Review: What Is the Current Evidence for Disease Subsets in Giant Cell Arteritis?

Abstract

Giant cell arteritis (GCA) is an autoimmune vasculitis affecting large and medium-sized arteries. Ample evidence indicates that GCA is a heterogeneous disease in terms of symptoms, immune pathology, and response to treatment. In the current review, we discuss the evidence for disease subsets in GCA. We describe clinical and immunologic characteristics that may impact the risk of cranial ischemic symptoms, relapse rates, and long-term glucocorticoid requirements in patients with GCA. In addition, we discuss both proven and putative immunologic targets for therapy in patients with GCA who have an unfavorable prognosis. Finally, we provide recommendations for further research on disease subsets in GCA.

Figure 1

Overview of immune pathology of giant cell arteritis (GCA). Immune cells and cytokines involved in the arterial inflammatory process of GCA and the relationship of these cells and cytokines with disease outcomes in GCA are shown. PAMP = pathogen‐associated molecular pattern; DAMP = damage‐associated molecular pattern; DC = dendritic cell; IL‐12 = interleukin‐12; VEGF = vascular endothelial growth factor; IFNγ = interferon‐γ; EEL = external elastic lamina; VSMCs = vascular smooth muscle cells; TNF = tumor necrosis factor; ELS = ectopic lymphoid structure; HEV = high endothelial venule; IEL = internal elastic lamina; PDGF = platelet‐derived growth factor; ET‐1 = endothelin 1; PTX3 = pentraxin 3.