ObjectiveTo summarize the clinical characteristic of IgG4 related lung disease. MethodsThe clinical manifestation,laboratory examination,imaging,diagnosis and treatment data of 2 patients with IgG4 related lung disease admitted in the PLA General Hospital from January 2000 to January 2014 were collected and analyzed retrospectively.Related literatures were also reviewed. ResultsThe serum IgG level of IgG4 related lung disease might be normal and the levels of IgG1,2,3 and 4 might increase.Some autoantibodies were positive.IgG4 related lung disease could be easily misdiagnosed as Sjogren's syndrome associated with interstitial pneumonia when the lacrimal gland and salivary gland were involved,and the chest CT occasionally showed multiple vesicles.The immunochemical staining of lung tissues revealed the increase of IgG4/IgG and the number of IgG4 positive lymphatic plasma cells >10/HP.The combination of clinical manifestation,laboratory examination,imaging and pathology results was more conducive for the diagnosis of IgG4 related lung disease.After the treatment of glucocorticoid,the clinical symptoms were relieved and the serum IgG4 level obviously decreased. ConclusionIgG4 related lung disease is rare in clinic,which can involve the lung alone or multiple organs.The increase of IgG4/IgG indicated by the immunochemical staining of lung tissues is the gold standard for diagnosis.Glucocorticoid has good treatment effect in IgG4 related lung disease.