[Pathogenesis of large vessel vasculitides]

Area of Science:

• Immunology
• Rheumatology
• Pathology

Background:

• Large vessel vasculitides include giant cell arteritis (GCA) and Takayasu arteritis (TAK).
• GCA typically affects individuals over 50, while TAK predominantly affects young women.
• Both are granulomatous arteritides impacting the aorta and its branches.

Purpose of the Study:

• To differentiate the distinct entities of GCA and TAK.
• To explore the underlying etiopathogenetic mechanisms and immune responses in GCA and TAK.
• To highlight clinical manifestations and diagnostic markers.

Main Methods:

• Comparative analysis of GCA and TAK based on age, affected vessels, and genetic associations.
• Review of immune cell infiltrates (T-helper cells, macrophages, CD8+ T-cells, γδ T-cells) in GCA and TAK.
• Examination of vascular remodeling processes, including intimal hyperplasia and fibrosis.

Main Results:

• GCA and TAK exhibit distinct human leukocyte antigen (HLA) associations and immune cell profiles.
• In GCA, CD4+ T-helper cells and macrophages dominate the inflammatory infiltrate.
• TAK involves CD8+ T-cells and γδ T-cells alongside other immune cells, suggesting different antigenic triggers.
• Both conditions lead to vascular remodeling, fibrosis, stenosis, and obstruction.

Conclusions:

• GCA and TAK are distinct large vessel vasculitides with unique HLA and potential etiopathogenetic backgrounds.
• Immune cell composition differs between GCA and TAK, indicating varied triggers.
• Clinical presentation includes inflammation-related symptoms, ischemia, and elevated inflammatory markers.