FMO5 and coronary artery disorder: Two potential pathways were inferred to be involved in the protective effect of hydroxychloroquine in CAD: (a) hydroxychloroquine may activate ERK5 (encoded by MAPK7) to prevent endothelial inflammation via inhibition of cell adhesion molecule expression24; and (b) hydroxychloroquine may inhibit endosomal activation of NADPH oxidase in response to pro-inflammatory agonists (TNF-α and IL-1β) and may decrease production of pro-inflammatory cytokines in stimulated immune cells25.