Abstract:
Endometriosis is a gynecological disease, the pathogenesis of which seems to be directly associated with inflammatory processes. Serum concentrations of IL-1β, IL-6, hs-CRP, IgG, YKL 40
and PRL, in comparison to the well-known CA 125 levels, were studied with the aim of identifying an additional noninvasive inflammatory marker or set of markers characteristic for endometriosis. The study group included 43 women with endometriosis (E), 35 women with benign gynecological disorders but without endometriosis (NE, non-endometriosis) as a comparative group, and a control group consisting of 18 healthy subjects (C). The serum concentrations of IL-1β, IL-6, hs-CRP, YKL-40, PRL and CA 125 were significantly higher in the E group (median values: 0.41 pg/mL, 2.42 pg/mL, 2.33 mg/L, 79.30 ng/mL, 21.88 ng/mL and 68.00 U/mL, respectively) than in the control group (median values: 0.21 pg/mL, 0.98 pg/mL, 0.52 mg/L, 49.77 ng/mL, 12.08 ng/mL and 12.20 U/mL respectively), with the significance of p = 0.011, p < 0.001, p = 0.028, p = 0.005, p < 0.001 and p < 0.001,
respectively. The IgG concentrations were significantly lower in the endometriosis group (median value: 1061.21 mg/dL) as compared to healthy women (median value: 1210.50 mg/dL; p = 0.025). Significant differences in concentrations of IL-6 (p = 0.040), hs-CRP (p = 0.007) and CA 125 (p < 0.001) were observed in stage III vs. stage IV of endometriosis. Significantly higher concentrations of IL-6 (p = 0.010), hs-CRP (p = 0.037) and PRL (p < 0.001) were observed in the NE group vs. the control group. Only CA 125 concentrations were significantly higher in endometriosis patients as compared to the non-endometriosis group (p < 0.001). The proposed panel of inflammatory markers, especially IL-6, PRL and CA 125, may become a useful tool to identify women with advanced endometriosis who could qualify for treatment.
Keywords: advanced endometriosis; serum parameters of inflammation; cytokines; CA 125; diagnostics of endometriosis
1. Introduction
Endometriosis is quite a common gynecological disease, which is difficult to diagnose and treat. It affects about 10% of young women, which represents approximately 200 million women of reproductive age [1]. That number increases up to 50% in the group of patients with chronic pelvic pain, infertility, or both [2]. The common symptoms of endometriosis are dysmenorrhea, dyspareunia and back pain, as well as bladder and/or bowel problems, which may vary in degree and intensity [1]. These symptoms are usually nonspecific, which makes the clinical diagnosis of the disease very difficult [3]. The gold standard for the diagnosis of endometriosis remains laparoscopy, which delivers both clinical and histological findings. However, the procedure is invasive and many patients are not willing to have it performed as soon as the disease is suspected. This, in turn, can delay diagnosis by as long as 9 years [4]. In some types of endometriosis, imaging techniques (e.g., ultrasonography, magnetic resonance imaging) are useful and strongly recommended for correct diagnosis [3]. On the other hand, superficial peritoneal endometriosis is hard to detect with the use of non-invasive procedures [4]. Moreover, even such renowned standards for endometriosis diagnostics as laparoscopy may fail in the very early stages of the disease [5].
Endometrial tissues are presented and developed in the ectopic site, especially in the pelvis. Endometrial infiltrates are most often found in the ovaries, peritoneum, uterosacral ligaments, pouch of Douglas and rectovaginal septum [6]. Sometimes, however, the changes occur far beyond the pelvic organs, e.g., in the lungs, pleura, spinal cord, nose and abdominal lymph nodes [2]. Based on the severity and anatomical extension of the lesions, endometriosis is graded into four stages: minimal, mild, moderate and severe—in accordance with the revised American Fertility Society (rAFS) classification [7], which was updated by the American Society for Reproductive Medicine (ASRM) [8].
