What is the primary inflammatory response in giant cell arteritis (GCA) (temporal arteritis)?

Updated: Sep 03, 2020
  • Author: Mythili Seetharaman, MD; Chief Editor: Herbert S Diamond, MD  more...
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The primary inflammatory response involves the activation of dendritic cells in the adventitia of arteries by an unknown antigen, with production of chemokines that recruit CD4+T helper cells. Activated CD4+ T helper cells polarize into Th1 cells (producing interferon gamma) and Th17 cells (producing interleukin 17).

Interferon gamma causes endothelial cells and vascular smooth muscle to recruit more Th1 cells, CD8+ T cells, and monocytes.The monocytes differentiate into macrophages and the characteristic giant cells that produce growth factors, other interleukins and proteolytic enzymes that progressively narrow and obstruct the vessel wall. [11] The inflammation tends to occur in a segmental or patchy manner, although long portions of arteries may be involved. [12]

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