells in the tissue. The histopathology of pulmonary IgG4 disease has not been well established. Six lung biopsies from patients with documented AP were studied, along with 12 additional cases showing similar pulmonary histopathology. For comparison,...