MTOR and systemic lupus erythematosus: mTOR signaling activation was discovered in SLE and attracted attention as a therapeutic target.[15] Rapamycin, a mTOR inhibitor, was first reported as a new therapeutic strategy for SLE in animal models and patients.[4] Recent study demonstrated that rapamycin could improve disease activity in active SLE patients for 12 months treatment.[7] However, there are fewer studies of sirolimus in cSLE.