STING1 and systemic lupus erythematosus: The observation that defects of the cytosolic exonuclease TREX1 cause monogenic cGAS/STING-driven AGS and are associated with SLE extended the concept of DNA waste disposal to the cytosolic and/or nuclear compartments and raised questions about nature and origin of the immunogenic TREX1 DNA substrates that trigger disease in the absence of the nuclease.