Serum macrophage migration inhibition factor for diagnosing endometriosis and its severity: case-control study.

Background: Endometriosis is a long-standing progressive disease that affects women of reproductive age. Macrophage migration inhibitory factor (MIF) is one of non-invasive blood biomarker that was detected in sera of endometriotic patients. The present study aimed to determine the accuracy of serum MIF in diagnosing endometriosis in women with infertility and chronic pelvic pain, and correlate its level to the stage of the disease.
Methods: Observational case-control study conducted at Fayoum University hospital from March 2016 till September 2018. Three hundred women candidate for diagnostic laparoscopy for either infertility or gynecologic chronic pelvic pain were included. The study group included patients with symptoms suggestive of endometriosis or chocolate cyst by ultrasound and proved by laparoscopy and histopathology. The control group included other causes of infertility or pelvic pain. All patients undergone either diagnostic or operative laparoscopy, and before laparoscopy blood sampling for quantitative measurement of macrophage migration inhibitory factor (MIF) protein in serum by ELISA technique.
Results: The level of serum MIF was significantly higher in endometriosis group compared to control group (1.75 ± 1.48 pg/ml and 0.51 ± 0.45 pg/ ml, respectively, P = < 0.001), with a progressive increase with advancing stage (stage I, 1.3 ± 1.03 pg/ml, stage II, 1.7 ± 1.57 pg/ml, stage III, 2.1 ± 1.19 pg/ml and in stage IV, 3.2 ± 2.6 pg/ml). Moreover, in patients presented with pain and infertile patients showed significantly higher levels of serum MIF (1.92 ± 1.13 vs 1.21 ± 1.17 and 1.82 ± 1.13 vs 1.32 ± 0.91 respectively with p-value < 0.001). ROC curve of serum MIF with a cut off value of 0.85 pg/ml or more achieves a sensitivity of 80.6%, specificity of 83.3%, positive predictive value of 82.9% and negative predictive value of 81.2%.
Conclusion: Serum MIF might be a promising marker not only for noninvasive diagnosis of endometriosis but as a target for detecting severity as well.