This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Which of the following is secondary mediator of the anaphylaxis is 
Select and explain. 
A. Histamine, B. Protease, C. Eosinophilic chemotactic factor, D. Leukotriene B4
D: Leukotriene B4
Answer: D: Leukotriene B4 
Explanation: ref Robbins 9/e p203 Leukotriene B4 (LTB4) is a leukotriene involved in inflammation. It is produced from leukocytes in response to inflammatory mediators and is able to induce the adhesion and activation of leukocytes on the endothelium, allowing them to bind to and cross it into the tissue.