IgG4-related Lung Disease Associated with Autoimmune Hemolytic Anemia: A Case Report and a Literature Review

We herein report a case of IgG4-related lung disease (IgG4-RLD) associated with autoimmune hemolytic anemia (AIHA). A 73-year-old Japanese female visited our hospital for an examination following an abnormal chest X-ray in 1999. She was diagnosed with bronchiolitis and AIHA, and treatment with prednisolone was started. After seven years, she visited our department due to a cough. Chest computed tomography (CT) demonstrated focal consolidation with ground-glass attenuations and thickened bronchial walls in the bilateral lungs. She was clinically diagnosed and treated for bronchial asthma. CT findings had shown no changes, and a lung biopsy was performed using video-assisted thoracic surgery at eleven years from the first diagnosis of AIHA. The pathological findings demonstrated the presence of peribronchovascular lymphoplasmacytic infiltrates with stromal fibrotic changes, admixed with many IgG4-positive plasma cells. Furthermore, the patient's serum IgG4 level was high, and her CT findings did not show any obvious abnormal findings in the any organs other than the lungs. She was diagnosed with IgG4-RLD based on the findings. We believe that this case report of IgG4-RLD associated with AIHA is clinically helpful for a better understanding of these diseases, although there are five reported cases of IgG4-related disease associated with AIHA.