This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arachidonic acid metabolites, Subject name: Pathology
All of the following are mediators of inflammation, except: 
Select and explain. 
A. Tumour necrosis factor-a (TNF-a), B. Interleukin-1, C. Myeloperoxidase, D. Prostaglandins
C: Myeloperoxidase
Answer: C: Myeloperoxidase 
Explanation: Inflammatory mediators are the substances that initiate and regulate inflammatory reactions. The most impoant mediators of acute inflammation are vasoactive amines, lipid products (prostaglandins and leukotrienes), cytokines (including chemokines), and products of complement activation. Myeloperoxidase (MPO) is an enzyme present in primary (or azurophilic) granules of the neutrophils and takes pa in formation of reactive oxygen species. In the presence of a halide such as Cl-, MPO conves H2O2 to HOCl. (Hypochlorous radical) is used during the process of respiratory burst.