CXCL1, IL-6 and GM-CSF have been shown to be upregulated in the tissue and plasma of women with endometriosis compared to healthy fertile controls and suggests that IL-33 could be indirectly attracting neutrophils and macrophages to the microenvironment, through the upregulation of these cytokines and chemokines5,40. Here, IL6 is linked to endometriosis.