IgG4-related disease with tracheobronchial miliary nodules and asthma: a case report and review of the literature

BACKGROUND: IgG4-related disease (IgG4-RD) is a systemic autoimmune disease that can affect multiple organs of the body. Pulmonary manifestations of IgG4-RD include pulmonary solid nodules, thickening of bronchovascular bundles, interstitial involvement, and ground glass opacities. Here we present a rare case of IgG4-RD with tracheobronchial nodules and review the relevant literature. CASE PRESENTATION: A 52-year-old man was admitted to our hospital with a history of intermittent cough for 27 months and recurrent wheezing for 17 months. He had been diagnosed with asthma prior to admission and was responsive to oral prednisone (30 mg/day, with gradual tapering). Bronchoscopy performed 2 years prior to admission showed tracheal and bronchial mucosal hyperemia, edema, and miliary nodules. Pathological tests showed chronic inflammation with focal lymphocytic infiltration in the bronchial mucosa. The patient had recurrent cough and wheezing after prednisone was stopped or the dose reduced. At the time of admission to our hospital, his serum immunoglobulin G4 (IgG4) level had increased to 7.35 g/L. Following bronchoscopy, the IgG4 expression in the bronchial mucosa was compared with that observed during the last two bronchoscopies. Bronchoscopy performed 7 months prior to admission revealed IgG4+ plasma cell infiltration in the bronchial tissue, with > 10 IgG4+ plasma cells per high power field and an IgG4+/IgG+ cell ratio of > 40%. The current bronchoscopy revealed a decrease in IgG4 expression in the bronchial tissue, probably because of the intermittent prednisone treatment. The case fulfilled the comprehensive clinical diagnostic criteria for IgG4-RD. He received prednisone and azathioprine, and he has never developed recurrence. CONCLUSIONS: Our case exhibited three important clinical indication: First, tracheobronchial miliary nodules could be the presentation of IgG4-related disease. Second, IgG4-related disease with pulmonary involvement has close connection with asthma. Last, IgG4-related disease can be very sensitive to prednisone, the infiltration of IgG4 positive plasma cells decreased after prednisone treatment and symptoms significantly improved in our case. In conclusion, we reported the first case of IgG4-RD presenting with miliary nodules on the tracheal and bronchial tube walls combined with asthma. The findings will further our understanding of the characteristics of IgG4-RD.