PADI4 and arthritic joint disease: Because PAD4 contributes to the pathogenesis of RA, we used murine arthritis models that are at least partially PAD4-dependent and mimic human RA with synovial tissue NET formation and the production of anti-H3Cit antibody: (Granulocyte-colony stimulating factor (G-CSF)-modified Collagen-Induced Arthritis (CIA) model in C57/Bl6J mice and standard CIA model in DBA/1 mice)15,41.