Recently, further cell subtyping in GCA identified the spatial distinction of CD206+/YKL-40+/MMP-9+ macrophages, engaged in tissue damage and situated in the media and damaged elastic lamina, and FRβ+/CD206− macrophages resided in the adventitia and intima, responsible for wall fibrosis and intimal hyperplasia [43]. Here, MMP9 is linked to temporal arteritis.