IL23A and temporal arteritis: Further, cytokines such as IL-12 and IL-23, produced by resident and infiltrating immune cells in GCA-arteries, significantly increased myofibroblast outgrowth ex-vivo.109 These data imply that various cytokines are involved in promoting this invasive myofibroblast phenotype observed in GCA-lesions.109 However, the cell type of origin of myofibroblasts is unclear as they might derive from VSMCs, fibroblasts or both.