IL4 and endometriosis: LC treatment has been shown to increase the production of both PGE1 and PGE2. It was suggested that PGE1 confers protection against endometriosis by attenuating the secretion of TNF-α, IFN-γ and interleukins (IL-2, IL-4 and IL-6), while PGE2 induces cytokine release and thus endometriosis through its apoptotic and inflammatory functions [19, 46].