Interleukin-6, intracellular adhesion molecule-1, and glycodelin A levels in serum and peritoneal fluid as biomarkers for endometriosis

OBJECTIVE: To compare levels of interleukin-6 (IL-6), intracellular adhesion molecule-1 (ICAM-1), and glycodelin A in serum and peritoneal fluid of patients with and without endometriosis, and to correlate levels with disease stage. METHODS: An observational study was undertaken at Mansoura University Hospital, Egypt, between March 2014 and June 2015. Patients aged 21-48 years laparoscopically diagnosed with endometriosis and those without endometriosis who underwent laparoscopy for tubal ligation were included. Levels of IL-6, ICAM-1, and glycodelin A were measured in samples of serum and peritoneal fluid. Receiver operating characteristic curves were used to evaluate diagnostic accuracy. RESULTS: Forty-eight women with endometriosis and 20 without the disorder were included. IL-6 and glycodelin A levels in serum and peritoneal fluid were higher in the endometriosis group than in the control group (P<0.001 for all); ICAM-1 levels did not differ. The sensitivity and specificity values were 93.8% and 80.0% for serum IL-6, 58.3% and 60.0% for serum ICAM-1, and 91.7% and 75.0% for serum glycodelin A. The corresponding values for peritoneal fluid markers were 85.4% and 89.0%, 60.4% and 50.0%, and 89.6% and 90.0%, respectively. IL-6 and glycodelin A levels in serum and peritoneal fluid increased with disease stage (P<0.001 for all). CONCLUSION: IL-6 and glycodelin A, but not ICAM-1, are potential biomarkers for endometriosis and are positively correlated with the disease stage.