ACTA1 and temporal arteritis: Parreau et al investigated the spatial distribution of fibroblasts across arterial layers of GCA and controls using immunohistochemical methods.108 A significant enrichment of myofibroblasts (CD90+α-SMA+) was observed in the adventitia and intima of GCA-TAs, correlating with the degree of hyperplasia.108 These were noted to form invading wells in areas of the damaged media.108 Myofibroblasts appeared to localise with inflammatory infiltrates108 and, given their proximity, interactions between these cell types are likely to occur.