Since PAD4 is essential for the formation of NETs (Li et al., 2010; Hemmers et al., 2011), PAD4 has also been implicated in NET-related pathologies, such as SLE and thrombosis, where NETs presumably promote deleterious inflammatory responses (Kessenbrock et al., 2009; Logters et al., 2009; Fuchs et al., 2010; Hakkim et al., 2010; Garcia-Romo et al., 2011; Villanueva et al., 2011). This evidence concerns the gene PADI4 and systemic lupus erythematosus.