RvE2 is produced by reduction of 18R HEPE products by 5-LOX to 5S-hydroperoxy, 18-hydroxy-EPE in whole blood (Oh et al. 2012). Unlike RvE1, RvE2 and RvE3 are biosynthesized from 18-HEPE via the 12/15-LOX pathway in eosinophils (Isobe et al. 2012b). Endogenous RvE1 has been shown to accumulate for between 48 and 72 hours, which is a delayed time point of inflammation (Hong et al. 2008). RvE2 appeared at the time point corresponding to initial PMN infiltration in rat peritoneal exudate stimulated by zymosan A and decreased within 24 hours (Isobe et al. 2012a). 18S-RvE1 is produced by 5-LOX and LTA4 hydrolase using 18S-HEPE as a substrate (Oh et al. 2011).