<prompt> Which of the following are slow reacting substances of anaphylaxis?LTB4 and C4LT A4 and B4LT A4 and C4LT C4 and D4  <response>: Answer- D. LT C4 and D4Slow-reactine substance of anaohvlaxis SRS-AA mixture of the leukotrienes LTC4, LDD4 and LTE4 are called slow reacting substances of anaphylaxis SRS-A.These are the most potent mediators causing bronchospasm.They are produced lipoxygenase pathway LOX pathway of arachidonic acid metabolism during inflammation. 