To summarize the clinical features, diagnosis and treatment experience of IgG₄-related lung disease for the sake of improving clinical understanding of this disease and reducing the misdiagnosis and mistreatment rates.

To analyze the general situation, clinical manifestation, laboratory examination, histopathology, therapy and prognosis of 2 patients with IgG₄-related lung disease, who were admitted in the department of respiratory diseases at Changhai Hospital. Publications related to IgG₄ lung disease were reviewed.

Both patients were male with elevated serum IgG₄ level (2.25 g/L and 10 g/L respectively). In one patient, radiologic finding showed solid nodules in the lung with ileocecal involvement. He responded well to glucocorticoid. The other patient's computed tomography of lung demonstrated bronchovascular type. Glucocorticoid therapy was effective to both patients. A total of 69 cases with IgG₄-related lung disease were reported worldwide, among whom 39 cases were admitted with chief complaints of respiratory symptoms. However, there were 41 cases suffering extra-pulmonary involvement. Serum IgG₄ levels detected in 48 cases were significantly elevated (307-52 500 mg/L). The radiographic pattern of solid nodule type was the most frequent, accounting for 50.7% (35 cases). A total of 31 (44.9%) patients received glucocorticoid therapy with good response and prognosis.

IgG₄-related lung disease is a rare immunological disease lack of specific symptoms. Serum immunological examination, radiographic characteristics and histopathology should be comprehensively considered for diagnosis. Glucocorticoid is so far the most acceptable therapy with good response rate.

IgG₄-related disease; Lung diseases; Immunoglobulin G