LIF and osteoarthritis: Interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6 seem to be the main proinflammatory cytokines involved in the pathophysiology of osteoarthritis, even though others, including IL-15, IL-18, IL-21, leukemia inhibitory factor (LIF), and chemokines are implicated [182,219].