In a study examining the role of IL-16 in endometriosis, researchers found that IL-16 concentrations in the peritoneal fluid of women with advanced endometriosis (stages III/IV) were significantly elevated (330 pg/mL) compared to those without endometriosis (229 pg/mL), with a statistical significance of p = 0.0016. Here, IL16 is linked to endometriosis.