The diagnostic role of cervico-vaginal fluid cytokines in endometriosis, and correlation with serum cytokine levels

Abstract

Aim: About 10% of women of reproductive age suffer from endometriosis, a serious chronic disease, causing pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Research has so far focused on non-invasive diagnostic markers mainly in blood, endometrial tissue and urine from endometriosis patients. To date, only one study was identified assessing cervico-vaginal fluid. This study aims to assess a panel of cytokines present in cervico-vaginal fluid for their diagnostic potential in endometriosis, and correlating them with their serum levels.

Materials and Methods; This case-control study was conducted in 30 women, of whom 10 were patients planned for surgery and confirmed to be suffering from endometriosis, and 20 were asymptomatic women who were the controls. The levels of interleukin (IL)–6, IL-1α, IL-17, IL-23 and tumour necrosis factor α were measured in cervico-vaginal fluid and also in serum. Analysis of samples was carried out using multiplex bead array. Statistical analysis was done using Mann-Whitney, median and chi-square tests.

Results: The cervico-vaginal levels of the different cytokines varied. The level of IL-23 was significantly lower in the follicular phase for the endometriosis group (p value = 0.031). There was a tendency for higher values for IL-6 and IL-1α in the luteal phase of the cycle, however these were not statistically significant. The serum levels of all the cytokines tested, were nearly all below the lower limit of detection of the assay, for both the endometriosis and the control groups, thus no conclusions can be reached from the serum cytokines. Conclusion: The identification of a potential biomarker would speed up the diagnostic workup for endometriosis. The findings of previous research, showing promising results for use of IL-1α in cervico-vaginal fluid for its diagnostic ability, were not confirmed by this research. However, other cytokines in cervico-vaginal fluid, such as IL-23 could potentially be useful biomarkers and should be investigated further.