IgG4-Related Arterial Disease

Immunoglobulin G4-related diseases (IgG4-RD) are systemic inflammatory conditions, characterized by high serum IgG4 concentrations, and pathologically IgG4-positive plasmacytes infiltrations and storiform fibrosis. We described IgG4-related inflammatory abdominal aortic aneurysm in 2008, and revealed the existence of vascular lesions. IgG4-related vascular lesions frequently occur in the aorta and branching medium-sized arteries with or without aneurysmal change. The inflammatory lesion mainly involves in the adventitia, indicating remarkable adventitial fibrous thickening with infiltration of inflammatory cells. Clinical symptoms associated with IgG4-related vascular lesions might be fever, abdominal pain, hydronephrosis, or few subjective symptoms. Comprehensive diagnostic criteria is applied according to image findings of thickening lesions, high serum IgG4 levels, and histopathological findings. As a treatment, open surgical repair or endovascular aneurysm repair is performed for the aneurysmal cases, and steroid administration is used for the cases with strong inflammation. This disease can lead to a lethal situation due to the rupture following aneurysmal formation, thus special attention is needed unlike IgG4-RD occupying in the other organs.