Coordinated but depressed expression of human leukocyte antigen-DR, intercellular adhesion molecule-1, and CD14 on peritoneal macrophages in women with pelvic endometriosis

The roles of polymorphonuclear myeloid-derived suppressor cells in endometriosis

OBJECTIVES

This study aimed to determine the systemic and local proportions, focal localization, and characteristics of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in endometriosis.

STUDY DESIGN

Peripheral blood and peritoneal fluid were obtained from patients with a benign gynecologic condition (controls) or endometriosis. PMN-MDSCs were defined as CD33⁺HLA-DR^low/-CD14^-CD15⁺ and monocytic (M)-MDSCs were defined as CD33⁺HLA-DR^low/-CD14⁺CD15^-, and were identified using flowcytometry. Ovarian endometriotic tissues were obtained, and the expression of lectin-type oxidized low density lipoprotein receptor-1 (LOX1) as a marker of PMN-MDSCs, arginine 1 (Arg1), and matrix metalloproteinase 9 (MMP9) were detected using immunohistochemistry. Anti-Ly6G antibody was administered to endometriosis model mice, and the number and weight of the lesions were measured, and cell proliferations and apoptosis in the lesions were analyzed using Ki67 immunohistochemistry and TUNEL assay.

RESULTS

In the peripheral blood, the proportion of PMN-MDSCs was significantly higher in endometriosis (3.20 vs 1.63 %, p < 0.05), but the proportion of M-MDSCs did not differ between the groups. In the peritoneal fluid, the proportion of PMN-MDSCs was significantly higher in endometriosis (7.82 × 10^-1% vs 6.48 × 10^-2%, p < 0.05), whereas the proportion of M-MDSCs did not differ between the groups. PMN-MDSCs were detected in the stromal cell layer of the endometriotic cyst wall. Double staining for LOX1 and Arg1, and LOX1 and MMP9 was confirmed. Administration of Ly6G antibody did not change the number or weight of endometriosis lesions, but significantly decreased Ki67-positive cells and increased TUNEL-positive cells in the lesions.

CONCLUSIONS

PMN-MDSCs may contribute to the pathogenesis of endometriosis via Arg1 and MMP9 expression.

Blood biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, a costly chronic disease causing pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but is expensive and carries surgical risks. Currently, there are no non-invasive or minimally invasive tests available in clinical practice to accurately diagnose endometriosis. Although other reviews have assessed the ability of blood tests to diagnose endometriosis, this is the first review to use Cochrane methods, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To evaluate blood biomarkers as replacement tests for diagnostic surgery and as triage tests to inform decisions on surgery for endometriosis. Specific objectives include:1. To provide summary estimates of the diagnostic accuracy of blood biomarkers for the diagnosis of peritoneal, ovarian and deep infiltrating pelvic endometriosis, compared to surgical diagnosis as a reference standard.2. To assess the diagnostic utility of biomarkers that could differentiate ovarian endometrioma from other ovarian masses.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. We searched CENTRAL to July 2015, MEDLINE and EMBASE to May 2015, as well as these databases to 20 April 2015: CINAHL, PsycINFO, Web of Science, LILACS, OAIster, TRIP, ClinicalTrials.gov, DARE and PubMed.

SELECTION CRITERIA

We considered published, peer-reviewed, randomised controlled or cross-sectional studies of any size, including prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE). We included studies comparing the diagnostic test accuracy of one or more blood biomarkers with the findings of surgical visualisation of endometriotic lesions.

DATA COLLECTION AND ANALYSIS

Two authors independently collected and performed a quality assessment of data from each study. For each diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis, and we calculated sensitivity and specificity estimates. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient datasets were available. The predetermined criteria for a clinically useful blood test to replace diagnostic surgery were a sensitivity of 0.94 and a specificity of 0.79 to detect endometriosis. We set the criteria for triage tests at a sensitivity of ≥ 0.95 and a specificity of ≥ 0.50, which 'rules out' the diagnosis with high accuracy if there is a negative test result (SnOUT test), or a sensitivity of ≥ 0.50 and a specificity of ≥ 0.95, which 'rules in' the diagnosis with high accuracy if there is a positive result (SpIN test).

MAIN RESULTS

We included 141 studies that involved 15,141 participants and evaluated 122 blood biomarkers. All the studies were of poor methodological quality. Studies evaluated the blood biomarkers either in a specific phase of the menstrual cycle or irrespective of the cycle phase, and they tested for them in serum, plasma or whole blood. Included women were a selected population with a high frequency of endometriosis (10% to 85%), in which surgery was indicated for endometriosis, infertility work-up or ovarian mass. Seventy studies evaluated the diagnostic performance of 47 blood biomarkers for endometriosis (44 single-marker tests and 30 combined tests of two to six blood biomarkers). These were angiogenesis/growth factors, apoptosis markers, cell adhesion molecules, high-throughput markers, hormonal markers, immune system/inflammatory markers, oxidative stress markers, microRNAs, tumour markers and other proteins. Most of these biomarkers were assessed in small individual studies, often using different cut-off thresholds, and we could only perform meta-analyses on the data sets for anti-endometrial antibodies, interleukin-6 (IL-6), cancer antigen-19.9 (CA-19.9) and CA-125. Diagnostic estimates varied significantly between studies for each of these biomarkers, and CA-125 was the only marker with sufficient data to reliably assess sources of heterogeneity.The mean sensitivities and specificities of anti-endometrial antibodies (4 studies, 759 women) were 0.81 (95% confidence interval (CI) 0.76 to 0.87) and 0.75 (95% CI 0.46 to 1.00). For IL-6, with a cut-off value of > 1.90 to 2.00 pg/ml (3 studies, 309 women), sensitivity was 0.63 (95% CI 0.52 to 0.75) and specificity was 0.69 (95% CI 0.57 to 0.82). For CA-19.9, with a cut-off value of > 37.0 IU/ml (3 studies, 330 women), sensitivity was 0.36 (95% CI 0.26 to 0.45) and specificity was 0.87 (95% CI 0.75 to 0.99).Studies assessed CA-125 at different thresholds, demonstrating the following mean sensitivities and specificities: for cut-off > 10.0 to 14.7 U/ml: 0.70 (95% CI 0.63 to 0.77) and 0.64 (95% CI 0.47 to 0.82); for cut-off > 16.0 to 17.6 U/ml: 0.56 (95% CI 0.24, 0.88) and 0.91 (95% CI 0.75, 1.00); for cut-off > 20.0 U/ml: 0.67 (95% CI 0.50 to 0.85) and 0.69 (95% CI 0.58 to 0.80); for cut-off > 25.0 to 26.0 U/ml: 0.73 (95% CI 0.67 to 0.79) and 0.70 (95% CI 0.63 to 0.77); for cut-off > 30.0 to 33.0 U/ml: 0.62 (95% CI 0.45 to 0.79) and 0.76 (95% CI 0.53 to 1.00); and for cut-off > 35.0 to 36.0 U/ml: 0.40 (95% CI 0.32 to 0.49) and 0.91 (95% CI 0.88 to 0.94).We could not statistically evaluate other biomarkers meaningfully, including biomarkers that were assessed for their ability to differentiate endometrioma from other benign ovarian cysts.Eighty-two studies evaluated 97 biomarkers that did not differentiate women with endometriosis from disease-free controls. Of these, 22 biomarkers demonstrated conflicting results, with some studies showing differential expression and others no evidence of a difference between the endometriosis and control groups.

AUTHORS' CONCLUSIONS

Of the biomarkers that were subjected to meta-analysis, none consistently met the criteria for a replacement or triage diagnostic test. A subset of blood biomarkers could prove useful either for detecting pelvic endometriosis or for differentiating ovarian endometrioma from other benign ovarian masses, but there was insufficient evidence to draw meaningful conclusions. Overall, none of the biomarkers displayed enough accuracy to be used clinically outside a research setting. We also identified blood biomarkers that demonstrated no diagnostic value in endometriosis and recommend focusing research resources on evaluating other more clinically useful biomarkers.

rhTNFR: Fc Suppresses the Development of Endometriosis in a Mouse Model by Downregulating Cell Proliferation and Invasiveness

Tumor necrosis factor α (TNF-α), a proinflammatory cytokine, may play an important role in the pathogenesis of endometriosis; therefore, TNF-α inhibitors potentially have an effect on endometriosis. To investigate the effect of anti-TNF-α treatment on endometriosis, 2 TNF-α inhibitors: recombinant human TNF receptor: Fc fusion protein (rhTNFR: Fc) and TNF-α monoclonal antibody (TNF-α mAb) were used to treat human eutopic endometrial stromal cells (hESCs), and the effects on cell survival, cell cycle, and invasiveness were compared. It was found that rhTNFR: Fc suppressed the TNF-α-induced hESC survival and invasiveness but not TNF-α mAb. Recombinant human TNF receptor: Fc fusion protein decreased the S phase of hESC compared with the TNF-α-treated group. Then, we used a surgically induced mouse model of endometriosis to study the effect of rhTNFR: Fc treatment in vivo. The fluorescence intensity and the size of implanted endometriotic lesions in the mouse model were decreased by rhTNFR: Fc. In conclusion, rhTNFR: Fc suppresses hESC survival and invasiveness and decreases the fluorescence intensity and implant size in the mouse model of endometriosis.

Dienogest improves human leucocyte antigen-DR underexpression and reduces tumour necrosis factor-α production in peritoneal fluid cells from women with endometriosis

OBJECTIVE

To determine the immunological effect of dienogest (DNG), an oral anti-endometriosis drug, on peritoneal fluid (PF) macrophages collected from women with endometriosis. Although it has been suggested that DNG has direct effects on endometriotic cells, including decreased cell proliferation and decreased anti-inflammatory cytokine production, the effects of DNG on PF cells are unclear.

STUDY DESIGN

The effects of DNG on PF cells from 34 women with endometriosis and 22 women without endometriosis (controls) were investigated. Expression of human leucocyte antigen (HLA)-DR in PF macrophages, obtained from the peritoneal cavity during laparoscopic surgery, was determined by flow cytometry. HLA-DR expression was measured again after PF cells had been cultured for 72 h in a humidified atmosphere at 37 °C in 5% CO₂-95% air with or without DNG. After 72 h of incubation, the concentration of pro-inflammatory tumour necrosis factor (TNF)-α in the media was measured by enzyme-linked immunosorbent assay.

RESULTS

HLA-DR expression was lower in PF macrophages from women with endometriosis compared with controls. However, after DNG treatment, HLA-DR expression in PF macrophages from women with endometriosis was increased to the same level as in controls. The TNF-α concentration in the media was decreased by DNG.

CONCLUSIONS

DNG can restore the antigen-presenting ability of PF macrophages by increased HLA-DR expression, and may have an anti-inflammatory effect on PF macrophages in women with endometriosis.

The expression of human leukocyte antigens class I and II in women with endometriosis or adenomyosis

OBJECTIVES

The human leukocyte antigen (HLA) system has been implicated in the aetiology of endometriosis. We aimed to compare the HLA class I and II expression in endometrial specimens from women with endometriosis or adenomyosis.

METHODS

We studied the HLA class I and II expression in endometrial specimens from 16 women with endometriosis and 15 with adenomyosis which were compared with 15 specimens from women without endometriosis or adenomyosis. Immunohistochemistry was performed using mouse antihuman IgG2a monoclonal antibody for HLA I and IgG1 for HLA II.

RESULTS

Women with endometriosis had significantly higher HLA I and II expression in stroma (100% and 87.5% vs. 66.7% and 40%, p < 0.02 and p = 0.007, respectively) and glands (87.5% and 56.3% vs. 46.7% and 20%, p < 0.02 and p = 0.04, respectively) compared to controls, while in the adenomyosis group the expression of HLA I was comparable with controls and the HLA II expression was increased in stromal cells (73.3% vs. 40%, p = 0.03) and decreased in glands (6.6% vs. 20%, p = NS).

CONCLUSION

Women with endometriosis had a significantly higher expression of HLA molecules whereas in adenomyosis there was a tendency of lower expression of these molecules. This could explain the suppression of cellular immunity in the peritoneal cavity.

Peripheral biomarkers of endometriosis: a systematic review

BACKGROUND

Endometriosis is estimated to affect 1 in 10 women during the reproductive years. There is often delay in making the diagnosis, mainly due to the non-specific nature of the associated symptoms and the need to verify the disease surgically. A biomarker that is simple to measure could help clinicians to diagnose (or at least exclude) endometriosis; it might also allow the effects of treatment to be monitored. If effective, such a marker or panel of markers could prevent unnecessary diagnostic procedures and/or recognize treatment failure at an early stage.

METHODS

We used QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria to perform a systematic review of the literature over the last 25 years to assess critically the clinical value of all proposed biomarkers for endometriosis in serum, plasma and urine.

RESULTS

We identified over 100 putative biomarkers in publications that met the selection criteria. We were unable to identify a single biomarker or panel of biomarkers that have unequivocally been shown to be clinically useful.

CONCLUSIONS

Peripheral biomarkers show promise as diagnostic aids, but further research is necessary before they can be recommended in routine clinical care. Panels of markers may allow increased sensitivity and specificity of any diagnostic test.

Peritoneal macrophage depletion by liposomal bisphosphonate attenuates endometriosis in the rat model

BACKGROUND

Activation of macrophages is central to the implantation of endometriosis (EM). We examined the hypothesis that macrophage depletion by intraperitoneal (IP) injection of liposomal alendronate (LA) could result in EM attenuation in a rat model, thus supporting the notion of the pivotal role of macrophages in EM pathology.

METHODS

In this study, 90 rats were subjected to an EM model and were divided randomly into seven groups: five groups were treated by 4x once-weekly IP injections of LA (0.02, 0.1, 1, 5 or 10 mg/kg) and the other two groups received saline injections (control) or empty liposomes. Sham-operated rats also received empty liposomes. Depletion of circulating monocytes was determined by flow cytometry analyzes of blood specimens. Four weeks after the initial surgery, the number, size and weight of implants were recorded, adhesions were graded, macrophage infiltration was assessed and the peritoneal fluid was analyzed for monocyte chemotactic protein 1 (MCP-1) and tumor necrosis factor alpha (TNFalpha).

RESULTS

Monocyte depletion following IP LA administration resulted in an inhibitory effect on the initiation and growth of EM implants, as expressed by implantation rate, adhesion scoring, implants' size and weight (>0.1 mg/kg LA, P < 0.05). Reduced numbers of infiltrating macrophages were observed in implants of the 1 mg/kg LA group. Peritoneal fluid MCP-1 levels were negatively correlated with LA dose (P < 0.001), whereas no significant correlation could be found for TNFalpha.

CONCLUSIONS

Macrophage depletion using IP LA has been shown to effectively inhibit the initiation and growth of EM implants, in a rat EM model. The clear dose-response effect may be viewed as a confirmation of the validity of the concept and encourages further study.

Association study of endometriosis and intercellular adhesion molecule-1 (ICAM-1) gene polymorphisms in a Japanese population

OBJECTIVE

Endometriosis is an immune-related, chronic inflammatory disease with polygenic predisposition. Cell adhesion molecules are expressed in endometriotic lesions, and in cells and tissues that are involved in the development and progression of the disease. In this study, we investigated the possible association between endometriosis and the G241R and K469E polymorphisms in the intercellular adhesion molecule-1 (ICAM-1) gene in a Japanese population.

METHODS

We compared the distribution of the G241R and K469E polymorphisms in the ICAM-1 gene in 126 endometriosis patients and 172 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in a Japanese population.

RESULTS

There were no significant differences between the cases and controls in the allele frequencies or genotype distributions of either the G241R or K469E polymorphisms in the ICAM-1 gene. The endometriosis patients were divided into a subgroup of women with severe disease only. However, no significant differences were observed in the allele frequencies and genotype distributions of the ICAM-1 K469E polymorphisms between this subgroup and the controls. In contrast, only one in 169 controls was heterozygous (G/A genotype), and the A allele in the G241R polymorphism was not found in any of the 126 endometriosis patients.

CONCLUSION

Our findings suggest that the G241R and K469E polymorphisms in the ICAM-1 gene are unlikely to be associated with an increased risk of endometriosis in the Japanese population.

IL-10-dependent down-regulation of MHC class II expression level on monocytes by peritoneal fluid from endometriosis patients

Endometriosis is a gynecologic disorder characterized by the ectopic growth of misplaced endometrial cells. Moreover, immunological abnormalities of cell-mediated and humoral immunity may be associated with the pathogenesis of endometriosis. The effects of peritoneal fluid (PF) from endometriosis patients on the expression levels of MHC class II and costimulatory molecules on the cell surfaces of monocytes were investigated. Compared to the PF of controls, the addition of 10% PF (n=10) from patients with endometriosis to culture medium significantly reduced the percentage of MHC class II-positive cells in cultures of a THP-1, monocytic cell line at 48 h. The effect of endometriosis patient PF (EPF) was dose-dependent, and similar effect was observed in peripheral blood monocytes. An inverse correlation was found between MHC class II expression level and IL-10 concentration in EPF (r=-0.518; p=0.019) and in the supernatant of peripheral blood monocyte cultured in EPF (r=-0.459; p=0.042) (n=20). The expression levels of costimulatory molecules (CD80 and CD86), but not of CD54 and B7-H1, were down-regulated by EPF. The mRNA level of HLA-DR was unaffected by EPF but protein level was reduced by EPF. Neutralizing IL-10 antibody abrogated MHC class II down-regulation on monocytes, which had been induced by EPF. However, in a functional assay, monocytes treated with EPF failed to stimulate T cell in mixed leukocyte reaction, although T cell proliferation was increased with EPF-treated monocytes and Staphylococcus enterotoxin B. These results suggest that MHC class II expression level on monocytes is down-regulated by EPF, but the cell stimulatory ability of monocytes does not coincide with MHC class II expression level.

Peritoneal fluid concentrations of interleukin-17 correlate with the severity of endometriosis and infertility of this disorder

This prospective study aimed to determine whether patients with endometriosis are having different level of interlukin-17 (IL-17) in peritoneal fluid when compared with patients without endometriosis. The patients with minimal/mild endometriosis had a significantly higher level of IL-17 in peritoneal fluid compared with those with moderate/severe endometriosis or without endometriosis. The concentration of IL-17 in peritoneal fluid was significantly higher when endometriosis and infertility coexist. However, the concentration of IL-17 in peritoneal fluid did not correlate with the phase of the menstrual cycle in the patients with or without endometriosis. Our study suggested that IL-17 might play an important role in the pathogenesis of early endometriosis and endometriosis-associated infertility.

Human leukocyte antigen expression by peritoneal macrophages from women with pelvic endometriosis is depressed but coordinated with costimulatory molecule expression

OBJECTIVE

To investigate the macrophage response in endometriosis, we determined expression of human leukocyte antigen (HLA)-ABC, HLA-DR, and their costimulatory molecules by peritoneal fluid (PF) macrophages.

DESIGN

Case-control study of immunologic markers.

SETTING

University hospital.

PATIENT(S)

We compared 38 Japanese women with endometriosis with 59 control subjects who were given other laparoscopic diagnoses.

INTERVENTION(S)

Venipuncture and laparoscopic peritoneal fluid collection.

MAIN OUTCOME MEASURE(S)

Expression of HLA-ABC, HLA-DR, CD54, CD40, CD58, CD80, and CD86 by peripheral blood (PB) monocytes and PF macrophages was quantitated as mean fluorescence intensities by flow cytometry. Expression of each marker on PF macrophages was divided by that on PB monocytes as an index of macrophage activation (macrophage activation ratio).

RESULT(S)

In women with endometriosis, PF macrophages showed significant positive correlations between expression of HLA-ABC and other costimulatory molecules and also between HLA-DR and their costimulatory molecules. However, expression of HLA-ABC and DR by PF macrophages, and also their activation ratios, were significantly lower than in controls.

CONCLUSION(S)

Coordination with costimulatory molecules but relatively low expression of HLA-ABC and HLA-DR indicates a positive but limited immune response (antigen presentation) to events in the peritoneal cavity in women with endometriosis. This may induce immune tolerance to implanted or metaplastic endometrial tissue.

Immunology of endometriosis

Endometriosis is a benign gynecologic disorder characterized by the ectopic growth of misplaced endometrial cells. A unifying hypothesis to explain endometriosis has not been elucidated as yet but numerous investigations have implicated disturbances in the immune response as fundamental to its etiology and pathogenesis. Clearly, the immune system is involved in endometriosis. It is not clear, however, whether and to what extent this involvement is a primary response leading to the initiation, promotion, and progression of the disease or a secondary response to the ectopic endometrial growth in an attempt to restore homeostasis. Thus, although numerous studies have shown alterations in cell-mediated and humoral immunity in subjects with endometriosis, the importance of these changes remains obscure. This review considers the past two decades of investigation of immune function changes in women with endometriosis with the expectation that this information will ultimately provide the basis for developing new approaches to patient management.