PTGS2 and allergic asthma: Eicosanoids are synthesized by almost all cell types and perform various functions.19 PGE2 exhibits a wide range of biological activities including regulation of immune responses, tissue repair and homeostasis.34,35 Using a mouse model of allergic asthma, it has been shown that airway inflammation is increased in PTGS2 knockout mice compared to the wildtype, suggesting an anti-inflammatory role of PGE2.