TNF and dermatomyositis: Considering that the expression of tissue nonspecific alkaline phosphatases can be up-regulated by cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β), a subset of CD68+ cells in the perimysium has been speculated to secrete these cytokines, resulting in increased perimysial connective tissue ALP activity in anti-Mi-2 DM patients.