As the expression of hypoxia-inducible factor (HIF)-1α and HIF-2α was constitutively detected in Mos recruited to inflamed joints in JIA patients, the ability of these key regulators to alter metabolic reactions and protein transcription potentially impacts the activation and polarization of Mos/Mφs in JIA [85]. Here, EPAS1 is linked to juvenile idiopathic arthritis.