MTOR and systemic lupus erythematosus: Sirolimus, an inhibitor of the mammalian target of rapamycin (mTOR), has been implicated in the pathogenesis of SLE.[16] Emerging studies have demonstrated the efficacy and safety of sirolimus as a novel immunosuppressant for SLE and LN.[17, 18, 19] However, no comparative studies have directly evaluated sirolimus against the SoC for LN patients.