Frequency of immunoglobulin G4-related aortitis in cases with aortic resection and their clinical characteristics compared to other aortitises

Aims To identify the frequency of immunoglobulin G4 (IgG4)-related aortitis in patients who undergo aorta surgery and are diagnosed by pathology as having chronic aortic inflammation and to compare IgG4-related aortitis with other non-infectious aortitises in terms of clinical characteristics. Methods The aorta specimen pathological reports of 1418 patients who underwent aortic aneurysm or dissection surgery were reviewed. In total, 41 had chronic aortic inflammation without atherosclerosis, cancer or infection. Their aorta biopsy specimens were subjected to IgG4 immunostaining. IgG4-related aortitis was diagnosed if the IgG4-positive plasma cell count exceeded 50 per high power field (HPF), the ratio of IgG4-positive to IgG-positive plasma cells exceeded 50% and dense lymphoplasmacytic infiltration, fibrosis and/or obliterative phlebitis were observed. Results Of the 41 non-infectious aortitis cases, 29, six and six had idiopathic aortitis, Takayasu's arteritis and Behcet's aortitis, respectively. Of the 29 idiopathic aortitis cases, three had IgG4-related aortitis. All were male and >65years of age. Two had thoracic aortic aneurysms and one had an abdominal aortic aneurysm. Their IgG4-positive plasma cell counts were 60/HPF or higher; lymphoplasmacytic infiltration and/or fibrosis, but not obliterative phlebitis, were observed. The IgG4-related aortitis cases were older (67 [range, 65-69] years) than the Takayasu's arteritis (47.5 [38-58] years) or Behcet's aortitis (47 [31-56] years) cases and more likely to be male than the Takayasu's arteritis cases (100% vs. 17%). Conclusion In patients with chronic aortic inflammation, 7% had IgG4-related aortitis. This disease may be more common in older male patients than in other demographic groups.