When we searched for autoantigens targeted by SLE serum in in vivo IFN-activated neutrophils from patients with SLE, we were struck by the finding that Ro52 is a prominent IFN-induced autoantigen in SLE neutrophils that is absent or minimally detected at the protein level in both healthy control and steady-state SLE neutrophils. The gene discussed is TRIM21; the disease is systemic lupus erythematosus.