TNF and diabetes mellitus: Circulating levels of acute-phase proteins are elevated in diabetes, such as serum amyloid A, C-reactive protein (CRP), fibrinogen, haptoglobin, plasminogen activator inhibitor, sialic acid, interleukin (IL)-1β, IL-1 receptor antagonist (IL-1Ra), IL-6 and tumor necrosis factor (TNF)-α [48,49,50,51].