title: Predominance of Th2 response in human abdominal aortic aneurysm: mistaken identity for IL-4-producing NK and NKT cells?
abstract: Abdominal aortic aneurysm (AAA) is a complex remodeling process that involves both synthesis and degradation of extracellular matrix proteins in the aortic wall, leading to decreased tensile strength, progressive dilation and eventual rupture. Chronic inflammation, increased local production of elastin-degrading proteases by inflammatory cells and destruction of medial elastic lamellae play important roles in aneurysm progression. Neovascularization in all layers of the arterial wall is prominent and angiogenesis can facilitate chronic inflammation. It is still unclear what initiates aneurysmal dilation and what determines its progression. The complex nature of the process has defied elucidation. Apart from macrophages, the predominant immune cell infiltrates reported so far are CD3(+)T cells that express CD4 and CD8. Infiltrates of type 2 Th cells and their production of IL-4 and IL-5 have been implicated in AAA development. However, NKT and NK cells have a Th0 cytokine profile and can also produce type 2 as well as type 1 (IL-2 and IFNgamma) cytokines. We have demonstrated the presence of NK and NKT cells in AAA tissue. With their growing importance in autoimmunity and transplantation, they may play a role in AAA development. Therefore, there is a need to use a combination of T and NK markers to fully characterize both innate and adaptive lymphoid cell subsets in local inflammatory infiltrates in order to elucidate their roles in AAA progression.
authors.affiliation: Biochemical Pharmacology, William Harvey Research Institute, John Vane Science Centre, Queen Mary, University of London, Charterhouse Square, London, EC1M 6BQ, UK. w.l.chan@qmul.ac.uk
authors.forename: Woon Ling
authors.initials: WL
authors.lastname: Chan
authors.forename: Nada
authors.initials: N
authors.lastname: Pejnovic
authors.forename: Tze Vun
authors.initials: TV
authors.lastname: Liew
authors.forename: Hamish
authors.initials: H
authors.lastname: Hamilton
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D006801:Humans; D015847:Interleukin-4 / Q000096:biosynthesis*; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism*; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D015847:Interleukin-4