The Concept of IgG4-related Disease and Clinical Significance of IgG4-related Cardiovascular Disease

Abstract

IgG4-related disease (IgG4-RD) is a recently established disease concept closely associated with elevated serum concentration of IgG4 and abundant IgG4-bearing plasma cell infiltration within affected tissues. The characteristic features of IgG4-RD can be summarized as follows: (1) systemic organ involvement; (2) the ability to involve multiple organs either simultaneously or in a metachronous fashion; (3) imaging findings of swelling, nodules, or increased organ wall thickness; (4) elevated serum IgG4 concentrations; (5) lymphoplasmacytic infiltrate within affected organs, characterized by abundant IgG4-bearing plasma cells; and, (6) favorable response to glucocorticoid therapy in most cases. IgG4 related cardiovascular diseases had been detected during systemic image analysis of other IgG4-RDs, such as autoimmune pancreatitis, and pathological evaluation of surgical specimens, such as aneurysm. At the beginning, these lesions had been recognized as wall thickening of abdominal aorta, and included in the spectrum of retroperitoneal fibrosis. Later, it was evident that these lesions showed systemic vascular distribution, such as thoracic aorta, coronary artery and iliac artery, which resulting in the proposal of the concept of IgG4 related cardiovascular diseases. Extensive studies have been done mainly by 2 approaches, pathological evaluation of surgical specimens and imaging analysis of cases with IgG4-related diseases.