TNF and systemic-onset juvenile idiopathic arthritis: Blocking TNF-α can strongly modulate the balance between effector T cells and regulatory T cells; as a result, approved TNF-α inhibitors play a crucial role in some severe autoimmune inflammatory diseases as well as numerous chronic inflammatory diseases such as psoriasis, rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and ankylosing spondylitis, refractory hemophagocytic lymphohistiocytosis, systemic juvenile idiopathic arthritis, Behcet's disease, dermatomyositis, and lupus (27–36).