Macrophages are recruited to the peritoneal cavity of patients with endometriosis in response to the presence of ectopic endometrial tissue, tissue damage, and various chemokines, such as IL-17A, monocyte chemotactic protein-1 (MCP-1), IL-8, and chemokine (C-C motif) ligand 5 (CCL5), to clear menstrual debris and refluxed heme-iron lesions [35-38]. This evidence concerns the gene CCL5 and endometriosis.