BAX and systemic lupus erythematosus: Chchd2 protein is a negative regulator of mitochondria‐mediated apoptosis, its down‐regulation increases the presence of Bax protein in the mitochondria‐enriched heavy membrane fraction, producing a strong apoptotic effect.43 The enzyme indoleamine 2,3‐dioxygenase 1 (IDO1) regulates immune responses to arrest inflammation and suppresses immunity through catabolism of tryptophan.44 In particular, IDO1 dysregulation has been documented in patients with SLE.45 Thus, the low expression levels of IDO1 in hiPSCs‐SLE could be a definite cause of an abnormal activation of the immune response.