Serum cytokines as biomarkers for prediction of endometriosis

Objective:To test the ability of serum cytokines served as biomarkers for the diagnosis of endometriosis.Methods:All 125 cares were randomly allocated to two groups according to their laparoscopic diagnosis.The first group consisted of patients with endometriosis and the second group was made up of infertile women with no pelvic pathology(controls group).Blood samples were collected preoperatively and stored.Cytokines were measured in the serum of all participants using the Bio-Plex Protein Array System.Results:Three cytokines were significantly higher in the serum of subjects with endometriosis than in the control group: interleukin-6(IL-6),monocyte chemotactic protein-1(MCP-1),and interferon-gamma(INF-γ)(P0.001).There was no statistically significant difference between subjects with endometriosis and controls in the serum concentration of vascular endothelial growth factor(VEGF),tumor necrosis factor-alpha(TNF-α),or interleukin-8(IL-8)(P=0.43,0.52,0.37).Interleukin-2(IL-2),Interleukin-10(IL-10),and interleukin-15(IL-15) were undetectable in the serum of both groups.With the exception of IL-8 and TNF-α,which was marginally higher in advanced-stage endometriosis than in earlier stages of the disease,there was a trend for all other cytokines and growth factors to be higher in early-stage endometriosis than in advanced stages of the disease.However,the difference between early and advanced stages of endometriosis did not reach statistical significance for any of the measured cytokines.None of the measured cytokines showed significant correlation with the cycle phase or stage of endometriosis.In a multivariate analysis,serum interleukin-6 provided an area under the curve of 73.21% to discriminate between endometriosis patients and controls at a cutoff point of 2.1pg/ml.Adding monocyte chemotactic protein-1 and interferon-gamma to interleukin-6 did not increase the discriminative ability over that achieved by measuring serum interleukin-6 alone(P0.01).Conclusion:Serum of subjects with endometriosis contains significantly higher levels of interleukin-6,monocyte chemotactic protein-1,and interferon-gamma than control women.Serum interleukin-6 measurements discriminate between women with endometriosis and controls.Interleukin-6 provides a promising serum marker for the nonsurgical prediction of endometriosis.