title: Reduced immunoregulatory CD31+ T cells in patients with atherosclerotic abdominal aortic aneurysm.
abstract: BACKGROUND
  Cell-mediated immunity is considered to contribute to the pathogenesis of abdominal aortic aneurysms (AAA). In particular, infiltrating macrophages and CD8+ T lymphocytes participate in the destruction of the aortic wall extracellular matrix and smooth muscle cells. We surmise that these pathological events are controlled by circulating regulatory lymphocytes.
  
  
  RESULTS
  Circulating CD4+/CD31+ cells were reduced in AAA patients (n=80, 8.9+/-0.6%) as compared with controls (n=69, 13.7+/-0.8%; P<0.001) and inversely proportional to AAA size. Exclusion of the aneurysm by an endoprothesis did not affect CD31+ T cell values. Reduction of blood CD4+/CD31+ cells was not attributable to their enrichment in AAA tissue. In contrast, CD8+/CD31+ cells were slightly reduced in the blood while increased in the aneurysmal tissue (29.2+/-0.5 versus 20.2+/-4.7% in blood, n=6; P<0.05). Remarkably, high percentages of CD4+/CD31+ cells were able to regulate proliferation and cytokine production of CD8+ lymphocytes, as well as CD8+ cell-mediated cytotoxicity of aortic smooth muscle cells (P<0.01). Finally, CD4+/CD31+ cells reduced the production and activity of metalloproteinase-9 by lipopolysaccharide-stimulated macrophages.
  
  
  CONCLUSIONS
  Circulating CD4+/CD31+ T cells regulate macrophage and CD8+ T cell activation and effector function in the arterial wall. Their reduction might promote the development of AAA.
authors.affiliation: Institut National de la Santé et de la Recherche Medicale (INSERM), EMI0016, Paris, France. giuseppina.caligiuri@umrs681.jussieu.fr
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Caligiuri
authors.forename: Patrick
authors.initials: P
authors.lastname: Rossignol
authors.forename: Pierre
authors.initials: P
authors.lastname: Julia
authors.forename: Emilie
authors.initials: E
authors.lastname: Groyer
authors.forename: Dikran
authors.initials: D
authors.lastname: Mouradian
authors.forename: Dominique
authors.initials: D
authors.lastname: Urbain
authors.forename: Namita
authors.initials: N
authors.lastname: Misra
authors.forename: Véronique
authors.initials: V
authors.lastname: Ollivier
authors.forename: Marc
authors.initials: M
authors.lastname: Sapoval
authors.forename: Pierre
authors.initials: P
authors.lastname: Boutouyrie
authors.forename: Srini V
authors.initials: SV
authors.lastname: Kaveri
authors.forename: Antonino
authors.initials: A
authors.lastname: Nicoletti
authors.forename: Antoine
authors.initials: A
authors.lastname: Lafont
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000276:immunology* / Q000473:pathology; D050197:Atherosclerosis / Q000276:immunology* / Q000473:pathology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D008875:Middle Aged; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism*
chemical_list: D019408:Platelet Endothelial Cell Adhesion Molecule-1