Immunology and endometriosis. Fact, artifact, or epiphenomenon?

Prevalence of endometriosis in women with systemic lupus erythematosus and Sjögren's syndrome

Endometriosis is associated with a number of immunologic alterations. It has been suggested that autoimmune disorders could be more frequent in patients with endometriosis. The aim of this study is to ascertain whether the prevalence of two well-known autoimmune diseases [systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS)] is increased in women with endometriosis. The clinical charts of four different populations assisted at the same hospital were manually revised: (i) SLE population ( n = 120), (ii) SS ( n = 22), (iii) endometriosis ( n = 342) and (iv) control population ( n = 501 consecutive unselected asymptomatic women). Among SLE women, the prevalence of endometriosis was 1.67% (2/120), similar to the 4.39% prevalence of the control group (22/501), the OR being 0.37 [95%CI 0.09—1.59]. Among SS women, the prevalence of endometriosis was 9.09 (2/22), also similar to the control group OR 2.17 [95%CI 0.48—9.90]. In the same way, when comparing endometriosis cases with asymptomatic women, similar frequencies of SLE (0.58% and 0.2%) and SS were found (0% and 0%). Women with endometriosis do not have an increased prevalence of SLE or SS. Lupus (2007) 16, 736—740.

The effect of intraperitoneal interleukin-2 on surgically induced endometriosis in rats

OBJECTIVE

To evaluate the effect of interleukin-2 (IL-2) on an experimental model of endometriosis.

STUDY DESIGN

Double blind and randomized experimental prospective placebo-controlled study. Experimental endometriosis was induced in 66 three-month-old female Wistar rats, by auto-transplanting fragments of endometrium to the peritoneum. After four weeks, the size of each implant was measured in millimeters by laparotomy (L2), and animals were randomly distributed for intraperitoneal administration of human-IL-2, rat-IL-2 or placebo. Four weeks later, the implants were measured (L3) and a second dose was given. After four weeks, endometriosis size was evaluated again (L4).

RESULTS

We found a reduction of experimental endometriosis at L3 that was only significant in IL-2 treated groups: 20.1% and 30.3% with human-IL-2 and rat-IL-2, respectively (p<0.001 with respect to L2 size), versus a non-significant reduction of 9.0% found in placebo group, but the differences were not statistically significant between groups. The decrease after a second dose (L4) was: 49.8%, 41.8% and 11.4% with human-IL-2, rat-IL-2 and placebo, respectively (p<0.001 in IL-2 groups versus L2 and L3, and p<0.05 in both groups versus placebo at L4).

CONCLUSION

Intraperitoneal administration of IL-2 reduces experimental endometriosis, and this effect is similar using rat-IL-2 or human IL-2 (non specie-specific effect).

Natural hair color and the incidence of endometriosis

OBJECTIVE

To investigate a previously hypothesized relation between natural hair color and endometriosis.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study II with 10 years of follow-up.

PARTICIPANT(S)

A total of 90,065 women, 25-42 years old, who had never been diagnosed with endometriosis, infertility, or cancer at baseline in 1989.

MAIN OUTCOME MEASURE(S)

Incidence of laparoscopically confirmed endometriosis according to natural hair color.

RESULT(S)

During 379,422 person-years of follow-up, 1,130 cases of laparoscopically confirmed endometriosis were reported among women with no past infertility. After adjusting for age, calendar time, parity, race, and body mass index at age 18, we observed no association overall. However, compared with women with any other hair color, we observed an increased rate of endometriosis among women with naturally red hair who had never been infertile (incidence rate = 1.3, 95% confidence interval [CI] = 1.0-1.7), but a decreased rate among women with naturally red hair among women who were infertile (incidence rate = 0.4, 95% CI = 0.2-1.2); P value, test for heterogeneity = .03.

CONCLUSION(S)

Overall, we did not observe a significant relation between red hair color and the rate of endometriosis, however this prospective cohort study suggests that the relation may differ by infertility status.

Immunology of endometriosis

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

Fibroblast growth factor (FGF), intracellular adhesion molecule (sICAM-1) level in serum and follicular fluid of infertile women with polycystic ovarian syndrome, endometriosis and tubal damage, and their effect on ICSI outcome

PROBLEM

The objective of this study was to determine the concentration of fibroblast growth factor (FGF) and soluble intracellular adhesions molecule (sICAM-1) in serum and follicular fluid (FF) of polycystic ovary (PCO), endometriosis and tubal factor infertility and male factor infertility patients, and to investigate the relationship between these parameters and the outcome of intracytoplasmic sperm injection (ICSI).

METHOD OF STUDY

The concentration of FGF and sICAM-1 in serum and FF were determined in patients undergoing controlled ovarian hyperstimulation (COH) for ICSI therapy for various etiology of infertility and the results of cytokines concentration and ICSI outcome were compared between the groups. Twenty patients with PCO (G.I), 17 with endometriosis (G.II), 19 with tubal damage (G.III) and 19 with male factor infertility (G.IV) were enrolled in this study. Quantitative determination of levels of FGF and sICAM-1 was performed using enzyme-linked immunosorbent assays (ELISAs).

RESULTS

The FGF level in serum of PCO patients (G.I) were 4.8 +/- 2.3 and in FF were 104.0 +/- 39.0 pg/mL. The corresponding values in the endometriosis patients group (G.II) were 5.9 +/- 3.1 and 125.4 +/- 74.9 pg/mL. The concentration of FGF in tubal factor infertility group (G.III) in serum was significantly higher (P = 0.009) than those observed in the PCO group (G.I) 7.4 +/- 4.5 pg/mL, whereas the concentration in FF was at the same level like the other groups investigated, 128.7 +/- 75.9 pg/mL. Besides, the sICAM-1 (pg/ml) concentration in FF showed a significant difference between the groups investigated (G.I, 175.3 +/- 52.8; G.II 194.4 +/- 32.2; G.III 233.1 +/- 54.3; and G.IV 215.1 +/- 54.4 ng/mL; P = 0.003). The sICAM-1 levels in serum were not significantly different between the groups (217.0 +/- 42.9; 216.3 +/- 73.6; 254.8 +/- 79.6; 237.56 +/- 78.4 ng/ml; P = 0.267). The fertilization rate was significantly higher in G.III (66.0 +/- 23.89%) in comparison to G.II (38.8 +/- 33.9%; P = 0.014) or G.IV (38.7 +/- 22.7%; P = 0.012). The pregnancy rates were similar in all groups (30, 35.3 and 35.0, 38.6%, respectively).

CONCLUSION

Both, FGF and sICAM-1 are present in serum and FF of patients undergoing controlled ovarian hyperstimulation for ICSI therapy. The FGF concentration in serum differs significantly between the groups investigated, whereas, no significant difference could be observed in the FF concentration of FGF. On the other hand, the sICAM in serum showed no significant difference between the groups, whereas, sICAM in FF demonstrated a significant difference between the patient groups investigated. On the whole, the ICSI outcome was not related to serum or FF concentrations of FGF or sICAM-1. Therefore, the mean concentration of FGF and sICAM-1 in serum and in FF could not be used to predict the fertilization rate in an ICSI program.

The epidemiology of endometriosis

The epidemiologic study of endometriosis presents researchers with unique challenges. As a result, few well-designed studies have been published. The authors briefly describe the primary pathogenic hypotheses, discuss methodologic issues specific to endometriosis, and review the small body of literature addressing risk factors. Finally, they offer a brief interpretation of these findings and suggest hypotheses for future research.

Serum concentrations of growth factors in women with and without endometriosis: the action of anti-endometriosis medicines

Endometriosis is a common gynecologic syndrome of unknown etiology and pathogenesis. Growth factors and inflammatory mediators produced by peritoneal leukocytes have recently been postulated to participate in the pathogenesis of endometriosis. Angiogenic factors released from peritoneal macrophages may also play a role in the development of this disease. In the present study, we investigate the soluble levels of vascular endothelial growth factor (VEGF), epidermal growth factor-receptor (EGF-R), granulocyte/macrophage-colony stimulating factor (GM-CSF), Insulin-like growth factor-1 (IGF-1) and interferon-gamma (IFN-gamma) in the serum of 28 women with and 20 without endometriosis. We also compared these levels before, during and after treatment with danazol and leuprorelin acetate depot, the two therapeutic regiments of choice concerning this disease. We found that only sVEGF levels were higher in women with endometriosis in comparison to controls (P < 0.001) while sEGF-R is not present. GM-CSF, IGF-1 and IFN-gamma soluble levels are not affected in either healthy or endometriotic subjects. The 6-month treatment with danazol decreased sVEGF levels (P < 0.02) and increased sEGF-R levels (P < 0.001). These observations support the view that VEGF may be associated with the disease process and that danazol may bring sVEGF levels to a normal threshold. However, future studies will be focused on the anti-angiogenic control of the action of VEGF in patients with endometriosis.

Angiogenic activity and IL-8 concentrations in peritoneal fluid and sera in endometriosis

OBJECTIVES

During menstruation endometrial fragments are transported into the peritoneal cavity where they form endometriotic lesions. Angiogenesis is proposed as one of the mechanisms in endometriosis pathogenesis. The aim of the study was to determine the angiogenic activity and interleukin 8 concentrations in peritoneal fluid and sera in endometriosis.

METHODS

Angiogenesis was determined in cutaneous assay in Balb/c mice; IL-8 concentrations were measured by ELISA test in sera and peritoneal fluid of 32 control and 56 endometriosis patients. Wilcoxon and Mann-Whitney tests and Spearman rank correlations were used in statistical analysis.

RESULTS

Peritoneal fluid and sera from the examined group had higher angiogenic activity and interleukin 8 concentrations. There was correlation found between AFS and neovascularization induced by sera and PF of patients with peritoneal lesions.

CONCLUSIONS

Angiogenesis plays an important role in pathogenesis of endometriosis. Although IL-8 takes part in neovascularization, there are other factors modulating angiogenesis in endometriosis.

Endometriosis: current concepts and therapy

Endometriosis is the growth of endometrial tissue in ectopic locations. The clinical picture is extremely pleiomorphic, which can make the diagnosis difficult. Despite 70 years of theories and experimentation, the cause is not clear, and it is likely that more than one mechanism is at work in most patients. Both medical and surgical treatments are available. In each case, the woman and her physician should formulate a comprehensive treatment plan that addresses the primary complaint as well as the patient's reproductive desires.

Paracrine regulation of matrix metalloproteinase expression in endometriosis

Following retrograde menstruation, shed endometrial tissue fragments attach to and invade the peritoneal surface to form established endometriotic lesions. With disease progression, the biochemically active lesions undergo remodeling and become fibrotic. Matrix metalloproteinase enzymes (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) play a significant role in normal endometrial remodeling during menses. Anomalous expression of MMPs and TIMPs has been identified in endometriotic lesions as compared to their highly regulated expression in eutopic endometrium. The paracrine mechanisms regulating misexpression of MMPs and TIMPs by endometriotic lesions are, however, not well defined. Misexpression of the MMPs and TIMPs may be due to innate anomalies in the eutopic endometrium from women with endometriosis, in the resident immune cells and peritoneal cells that juxtapose the ectopic endometrium, and/or numerous substances present in peritoneal fluid of women with endometriosis. The majority of MMPs are under strict transcriptional regulation. Steroid hormones and cytokines appear to act on the MMP promoter, either independently or in consort, to provide both positive and negative regulation of these genes. Misregulated expression of MMPs and TIMPs is associated with a more aggressive phenotype and a cascade of events facilitating peritoneal extracellular matrix degradation and establishment or remodeling of endometriotic lesions. The mechanisms by which MMP and TIMP expression are misregulated warrant further investigation as such information may provide insight into novel therapeutic modalities for endometriosis.

Modulation of neutrophil apoptosis by plasma and peritoneal fluid from patients with advanced endometriosis

BACKGROUND

The increased production of pro-inflammatory chemoattractant cytokines for neutrophils in endometriosis suggests that changes in the immune system play an important role in the pathophysiology of endometriosis. The effects of plasma and peritoneal fluid from patients with advanced endometriosis on the apoptosis of neutrophils were investigated.

METHODS

Apoptotic changes of neutrophils were evaluated by morphological changes using Giemsa staining. Apoptosis was confirmed by DNA electrophoretic analysis.

RESULTS

Compared with the plasma (n = 20) and peritoneal fluid (n = 5) of healthy controls, the addition of 10% plasma (n = 20) and peritoneal fluid (n = 10) from patients with endometriosis to an in-vitro culture of neutrophils from healthy subjects reduced the percentage of apoptotic cells from 65.3 +/- 6.6 to 27.2 +/- 4.6% (P < 0.001) and from 45.3 +/- 4.8 to 10.5 +/- 4.3% (P < 0.001) respectively. Neutralizing interleukin-8 antibody abrogated the delay of neutrophil apoptosis induced by peritoneal fluid, but not in the plasma of endometriosis patients.

CONCLUSIONS

These findings show that interleukin-8 is one of the neutrophil survival factors in the peritoneal fluid of endometriosis patients and that an unidentified survival factor is also present in the plasma of patients with endometriosis.

Reduced developmental potential in oocytes from women with endometriosis

PURPOSE

To study retrospectively the outcome of intracytoplasmatic sperm injection (ICSI) in women with endometriosis compared with women with no known female infertility factor.

METHODS

All couples treated with ICSI because of male infertility plus verified endometriosis (n = 26) and all couples treated with ICSI because of male infertility only (n = 125) during the period January 1995 to June 1999 were included. Data were collected from patient files and ICSI protocols.

RESULTS

The time to complete down regulation was significantly longer (p = 0.0108), the dose of FSH significantly higher (0.0247), the day for oocyte pickup significantly later (p = 0.0091), and the cleavage rate of oocytes significantly lower (p = 0.0011) in women with endometriosis compared with controls. There was no significant difference in implantation rate or pregnancy rate between the groups.

CONCLUSIONS

Women with endometriosis presented significantly reduced follicular response and oocyte cleavage rate, two mechanisms that might be related to a disturbed oogenesis.

Autoantibody studies of female patients with reproductive failure

The aim of this study was to investigate the prevalence and character of autoimmune derangements in women with reproductive failure. A total of 108 females (age range 17-43, mean 27.5 years), including 16 with primary menstrual cycle disturbances and polycystic ovaries (PCO), 20 with polycystic ovary syndrome (PCOS), 38 with endometriosis (E), and 34 with chronic anovulation, luteal phase insufficiency, subfertility or unexplained infertility (INF) were investigated. A control group of 392 women was formed from an unselected population sample (age range 17-43, mean 31.0 years). All sera were tested by indirect immunofluorescence method to assess common autoantibodies: nuclear (ANA), smooth muscle (SMA), parietal cell (PCA), thyroid microsomal (TMA), reticulin (ARA), mitochondrial (AMA) and liver/kidney microsomal autoantibodies (LKMA). Enzyme-linked immunosorbent assay was used to detect antibodies against beta2-glycoprotein I (anti-beta 2GPI) and carbonic anhydrase (anti-CA). Our results showed that 40.7% of patients' sera and 14.8% of control sera contained one or more common autoantibodies, ANA and SMA were most frequently detected (difference between two groups P<0.005). Anti-beta 2GPI were found in eight cases (7.4%), including two patients with INF but without other autoantibodies. Anti-CA were revealed in nine cases (8.3%) including patients' PCOS, E and INF. A comparison of patients' clinical data with antibody assay results did not reveal any significant associations. Our results indicate a high prevalence of autoimmune reactions in women with reproductive failure due to the most common causes PCO, PCOS and E as well as in unexplained infertility. This might reflect the propensity to develop autoimmune reactions in such patients, including pathogenic autoimmune reactions to specific target antigens.

Increase in serum leptin concentrations among women with endometriosis during danazol and leuprolide depot treatments

OBJECTIVE

This study was undertaken to evaluate serum leptin concentrations in women with endometriosis during treatment with danazol and with leuprolide depot.

STUDY DESIGN

Twenty patients aged 18 to 42 years with regular menses and documented pelvic endometriosis were recruited from a university hospital setting. Treatment was 200 mg danazol 3 times daily for 6 months or 3.75 mg leuprolide depot every 28 days for 6 months. Serum leptin concentrations were measured before, during, and after treatment. A single blood sample was taken from each of 10 control women without endometriosis for comparison. Serum leptin level was measured with a radioimmunoassay kit with human leptin, and analysis of variance and paired t tests were used for statistical analysis.

RESULTS

Serum leptin levels were almost the same among women with endometriosis as in the control group. Leptin levels were higher among women with endometriosis during treatment with danazol and leuprolide(P <.001). Three months after treatment, leptin values remained moderately higher than before treatment.

CONCLUSION

Danazol and leuprolide increased serum leptin levels. The mechanism of leptin increase is unclear. Further studies are needed to determine whether an adipogonadal axis exists.