TECK has a key role in the segregation and compartmentalization of the mucosal immune system through recruitment of immune cells to specific locations.17 In our previous study we showed that TECK derived from endometriotic-associated cells enhances ESC invasion by upregulating the expression of MMP2/9.14 In this study, we further show that the percentage of CD4+Foxp3+ T cells in peritoneal fluid is positively correlated with the progression of endometriosis. This evidence concerns the gene CD4 and endometriosis.