Coronary artery disease concomitant with immunoglobulin G4-related disease: a case report and literature review

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune condition associated with high serum IgG4 levels which was first reported as autoimmune pancreatitis in 2001. Since then, many additional organs, such as bile duct, salivary gland, retroperitoneal organs, and liver, have been reported with high serum IgG4 levels in cases of IgG4-RD. However, evidence of the relationship between IgG4-RD and coronary artery disease (CAD) has been scare. Here, we report a case of CAD concomitant with IgG4-RD. CASE SUMMARY: A 74-year-old man was referred to our hospital with a chief complaint of chest pain and was admitted. The patient was found to have had a myocardial infarction with ST-segment elevation and underwent an emergent percutaneous coronary intervention. Owing to a rapidly increased blood glucose level, computed tomography was performed and showed autoimmune pancreatitis. An elevated serum level of IgG4 led to a diagnosis of IgG4-RD involving acute coronary syndrome (ACS). DISCUSSION: Cardiac involvement in IgG4-RD has been reported; however, cases of ACS concomitant with IgG4-RD are rare. Our report suggests that CAD, specifically ACS, can coexist in patients with IgG4-RD. Therefore, cases of concomitant CAD and IgG4-RD should be accurately diagnosed and evidence should be collected to elucidate the mechanism and characteristics of this condition.