Which of the following statements regarding cytokines is incorrect?
A. Cytokines Act directly on target cells and may potentiate the actions of one another. B. Interleukin 1 (IL-1) is a major proinflammatory mediator with multiple effects, including regulation of skeletal muscle proteolysis in patients with sepsis or significant injury. C. Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability. D. Tumor necrosis factor alpha (TNF-a), despite its short plasma half-life, appears to be a principal mediator in the evolution of sepsis and the multiple organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates
Platelet-activating factor (paf) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability.-cytokines are soluble peptide molecules that are synthesized and secreted by a number of cell types in response to injury, inflammation, and infection. cytokines, which include the interleukins, tumor necrosis factor, colony-stimulating factors, and the interferons, comprise only one category of inflammatory mediators involved in the host response. endotoxin, complement fragments, eicosanoids, kinins, nitric oxide, oxidants, and paf are noncytokine mediators that also have important roles in the systemic inflammatory response. il-1 and tnf-a, like other cytokines, have multiple effects on target cells and potentiate the actions of other mediators to produce an amplified inflammatory response. tnf-a is thought to play a central role in the stress response, particularly in response to endotoxemia.