However, others and we have shown that abrogating NET formation by genetically deleting or pharmacologically inhibiting NOX2 (19–27), peptidyl arginine deiminase, type IV (23, 84), and neutrophil elastase (85) exacerbated rather than ameliorated SLE phenotypes, or at best, had no effect. Here, PADI4 is linked to systemic lupus erythematosus.