Cytokine and immune cell levels in peritoneal fluid and peripheral blood of women with early- and late-staged endometriosis

Identification of a disulfidptosis-related genes signature for diagnostic and immune infiltration characteristics in endometriosis

Endometriosis (EMs) is the prevalent gynecological disease with the typical features of intricate pathogenesis and immune-related factors. Currently, there is no effective therapeutic intervention for EMs. Disulfidptosis, the cell death pattern discovered recently, may show close relationships to immunity and EMs. In this study, bioinformatics analysis was used to investigate the role of disulfide breakdown related genes (DRGs) in EMs. The EMs gene expression matrix was subjected to differential analysis for identifying overlap between differentially expressed genes (DEGs) in EMs and genes associated with disulfide poisoning. Immunoinfiltration analysis was performed. In addition, the association of hub genes with immune cells was examined. Multiple machine learning methods were employed to identify hub genes, construction of predictive models, and validation using external datasets and clinical samples. Totally 15 overlapping genes were identified. Immune-correlation analysis showed that NK cells played a vital role, and these 15 genes were closely related to NK cells. PDLIM1 was further determined as the hub gene through machine learning techniques. Clinical samples and external datasets were adopted for validating the performance in diagnosis. According to the above findings, we built the predictive model, and calculated the AUCs obtained from three external validation datasets to demonstrate the model accuracy. RT-qPCR and IHC analyses were applied to confirm the results. Colony formation was used to verify the effect of PDLIM1 on the proliferation of primary EMs cells. A strong correlation between disulfidptosis and EMs was identified in this study, highlighting its close correlation with the immune microenvironment. Moreover, our results shed new lights on exploring biomarkers and potential therapeutic targets for EMs.

The Role of NK and T Cells in Endometriosis

Endometriosis, a debilitating condition, affects one in ten women of reproductive age. Its pathophysiology remains unclear, though deficiencies in immune surveillance are thought to create an environment conducive to the evasion of ectopic endometrial cells from the immune system. Our research explores the immunological impact of endometriosis both locally and systemically, emphasizing natural killer (NK) and T cell subpopulations. We incorporated 62 female patients who underwent laparoscopic surgery; of those, 47 had endometriosis, and 15 were controls. We collected peritoneal fluid (PF) and peripheral blood (PB) samples which were tagged with monoclonal antibodies and subsequently scrutinized using flow cytometry. Our findings revealed significant differences in immunological profiles based on demographic factors and symptomatology. In the endometriosis cohort, there was an increase in PB CD56HiCD16dim and PF CD8+ CD56dimCD16Hi NK cells. CD16+ CD4 T cell levels were significantly lower in the PB of endometriosis patients who smoke. Individuals with more severe disease displayed significantly higher levels of PB CD16+ CD8 T cells, which also increased in those with non-menstrual pelvic pain. Dysmenorrhea severity correlated with a progressive increase in PF CD8+ CD56dimCD16Hi NK cells. These variations in specific lymphocyte subsets, namely, within NK and T cells, suggest potential immunological mechanisms in the evolution and clinical presentation of endometriosis.

Identification and Immune Characteristics Study of Pyroptosis‑Related Genes in Endometriosis

Endometriosis (EMT) is a prevalent gynecological disorder characterized by pain and infertility associated with the menstrual cycle. Pyroptosis, an emerging cell death mechanism, has been implicated in the pathogenesis of diverse diseases, highlighting its pivotal role in disease progression. Therefore, our study aimed to investigate the impact of pyroptosis in EMT using a comprehensive bioinformatics approach. We initially obtained two datasets from the Gene Expression Omnibus database and performed differential expression analysis to identify pyroptosis-related genes (PRGs) that were differentially expressed between EMT and non-EMT samples. Subsequently, several machine learning algorithms, namely least absolute shrinkage selection operator regression, support vector machine-recursive feature elimination, and random forest algorithms were used to identify a hub gene to construct an effective diagnostic model for EMT. Receiver operating characteristic curve analysis, nomogram, calibration curve, and decision curve analysis were applied to validate the performance of the model. Based on the selected hub gene, differential expression analysis between high- and low-expression groups was conducted to explore the functions and signaling pathways related to it. Additionally, the correlation between the hub gene and immune cells was investigated to gain insights into the immune microenvironment of EMT. Finally, a pyroptosis-related competing endogenous RNA network was constructed to elucidate the regulatory interactions of the hub gene. Our study revealed the potential contribution of a specific PRG to the pathogenesis of EMT, providing a novel perspective for clinical diagnosis and treatment of EMT.

Crimson clues: advancing endometriosis detection and management with novel blood biomarkers

Endometriosis is an inflammatory condition affecting approximately 10% of the female-born population. Despite its prevalence, the lack of noninvasive biomarkers has contributed to an established global diagnostic delay. The intricate pathophysiology of this enigmatic disease may leave signatures in the blood, which, when detected, can be used as noninvasive biomarkers. This review provides an update on how investigators are utilizing the established disease pathways and innovative methodologies, including genome-wide association studies, next-generation sequencing, and machine learning, to unravel the clues left in the blood to develop blood biomarkers. Many blood biomarkers show promise in the discovery phase, but because of a lack of standardized and robust methodologies, they rarely progress to the development stages. However, we are now seeing biomarkers being validated with high diagnostic accuracy and improvements in standardization protocols, providing promise for the future of endometriosis blood biomarkers.

Bioinformatics identification and validation of biomarkers and infiltrating immune cells in endometriosis

Background

Endometriosis (EM) is a common gynecological disorder that often leads to irregular menstruation and infertility. The pathogenesis of EM remains unclear and delays in diagnosis are common. Thus, it is urgent to explore potential biomarkers and underlying molecular mechanisms for EM diagnosis and therapies.

Methods

Three EM-related datasets (GSE11691, GSE25628, and GSE86534) were downloaded from the Gene Expression Omnibus (GEO) which were integrated into a combined dataset after removing batch effect. Differentially expressed immune cell-related genes were obtained by CIBERSORT, WGCNA, and the identification of differentially expressed genes. Random forest model (RF), support vector machine model (SVM), and generalized linear model (GLM) were then constructed and the biomarkers for EM were determined. A nomogram evaluating the risk of disease was constructed and the validity was assessed by the calibration curve, DCA curve, and clinical impact curve. Single-gene Gene Set Enrichment Analysis (GSEA)was performed to explore the molecular mechanisms of biomarkers. The ceRNA regulatory network of biomarkers was created by Cytoscape and potential target drugs were obtained in the DGIdb database (Drug-Gene Interaction database).The expression levels of biomarkers from clinical samples was quantified by RT-qPCR.

Results

The ratio of eight immune cells was significantly different between the eutopic and ectopic endometrium samples. A total of eight differentially expressed immune cell-related genes were investigated. The SVM model was a relatively suitable model for the prediction of EM and five genes (CXCL12, PDGFRL, AGTR1, PTGER3, and S1PR1) were selected from the model as biomarkers. The calibration curve, DCA curve, and clinical impact curve indicated that the nomogram based on the five biomarkers had a robust ability to predict disease. Single gene GSEA result suggested that all five biomarkers were involved in labyrinthine layer morphogenesis and transmembrane transport-related biological processes in EM. A ceRNA regulatory network containing 184 nodes and 251 edges was constructed. Seven drugs targeting CXCL12, 49 drugs targeting AGTR1, 16 drugs targeting PTGER3, and 21 drugs targeting S1PR1 were extracted as potential drugs for EM therapy. Finally, the expression of PDGFRL and S1PR1 in clinical samples was validated by RT-qPCR, which was consistent with the result of public database.

Conclusions

In summary, we identified five biomarkers (CXCL12, PDGFRL, AGTR1, PTGER3, and S1PR1) and constructed diagnostic model, furthermore predicted the potential therapeutic drugs for EM. Collectively, these findings provide new insights into EM diagnosis and treatment.

Immunopathogenesis of endometriosis: An overview of the role of innate and adaptive immune cells and their mediators

BACKGROUND

Endometriosis is a chronic inflammatory disease associated with the growth and proliferation of endometrial-like tissues outside the uterus. Although the exact etiology and mechanism of the pathogenesis of the disease have not been fully elucidated, the immune system cells and the mediators produced by them can be named as effective factors in the onset and progression of the disease.

AIMS

We aim to attempt to review studies on the role of the immune system in endometriosis to better understand the pathogenesis of endometriosis.

CONTENT

Abundant production of inflammatory mediators by neutrophils and macrophages and reduced cytotoxicity of defined cells promote endometriosis at the early stages of the disease. Following an increase in the inflammation of the environment, the body takes compensatory mechanisms to reduce inflammation and establish homeostasis. For this purpose, the body produces remodeling and anti-inflammatory factors leading to slow conversion of the inflammatory environment into a non-inflammatory environment with proliferative and immunosuppressive properties. Environmental conditions induce M2 macrophages, TH2 cells, and Tregs differentiation, promoting disease progression by producing angiogenic and immunosuppressive factors. However, the exact molecular mechanism involved in changing inflammatory to non-inflammatory conditions is not yet fully understood.

IMPLICATIONS

Due to the common characteristics of endometriotic cells and cancer cells, most potential treatment options for endometriosis have been suggested due to the results of these methods in the treatment of cancer. In this pathway, immune system cells and soluble mediators can be used as targets.

Hypothetical roadmap towards endometriosis: prenatal endocrine-disrupting chemical pollutant exposure, anogenital distance, gut-genital microbiota and subclinical infections

BACKGROUND

Endometriosis is a gynaecological hormone-dependent disorder that is defined by histological lesions generated by the growth of endometrial-like tissue out of the uterus cavity, most commonly engrafted within the peritoneal cavity, although these lesions can also be located in distant organs. Endometriosis affects ~10% of women of reproductive age, frequently producing severe and, sometimes, incapacitating symptoms, including chronic pelvic pain, dysmenorrhea and dyspareunia, among others. Furthermore, endometriosis causes infertility in ~30% of affected women. Despite intense research on the mechanisms involved in the initial development and later progression of endometriosis, many questions remain unanswered and its aetiology remains unknown. Recent studies have demonstrated the critical role played by the relationship between the microbiome and mucosal immunology in preventing sexually transmitted diseases (HIV), infertility and several gynaecologic diseases.

OBJECTIVE AND RATIONALE

In this review, we sought to respond to the main research question related to the aetiology of endometriosis. We provide a model pointing out several risk factors that could explain the development of endometriosis. The hypothesis arises from bringing together current findings from large distinct areas, linking high prenatal exposure to environmental endocrine-disrupting chemicals with a short anogenital distance, female genital tract contamination with the faecal microbiota and the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis.

SEARCH METHODS

We performed a search of the scientific literature published until 2019 in the PubMed database. The search strategy included the following keywords in various combinations: endometriosis, anogenital distance, chemical pollutants, endocrine-disrupting chemicals, prenatal exposure to endocrine-disrupting chemicals, the microbiome of the female reproductive tract, microbiota and genital tract, bacterial vaginosis, endometritis, oestrogens and microbiota and microbiota-immune system interactions.

OUTCOMES

On searching the corresponding bibliography, we found frequent associations between environmental endocrine-disrupting chemicals and endometriosis risk. Likewise, recent evidence and hypotheses have suggested the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis. Hence, we can envisage a direct relationship between higher prenatal exposure to oestrogens or estrogenic endocrine-disrupting compounds (phthalates, bisphenols, organochlorine pesticides and others) and a shorter anogenital distance, which could favour frequent postnatal episodes of faecal microbiota contamination of the vulva and vagina, producing cervicovaginal microbiota dysbiosis. This relationship would disrupt local antimicrobial defences, subverting the homeostasis state and inducing a subclinical inflammatory response that could evolve into a sustained immune dysregulation, closing the vicious cycle responsible for the development of endometriosis.

WIDER IMPLICATIONS

Determining the aetiology of endometriosis is a challenging issue. Posing a new hypothesis on this subject provides the initial tool necessary to design future experimental, clinical and epidemiological research that could allow for a better understanding of the origin of this disease. Furthermore, advances in the understanding of its aetiology would allow the identification of new therapeutics and preventive actions.

Multiplex analysis of 40 cytokines do not allow separation between endometriosis patients and controls

Endometriosis is a common gynaecological condition characterized by severe pelvic pain and/or infertility. The combination of nonspecific symptoms and invasive laparoscopic diagnostics have prompted researchers to evaluate potential biomarkers that would enable a non-invasive diagnosis of endometriosis. Endometriosis is an inflammatory disease thus different cytokines represent potential diagnostic biomarkers. As panels of biomarkers are expected to enable better separation between patients and controls we evaluated 40 different cytokines in plasma samples of 210 patients (116 patients with endometriosis; 94 controls) from two medical centres (Slovenian, Austrian). Results of the univariate statistical analysis showed no differences in concentrations of the measured cytokines between patients and controls, confirmed by principal component analysis showing no clear separation amongst these two groups. In order to validate the hypothesis of a more profound (non-linear) differentiating dependency between features, machine learning methods were used. We trained four common machine learning algorithms (decision tree, linear model, k-nearest neighbour, random forest) on data from plasma levels of proteins and patients’ clinical data. The constructed models, however, did not separate patients with endometriosis from the controls with sufficient sensitivity and specificity. This study thus indicates that plasma levels of the selected cytokines have limited potential for diagnosis of endometriosis.

Serum and peritoneal fluid levels of interleukin-6 and interleukin-37 as biomarkers for endometriosis

This study aimed to compare the levels of interleukin (IL)-1β, IL-6, IL-10, and IL-37 in the serum and peritoneal fluid of women with and without endometriosis. In addition, it aimed to determine the diagnostic values of the cytokines with significantly different concentrations. The levels of IL-1β, IL-6, IL-10, and IL-37 in the serum and peritoneal fluid samples of 40 women with endometriosis and 32 women without endometriosis were measured using an enzyme-linked immunosorbent assay. The serum and peritoneal fluid levels of IL-1β and IL-10 were not statistically significantly different between the endometriosis and control groups. The IL-6 and IL-37 levels in the serum and peritoneal fluid were higher in the endometriosis group than in the control group, and they were correlated with the stage of endometriosis. The AUC for the IL-37 was 0.897 for the serum and 0.934 for the peritoneal fluid, while the AUC for the IL-6 was 0.905 for the serum and 0.952 for the peritoneal fluid. Our results suggest that the serum and peritoneal fluid IL-6 and IL-37 levels were significantly increased in the endometriosis patients, indicating that these cytokines may serve as biomarkers for the diagnosis of endometriosis.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

The involvement of multifunctional TGF-β and related cytokines in pathogenesis of endometriosis

PURPOSE

Transforming growth factor β (TGF-β) is one of the major immune and inflammation factors responsible for regulating cell proliferation, differentiation, angiogenesis, and immune responses. Deregulated TGF-β activity, especially its influence in peritoneal cytokine cross-talk, has been implicated in pathologies of endometriosis. The aim of this study was to determine whether TGF-β could be involved in the pathogenesis of endometriosis. For this purpose, we evaluated concentrations of TGFβ1, TGF-β2, TGF-β3 and interleukin (IL)-1β, IL-6, IL-10, IL-17, IL-21 and IL-22 in peritoneal fluid (PF) and serum of women with endometriosis.

METHODS

A total of 66 women of reproductive age were involved in the study, 51 endometriosis patients, and 15 women from the control group. PF and serum levels of all cytokines were measured with ELISA in women with or without endometriosis.

RESULTS

Higher PF and serum levels of TGF-β1, TGF-β2, TGF-β3, presented also as a total TGF-β in women with endometriosis compared to control were observed. The biggest increase was measured in the case of TGF-β1. The higher levels of IL-1β, IL-6, IL-10, and IL-17 in PF and serum of endometriosis women than control was observed. Higher PF levels of studied parameters in comparison with serum levels were found.

CONCLUSIONS

In endometriosis, TGF-β could affect differentiation of T helper (Th) cells, hence produce more IL-17 and IL-10 to PF and might have an indirect influence on inflammation, which is associated with higher IL-1β and IL-6 levels. In consequent, TGF-β in peritoneal fluid may promote an environment favorable to ectopic lesion formation.

Expression of inflammatory cytokines in serum and peritoneal fluid from patients with different stages of endometriosis

OBJECTIVE

To investigate the level of inflammatory cytokines in endometriosis patients, and explore the relationship between IL-37 concentration and endometriosis stages.

METHODS

Inflammatory cytokine concentrations from 27 patients with different stages of endometriosis and 52 controls without endometriosis were examined by ELISA. Then, the specificity and sensitivity of cytokines for distinguishing from controls and the different stages of endometriosis were analyzed using the ROC curve.

RESULTS

The difference in serum concentrations of IL-37, IL-17A, IL-10, and IL-2 between the endometriosis and control groups was statistically significant (p < .01). Compared with controls, significantly higher levels of serum IL-37 and IL-10, and significantly lower levels of serum IL-17A and IL-2 were detected in patients with endometriosis (p < .01). Furthermore, IL-2 concentration was significantly higher in peritoneal fluid (PF) in the endometriosis group (p = .0034), IL-10 concentrations in PF were significantly lower in the early-stages of endometriosis than in the more advanced groups (p = .0439), and IL-4 concentration in PF was significantly higher in more advanced endometriosis (p = .0228). The sensitivity and specificity of serum IL-37 for distinguishing endometriosis were 81.48% and 83.33%, respectively, and the cutoff concentration was 69.84 pg/ml. For IL-17A, the sensitivity and specificity were 96.30% and 100%, respectively, and the cutoff concentration was 57.54 pg/ml. For IL-10, the sensitivity and specificity was 92.59% and 100%, respectively, and the cutoff concentration was 3.301 pg/ml. For IL-2, the sensitivity and specificity were 74.07% and 93.75%, respectively, and the cutoff concentration was 1.813 pg/ml. For PF IL-2, the sensitivity and specificity were 29.73% and 100%, respectively, and the cutoff concentration was 1.06 pg/ml.

CONCLUSIONS

IL-37, IL-17A, IL-10, and IL-2 may play a significant role in immune response in endometriosis. IL-37 levels may be used as a diagnostic marker for endometriosis.

Brain-Derived Neurotrophic Factor in Plasma of Women with Endometriosis

Purpose

Endometriosis is one of the most common benign gynecological diseases affecting women of reproductive age; it is characterized by the presence and growth of ectopic endometrial tissue outside the endometrial cavity. This complex disease is frequently associated with infertility and pelvic pain. Given the relationship and the apparent importance of the role that neurotrophins play in the reproductive system, and in particular brain-derived neurotrophic factor (BDNF) which is involved in both the central and peripheral pain pathways, we were interested in determining whether the presence of endometriosis is associated and correlated with plasma and follicular fluid variation of BDNF.

Methods

We determined BDNF level in plasma and in follicular fluid from infertile women with endometriosis and fertile women without the disease.

Results

BDNF plasma levels were significantly higher in endometriotic patients than in control women (p<0.001). After surgery this level decreased significantly (p<0.001), ranging within the values of control women in follicular phase. In follicular fluid, BDNF values were significantly lower in infertile women for endometriosis than in infertile women for male factors (p<0.001).

Conclusion

These data raise the possibility that neuroinflammatory reactions in endometriosis could have a neuroprotective effect and support the hypothesis that BDNF represents an important link in the networks of human homeostasis, thus providing an early marker for patients affected by endometriosis. Moreover, low BDNF levels in follicular fluid may refect an altered ovary production and may be a marker of poor oocyte quality and poor fertility in women suffering from endometriosis.

Expansion of monocytic myeloid-derived suppressor cells in endometriosis patients: A pilot study

Endometriosis is a chronic inflammation disease and is closely associated with immune dysregulation. Myeloid-derived suppressor cells (MDSCs) are a negative regulator of the immune system. The aim of this study was to evaluate the possible role of MDSCs in endometriosis patients. We collected the peripheral blood and peritoneal fluid from endometriosis patients and controls and analyzed M-MDSCs level using specific monoclonal antibodies recognizing HLA-DR, CD33, CD11b, CD14 markers by flow cytometry. We found that there existed abnormal expansion of monocytic MDSCs (M-MDSCs) (HLA-DR-/lowCD33+CD11b+ CD14+) in peripheral blood and peritoneal fluid of patients with endometriosis. Functional studies revealed that M-MDSCs from endometriosis patients significantly suppressed T-cell responses and produced high level of reactive oxygen species (ROS). The elevation of M-MDSCs from endometriosis patients may contribute to the disease progression.

Relevant human tissue resources and laboratory models for use in endometriosis research

Endometriosis is characterized by the growth of endometrium‐like tissue outside the uterus, most commonly on the pelvic peritoneum and ovaries. Although it may be asymptomatic in some women, in others it can cause debilitating pain, infertility or other symptoms including fatigue. Current research is directed both at understanding the complex etiology and pathophysiology of the disorder and at the development of new nonsurgical approaches to therapy that lack the unwanted side effects of current medical management. Tools for endometriosis research fall into two broad categories; patient‐derived tissues, and fluids (and cells isolated from these sources) or models based on the use of cells or animals. In this review, we discuss the literature that has reported data from the use of these tools in endometriosis research and we highlight the strengths and weaknesses of each. Although many different models are reported in the literature, hypothesis‐driven research will only be facilitated with careful experimental design and selection of the most appropriate human tissue from patients with and without endometriosis and combinations of physiologically relevant in vitro and in vivo laboratory models.

Endometriosis-associated changes in serum levels of interferons and chemokines

BACKGROUND/AIM

The aim of the study was to evaluate the serum concentration of main chemokines and interferons in patients with diagnosed endometriosis.

MATERIALS AND METHODS

A total of 160 women were divided in two study groups (group 1 - endometriosis; group 2 - healthy women). Serum levels of IFN-α, IFN-γ, MCP-1, MIP-1α, MIP-1β, RANTES, eotaxin, IL-8, MIG, IP-10, and IL-17A were measured with Human Multiplex Cytokine Panels. Results. Serum levels of IFN-γ, MCP-1, and IL-8 were significantly higher (mean 14.03, 57.24, and 534.24, respectively, compared to 0.58, 20.51, and 259.82, respectively), and serum levels of IP-10 and eotaxin were significantly lower in women with endometriosis compared to the controls (mean 1.15 and 1.01, respectively, compared to 3.90 and 3.22, respectively). Conclusions. According to our results women with endometriosis have elevated levels IFN-γ, MCP-1, and IL-8, and lower serum levels of IP-10 and eotaxin, indicating unbalanced immune activity in endometriosis.

The association between interleukin-4 -590C/T genetic polymorphism, IL-4 serum level, and advanced endometriosis

Aim of the study

Aim of the study was to investigate interleukin (IL)-4 serum levels in patients with advanced endometriosis and whether IL-4 promoter region (-590C/T) genetic polymorphism is involved in genetic susceptibility to endometriosis.

Material and methods

IL-4 serum levels and IL-4 -590C/T genetic polymorphism were determined for 80 patients with advanced endometriosis and 85 healthy fertile women using a multiplex cytokine kit, with a Luminex 200 system; high molecular weight genomic DNA was extracted from peripheral blood leukocytes, and further analyzed by PCR amplification and restriction fragment length polymorphism (PCR-PFLP). The relationship between IL-4 serum levels, genotypes and haplotypes and the presence of endometriosis was explored.

Results

Interleukin 4 serum levels were significantly higher in the endometriosis group compared to controls (138,459 compared to 84,710, p < 0.001). No significant difference was observed in IL-4 serum levels between genotypes. There were no differences in IL-4 -590C/T genotypes and allele frequencies between control women and patients with endometriosis (χ² = 0.496, and χ² = 0.928, OR = 1.3636, CI: 0.725-2.564).

Conclusions

The results suggest that in patients with advanced stages of endometriosis there is a higher serum level of IL-4, and that this value, or the presence of the disease, is not influenced by the presence of IL-4 -590C/T genetic polymorphism.

Limited value of pro-inflammatory oxylipins and cytokines as circulating biomarkers in endometriosis - a targeted 'omics study

Endometriosis is a common, complex gynecologic disorder characterized by the presence of endometrial-like tissues at extrauterine sites. Elevation in protein and lipid mediators of inflammation including oxylipins and cytokines within the peritoneum characterize the inflamed pelvic region and may contribute to the survival and growth of displaced endometrial tissues. The presence of a clinically silent but molecularly detectable systemic inflammation in endometriosis has been proposed. Thus, we examined serum oxylipin and immunomodulatory protein levels in 103 women undergoing laparoscopy to evaluate systematically any involvement in systemic pathophysiological inflammation in endometriosis. Oxylipin levels were similar between women with and without endometriosis. Stratification by menstrual phase or severity did not offer any difference. Women with ovarian endometriosis had significantly lower 12-HETE relative to peritoneal endometriosis (−50.7%). Serum oxylipin levels were not associated with pre-operative pain symptoms. Changes to immunomodulatory proteins were minimal, with IL-12(p70), IL-13 and VEGF significantly lower in mild endometriotic women compared to non-endometriotic women (−39%, −54% and −76% respectively). Verification using C-reactive protein as a non-specific marker of inflammation further showed similar levels between groups. The implications of our work suggest pro-inflammatory mediators in the classes studied may have potentially limited value as circulating biomarkers for endometriosis, suggesting of potentially tenuous systemic inflammation in endometriosis.

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.

Prospective Evaluation of a Panel of Plasma Cytokines and Chemokines as Potential Markers of Pelvic Endometriosis in Symptomatic Women

BACKGROUND

Endometriosis is a chronic inflammatory disease for which no accurate peripheral diagnostic marker is available. Many cytokines and chemokines have been found altered in the plasma and peritoneal fluid of women with endometriosis compared to healthy controls, but little is known about their diagnostic utility to confirm or discard endometriosis among symptomatic women.

OBJECTIVE

The study aims to assess the diagnostic value of a panel of plasma cytokines and chemokines to detect endometriosis in women undergoing laparoscopy for gynecological complains.

METHODS

We performed a prospective cohort study evaluating simultaneously plasma concentrations of interleukin (IL)-2, IL-4, IL-6, IL-10, MCP-1/CCL2, IP-10/CXCL10 and eotaxin/CCL11 in 75 symptomatic women (chronic pelvic pain, infertility or ovarian cyst) submitted to laparoscopy. Assays were performed by Cytometric Bead Array System. Endometriosis was confirmed by histopathological examination of surgical specimens.

RESULTS

Plasma IL-2, IL-4, IL-6, IL-10, MCP-1/CCL2, IP-10/CXCL10 and eotaxin/CCL11 concentrations were not able to distinguish the women who eventually were diagnosed with endometriosis.

CONCLUSION

Although previously shown to be altered in women with endometriosis compared to healthy women, the tested cytokines and chemokines were not useful to predict the presence of endometriosis among symptomatic women. This finding suggests that inflammatory markers modified by endometriosis may also be altered by other conditions associated with similar symptoms, which limits their use in clinical practice.

Serum markers for the noninvasive diagnosis of endometriosis

Endometriosis is a disease that affects millions of women worldwide and its diagnosis is still challenging. Medical history, symptoms together with imaging data may address the correct diagnosis, but the gold standard remains laparoscopic assessment with histological confirmation. The development of serum markers as diagnostic tools for endometriosis may allow a prompt and noninvasive diagnosis. Several serum biomarkers have been investigated over the years, but none of these have shown a clinical utility and nowadays the more realistic diagnostic biomarker consists in a panel of biomarkers. The recent introduction of new technologies such as genomics and proteomics may represent the future perspective of endometriosis diagnosis.

Diagnostic potential of peritoneal fluid biomarkers of endometriosis

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus, in different parts of the peritoneal cavity. It affects up to 10% of reproductive-age women and up to 50% of women with infertility. Surgical diagnosis of endometriosis is still the gold standard, with no diagnostic biomarkers available. Medical therapies target the symptoms and not the disease itself, and surgical treatment cannot prevent recurrence. As peritoneal fluid reflects the altered peritoneal microenvironment of endometriosis patients, it can provide a wealth of information on pathophysiological processes and potential biomarkers. This report reviews the molecular biomarkers identified in peritoneal fluid over the last 5 years and discusses their potential applications for diagnosis, prognosis and drug therapy.

An increased level of IL-6 suppresses NK cell activity in peritoneal fluid of patients with endometriosis via regulation of SHP-2 expression

STUDY QUESTION

Is the decreased natural killer (NK) cell cytolytic activity in the peritoneal fluid (PF) of endometriosis patients due to primary cytokine activity?

SUMMARY ANSWER

An increased level of interleukin-6 (IL-6) in the PF of patients with endometriosis suppresses NK cell cytolytic activity by down-regulating cytolytic granule components, such as granzyme B and perforin, through the modulation of Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) expression.

WHAT IS ALREADY KNOWN

Endometriosis is known to be related to a defect in NK cell cytolytic activity. Additionally, the levels of inflammatory cytokines are elevated in the PF of women with endometriosis.

STUDY DESIGN, SIZE, DURATION

The effects of PF on the differentiation and functional activity of NK cells were investigated in patients with or without endometriosis, and cytokines that reduce NK cell cytolytic activity in endometriosis patients were examined. The study included women who underwent laparoscopic examination for the diagnosis of endometriosis from August 2012 to July 2013 (33 women with, and 15 women without, endometriosis).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women of reproductive age (20-40 years old) who underwent laparoscopic examination for endometriosis were included. Cytokines present in the PF were identified by enzyme-linked immunosorbent assay. The cytolytic activity of NK cells in the PF was also analyzed using a calcein-acetoxy methyl ester (AM) release assay.

MAIN RESULTS AND THE ROLE OF CHANCE

PF from patients with endometriosis suppressed the differentiation and cytotoxicity of NK cells compared with PF from controls (P < 0.05). Increased levels of IL-6 were also found in the PF of patients with endometriosis (P < 0.01), and IL-6 levels were negatively correlated with the cytolytic activity of NK cells (rs = -0.558, P = 0.03). Furthermore, IL-6 reduced the cytolytic activity of NK cells, concomitantly with the down-regulation of granzyme B and perforin (P < 0.05), by modulating SHP-2. Importantly, the addition of anti-IL-6 to the PF of endometriosis patients restored the activity of NK cells (P < 0.01), suggesting that IL-6 plays a crucial role in the reduction of NK cell activity in the PF of patients with endometriosis.

LIMITATIONS, REASONS FOR CAUTION

PF contains various inflammatory cytokines in addition to IL-6 and so it is possible that other cytokines may affect the differentiation and activity of NK cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our results imply that the suppression of IL-6 using an anti-IL-6 antibody or soluble IL-6 receptor could rescue the impairment of NK cell activity in patients with endometriosis.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the KRIBB Creative Research Program (KCS3051312); the STP project (DTM0111221) of the Ministry of Knowledge & Economy and the Basic Science Research Program (RBM0271312) of the National Research Foundation of Korea (NRF) from the Ministry of Education, Science & Technology. There are no conflicts of interest.

Evaluation of mean platelet volume, neutrophil/lymphocyte ratio and platelet/lymphocyte ratio in advanced stage endometriosis with endometrioma

OBJECTIVE

We compared the preoperative values of mean platelet volume (MPV) and peripheral systemic inflammatory response (SIR) markers (neutrophil/lymphocyte ratio and platelet/lymphocyte ratio) between patients with advanced-stage (stage 3/4) endometriosis having endometrioma (OMA) and patients with a non-neoplastic adnexal mass other than endometrioma (non-OMA).

MATERIAL AND METHODS

Patients who underwent operations with the pre-diagnosis of infertility or adnexal mass and who underwent laparoscopic tubal ligation were included.

RESULTS

Haemoglobin levels, leucocyte count, platelet count, neutrophil count and lymphocyte count were not significantly different between patients with advanced stage endometriosis having OMA, patients with non-OMA and patients in the control group (p=0.970, p=0.902, p=0.373, p=0.501 and p=0.463, respectively). Patients with stage 3/4 endometriosis having OMA, patients with non-OMA and control patients were also not significantly different in terms of MPV (p=0.836), neutrophil/lymphocyte ratio (NLR) (p=0.555) and platelet/lymphocyte ratio (PLR) (p=0.358). Preoperative cancer antigen 125 (Ca-125) levels were significantly higher in patients with OMA (p=0.006). Mean size of the OMAs was significantly lower than non-OMAs (p=0.000).

CONCLUSION

It is very important to determine advanced stage endometriosis and OMAs during preoperative evaluation in order to inform patients and plan an appropriate surgical approach. We demonstrate that MPV, NLR and PLR values are not useful for this purpose in patients with advanced stage endometriosis that are proven to develop severe inflammation at either the cellular or molecular level.

Interleukin-19 and interleukin-22 serum levels are decreased in patients with ovarian endometrioma

OBJECTIVE

To determine the serum levels of interleukin (IL)-10 family ILs in women with ovarian endometriosis and investigate the correlation of these levels with disease activity.

DESIGN

A case-control laboratory study.

SETTING

Tertiary-care university hospital.

PATIENT(S)

Two hundred nineteen women, with (n = 112) and without (n = 107) endometriosis.

INTERVENTION(S)

Complete surgical excision with pathological analysis.

MAIN OUTCOME MEASURE(S)

Blood samples were obtained during surgical procedures. IL-10, -19, -20, and -22 were assayed by ELISA in sera, and the concentrations correlated with the extent and the severity of the disease.

RESULT(S)

IL-19 was detectable in 18.3% and IL-22 in 47.9% of sera samples from all 219 women studied. Serum IL-19 was lower in women with endometriosis (median, 292.7 pg/mL; range, 32.2-1,339.3) than in endometriosis-free women (median, 1,035.8 pg/mL; range, 32.2-2,000.0). In addition, serum IL-22 levels were decreased in women affected by endometriosis (median, 352.0 pg/mL; range, 31.2-1,392.2) as compared with endometriosis-free women (median, 709.2 pg/mL; range, 73.3-2,012.0). We found significant correlations between serum IL-22 concentrations and intensity of deep dyspareunia (r = -0.303) and noncyclic chronic pelvic pain (r = -0.212). IL-19 was correlated with the intensity of deep dyspareunia (r = -0.749).

CONCLUSION(S)

Serum IL-19 and IL-22 are decreased in women with ovarian endometrioma. IL-10 family ILs may be involved in the pathogenesis of endometriosis.

Serum and peritoneal fluid immunological markers in adolescent girls with chronic pelvic pain

The aim of this study was to determine serum and peritoneal interleukin (IL)-2, IL-4, and monocyte chemotactic protein-1 levels as diagnostic markers of endometriosis in adolescent girls. The design of the study encompassed 50 adolescent girls, aged 13 to 19 years after menarche, with chronic pelvic pain who qualified for diagnostic laparoscopy. The patients were allocated into 2 groups: group I (endometriosis) consisted of subjects with diagnosed endometriosis (n = 33, 66%) and group II (control) whose laparoscopic examinations revealed no evidence of endometriosis (n = 17, 34%). IL-2, IL-4, and Monocyte chemotactic protein 1 concentrations in serum and peritoneal samples were assessed using commercially available human enzyme-linked immunosorbent assay kits. The results were analyzed statistically with the Statistica 8.0 computer software. The value of P < 0.05 was the level of statistical significance. The results in adolescents with endometriosis had significantly higher concentrations of serum IL-4 (3.90 ± 1.58 pg/mL vs. 3.04 ± 1.72 pg/mL; P = 0.04) and peritoneal fluid IL-4 (5.03 ± 8.92 pg/mL vs. 2.74 ± 1.11 pg/mL; P = 0.03), and lower peritoneal fluid IL-2 (92.44 ± 292.75 pg/mL vs. 174.23 ± 389.77 pg/mL; P = 0.01) compared with the control. In a receiver-operating characteristic analysis, serum IL-4 as well as peritoneal fluid IL-2 and IL-4 provided the best discriminative ability between subjects with endometriosis and controls. Using cutoff points for serum IL-4 (3.00 pg/mL), peritoneal fluid IL-2 (21.00 pg/mL) and IL-4 (2.7 pg/mL), relatively high odd ratios were obtained in the prediction of endometriosis in adolescents (3.2; 6.4; 3.3). The Serum IL-4, peritoneal IL-2 and IL-4 provided a good method of discrimination between subjects with endometriosis and controls.

Ovarian endometrioma but not deep infiltrating endometriosis is associated with increased serum levels of interleukin-8 and interleukin-6

Cytokines, and specifically interleukin 6 (IL-6) and interleukin 8 (IL-8), have been associated with the pathogenesis of endometriosis. We studied serum concentrations of IL-6 and IL-8 in patients with deep infiltrating endometriosis (DIE) or ovarian endometriomas (OE), but no other forms of associated endometriosis disease type. We carried out a case-control study including 19 patients with OE alone (OE group), 14 patients with DIE alone (DIE group) and 24 healthy patients without endometriosis (C group). Serum concentrations of IL-6 and IL-8 were measured in the three groups of patients. Serum levels of both IL-6 and IL-8 were significantly higher in the OE group. A high positive correlation was found between serum IL-6 and IL-8 levels in the OE group but not in the DIE and C groups. Serum IL-8 alone achieved the highest predictive value of the presence of OE (adjusted OR: 1.44; sensitivity: 78.2%; specificity: 76.2%). The combination of IL-6 and IL-8 levels did not significantly improve the discrimination between subjects with OE and those with DIE over that of IL-8. OE but not DIE are associated with increased serum levels of IL-6 and IL-8, and thus these may become useful tools for discriminating OE alone from DIE.

Downregulative effects of nitric oxide on oocyte fertilization and embryo development: possible roles of nitric oxide in the pathogenesis of endometriosis-associated infertility

AIMS

To investigate the effects of elevated nitric oxide (NO) levels in peritoneal fluids (PF) on oocyte fertilization and pre-implantation embryo development, and the relation of those effects to endometriosis-associated infertility.

METHODS

PF from women undergoing laparoscopy for infertility of minor endometriosis, tubal blockage and operation for tubal ligation was aspired at the pouch of the cul-de-sac during surgery. Oocytes and embryos of adult ICR mice were cultured in vitro with or without endometriotic PF. The fertilization rate of oocyte and the cleavage rate of 2-cell embryos were examined. Also, the clinical indexes of IVF-ET of women with minor endometriosis and tubal infertility were analyzed.

RESULTS

Oocyte fertilization rate of endometriotic women with IVF-ET treatment was significantly lower than that of tubal block women. The dose-related adverse effects of endometriotic PF and SNP (NO donor) in culture medium on oocyte fertilization and embryos development were confirmed.

CONCLUSION

Increased NO levels in PF play an important role in mediating the effects of endometriotic PF on oocyte fertilization and embryo development. IVF might serve as an alternative treatment for endometriosis-associated infertility.

A structured questionnaire improves preoperative assessment of endometriosis patients: a retrospective analysis and prospective trial

PURPOSE

To determine whether a structured questionnaire can improve preoperative assessment of patients with endometriosis.

METHODS

Hospital records for patients with endometriosis were evaluated retrospectively to determine the completeness of information. A structured electronic questionnaire was developed and used to assess preoperatively patients with suspected or proved endometriosis. Data from both assessments were compared.

RESULTS

Data analysed retrospectively showed that there were valid answers for 89.2% of questions on a standard patient history template, but information was available for only 46.3% of parameters considered specific to endometriosis. Data from 69 patients investigated by structured electronic questionnaire gave improved rates of 90.3% for standard patient history items and 88.5% for endometriosis-specific parameters. Significant improvement in valid answers was achieved in 66.7%.

CONCLUSIONS

A structured questionnaire improved the documentation of endometriosis-specific parameters. Further studies are needed to ensure that it enhances the effectiveness of preoperative counselling and decisions about surgery.

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.

Different HLA-DR expression in endometriotic and adenomyotic lesions: correlation with transvaginal ultrasonography findings

OBJECTIVE

Human leukocyte antigen-DR (HLA-DR) has been implicated in eutopic and ectopic glandular epithelial cells in endometriosis. We investigated the expression of HLA-DR in endometriotic and adenomyotic tissues within the stromal and glandular cells. Moreover, we correlate the HLA-DR expression according the transvaginal ultrasonography findings.

METHODS

We studied operative and pathologic reports of 113 women who underwent laparoscopic or laparotomy treatment of endometrioma or adenomyosis. Tissues from 51 women with endometrioma and 62 women with adenomyosis were retrospectively evaluated. The distribution and intensity of the HLA-DR immunostaining was assessed using electron microscopy. Pathologic finding of the uterine junction zone and the size of endometrioma were evaluated with the laparoscopic results and the ultrasound findings.

RESULTS

In adenomyosis tissues, the percentage of HLA-DR cells expression was significantly higher in stromal cells (83.9%) compared to glandular cells (25.8%), (p<0.001). The number of HLA-DR-positive endometriotic glandular cells was significantly higher than the total glandular adenomyotic cells (p<0.005). HLA-DR-positive cells was significantly different between stromal (p<0.016) and glandular cells (p<0.044) in each side of endometrioma. Finally, HLA-DR-positive percentage cells were significantly more frequent in the secretory phase than the proliferative in stromal and glandular cells in both groups.

CONCLUSION

HLA-DR antigen expression in endometrium and adenomyotic tissues. However, HLA-DR expression is distributed preferentially in glandular epithelial cells in endometrioma and in the adenomyotic stroma. In both groups the HLA-DR expression was significantly higher in the secretory phase than the proliferative or glandular and stroma cells. Larger perspective studies are needed to establish the expression of HLA antigens in immune reactions which occur in adenomyosis and endometriosis.