CXCL8 and hyperinsulinemic hypoglycemia, familial, 4: For example, Rora deficiency in mast cells and macrophages leads to increased production of TNF‐α and IL‐6 upon activation,[46] whereas ectopic expression of RORα1 in human primary smooth muscle cells suppresses TNF‐α‐induced expression of IL‐6, IL‐8, and COX‐2 through upregulation of the inhibitory protein IκBα.[47] Proinflammatory roles of RORA have also been reported in various cell types.[48, 49]