Increased serum IgG4 levels and intimal IgG4-positive cell infiltration in rapidly growing aortic aneurysm

A 67-year-old Japanese man had been complaining of discomfort in the chest and back and feeling febrile for 2 weeks. Chest computed tomography indicated a thoracic aortic aneurysm. He occasionally showed a high fever (up to 38.0°C), even after hospital admission, irrespective of antibiotic therapy. The patient was found to have elevated serum IgG4 levels (366 mg/dL). The aneurysm demonstrated rapid growth; therefore, rifampicin-soaked woven...