Endometrial autoantigens eliciting immunoglobulin (Ig)G, IgA, and IgM responses in endometriosis**Presented at the 4th International Congress of Immunology of Reproduction, Kiel, Germany, July 26 to 30, 1989; and at the 45th Annual Meeting of The American Fertility Society, San Francisco, California, November 13 to 16, 1989

B Cell Lineage in the Human Endometrium: Physiological and Pathological Implications

Immunocompetent cells of B lineage function in the humoral immunity system in the adaptive immune responses. B cells differentiate into plasmacytes upon antigen-induced activation and produce different subclasses of immunoglobulins/antibodies. Secreted immunoglobulins not only interact with pathogens to inactivate and neutralize them, but also involve the complement system to exert antibacterial activities and trigger opsonization. Endometrium is a mucosal tissue that lines the mammalian uterus and is indispensable for the establishment of a successful pregnancy. The lymphocytes of B cell lineage are a minority in the human cycling endometrium. Human endometrial B cells have therefore been understudied so far. However, the disorders of the female reproductive tract, including chronic endometritis and endometriosis, have highlighted the importance of further research on the endometrial B cell lineage. This review aims to revisit lymphopoiesis, maturation, commitment, and survival of B cells, shedding light on their physiological and pathological implications in the human endometrium.

Commonalities and Disparities between Endometriosis and Chronic Endometritis: Therapeutic Potential of Novel Antibiotic Treatment Strategy against Ectopic Endometrium

Chronic endometritis (CE) is a local mucosal inflammatory disorder of the uterine lining, which is histopathologically recognized as the unusual infiltration of CD138(+) plasmacytes into the endometrial stromal compartment. Accumulating body of research documented that CE is associated with female infertility and several obstetric/neonatal complications. The major cause of CE is thought to be intrauterine infection represented by common bacteria (Escherichia coli, Enterococcus faecalis, Streptococcus, and Staphylococcus), Mycoplasma/Ureaplasma, and Mycobacterium. Additionally, local dysbiosis in the female reproductive tract may be involved in the onset and development of CE. Antibiotic treatments against these microorganisms are effective in the elimination of endometrial stromal plasmacytes in the affected patients. Meanwhile, endometriosis is a common female reproductive tract disease characterized by endometriotic tissues (ectopic endometrium) growing outside the uterus and potentially causes chronic pelvic symptoms (dysmenorrhea, dyspareunia, dyschezia, and dysuria), infertility, and ovarian cancers. Endometriosis involves endocrinological, genetic, and epigenetic factors in its etiology and pathogenesis. Recent studies focus on immunological, inflammatory, and infectious aspects of endometriosis and demonstrate several common characteristics between endometriosis and CE. This review aimed to better understand the immunological and microbial backgrounds underlying endometriosis and CE and look into the therapeutic potential of the novel antibiotic treatment strategy against endometriosis in light of endometrial infectious disease.

Impact of the vitamin D deficiency on COVID-19 infection and mortality in Asian countries

BACKGROUND AND AIMS

COVID-19 is a pandemic that has affected beyond 100 million and caused nearly 3 million deaths globally. Vitamin D is a known risk factor for COVID-19. Therefore, we aimed to investigate the association of prevalence of vitamin D deficiency and mean vitamin D level with COVID-19 infection and mortality in Asia, predicting with other confounding factors such as median age, obesity, and diabetes.

METHODS

COVID-19 infections and mortalities among the Asian countries were retrieved from the Worldometer website. Information on prevalence of vitamin D deficiency and mean vitamin D values in each Asian country was retrieved through literature searching on PubMed® and Google scholar. The associations between COVID-19 infections and mortalities with prevalence of vitamin D deficiency and mean vitamin D level were explored with correlation coefficients. As a predictive analysis, multiple linear regression was carried out with all confounders.

RESULTS

Positive correlations were observed for prevalence of vitamin D deficiency with COVID-19 infections (r = 0.55; p = 0.01; R2 = 0.31) and mortalities (r = 0.50; p = 0.01; R2 = 0.25). Moreover, the associations for the COVID-19 infections and mortalities improved to r = 0.76 (p = 0.002; R2 = 0.58) and r = 0.65 (p = 0.03; R2 = 0.42), respectively, after predicting with confounding factors. Similarly, mean vitamin D level had a significant negative correlation with COVID-19 infections (r = -0.77; p = 0.04; R2 = 0.59) and mortalities (r = -0.80; p = 0.03; R2 = 0.63) when combining with confounders.

CONCLUSION

Prevalence of vitamin D deficiency is significantly positively associated whereas the mean vitamin D level is significantly negatively associated with both infection and mortality rate of COVID-19 among Asian countries upon predicting with all confounders.

Biomarkers for the Noninvasive Diagnosis of Endometriosis: State of the Art and Future Perspectives

BACKGROUND

Early and accurate diagnosis of endometriosis is crucial for the management of this benign, yet debilitating pathology. Despite the advances of modern medicine, there is no common ground regarding the pathophysiology of this disease as it continues to affect the quality of life of millions of women of reproductive age. The lack of specific symptoms often determines a belated diagnosis. The gold standard remains invasive, surgery followed by a histopathological exam. A biomarker or a panel of biomarkers is easy to measure, usually noninvasive, and could benefit the clinician in both diagnosing and monitoring the treatment response. Several studies have advanced the idea of biomarkers for endometriosis, thereby circumventing unnecessary invasive techniques. Our paper aims at harmonizing the results of these studies in the search of promising perspectives on early diagnosis.

METHODS

We selected the papers from Google Academic, PubMed, and CrossRef and reviewed recent articles from the literature, aiming to evaluate the effectiveness of various putative serum and urinary biomarkers for endometriosis.

RESULTS

The majority of studies focused on a panel of biomarkers, rather than a single biomarker and were unable to identify a single biomolecule or a panel of biomarkers with sufficient specificity and sensitivity in endometriosis.

CONCLUSION

Noninvasive biomarkers, proteomics, genomics, and miRNA microarray may aid the diagnosis, but further research on larger datasets along with a better understanding of the pathophysiologic mechanisms are needed.

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.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included 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).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

Lack of Evidence That Male Fetal Microchimerism is Present in Endometriosis

INTRODUCTION

Fetal microchimerism has been implicated in the etiology of autoimmune diseases. This study was done to test the hypothesis that male fetal microchimerism is present in eutopic and ectopic endometrium (EM) obtained from women with endometriosis but not in eutopic EM from women without endometriosis.

METHODS

A total of 31 patients were selected, including women with endometriosis (paired eutopic and ectopic EM; n = 19) and women without endometriosis (eutopic EM; n = 12). Tricolor interphase fluorescence in situ hybridization analysis was performed by cohybridization of CEP Y SpectrumAqua and CEP X SpectrumGreen (SG)/CEP Y SpectrumOrange probes.

RESULTS

Ectopic EM from women with endometriosis had 75% XX chromosomes (double SG signals) and 25% X chromosomes (single SG signal). Y chromosomes were not observed in any of the eutopic/ectopic endometrial tissues from cases or controls.

CONCLUSIONS

We were unable to confirm our hypothesis that male fetal microchimerism is present in eutopic and/or ectopic EM obtained from women with endometriosis.

Comprehensive endometrial immunoglobulin subclass analysis in infertile women suffering from repeated implantation failure with or without chronic endometritis

PROBLEM

Chronic endometritis (CE) is a local inflammatory condition with unusual plasmacyte infiltration in the endometrial stromal area. CE is frequently found in infertile women with repeated implantation failure (RIF). In this study, we comprehensively investigated the endometrial immunoglobulin (Ig) subclass expression in infertile women suffering from RIF with versus without CE.

METHOD OF STUDY

Endometrial biopsy specimens obtained from 28 infertile women with RIF and CE (the RIF-CE group), 23 infertile women with RIF but without CE (the RIF-non-CE group), and 22 proven fertile women undergoing hysterectomy for benign endometrial pathology (the control group) were immunostained for Ig subclass expression.

RESULTS

The density of IgM+, IgA1+, IgA2+, IgG1+, and IgG2+ stromal cells were significantly higher in the RIF-CE group than that in the RIF-non-CE and control group. The density of IgG2+ stromal cells was significantly higher than that of any other Ig subclass-positive cells (P<0.045) in the RIF-CE group. In serial section staining, the immunoreactivity for CD138 and Ig subclasses in the endometrial stroma was detectable in adjacent cells of some specimens in the RIF-CE group.

CONCLUSIONS

The endometrium of infertile women with RIF-CE was characterized by increase in IgM, IgA, and IgG expression and predominance of IgG2 over other Ig subclasses.

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.

Serum antiendometrial antibodies and diagnosis of endometriosis

PROBLEM

The purpose of the present prospective multi-center study is to investigate the relationship between laparoscopic diagnosis of endometriosis and results of a serum antiendometrial antibody (AEA) assay.

METHOD OF STUDY

Indirect immunofluorescence detection of AEA was performed on serum specimens from patients presenting with dysmenorrhea or chronic pelvic pain and infertility (n = 2609) utilizing frozen sections of endometrium acquired on cycle days 18-21 from normally cycling women without endometriosis. Diagnostic laparoscopy was performed within 1 year of AEA assay on 527 tested women.

RESULTS

The relationship between the serum AEA and laparoscopic verification was characterized by a positive predictive value = 88%, negative predictive value = 86%, sensitivity = 87% and specificity = 87%.

CONCLUSION

The AEA assay is a very good screening test for patients suspected of having endometriosis and should be utilized prior to laparoscopy in diagnostic categories of dysmenorrhea or chronic pelvic pain and infertility.

Endometriosis: an inflammatory disease with a Th2 immune response component

BACKGROUND

Efforts have been made to correctly characterize the role of the immune response in endometriosis. The objective of this study was to analyse the interaction between Th1 and Th2 immune response patterns and endometriosis by evaluating a panel of cytokines.

METHODS

Between January 2004 and November 2005, 98 patients, classified into two groups according to the histologically confirmed presence (Group A) or absence of endometriosis (Group B), were evaluated. Interleukins (IL) 2, 4 and 10, tumour necrosis factor-alpha and interferon-gamma (IFN-gamma) were measured by flow cytometry in the peripheral blood and peritoneal fluid of all patients.

RESULTS

IFN-gamma and IL-10 levels were significantly higher in the peritoneal fluid of patients with endometriosis compared to those without endometriosis (P < 0.05). There was a significant alteration in the IL-4/IFN-gamma (P < 0.001), IL-4/IL-2 (P = 0.006), IL-10/IFN-gamma (P < 0.001) and the IL-10/IL-2 ratios (P < 0.001) in the peritoneal fluid of patients with endometriosis, with a predominance of IL-4 and IL-10, reflecting a shift towards Th2 immune response despite the increase in IFN-gamma concentrations.

CONCLUSIONS

Endometriosis is an inflammatory disease involving a possible shift towards Th2 immune response component, as demonstrated by the relative increase in cytokines characteristic of this pattern of immune response.

Use of proteomic analysis of endometriosis to identify different protein expression in patients with endometriosis versus normal controls

OBJECTIVE

To use proteomic techniques, including two-dimensional electrophoresis (2-DE), Western blot, and mass spectrometry, to screen and identify proteins that were expressed differently in patients with endometriosis versus normal controls.

DESIGN

First, we aimed to find a difference in the way serum and eutopic endometrial proteins were expressed in women with and without endometriosis. Second, we were interested in searching for endometriotic proteins, which were specifically recognized by sera from patients with endometriosis.

SETTING

Collaborative investigation in an academic research environment.

PATIENT(S)

Consenting women of reproductive age taking no medications and with laparoscopically proven endometriosis.

INTERVENTION(S)

Surgical excision of eutopic and ectopic endometrial biopsy and phlebotomization of patients with endometriosis and controls.

MAIN OUTCOME MEASURE(S)

Protein expression.

RESULT(S)

Thirteen protein spots from serum correlated with 11 known proteins and 11 protein spots from endometrium correlated with 11 known proteins were found differently expressed between women with and without endometriosis. Some proteins may be cytoskeletons, and some may be involved in the regulation of cell cycle, signal transduction, or immunological function. Three proteins, which were identified as vimentin, beta-actin, and ATP synthase beta subunit, hybridized significantly differently between endometriosis sera and normal sera.

CONCLUSION(S)

The data help to establish a human endometriosis proteome database and broaden our understanding of the pathogenesis of endometriosis. Further study of the proteins identified herein will assist in the eventual development of new diagnoses and treatments for endometriosis.

Immunology and Endometriosis

PROBLEM

Accumulating data suggests that aberrant immune responses during retrograde menstruation may be involved in the development of endometriosis.

METHOD OF STUDY

The role of immunology in the etiology of endometriosis is reviewed and summarized from the available literature.

RESULTS

Immunologic factors may affect a woman's susceptibility to implantation of exfoliated endometrial cells. Immune alterations include increased number and activation of peritoneal macrophages, decreased T cell reactivity and natural killer cell cytotoxicity, increased circulating antibodies, and changes in the cytokine network.

CONCLUSION

There is substantial evidence that immunologic factors play a role in the pathogenesis of endometriosis and endometriosis-associated infertility. Decreased natural killer cell cytotoxicity leads to an increased likelihood of implantation of endometriotic tissue. In addition, macrophages and a complex network of locally produced cytokines modulate the growth and inflammatory behavior of ectopic endometrial implants.

Immunobiology of endometriosis

OBJECTIVE

To provide a review of the humoral and cellular immunology of endometriosis and to discuss the rationale for future approaches to diagnosis and treatment.

DESIGN

Literature survey.

RESULT(S)

Defective immunosurveillance in women who are destined to develop endometriosis may allow for the survival of ectopic endometrial tissue. The evidence includes endometrial cell resistance to apoptosis, perhaps through the secretion of proteins that interfere with implant recognition and/or FasL expression by stromal cells, inducing apoptosis of Fas-bearing immune cells. Although the immune response may be defective, aspects of it clearly are enhanced in endometriosis, as is seen by the generalized polyclonal B-cell autoimmune activation and secretion of immune proteins. Several cytokines, chemokines, and growth factors (including vascular growth factors) are increased in women with endometriosis.

CONCLUSION(S)

A complex network of locally produced cytokines modulate the growth and inflammatory behavior of ectopic endometrial implants. Proinflammatory proteins from endometriotic lesions and associated immune cells contribute to the enhanced inflammatory reaction associated with endometriosis that subserves the survival of these lesions instead of leading to their demise.

Localization in tissues and secretion of eotaxin by cells from normal endometrium and endometriosis

Our laboratories have focused recently on the production and localization of eotaxin, a C-C-chemokine of 8.4 kDa, whose major biological activity is the chemoattraction of eosinophils. Given evidence of autoimmune activity in the endometriosis syndrome, we hypothesized that eosinophil chemoattractants might be expressed in endometriosis. In histological sections, we observed eotaxin protein localized mainly in epithelial cells, with only very faint immunostaining in the surrounding stromal cells. Prominent eotaxin accumulation was noted in the luminal epithelium of secretory endometrium. Eotaxin distribution in endometriosis was similar to that seen in eutopic endometrium but with higher levels of eotaxin staining in the glandular epithelium. Peritoneal fluid concentrations of eotaxin were significantly higher in women with moderate or severe endometriosis than in women with minimal or mild endometriosis or no disease. The treatment of isolated human endometriosis epithelial cells with estradiol, medroxyprogesterone acetate, tumor necrosis factor-alpha, and interferon-gamma stimulated measurable eotaxin secretion into the conditioned media. The results indicate that eotaxin is produced in epithelial cells of normal endometrium and endometriosis tissues, varies across the menstrual cycle, and is elevated in women with endometriosis. We postulate that eotaxin, interacting with other known cytokines and immune cells, contributes to an inflammatory reproductive tract environment, leading to endometrial or blastocyst dysfunction.

Anti-endometrial autoantibodies in women with a diagnosis of infertility

PROBLEM

The purpose of this study was to investigate the frequency of anti-endometrial antibodies (AEA) in infertile women.

METHOD OF STUDY

Sera from fertile women (n = 6), and from patients with ovulatory dysfunction (n = 11), tubal obstruction (n = 9) and unexplained infertility (n = 5) were investigated for the presence of anti-endometrial membrane antibodies. We used two human endometrial cancer cell lines and human endometrial cells from gynecological biopsies as an antigenic source for analysis. The immunoenzymatic assay (ELISA) was performed with cultured endometrial cells in monolayers. Immunoblot analysis was performed with these two cell lines.

RESULTS

A good correlation between the response with each cell line and with human endometrial cells was obtained, indicating that the antigens analyzed were probably similar. Endometrial antibodies were detectable in a high percentage of women with tubal obstruction (77.8 and 66.7%, respectively) and ovulatory dysfunction (54.5 and 45.5%, respectively). Unexplained infertility showed anti-endometrial immunological response (40 and 60%, respectively). Some endometrial antigens in infertile women are the target for autoimmune response. The serum from a patient with tubal obstruction and ovulatory dysfunction showed two antigens by immunoblot, with molecular weights of 97 and 50 kDa.

CONCLUSION

The presence of anti-endometrial antibodies, detected by ELISA, is associated with infertility, mainly with ovulatory dysfunction and tubal obstruction. Some endometrial antigens may be involved in these two pathologies.

Immunology and endometriosis. Fact, artifact, or epiphenomenon?

Endometriosis is a complex and intriguing disease. If retrograde menstruation normally occurs, then why do all women not develop endometriosis? The exact prevalence of endometriosis is unknown; however, a 20% to 90% prevalency rate has been reported in women with pelvic pain and infertility. This article reviews the factors involved.

Human autoantibodies recognizing human and mouse preimplantation stages

PROBLEM

To find out whether autoantibodies against human preimplantation stages are present in some human sera and, if so, whether the antibodies could be capable to affect the egg development and/or to trigger an activation of the complement system at the procedures of assisted conception.

METHODS

1. Immunohistochemistry on blots of human preimplantation stages. 2. Immunohistochemistry on paraffin sections of human and mouse preimplantation stages. 3. Culture of mouse morulae to analyze complement activation.

RESULTS

1. Some human sera contained autoantibodies against human preimplantation stages. 2. Human-mouse cross-reacting antibodies against preimplantation stages occurred. 3. Immune complexes, formed on mouse preimplantation stages, activated the complement systems in egg cultures, resulting in a damaging of the eggs.

CONCLUSION

The presence of natural autoantibodies to preimplantation stages may be associated with reproduction failure, caused by a direct effect by the autoantibodies and/or an activation of the uterine complement system by the immune complexes formed.

Antibodies to endometrial transferrin and alpha 2-Heremans Schmidt (HS) glycoprotein in patients with endometriosis

PROBLEM

Identifying the endometrial antigens inciting autoimmunity is important in setting up an antibody assay for a non-invasive diagnosis and clinical monitoring of endometriosis.

METHODS

Two-dimensional gel electrophoresis of endometrial extracts, Western blot analysis, passive hemagglutination and enzyme-linked immunosorbent assay (ELISA), amino acid sequencing and molecular studies were done on chosen antigens. Forty-six women with endometriosis, 4 women with uterine leiomyomata, 4 with pelvic adhesions, 3 with repeat Cesarean sections (conditions that coexist with or predispose to endometriosis) and 46 controls participated.

RESULTS

Antigens with molecular weights (MW) of 64 kDa [isoelectric point (pI) of 3.5-4.0] and 72 kDa (pI of 4.5) bound to IgG in all patients with endometriosis, but not the controls. Amino acid sequencing of the proteins revealed that they had homology to alpha 2-Heremans Schmidt (HS) glycoprotein (MW: 64 kDa) and transferrin (MW: 72 kDa). Endometriosis patients had significant antibody levels to these two proteins (predictive value of 80-90%). The analysis of patients' endometrial RNA detected the message for alpha 2-HS glycoprotein and transferrin. Albumin (pI 5.5) and collagen (pI 3.5) failed to elicit antibody responses.

CONCLUSIONS

Patients with endometriosis have significant antibodies to endometrial transferrin and alpha 2-HS-glycoprotein. We can effectively use an antibody assay using these antigens for diagnosing endometriosis.

Thoracic endometriosis syndrome: new observations from an analysis of 110 cases

PURPOSE

To determine the demographics, clinical presentations, pathological findings, and the effectiveness of treatment in 110 patients with thoracic endometriosis syndrome (TES).

METHODS

Retrospective analysis based on data published in the English medical literature.

RESULTS

The mean age at presentation of TES was 35 +/- 0.6 years (+/- standard error of the mean) with a range from 15 to 54. The trends of age-specific incidence for pelvic endometriosis and TES were similar. The peak incidence for pelvic endometriosis occurred between 24 and 29 years, whereas the peak incidence for TES was between 30 and 34 years. Pneumothorax was the most common presentation, occurring in 80 of 110 (73%), followed by hemothorax in 15 (14%), hemoptysis in 8 (7%), and lung nodules in 7 (6%). The right hemithorax was involved in more than 90% of all manifestations except for nodules. Hemothorax was more often associated with presence of pleural and pelvic endometriosis compared with other manifestations (P < 0.003, P < 0.02). Compared with hormonal treatment, surgical pleurodesis resulted in low recurrence rate for pneumothorax or hemothorax among patients treated with danazol or oral contraceptives.

CONCLUSIONS

There is a significant association between the presence of pelvic endometriosis and TES, with the latter occurring approximately 5 years later. Pneumothorax is the most common manifestation. The most plausible explanation for pathogenesis involves peritoneal-pleural movement of endometrial tissue through diaphragmatic defects and microembolization through pelvic veins. Diagnosis is established on clinical grounds in most cases. Surgical pleural abrasion is superior to hormonal treatment in the long-term management of pneumothorax. Earlier diagnosis and effective therapy of TES can decrease the morbidity of this disease in women during their reproductive period.

Human peritoneal macrophage and T lymphocyte populations in mild and severe endometriosis

PROBLEM

The aim of this study was to characterize the phenotype of peritoneal lymphocyte and macrophage populations in mild versus severe endometriosis.

METHOD

Using dual staining, antigen expression on peritoneal leukocytes from 24 women with endometriosis and 21 control patients was analyzed by flow cytometry.

RESULTS

All groups had CD4:CD8 ratios of 0.6, with subpopulations of CD8+ cells expressing cytotoxic marker S6F1. Mild and severe endometriosis patients had increased CD3/DR+ cells, relative to controls. Two populations of macrophages were identified by size in all groups. Mild endometriosis patients had increased percentages of small macrophages expressing CD14 and HLA DQ, compared to controls and severe disease patients. In severe disease patients, antigen expression on small macrophages did not differ from controls, but decreased percentages of large macrophages expressed CD14 relative to controls and mild disease patients.

CONCLUSION

All women with endometriosis exhibit activated peritoneal lymphocytes, whereas macrophage expression of CD14 is differentially expressed as a function of disease stage. Alterations in the functional capacity of these cells may contribute to the pathophysiology of this disease.

Detection of antiendometrial antibodies in sera of patients with endometriosis by dual-colored, double-labeling immunohistochemical method and western blot

PROBLEM

This study was undertaken to determine whether specific binding activities against endometrial proteins in sera of patients with endometriosis are detectable and, if so, to identify endometrial antigens involved in autoimmunity in endometriosis.

METHOD

Sera from 33 patients with endometriosis and 20 cord sera (controls) were tested against endometria of patients and their protein extracts by dual-colored, double-labeling immunohistochemical method, and Western blotting.

RESULTS

Antiendometrial binding activities were detected in sera of 2 (10.0%) control patients and 13 (48.2%) patients with endometriosis by the immunohistochemical method. Endogenous immunoglobulin G (IgG) binding to endometrial proteins had molecular weights (MW) of 26, 28, 54, 85, 107 and 116 kDa. Most sera of both control and patients showed reactivity against endometrial proteins with MW of 34, 36, 56 and 77 kDa. However, there were specific IgG autoantibodies reactive against the endometrial proteins of 71, 92, and 103 kDa in sera of 55.2% (16/29) of patients but not in the control sera. Over 80% (10/12) of patients' sera with binding activities detectable by the immunohistochemical method also tested positive by Western blot analysis.

CONCLUSIONS

These data show that specific IgG antibodies reactive against endometrial antigens are detectable in sera from some patients with endometriosis.

Target antigen(s) in endometrial autoimmunity of endometriosis

OBJECTIVE

To obtain the molecular weights (MW) of endometrial antigens eliciting immunoglobulin (Ig) G auto-antibodies in all endometriosis patients irrespective of their place of origin or race, and to verify their specificity and immunogenicity.

STUDY DESIGN AND RESULTS

We tested the serum and peritoneal fluid (P.F.) of 76 endometriosis patients and 24 controls from 4 cities against endometrial and implant antigens by Western blot analysis. Endometrial and implant antigens with MW of 34, 46/48, 64, 84, 94 and 120 kDa bound with IgG in serum and PF of most patients, but not the controls. Antigen(s) with MW of 64 kDa was reactive against serum or P.F. IgG of patients from all cities. Specificity: Endometrial and implant extracts did not react with monoclonal antibodies to WBC subsets and 5 sera with nuclear antibodies. Also, the presence of nuclear and endometrial antibodies did not correlate in 20 other patients with endometriosis. Immunogenicity: We immunized rabbits with the native and eluted (MW 29 to 68 kDa and > or = 68 kDa) endometrial and implant proteins. The antiserum had specific IgG binding to the same glandular epithelial antigens as those bound by the patient's serum.

CONCLUSIONS

Endometrial antigens with MW of 34, 46/48, 64, 94 and 120 kDa, especially 64 kDa appear to be specific, immunogenic and relevant to endometrial autoimmunity in all patients with endometriosis.

Markers for endometriosis

Screening for endometriosis is subject to general rules. The two most important conditions, i.e. the disorder should be well-defined and serious, and there must be an effective way to treat or prevent it through screening, are not satisfied for endometriosis. Given the lack of understanding of the pathogenesis of this disease and the disreputable evidence of treatment effectiveness, other criteria for worthwhile screening programmes, such as prevalence, cost effectiveness and screening test performance, cannot be evaluated. Markers may be applied in the diagnostic process in the individual patient, although it should be realized that the best results will be obtained in patients with advanced disease, in whom routine pelvic examination will establish the diagnosis on purely clinical grounds anyway. The development of appropriate tissue markers may in the future shed more light on the intricate mechanisms involved in the pathogenesis of endometriosis.

Antiendometrial autoantibodies are generated in patients with endometriosis

PROBLEM

Our aim was to investigate endometrial antigens involved in the autoimmunity of endometriosis.

METHOD

We detected endometrial antigens against which autoantibodies directed with Western blotting.

RESULTS

Thirteen (72.2%), 14 (77.8%), and 15 (83.3%) of 18 serum samples from endometriosis patients had antibodies reactive against endometrial antigen wtih MW of 26 kd, 34 kd, and 42 kd, respectively, while 6 (33.3%), 8 (44.4%), and 8 (44.4%) of 18 samples from normal control women reacted against these antigens, respectively. The frequencies of antibodies to the endometrial antigens were significantly (P < 0.05) higher in the endometriosis patients than in the normal control women. Antibodies in peritoneal fluid (PF) reacted against antigens with MW of 26, 34, 38, 42, and 64 kd, while those from the normal control reacted against antigens with MW of 38, 42, and 64 kd. Serum samples from normal fertile males did not show any reactivity against these endometrial antigens.

CONCLUSIONS

Our results show that autoantibodies reactive against endometrial antigens are present in patients with endometriosis.