Tumor necrosis factor (TNF, cachexin, or cachectin, and formerly known as tumor necrosis factor alpha or TNFα) is an adipokine involved in systemic inflammation and is a member of a group of cytokines that stimulate the acute phase reaction. It is produced chiefly by activated macrophages, although it can be produced by many other cell types such as CD4+ lymphocytes, NK cells, neutrophils, mast cells, eosinophils, and neurons.