Elevated soluble Fas ligand levels may suggest a role for apoptosis in women with endometriosis

OBJECTIVE: To evaluate soluble Fas ligand concentrations in serum and peritoneal fluid from women with endometriosis and from fertile controls without endometriosis, and to study levels of soluble Fas ligand in conditioned media of cultured endometrial stromal cells. DESIGN: Prospective, experimental trial. SETTING: Two academic IVF centers. PATIENT(S): Twenty-nine fertile women without endometriosis and 57 infertile women with endometriosis (32 with stage I or II disease and 25 with stage III or IV disease). MAIN OUTCOME MEASURE(S): Enzyme-linked immunosorbent assay was used to measure soluble Fas ligand concentrations in paired samples of serum and peritoneal fluid from women with and without endometriosis. Concentrations were also measured in conditioned media of cultured endometrial stromal cells at basal conditions and after stimulation with interleukin-8 (0.001-10 ng/mL) and tumor necrosis factor-alpha (1-10 ng/mL). RESULT(S): Compared with fertile controls and women with early-stage of endometriosis, women with moderate to severe endometriosis had elevated serum (87.2 +/- 6.4, 88.2 +/- 6.9, and 162.3 +/- 7.8 pg/mL, respectively) and peritoneal fluid (81.0 +/- 6.0, 80.5 +/- 6.8, and 166.2 +/- 10.3 pg/mL, respectively) concentrations of soluble Fas ligand. Serum levels of soluble Fas ligand positively correlated with levels in peritoneal fluid. Comparison of patients in the same menstrual cycle in each group revealed that increased levels of soluble Fas ligand in patients with advanced endometriosis were not attributable to the difference in cycle phases. Soluble Fas ligand was not detected in conditioned media of endometrial stromal cells under baseline conditions or after stimulation. CONCLUSION(S): Serum and peritoneal fluid of women with moderate to severe endometriosis contain elevated concentrations of soluble Fas ligand compared to women with minimal or mild endometriosis and women without endometriosis. These findings suggest a role for apoptotic dysregulation in the pathophysiology of endometriosis.     

Endometrial antigens involved in the autoimmunity of endometriosis

Serum and peritoneal fluid from five fertile women without endometriosis and serum (n = 23) and peritoneal fluid (n = 12) from infertile women with endometriosis were tested for the presence of antibodies against endometrial tissue antigens by a Western blot analysis. Antigens with molecular weights (MW) of 19, 31, 38, and 42 kd reacted with antibodies in the serum and peritoneal fluid from both fertile and infertile women. Antibodies in 20 of 23 (87%) sera and all 12 (100%) peritoneal fluid samples from endometriosis patients reacted against endometrial antigens with molecular weights (MW) of 26 kd and/or 34 kd. Serum from 10 patients (43%) and peritoneal fluid from 6 patients (50%) also had antibodies to an endometrial antigen with MW of 21.5 kd. Reactivity to other endometrial antigens with MW 16, 24, 48, and 75 kd was also noted in patients with endometriosis. Antibodies in the serum and peritoneal fluid from fertile women failed to react against these antigens. It is concluded that the humoral and local endometrial autoimmunity detected in patients with endometriosis is primarily directed against antigens with MW of 26 and 34 kd.     

Antigenic differences between the endometrium of women with and without endometriosis

Serum and peritoneal fluid from 12 women with endometriosis, 4 women with uterine leiomyomata and 6 fertile women without endometriosis (controls) and serum from 4 women with adenomyosis were tested with a passive hemagglutination assay for antibodies against endometrium from all the controls, 8 patients with endometriosis and all patients with uterine leiomyomata and from implants from 8 patients with endometriosis. Serum antibody titers in patients with endometriosis or leiomyomata were significantly higher against endometrial or implant antigens from patients with endometriosis and 2 patients with leiomyomata than those against the controls' endometrium. Peritoneal fluid endometrial antibody titers failed to reflect these antigenic differences. Controls and patients with adenomyosis had low titers of endometrial antibodies in their serum or peritoneal fluid. Antigenic differences appear to exist between the endometrium of patients with endometriosis and that of controls.     

Peritoneal fluid volume, 17beta-estradiol and progesterone concentrations in women with endometriosis and/or luteinized unruptured follicle syndrome

Data on the presence of an ovulation ostium and the volume and the concentrations of estradiol (17 beta-estradiol) and progesterone In women with endometriosis (n = 80) and women with luteinized unruptured follicle (LUF) syndrome (n = 32) are reported and compared with data obtained from normal ovulatory women, previously reported. in women with endometriosis, less ovulation ostia were observed, the difference being significant in moderate and severe endometriosis. During the luteal phase, no statistical difference was found in the amount of peritoneal fluid of women with endometriosis. Estradiol and progesterone levels in the peritoneal fluid of normal women and women with mild endometriosis were not significantly different. Lower steroid concentrations found in peritoneal fluid of women with moderate (phase days 20-22) and severe endometriosis (phase days 14-19 and 20-22) may explain the high incidence of infertility reported in these women (peritoneal steroids deficiency). During the phases days 14-19 and 20-22, very low peritoneal steroid concentrations were found in women with LUF syndrome. It is suggested that progesterone assay in peritoneal fluid is an aid to diagnose the luteinized unruptured syndrome.     

Decreased peritoneal concentrations of interleukin-15 in women with advanced stage endometriosis

OBJECTIVE: To assess the concentrations of interleukin-15 (IL-15) in peritoneal fluid from women with endometriosis and fertile disease-free controls. STUDY DESIGN: Peritoneal fluid samples were obtained from 50 women with endometriosis and 29 fertile women having tubal ligation. Concentrations of IL-15 were measured. RESULTS: The mean (S.D.s) concentration of IL-15 in peritoneal fluid was 11.17 pg/mL (3.89) for women with endometriosis, and 12.59 pg/mL (4.11) for fertile disease-free controls. The difference of peritoneal IL-15 concentrations between endometriosis and control women was not statistically significant. However, peritoneal IL-15 concentrations were significantly lower in women with moderate/severe endometriosis when compared with those in women with minimal/mild endometriosis, and in controls (P<0.05). In addition, peritoneal IL-15 concentrations did not correlate with the phase of menstrual cycle in endometriosis or control women. CONCLUSIONS: Our results suggest that the decreased peritoneal IL-15 concentrations in women with moderate/severe endometriosis imply a role of IL-15 in the pathogenesis of advanced endometriosis as compared to those with minimal/mild endometriosis and fertile disease-free controls.     

Peritoneal fluid concentrations of epithelial neutrophil-activating peptide-78 correlate with the severity of endometriosis

OBJECTIVE: To assess the release of epithelial neutrophil-activating peptide-78 (ENA-78) into peritoneal fluid in women with and without endometriosis. DESIGN: Retrospective study. SETTING: Nagoya City University Hospital. PATIENT(S): Surgery was scheduled in the proliferative or secretory phase of the menstrual cycle for 59 women with (n = 35) and without (n = 24) endometriosis. INTERVENTION(S): Peritoneal fluid samples were obtained at laparotomy or laparoscopy. MAIN OUTCOME MEASURE(S): The ENA-78 concentrations in the peritoneal fluid were measured using enzyme-linked immunosorbent assay (ELISA). RESULT(S): The concentrations of ENA-78 in the peritoneal fluid were markedly elevated in the endometriosis patients as compared with the controls, especially in women with severe stage disease. CONCLUSION(S): We conclude that ENA-78 is an important factor that may contribute to the pathogenesis of endometriosis, possibly promoting neovascularization.     

Identifying the presence of antibodies against endometrial antigens. A preliminary study.

Serum and peritoneal fluid from women with and without evidence of endometriosis were tested for the presence of antibodies against endometrial tissue antigens with Western blot analysis. Serum antibodies against endometrial cytosolic antigens of molecular weight 45, 52, 58, 62 and 66 kd were present in samples obtained from women both with and without endometriosis. The patients with endometriosis had serum antibodies against 34-kd endometrial cytosolic antigen, which was not present in serum from fertile women without endometriosis. The peritoneal fluid from patients with endometriosis also reacted with 34-kd endometrial antigen but not the peritoneal fluid from control fertile women. There was no difference in the antigens detected with serum antibody when endometrium from fertile women without evidence of endometriosis and from women with endometriosis was used as a source of antigen. The presence of serum antibody against 34-kd endometrial antigen is specific to endometriosis. However, this antigen is expressed by endometrium of women both with or without endometriosis. Isolation and identification of this antigen may lead to development of a noninvasive aid for the diagnosis of endometriosis.     

Antizona and antisperm antibodies in women with endometriosis and/or infertility

OBJECTIVE: To measure the levels of antigamete antibodies in serum and peritoneal fluid of women with endometriosis and/or infertility. DESIGN: Antibody activity against human sperm and porcine oocytes was analyzed in selected subgroups of women. SETTING: Clinic of reproduction. PATIENT(S): Women with endometriosis and/or infertility. INTERVENTION(S): No treatment was implemented before peritoneal fluid and blood sample collection. MAIN OUTCOME MEASURE(S): Quantitative ELISA. RESULT(S): Four groups of women (n = 98) were analyzed for the presence of antizona and antisperm antibodies: infertile with endometriosis (n = 30), idiopathic infertility (n = 28), fertile with endometriosis (n = 20), and healthy fertile controls (n = 20). Antibodies were analyzed simultaneously in serum and peritoneal fluid. No statistically significant differences in antibody levels were detected in serum samples among the analyzed groups. The median values for antizona and antisperm antibodies in peritoneal fluid were significantly higher in women with idiopathic infertility than in the control group. In women with unexplained infertility, a high degree of correlation (Spearman) was found between the presence of antizona antibodies in peritoneal fluid and serum (r = 0.579). A positive predictive value of 80% was calculated for the presence of antizona antibodies (>5 ng/oocyte) in the peritoneal fluid of patients with infertility. CONCLUSION(S): Antizona antibodies locally produced in the peritoneal fluid have diagnostic value for infertility status; however, they cannot be treated as a marker or prognostic factor for minimal endometriosis and/or its treatment.     

Iron overload in the peritoneal cavity of women with pelvic endometriosis

OBJECTIVE: To examine the possible involvement of iron in the physiopathology of endometriosis. DESIGN: Prospective study. SETTING: Department of gynecology in a university hospital. PATIENT(S): Seventy patients undergoing laparoscopy. INTERVENTION(S): Collection of peritoneal fluid (n = 57), blood samples, and biopsy samples from endometrium (n = 62) and from endometriotic (n = 33) and normal-appearing peritoneum (n = 53). MAIN OUTCOME MEASURE(S): Measurement of iron and ferritin in serum and peritoneal fluid and staining of iron deposits with Prussian blue in tissues. RESULT(S): Iron and ferritin concentrations were significantly higher in the peritoneal fluid of patients with endometriosis compared with controls during the secretory phase. Higher rates of ferritin and hemosiderin deposits were observed in the peritoneum adjacent to red (100%), black (57%), and white (62%) lesions compared with normal-appearing peritoneum (25%). Deposits were more frequent during the secretory phase than the proliferative phase in healthy peritoneum from controls, whereas they were found throughout the cycle in the vicinity of lesions in patients with endometriosis. Similar rates of iron deposition were observed in the stroma of black and white lesions and in eutopic endometrium from patients with endometriosis. CONCLUSION(S): Iron overload was observed in the cellular and peritoneal fluid compartments of the peritoneal cavity of women with endometriosis. Iron deposits seem to be related to the presence of lesions, suggesting that iron may be involved in the pathogenesis of endometriosis.     

Effect of peritoneal fluid from patients with mild and severe endometriosis on endometrial stromal cell proliferation

The aim of this study was to evaluate and compare the mitogenic effect of peritoneal fluid (PF) from women with mild and severe endometriosis on the endometrial stromal cell proliferation. Increasing concentrations of PF from women with and without mild or severe endometriosis were added to primary endometrial stromal cell cultures and³H-thymidine incorporation was used to assess DNA synthesis in these cultures. PF from women with mild endometriosis induced a statistically significant dose-dependent increase in stromal cell thymidine uptake ranged from 5.8 to 14.5 fold, whereas PF from women with severe endometriosis produced an average 51% inhibition of stromal cell proliferation of compared with cells exposed to non-endometriosis PF or exposed to nutrient medium supplemented with 2.5% calf serum alone. PF samples from patients with stage I endometriosis induced a statistically dose-dependent increase in stromal cell proliferation, whereas PF from patients with stage IV endometriosis caused a significant inhibition.     

Increased granulocyte chemotactic protein-2 concentrations in peritoneal fluid of women with endometriosis

BACKGROUND: To evaluate the release of granulocyte chemotactic protein-2 (GCP-2) into peritoneal fluid in women with endometriosis, we measured its concentration with reference to the disease stage and the phase of the menstrual cycle. METHODS: Surgery was scheduled in the proliferative or secretory phase of the menstrual cycle for 64 women with endometriosis (n = 38) or cystadenomas (n = 26). GCP-2 concentrations in the peritoneal fluid were measured using an enzyme-linked immunosorbent assay. RESULT: Our findings indicated elevated concentrations of GCP-2 in peritoneal fluid from women with endometriosis during the proliferative phase, which were positively correlated with the stage of endometriosis. CONCLUSION: Inflammation associated with endometriosis may be involved in the pathogenesis of the disease through increasing levels of peritoneal fluid GCP-2.     

Pyruvate reduces in vitro the embryotoxic effect of peritoneal fluid from infertile women with endometriosis

OBJECTIVES: To ascertain the embryotoxicity of peritoneal fluid from infertile women with endometriosis (PF-E), on mouse embryos in culture and to examine the effect of pyruvate in the culture medium on PF-E induced embryotoxicity. STUDY DESIGN: Blood-free peritoneal fluid samples were obtained during laparoscopic investigation for infertility from 21 infertile women with endometriosis. The severity of endometriosis ranged from minimal or mild (PF-min to mild-E; n=7), moderate (PF-mod-E; n=7), to severe (PF-sev-E; n=7). Peritoneal fluid samples were centrifuged at 600 x g for 10 min and 4 degrees C, and the supernatant was incubated at 56 degrees C for 30 min in a water bath to inactivate the complement protein. Mice were super ovulated with intraperitoneal injection (IP) of 5IU of pregnant mare serum gonadotrophin and human chorion gonadotrophin. Twenty-four hours after confirmation of mating two-cell mouse embryos were obtained. They were then cultured in modified Whitten's medium (mWM) with peritoneal fluid from patients with endometriosis, and either in the absence or presence of excess pyruvate (0.062 mmol(-1)). Embryos were cultured for 72 h. RESULTS AND CONCLUSION: Addition of 5% PF-E significantly (p<0.001) suppressed embryo growth at 24, 48, and 72 h of culture and the degree of suppression correlated with the severity of the disease. The presence of 0.062 mmol(-1) pyruvate in the culture medium significantly (p<0.001) reduced the embryotoxicity of PF-min to mild-E and PF-mod-E at each stage of development, but was only seen at 24h of culture (p<0.001) in cultures with PF-sev-E even when the concentration of pyruvate in the medium was increased to 0.31 mmol(-1). This study confirms the embryotoxicity of PF-E in vitro, which was reduced by the presence pyruvate in the culture medium, particularly in cultures containing fluid from women with endometriosis of minimum or mild to moderate severity.     

Elevated angiogenin levels in the peritoneal fluid of women with endometriosis correlate with the extent of the disorder

OBJECTIVE: To assess the release of angiogenin into peritoneal fluid in women with and without endometriosis by measuring its concentration with reference to disease stage, presence of red lesions, and phase of the menstrual cycle. DESIGN: Retrospective study. SETTING: Nagoya City University Hospital. PATIENT(S): Sixty-four women with endometriosis (n = 38) and cystadenomas (n = 26) for whom surgery was scheduled in the proliferative or secretory phase of the menstrual cycle. INTERVENTION(S): Peritoneal fluid samples were obtained at laparotomy or laparoscopy. MAIN OUTCOME MEASURE(S): Angiogenin concentrations in the peritoneal fluid, as measured by ELISA. RESULT(S): Angiogenin concentration in the peritoneal fluid was markedly elevated in the endometriosis patients (median 515 ng/mL, interquartile range 151-1763 ng/mL) compared with the cystadenoma (control) patients (195 ng/mL, 98-324 ng/mL), with values correlating with the extent of the disease. No significant differences between the proliferative phase and the secretory phase were observed in either the controls or the endometriosis patients. CONCLUSION(S): The inflammation associated with endometriosis, through increasing levels of peritoneal fluid angiogenin, might promote angiogenesis for progression of the disease and correlate with the extent of the disorder.     

Rapid peptidomic profiling of peritoneal fluid by MALDI-TOF mass spectrometry for the identification of biomarkers of endometriosis

Peptidomic profiling of peritoneal fluid by Matrix Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF-MS) may represent a promising, suitable, rapid method for early diagnosis and staging of endometriosis. In a case-control study, peritoneal fluid was collected from 23 patients affected by endometriosis (eight minimal/mild endometriosis and 15 moderate/severe endometriosis) and six “endometriosis free” women undergoing laparoscopy. MALDI-TOF mass spectra of the peptide fraction extracted from peritoneal fluid samples lead to identify biomarkers potentially suitable for discriminating between peritoneal fluid samples from women affected by minimal/mild endometriosis and those from women affected by moderate/severe endometriosis. Peptidomic analysis of peritoneal fluid samples may define putative peptide biomarkers suitable for staging endometriosis and improve our understanding of the pathogenesis of endometriosis.     

Monocyte chemotactic protein-1 concentration in peritoneal fluid of women with endometriosis and its modulation of expression in mesothelial cells

Objective: To investigate monocyte chemotactic protein-1 concentrations in the peritoneal fluid (PF) of women with or without endometriosis, then assess peritoneal mesothelial cells as a potential source of monocyte chemotactic protein-1.

Design: Prospective study.

Setting: University medical center.

Patient(s): Women with (n = 60) or without (n = 18) endometriosis.

Intervention(s): First monocyte chemotactic protein-1 levels in PF were measured, then mesothelial cells in culture were treated with cytokines.

Main Outcome Measure(s): In PF and culture supernatants, monocyte chemotactic protein-1 was measured by ELISA. In vitro monocyte chemotactic protein-1 messenger RNA expression was evaluated by Northern analysis.

Result(s): The median concentration of monocyte chemotactic protein-1 in PF of control women was 137 pg/mL (conversion factor to SI unit, 0.115; range, 12 to 418 pg/mL); that of women with moderate endometriosis was 205 pg/mL (range 65 to 6,000 pg/mL); and that of those with severe endometriosis was 1,165 pg/mL (0 to 2,602 pg/mL). Within the moderate to severe endometriosis group, monocyte chemotactic protein-1 levels were higher in women with untreated endometriosis (354 pg/mL range 0 to 6,000 pg/mL) than in women receiving GnRH agonist (128 pg/mL, range 0 to 216 pg/mL). In the control group, monocyte chemotactic protein-1 levels were higher in the proliferative phase than in the secretory phase. Mesothelial cells produced constitutively monocyte chemotactic protein-1; moreover, both interleukin-1 and tumor necrosis factor- induced higher levels of monocyte chemotactic protein-1.

Conclusion(s): Levels of monocyte chemotactic protein-1 in PF were higher during the proliferative phase than secretory phase of control women and increased in moderate to severe endometriosis. The regulated expression of monocyte chemotactic protein-1 may recruit macrophages into PF and contribute to the pathogenesis of endometriosis.     

Vascular endothelial growth factor concentrations in the serum and peritoneal fluid of women with endometriosis.

OBJECTIVES: To investigate whether there is an association between vascular endothelial growth factor (VEGF) levels in serum and peritoneal fluid, and the presence of pelvic endometriosis and its clinical symptoms. METHODS: Blood and peritoneal fluid sample levels of VEGF were measured in 46 women undergoing laparoscopy: 32 with suspected endometriosis and 14 with confirmed endometriosis. Data were analyzed according to phase of the menstrual cycle, symptoms, disease stage, and disease site. RESULTS: There were no significant associations between serum and peritoneal fluid levels of VEGF and the presence of endometriosis, even when controlling for the menstrual phase. However, among the women with confirmed endometriosis, there was a significant increase (P=0.002) in the mean peritoneal VEGF level in those in the late secretory phase compared with those in the proliferative and early secretory phases. CONCLUSIONS: Measuring VEGF levels in symptomatic patients is not helpful to differentiate those with endometriosis from those with a different condition. However, in the late secretory and menstrual phases, mean VEGF levels were higher in women with confirmed endometriosis than in those suspected of having the disease.     

Peritoneal fluid-mediated enhancement of eutopic and ectopic endometrial cell proliferation is dependent on tumor necrosis factor-alpha in women with endometriosis

OBJECTIVE: To determine the effect of autologous peritoneal fluid and tumor necrosis factor-alpha (TNF-alpha) on proliferation of endometrial cells from women with endometriosis. DESIGN: Endometrial cells from eutopic and ectopic endometrium were cultured in vitro with peritoneal fluids or recombinant TNF-alpha for 72 hours before DNa synthesis determination by 3H-thymidine labeling and liquid scintillation counting. SETTING: An institute for the study and treatment of endometriosis and university-based research laboratories. PATIENT(S): Thirty-five women with endometriosis and 17 controls without endometriosis. MAIN OUTCOME MEASURE(S): In vitro incorporation of 3H-thymidine in endometrial cells was examined. RESULT(S): Peritoneal fluid from women with endometriosis enhanced proliferation of autologous and heterologous endometrial cell cultures from women with endometriosis. The soluble TNF-receptor etanercept blocked the ability of peritoneal fluid from women with endometriosis to enhance proliferation of eutopic or ectopic endometrial cells. Recombinant TNF-alpha also enhanced proliferation of eutopic and ectopic endometrial cells from women with endometriosis. In contrast, autologous peritoneal fluid, heterologous peritoneal fluid from women with endometriosis, and recombinant TNF-alpha failed to enhance, and often inhibited, the proliferation of eutopic endometrial cells from controls without endometriosis. CONCLUSION(S): Endometrial cells from women with endometriosis can utilize factors in peritoneal fluids, such as TNF-alpha, to facilitate proliferation in ectopic environments. Endometrial cells from women without endometriosis do not share this ability, suggesting that this abnormality is etiologically related to development of the disease. Therapy with agents that block the effects of TNF-alpha may be warranted.     

The role of unfolded protein response in the pathogenesis of endometriosis: contribution of peritoneal fluid

Research questionEndoplasmic reticulum stress (ERS) is caused by the accumulation of the misfolded or unfolded proteins in the endoplasmic reticulum and induces the unfolded protein response (UPR). Peritoneal fluid is important in the pathogenesis of endometriosis. In this study, the role of UPR associated with ERS in endometriosis, and peritoneal fluid, were investigated.DesignNormal, eutopic and ectopic endometrium tissues were divided into menstrual cycle phases, and endometrial stromal cells (ESC) were treated with 10–20% concentration of control peritoneal fluid and peritoneal fluid obtained from women with endometriosis for 10, 30 and 60 min, and 24 and 48 h. The UPR signalling proteins were analysed immunohistochemically and immunocytochemically. Data were compared statistically.Resultsp-IRE1 was increased in ectopic glandular and stromal cells in the early proliferative phase compared with normal and eutopic endometrium. p-PERK increased in ectopic glandular and stromal cells in the late proliferative phase compared with normal endometrium. ATF6 was increased in ectopic glandular epithelium compared with normal endometrium in the proliferative phases, versus eutopic endometrium in the late secretory phase. p-IRE1 and p-PERK were increased in high concentrations of ESC treated with peritoneal fluid obtained from women with endometriosis for 10, 30 and 60 min compared with controls. In ESC treated with peritoneal fluid from women with endometriosis, p-IRE1 decreased at 24–48 h compared with 30 min.ConclusionsIn endometriosis, UPR pathways are activated as highly dependent on cell type and phase. Also, p-PERK and p-IRE1 increased because of exposure to high-dose peritoneal fluid from women with endometriosis in stromal cells. Our findings provide a basis for further studies searching for a potential biomarker for the diagnosis of endometriosis.     

Peritoneal fluid concentrations of ciliary neurotrophic factor,a gp130 cytokine,in women with endometriosis

Ciliary neurotrophic factor (CNTF) is a gp130 neuroregulatory cytokine belonging to the interleukin-6-type cytokine superfamily. Several lines of evidence suggest that the concentrations of interleukin-6 are elevated in the peritoneal fluid of endometriosis patients. To our knowledge, no study on whether this might also be the case for CNTF levels has been published previously. The CNTF concentrations in the peritoneal fluid were measured by ELISA in 51 women with (n = 31) and without (n = 20) endometriosis. Surgery was scheduled during the proliferative or the secretory phase of the menstrual cycle. CNTF was detectable in the peritoneal fluid of 43% of the women tested. The concentrations of CNTF showed no correlation with the presence of endometriosis or the phase of the menstrual cycle. We found no evidence to suggest that CNTF is involved in the pathogenesis of pelvic endometriosis.