An elevated IgG4 response in chronic infectious aortitis is associated with aortic atherosclerosis.
Recently, it was shown that infectious bacterial aortitis can stimulate an elevated IgG4⁺ plasma cell response in the vessel wall, which could mimic IgG4 aortitis/periaortitis. However, the factors that are associated with an elevated IgG4⁺ plasma cell response in infectious aortitis are unclear. To ascertain these factors, 17 cases of infectious aortitis and 6 cases of non-infectious severe abdominal aortic atherosclerosis were assessed for the magnitude of IgG4⁺ plasma cell response. The degree of IgG4⁺ plasma cell infiltration was determined by immunohistochemistry. Infectious cases were subcharacterized as chronic (>3 weeks duration) or acute (<3 weeks duration) based on the duration of symptoms, and as involving either the ascending aorta or the distal aorta, ie, the descending thoracic and/or abdominal aorta. There was a 5-16-fold greater degree of IgG4⁺ plasma cell infiltration in the chronic distal infectious aortitis group compared with the other three infectious aortitis groups (P ≤ 0.0007), and compared with non-infectious severe abdominal aortic atherosclerosis (P<0.0008). This resulted in a greater IgG4/IgG ratio in the chronic distal infectious aortitis group compared with the acute ascending and acute distal infectious aortitis groups (P<0.03). The degree of IgG4⁺ plasma cell infiltration in chronic distal infectious aortitis overlaps with that seen in the aortitis and periaortitis of IgG4-related disease. In the chronic infectious aortitis cases, the degree of IgG4⁺ plasma cell infiltration was more intense in patients with moderate to severe aortic atherosclerosis compared with those patients with less aortic atherosclerosis (P=0.007). These findings indicate that an elevated IgG4⁺ plasma cell response occurs in the descending thoracic and abdominal aorta in the setting of chronic bacterial infectious aortitis and pre-existing atherosclerosis. This inflammatory response to chronic infection in atherosclerosis-laden aortas may have implications for the development of IgG4-rich inflammatory atherosclerotic aortic aneurysms.
Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Zakir
Z
Siddiquee
Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
R Neal
RN
Smith
Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.|Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA.
James R
JR
Stone
D000368:Aged; D001011:Aorta / Q000473:pathology; D001025:Aortitis / Q000209:etiology* / Q000276:immunology*; D050197:Atherosclerosis / Q000150:complications / Q000276:immunology*; D001424:Bacterial Infections / Q000150:complications / Q000276:immunology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000473:pathology
D007074:Immunoglobulin G