Immunohistochemical Interplay in Associated Large Vessel Vasculitis and consequent Ascending Aortic Aneurysm and Review of Literature

Abstract

Large vessel vasculitis (LVV), such as giant cell arteritis (GCA) and Takayasu’s arteritis (TA), are autoimmune diseases characterized by granulomatous inflammation of large vessels, including the aorta and its branch vessels. Disease etiology is still unknown. Comparative immunohistochemical (IMH) studies between GCA and TA cases might be important. The purpose of the study was to assess and to compare composition and distribution of the inflammatory infiltrate of the ascending aortic aneurysmal wall. Ascending aortic aneurysm (AAA) tissue blocks belonging to one male patient of 59 years and one female patient aged 36 years, diagnosed with GCA and TA, respectively, were used for histological and IMH analysis. Immunohistochemistry staining was performed using antibodies directed against markers of lymphocytes and macrophages. Histological analysis showed in both cases lymphocytes, macrophages, epithelioid histiocytes and multinucleated giant cells that infiltrate all layers of the arterial wall, intimal hyperplasia and adventitial fibrotic changes of different degrees. Immunohistochemical examination showed that the media and adventitia from GCA aortitis case had increased number of T cells and macrophages compared with TA aortitis case, and a less number of B cells in both. Our study made a morphologic and morphometric analysis of lymphocyte infiltration within aneurysm aortic tissue and demonstrated that immune inflammation is a typical feature of GCA and TA diseases. We also noted the utility of immunohistochemical staining of the aortic biopsies for evaluation of indeterminate or healing GCA and TA cases. Keywords: immunohistochemical, granulomatous inflammation, aortic aneurysm, large vessel vasculitis