CGAS and systemic lupus erythematosus: A recent paper provided the first direct evidence that the cGAS pathway is activated in at least a subset of SLE patients: the second messenger cyclic-guanine, adenosine-2,3-phosphate (cGAMP), which is synthesized exclusively by cGAS upon DNA binding, was detected by mass spectrometry in 7 of 30 SLE patients (71).