[Clinical features of IgG4-related lung disease]

Objective: To explore the clinical features of IgG4-related lung disease. Methods: The clinical data of 60 patients diagnosed with IgG4-related lung disease in Peking University People's Hospital from February 2012 to May 2021 were retrospectively collected. Analysis was made to explore the features of clinical manifestation, laboratory, imaging, prognosis and other characteristics of the disease. Results: A total of 60 patients were included, with 40 males, age of (58.2±12.9) years, an age of onset of (57.1±13.2) years, and 31.7% (19 cases) of the patients had a history of allergic disease. 36.7% (22 cases) of the patients had respiratory symptoms during the disease. 94.6% (53/56) of patients had serum IgG4>1.35 g/L, 24.1% (14/58) of patients had increased eosinophils, 79.2% (38/48) of patients had increased IgE level, and 53.7% (29/54) of patients had decreased C3 or C4. Common imaging findings included nodular changes (38 cases, 63.3%), mediastinal and/or hilar lymphadenopathy (34 cases, 56.7%), and ground glass opacities (31 cases, 51.7%). Fifty-three cases (88.3%) showed two or more imaging changes. The pathological examination of the patient was mainly characterized by lymphoplasmacytic infiltration and fibrosis, with only one case of phlebitis obliterans. Compared with the asymptomatic group (38 cases), patients with respiratory symptoms (22 cases) showed higher level of serum total IgG and eosinophils (43.2 vs 17.8 g/L, 0.30×10⁹/L vs 0.14×10⁹/L, P<0.05), lower proportion of allergic diseases, and higher proportion of consolidation shadows on chest CT (P<0.05). There were no significant differences in serum IgG4, IgE, complement levels, and imaging outcomes after treatment between the two groups (P>0.05). Conclusions: The clinical manifestations of IgG4-related lung disease are atypical, and asymptomatic patients account for a high proportion. The imaging of the disease is highly heterogeneous, and patients are prone to show coexisted multiple imaging changes. The main clinical features and imaging outcomes of patients with and without respiratory symptoms are not significantly different.