NETs have been shown to occur in several inflammatory disease states, including lupus [28], sepsis [32,33] and cystic fibrosis [29-31] and are thought to serve as a means for PAD4 to enter into the extracellular space, where it may citrullinate substrates and exacerbate inflammation [9]. This evidence concerns the gene PADI4 and systemic lupus erythematosus.