TNF and juvenile idiopathic arthritis: In JIA patients, there are several causes of growth delay, such as increased catabolic demands secondary to active disease, decreased levels of insulin-like growth factor 1 (ILGF-1) in children secondary to elevated levels of IL-6 and corticosteroids, suppressive effect of corticoids on osteoblasts, and those related to malnutrition such as cachexia associated with increased levels of TNF-a and IL-1 and anorexia related to medication side effects [31].