Evidence of T-cell activation and potential cytokine action in human endometrium

Interferon Signaling in the Endometrium and in Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease that develops in reproductive-aged women who experience pelvic pain and infertility. Even though endometriosis is not a new disease, its molecular etiology has not been clearly elucidated. Defects in the immune system might be one of the factors that promote endometriosis progression. For example, elevated levels of proinflammatory cytokines are associated with endometriosis. Interferon is one of the cytokines that is elevated in endometriotic tissues compared with normal endometrium. Therefore, high interferon levels play a crucial role in endometriosis progression. In addition to endometriosis, however, interferon has a critical role in endometrial function, particularly in the initiation and maintenance of pregnancy. Therefore, this review describes the double-edged sword of interferon signaling in normal endometrial function versus endometriosis progression and also discusses interferon targeting as a new nonhormonal therapy for endometriosis. This approach may increase the efficacy of endometriosis treatment and reduce the adverse effects associated with current hormonal therapy for this disease.

Transcriptomic analysis of interferon-γ-regulated genes in endometrial explants and their possible role in regulating maternal endometrial immunity during the implantation period in pigs, a true epitheliochorial placentation species

The implantation process requires precisely controlled interactions between the maternal uterine endometrium and the implanting conceptus. Conceptus-derived secretions affect endometrial cells to facilitate the adhesion and attachment of trophoblasts, and endometrial secretions support the growth and development of the conceptus. In pigs, the conceptus secretes a large amount of type II interferon, interferon-γ (IFNG), during the implantation period. However, the role of IFNG in the implantation process has not been fully understood in pigs. Thus, to determine the role of IFNG in the endometrium during early pregnancy in pigs, we treated endometrial explant tissues with increasing doses of IFNG and analyzed the transcriptome regulated by IFNG using an RNA-sequencing analysis. Data analyses identified 276 differentially regulated genes, their Gene Ontology terms, and 94 signature genes in a Gene Set Enrichment Analysis. Furthermore, we analyzed the expression of IFNG-regulated genes, including CIITA, KYNU, IDO1, WARS, and MHC class II molecules, in the endometrium throughout pregnancy and found that levels of those genes in the endometrium were highest on Day 15 of pregnancy, corresponding to the time of peak IFNG secretion by porcine conceptuses. In addition, immunohistochemical analyses revealed that CIITA, KYNU, and IDO proteins were expressed in a cell type- and pregnancy status-specific manner in the endometrium. These results show that genes overrepresented in endometrial tissues in response to IFNG were mainly related to immune responses, suggesting that conceptus-derived IFNG could play critical roles in regulating the maternal immune response for the establishment of pregnancy in pigs.

Analysis of interferon-γ receptor IFNGR1 and IFNGR2 expression and regulation at the maternal-conceptus interface and the role of interferon-γ on endometrial expression of interferon signaling molecules during early pregnancy in pigs

It has long been known that pig conceptuses produce interferon-γ (IFNG) at the time of implantation, but the role of IFNG and its mechanism of action at the maternal-conceptus interface are not fully understood. Accordingly, we analyzed the expression and regulation of IFNG receptors IFNGR1 and IFNGR2 in the endometrium during the estrous cycle and pregnancy in pigs. Levels of IFNGR1 and IFNGR2 messenger RNA (mRNA) expression changed in the endometrium, with the highest levels during mid pregnancy for IFNGR1 and on Day 12 of pregnancy for IFNGR2. The expression of IFNGR1 and IFNGR2 mRNAs was also detected in conceptuses during early pregnancy and chorioallantoic tissues during mid to late pregnancy. IFNGR1 and IFNGR2 mRNAs were localized to endometrial epithelial and stromal cells and to the chorionic membrane during pregnancy. IFNGR2 protein was also localized to endometrial epithelial and stromal cells, and increased epithelial expression of IFNGR2 mRNA and protein was detectable during early pregnancy than the estrous cycle. Explant culture studies showed that estrogen increased levels of IFNGR2, but not IFNGR1, mRNAs, while interleukin-1β did not affect levels of IFNGR1 and IFNGR2 mRNAs. Furthermore, IFNG increased levels of IRF1, IRF2, STAT1, and STAT2 mRNAs in the endometrial explants. These results in pigs indicate that IFNGR1 and IFNGR2 are expressed in a stage of pregnancy- and cell-type specific manner in the endometrium and that sequential cooperative action of conceptus signals estrogen and IFNG may be critical for endometrial responsiveness to IFNs for the establishment of pregnancy in pigs.

Role of the innate immunity in female reproductive tract

The mucosal immune system in the female reproductive tract (FRT) is well equipped to meet the sexually transmitted pathogens, allogeneic sperm, and the immunologically distinct fetus. Analysis of the FRT indicates that epithelial cells provide a physical barrier against pathogens and microbial infections as well as secretions containing anti-microbial peptides, cytokines, and chemokines which recruit and activate immune cells. Epithelial and immune cells confer protection in part through Toll-like receptors. The aim of this literature is to review the diverse components of the innate immune system, contributing to an exclusive protection system throughout the FRT.

The role of interferons in early pregnancy

The interferons (IFNs) form part of the large family of glycoproteins known as cytokines. They are secreted by host cells as a line of defence against pathogens and certain tumours. IFNs affect cell proliferation and differentiation and also play a very important role in the functioning of the immune system. Miscarriage in both humans has been associated with higher levels of IFN, particularly IFN-γ. However, this cytokine is evidently vital in successful murine pregnancies since it is involved in maintaining the decidual layer in addition to remodelling of the vasculature in the uterus. The effects of IFN on human pregnancies are more difficult to study. Hence, there is still a lot more to be discovered in the hope of reaching a definite conclusion regarding the impact of IFN.

Expression of interferon-γ in decidual natural killer cells from women with hypertensive disorder complicating pregnancy

AIM

Hypertensive disorder complicating pregnancy (HDCP) is one of the most frequent and serious pregnancy-related diseases, which is closely related to disorders of the maternal immune system, especially the local immune microenvironment of the maternal-fetal interface. Uterine decidual natural killer (dNK) cells are the major immune cells in the maternal-fetal interface and they play an important role in establishing and maintaining a normal pregnancy. The aim of this study was to investigate the phenotype and function of dNK cells from women with HDCP.

MATERIAL AND METHODS

Decidual tissues were collected from women with normal pregnancy (normal control group, n = 15 cases) and HDCP (HDCP group, n = 20 cases), respectively. The mononuclear cells were extracted from tissues and flow cytometry (FCM) was utilized to sort out dNK cells. The phenotypes of dNK cells (CD56(bright)CD16⁻CD3⁻ vs CD56(dim)CD16⁺CD3⁻) were detected by FCM. After being co-cultured with Phorbol 12-myristate 13-acetate, ionomycin and monensin, the expression level of interferon (IFN)-γ in the dNK cells was detected by FCM.

RESULTS

The phenotypes of dNK cells from the two groups were dominated by the CD56(bright)CD16⁻CD3⁻ subset, with no significant statistical difference (P < 0.05). The expression level of IFN-γ in the dNK cells from women with HDCP was on a lower trend than those from women with normal pregnancy, having significant statistical difference (P = 0.000 < 0.05).

CONCLUSIONS

Our results indicated that although the phenotype of dNK cells from women with HDCP is of no difference, their functions are abnormal. Impaired cell function leads to a lower expression level of IFN-γ and this may account for one of the pathogeneses of HDCP.

Contribution of interferon-gamma receptor 1 gene polymorphisms to pre-eclampsia in China

PROBLEM

As gene polymorphisms of cytokines receptors have been found to significantly influence cell responses to cytokines, the aim of this study was to test the hypothesis that IFN-gamma receptor 1 (IFNGR1) gene polymorphisms may contribute to the pathogenesis of pre-eclampsia.

METHOD OF STUDY

One hundred and sixty-four pre-eclamptic patients (121 patients with mild pre-eclampsia and 43 patients with severe pre-eclampsia) and 171 controls were included. Polymorphisms of the IFNGR1 gene at positions -611, -270, +56 and +95 were genotyped with the matrix-assisted laser desorption/ionization time of flight mass spectrometry.

RESULTS

This study showed a positive association between -56C/C genotype (OR = 1.7; 95% CI = 1.1-2.7) and pre-eclampsia. Although the genotype frequencies (except for -56C/C) of the two polymorphisms were comparable between cases and controls, higher frequency of the -611A/-56C haplotype (OR = 1.450; 95% CI = 1.070-1.966) was noticed in patients versus controls. All patients and controls were homozygous for the -270T/T and +95T/T genotypes. Specifically, the frequency of the -56C allele (OR = 1.838; 95% CI = 1.127-2.995) was higher among patients with severe pre-eclampsia.

CONCLUSION

The IFNGR1 gene polymorphisms may contribute to the pathogenesis of pre-eclampsia in our population.

Interferon gamma in successful pregnancies

Interferon gamma (IFNG) is a proinflammatory cytokine secreted in the uterus during early pregnancy. It is abundantly produced by uterine natural killer cells in maternal endometrium but also by trophoblasts in some species. In normal pregnancies of mice, IFNG plays critical roles that include initiation of endometrial vasculature remodeling, angiogenesis at implantation sites, and maintenance of the decidual (maternal) component of the placenta. In livestock and in humans, deviations in these processes are thought to contribute to serious gestational complications, such as fetal loss or preeclampsia. Interferon gamma has broader roles in activation of innate and adaptive immune responses to viruses and tumors, in part through upregulating transcription of genes involved in cell cycle regulation, apoptosis, and antigen processing/presentation. Despite this, rodent and human trophoblast cells show dampened responses to IFNG that reflect the resistance of these cells to IFNG-mediated activation of major histocompatibility complex (MHC) class II transplantation antigen expression. Lack of MHC class II antigens on trophoblasts is thought to facilitate survival of the semiallogeneic conceptus in the presence of maternal lymphocytes. This review describes the dynamic roles of IFNG in successful pregnancy and briefly summarizes data on IFNG in gestational pathologies.

Role of cytokines in endometrium and at the fetomaternal interface

Cytokines were first recognized as factors involved in the immune responses. However, emerging evidence suggests that cytokines serve as the unanimous language through which cells in organ systems as diverse as hypothalamus to endometrium communicate. Evidence for the participation of these factors in the normal function of the endometrium and uteroplacental unit and development of the embryo is being recognized. This review will highlight the significant insight gained over the past several years for the role of cytokines in the field of reproductive biology. Major emphasis will be placed on interleukins, tumour necrosis factor-α, transforming growth factors, colony stimulating factors and interferon-gamma.

Peptides and proteins in the human endometrium

Human endometrium is composed of three layers: stratum compactum, stratum spongiosum and stratum basale. Stratum compactum is the superficial layer made up of openings of the uterine glands and some stromal cells. Stratum spongiosum is the middle layer containing mainly dilated glands and little stroma. Stratum basale is the deepest layer adjoining the muscularis. It consists of primordial glands and compact stroma. Stratum compactum and stratum spongiosum form stratum functionale which is subject to cyclic changes and is removed during menstruation.

Beta3 integrin expression within uterine endometrium and its relationship with unexplained infertility

The aim of this study was to investigate whether the endometrium of women with unexplained infertility differs in the presence of the beta 3 (beta3) integrin molecule from the endometrium of normal fertile women. In a retrospective case-control study 30 endometrial biopsies from hysterectomies with nonendometrial pathology and 30 endometrial samples from women with a history of unexplained infertility were collected during the window of implantation. Immunohistochemically staining with a monoclonal antibody against beta3 integrin subunit in endometrial biopsies was performed and then assessed semiquantitively by microscope on different endometrial compartments including glandular epithelial cells, vessels, lymphocytes, macrophages and stromal cells. Chi-square test was used to compare the expression and defect of beta3 integrin subunit between two groups. The results showed that beta3 integrin molecules were present in fertile and infertile endometrial uterine tissues. The majority of glandular epithelial cells expressed beta3 integrin in fertile endometrium. However, the endometrial expression of beta3 integrin was reduced significantly in infertile endometrium during the window of implantation (p < 0.05). A few numbers of vessels and stromal cells expressed beta3 integrin molecule with no statistical significance between the two groups. In conclusion Abnormal endometrial integrin expression is a frequent finding in women with unexplained infertility. A therapeutic potential approach in improving uterine endometrium receptivity together with up-regulation of beta3 integrin in this population of women suggested.

Innate Immunity in the Female Reproductive Tract: Role of Sex Hormones in Regulating Uterine Epithelial Cell Protection Against Pathogens

The mucosal immune system in the upper female reproductive tract is uniquely prepared to maintain a balance between the presence of commensal bacteria, sexually transmitted bacterial and viral pathogens, allogeneic spermatozoa, and an immunologically distinct fetus. At the center of this dynamic system are the epithelial cells that line the Fallopian tubes, uterus, cervix and vagina. Epithelial cells provide a first line of defense that confers continuous protection, by providing a physical barrier as well as secretions containing bactericidal and virucidal agents. In addition to maintaining a state of ongoing protection, these cells have evolved to respond to pathogens, in part through Toll-like receptors (TLRs), to enhance innate immune protection and, when necessary, to contribute to the initiation of an adaptive immune response. Against this backdrop, epithelial cell innate and adaptive immune function is modulated to meet the constraints of procreation. The overall goal of this review is to focus on the dynamic role of epithelial cells in the upper reproductive tract, with special emphasis on the uterus, to define the unique properties of these cells as they maintain homeostasis in preparation for successful fertilization and pregnancy while at the same time confer protection against sexually transmitted infections, which threaten to compromise women's reproductive health and survival. By understanding the nature of this protection and the ways in which innate and adaptive immunity are regulated by sex hormones, these studies provide the opportunity to contribute to the foundation of information essential for ensuring reproductive health.

Innate and adaptive immunity in female genital tract: cellular responses and interactions

The mucosal immune system in the female reproductive tract (FRT) has evolved to meet the unique requirements of dealing with sexually transmitted bacterial and viral pathogens, allogeneic spermatozoa, and the immunologically distinct fetus. Analysis of the FRT indicates that the key cells of the innate and adaptive immune systems are present and functionally responsive to antigens. Acting through Toll-like receptors in the Fallopian tubes, uterus, cervix, and in the vagina, epithelial cells, macrophages, natural killer cells, and neutrophils confer protection through the production of chemokines and cytokines, which recruit and activate immune cells, as well as bactericidal and virucidal agents, which confer protection at times when adaptive immunity is downregulated by sex hormones to meet the constraints of procreation. The overall goal of this paper is to define the innate immune system in the FRT and, where possible, to define the regulatory influences that occur during the menstrual cycle that contribute to protection from and susceptibility to potential pathogens. By understanding the nature of this protection and the ways in which innate and adaptive immunity interact, these studies provide the opportunity to contribute to the foundation of information essential for ensuring reproductive health.

CD8+ T cells in human uterine endometrial lymphoid aggregates: evidence for accumulation of cells by trafficking

Lymphoid aggregates (LA) develop during the proliferative phase of the menstrual cycle in the human uterine endometrium (EM). They contain mostly CD8+ T cells and B cells. As these LA are absent immediately following menses, they may arise by division of cells resident in the EM, or by division of a limited number of precursor cells that traffic into the EM during the early proliferative phase of the menstrual cycle. Alternatively, they may arise by the continuous trafficking of cells into the EM throughout the proliferative phase of the menstrual cycle. In this study we investigated the distribution and frequency of CD8+ T cells in the aggregates using expression of Vbeta2 or Vbeta8 as markers of clonality and Ki-67 as a marker of dividing cells. Confocal microscopic analysis of endometrial tissues showed the random distribution of CD8+ T cells within aggregates within the same sample and in aggregates from different samples. Furthermore, comparisons of the distribution of Vbeta2 and Vb8 with expected values predicted from Poisson distribution values were not significantly different, suggesting that CD8+ T cells do not arise by division from single precursors. A low level of T-cell division within LAs was confirmed by positive staining for Ki-67. Dividing T cells were randomly dispersed throughout the LA and the frequency of dividing cells did not vary greatly between aggregates within the same tissue. Nearest-neighbour analysis of dividing cells showed no statistically significant deviations from a random distribution. Taken together, these results suggest that LA develop during the menstrual cycle largely by the trafficking of cells to nucleation sites within the EM, rather than by division of a limited number of precursor cells.

Expression of the alpha2beta1 and alpha3beta1 integrins at the surface of mesothelial cells: a potential attachment site of endometrial cells

OBJECTIVE

To localize alpha2beta1 and alpha3beta1 integrins in the cell membrane of peritoneal mesothelium in vivo and in vitro.

DESIGN

Descriptive study using confocal and two-photon laser-scanning microscopy.

SETTING

University-based laboratory.

PATIENT(S)

Women without endometriosis undergoing surgery for benign conditions.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Peritoneal biopsies (n = 9) and mesothelial monolayer cultures (n = 4) were incubated with antibodies to the alpha2 and alpha3 subunits and to the intact alpha2beta1 and alpha3beta1 integrins. Specimens were examined with laser-scanning microscopy.

RESULT(S)

The alpha2 and alpha3 subunits and the intact alpha2beta1 and alpha3beta1 integrins were identified at the base of the mesothelial cells (i.e., toward the basement membrane). There was also expression of the alpha2 and alpha3 subunits and the intact alpha2beta1 and alpha3beta1 integrins at the cell surface (i.e., toward the peritoneal cavity).

CONCLUSION(S)

The resolution of the confocal and two-photon laser-scanning microscope enabled localization of integrins in mesothelial cells. The presence of alpha2beta1 (collagen-laminin receptor) and alpha3beta1 integrins (collagen-laminin-fibronectin receptor) at the base of mesothelial cells suggests a role for these molecules in adhesion to the basement membrane. The presence of these molecules at the cell surface suggests a potential locus for cell adhesion in such processes as endometriosis and cancer metastasis.

The expression of killer cell inhibitory receptors on natural killer cells and activation status of CD4+ and CD8+ T cells in the decidua of normal and abnormal early pregnancies

The establishment of the human placenta in early pregnancy is characterized by the presence of large numbers of natural killer cells within the maternal decidua. These NK cells have an unusual phenotype, CD3- CD16- CD56(bright), distinguishing them from peripheral blood NK cells. They may control trophoblast migration and placentation. Using a panel of monoclonal antibodies to several members of the KIR family and flow cytometry, we found that KIRs are expressed on decidual NK cells. There is variation in both the percentage of cells expressing a particular receptor and the density of receptor expression between decidual NK cells from different individuals. In anembryonic pregnancy, the proportions of decidual NK cells with a particular KIRs (GL183 and EB6) decreased significantly when compared with normal pregnancy (p = 0.01 and 0.01, respectively), raising the possibility that these NK receptors may be involved in recognition of the allogeneic fetus by the mother at the implantation site. In the decidua, more CD4+ and CD8+ T cells expressed CD69 and HLA-DR than in blood, indicating that T cells are regionally activated during early pregnancy. When compared with normal pregnancy, decidual HLA-DR+CD4+CD3+, CD69+CD8+CD3+ and HLA-DR+CD8+CD3+ T lymphocytes are significantly increased in anembryonic pregnancy. The over-activation of decidual T cells during anembryonic pregnancy may thus contribute to the increased NK cytotoxicity activity.

Regulation by human uterine cells of PBMC proliferation: influence of the phase of the menstrual cycle and menopause

To determine the influence of human uterine cells recovered at different stages of the menstrual cycle and following menopause on the proliferation of peripheral blood mononuclear cells (PBMC), whole cell suspensions of uterine tissues were co-cultured with autologous and heterologous PBMC. PBMC proliferation in response to tetanus toxoid (TT) or Con A was inhibited by uterine endometrial cells and was dependent on the phase of the menstrual cycle. Inhibition by cells from the proliferative phase was significantly greater than by cells from the secretory phase. Uterine cells isolated from post-menopausal women also inhibited proliferation of PBMC. Cell fractionation studies indicated that epithelial cells are the primary source of uterine inhibitory activity. When epithelial cells and PBMC were cultured in separate compartments, epithelial cells released a soluble factor(s) that inhibited the PBMC proliferation. These results suggest that uterine epithelial cells produce cytokines that down-regulate the proliferation of PBMC in response to antigens and mitogens. This may be important for the control of uterine immune responses, as well as the growth of the reproductive tract in preparation for implantation during the secretory phase of the menstrual cycle.

Influence of ovarian hormones on urogenital infection

Numerous studies have examined the influence of hormones on infectious diseases and there is now a wealth of data relating to the more specific effect of the sex hormones, oestrogen and progesterone, on urogenital infections. The interaction between these hormones and the immune system is complex and the variation of hormonal effect between species further complicates the true picture as related to humans. Although it is difficult therefore to draw general conclusions regarding predominant effects of specific hormones, there is the suggestion that oestrogen enhances the pathogenicity of many urogenital micro-organisms. Our understanding of the influential role played by sex hormones in disease pathogenesis is at an early stage and illustrates well the importance of drawing together and interpreting as a whole both epidemiological and molecular studies.

Expression of alpha6 and beta4 integrin subunits on human endometrium throughout the menstrual cycle and during early pregnancy

OBJECTIVE

To evaluate the expression of alpha6 and beta4 integrin subunits on surface and glandular endometrium throughout the menstrual cycle and during early pregnancy.

SETTING

Second Department of Obstetrics and Gynecology, University of Catania, Catania, Italy.

PATIENT(S)

Thirty-two women. Nineteen of the women regularly menstruated in different phases of the cycle, and 13 were in the sixth to ninth week of gestation and required voluntary abortion.

INTERVENTION(S)

Endometrial specimens collected during endometrial biopsy, hysterectomy, or voluntary abortion.

MAIN OUTCOME MEASURE(S)

Immunohistochemical staining for alpha6 and beta4 integrin subunits in endometrial tissues.

RESULT(S)

Both subunits (poorly expressed in preimplantation days) reached a significant peak on the endometrial surface during the implantation window, which tended to disappear in the postimplantation phase. On glandular endometrium they exhibited an opposite trend, showing high levels in the preimplantation and postimplantation days, whereas their expression decreased during the implantation window. The two subunits tended to disappear in early pregnancy.

CONCLUSION(S)

alpha6 and beta4 integrin subunits are uniformly distributed and highly expressed on the endometrial surface during the implantation window; they decreased dramatically in the postimplantation phase. These results could suggest involvement of integrin-extracellular matrix components in blastocyst-endometrium interaction during the early stages of implantation.

Decrease in interferon gamma production and impairment of T-lymphocyte proliferation in peritoneal fluid of women with endometriosis

OBJECTIVE

Our purpose was to verify regional immune modulations and to test the effect of gonadotropin-releasing hormone agonist in women with endometriosis.

STUDY DESIGN

Concentrations of peritoneal cytokines, including interleukin-1 beta, interleukin-2, soluble interleukin-2 receptor, interleukin-6, granulocyte-monocyte colony-stimulating factor, interferon gamma, and tumor necrosis factor-alpha were compared in women with and without endometriosis. Peritoneal cytokine and interleukin-2 production were examined by adding various mitogens to peritoneal fluid mononuclear cells of women with advanced endometriosis before and after gonadotropin-releasing hormone agonist treatment.

RESULTS

A significant increase in peritoneal interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha and a decrease in interferon gamma were noted in women with endometriosis. After gonadotropin-releasing hormone agonist treatment interleukin-6 decreased and interferon gamma increased. A significant impairment of interleukin-2 production of peritoneal fluid mononuclear cells by phytohemagglutinin and pokeweed mitogen stimulation was demonstrated in endometriosis, and production could be restored after gonadotropin-releasing hormone agonist treatment.

CONCLUSION

These results indicate that regional immunologic dysfunction might be invoked in the disease process of endometriosis.

Activation status of T and NK cells in the endometrium throughout menstrual cycle and normal and abnormal early pregnancy

Endometrial lymphocytes were studied at all stages throughout the menstrual cycle and early pregnancy by flow cytometry to examine different lymphocyte subpopulations and the expression of the T- and NK-cell activation markers. After pregnancy, CD8+CD3+ lymphocytes were decreased in the decidua. In both endometrium and decidua, more T cells expressed CD69, CD71, HLA-DR, and CD38 antigens than in peripheral blood. After pregnancy, CD71+CD3+ lymphocytes were further increased. CD25+CD3+ lymphocytes decreased significantly in the endometrium and decidua of ectopic pregnancies, but not in the decidua of normal pregnancies. These findings indicate that T cells are regionally activated in the first trimester, and it may be the result of the stimulation by fetal antigens. NK cells were the most abundant cell type in the decidua, which expressed the phenotype CD16- CD56+, and CD57-CD56+. The proportion of activated decidual NK cells was increased in anembryonic pregnancies more than in normal pregnancies, although the total NK subpopulation was similar in both groups. This might result in increased NK cytotoxicity in anembryonic pregnancies. In conclusion, T cells are activated, but NK cytotoxicity is decreased in the decidua of early normal pregnancies. This might be important in the control of trophoblast growth and placental development.

Increased expressions of CD69 and HLA-DR but not of CD25 or CD71 on endometrial T lymphocytes of nonpregnant women

To investigate lymphocyte subpopulations and the status of T-cell activation at different phases of the menstrual cycle, lymphocytes in endometrial tissue were analyzed by dual-color flow cytometry in 39 patients. Compared with peripheral blood, the lymphocytes in the endometrium had a higher CD3-/(CD56+ or CD16+) ratio (25.2% +/- 6.8% vs 11.1% +/- 7.0%), but an inverted CD3+ CD8-/CD3+ CD8+ ratio (0.5 vs 1.8) and a minimal amount of B cells (3.3% +/- 3.1%). TcR gamma delta + T cells accounted for a minor proportion (7.8% +/- 5.1%) in endometrium. The proportions of TcR alpha beta + (85.0% +/- 6.6%) and CD3+ CD56+ (7.4% +/- 4.4%) endometrial T lymphocytes were found significantly different from those in peripheral blood (89.1% +/- 5.6% and 3.8% +/- 3.4%, respectively). As the endometrium proceeded from proliferative phase to luteal phase, the proportion of CD3+ CD8+ T cells in peripheral blood increased from 35.6% +/- 6.9% to 41.3% +/- 8.4% and CD3+ CD8- T cells decreased from 64.4% +/- 6.9% to 58.7% +/- 8.4%. The endometrial T cells expressed high levels of CD69 (84.1% +/- 18.9%) and DR (75.9% +/- 9.7%), but rarely expressed CD25 (7.0% +/- 5.4%) and CD71 (2.8% +/- 1.8%). The patterns of expression of these activation markers were similar in both proliferative and luteal phases. Our observations suggest that endometrial T lymphocytes are in a state of recent and persistent activation. Lymphocytes expressing the NK cell markers (CD56 or CD16) and CD8+ accounted for a significant proportion, suggesting that they may play important roles in local defense.

Regulation of monocyte chemotactic protein-1 gene expression in human endometrial cells in cultures

Bone marrow-derived leukocytes are present in human endometrium/decidua and are believed to serve a variety of functions in this tissue. The number and type of leukocytes in endometrium/decidua vary with the hormonal milieu of the ovarian cycle, with blastocyst implantation, and during pregnancy. The factors that regulate the recruitment of specific leukocytes to the endometrium and those that modulate the function or replication of leukocytes in this tissue are not well defined. In this study, we evaluated the potential for synthesis of monocyte chemotactic protein-1 (MCP-1), a polypeptide with monocyte/macrophage chemotactic and activating properties, in human endometrium and in separated endometrial stromal and epithelial cells. MCP-1 mRNA was readily detected by northern analysis of total RNA isolated from human endometrial tissue (n = 39 tissues from ovulatory women; n = 3 atrophic endometria from anovulatory women; n = 6 from women ingesting oral contraceptives or medroxyprogesterone acetate) and decidua parietalis at midtrimester (n = 6 pregnancies) and at term (n = 6 pregnancies). The levels of MCP-1 mRNA varied considerably among tissues; but in this relatively small number of samples, there was no apparent relationship between day of cycle, endocrine status, or duration of pregnancy and the level of MCP-1 mRNA. MCP-1 mRNA was detected in separated endometrial stromal cells and epithelial cells in culture. In confluent human endometrial stromal cells in the absence or presence of fetal bovine serum (10%, v/v), MCP-1 mRNA was detected by northern analysis of total RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of lymphocyte subpopulations and T cell activation in endometriosis

PROBLEM

Numerous studies have characterized the lymphocyte subpopulations in normal eutopic endometrium and suggested a role for the cytokine secretory products of these lymphocytes in regulating endometrial cell proliferation and differentiation. Recent studies have shown that ectopic endometrium contains a greater concentration of scattered stromal lymphocytes than does eutopic endometrium. However, the lymphocyte subpopulations and their activation status have not been characterized in ectopic endometrium.

METHODS

We performed immunohistochemical studies on serial sections of proliferative and secretory phase eutopic endometrium and ectopic endometrium obtained during the proliferative phase using monoclonal antibodies to CD4 (T helper-inducer cells), CD8 (T cytolytic-suppressor cells), CD22 (B-cells), CD56 (natural killer cells), and VLA-1 (T-cell activation marker).

RESULTS

Ectopic endometrium contained significantly more scattered stromal CD4, CD8, and activated T cells than did proliferative and secretory eutopic endometrium. There were more activated T-cells in proliferative than in secretory eutopic endometrium. Ectopic endometrium contained significantly fewer NK cells than proliferative and secretory endometrium.

CONCLUSIONS

These results demonstrate that (1) the increased lymphocyte population in ectopic endometrium is due to increased numbers of CD4 and CD8 cells, and (2) a greater number of activated T cells are present in ectopic endometrium as compared to eutopic endometrium. Increased concentration of stromal T cells and enhanced VLA-1 expression in ectopic endometrium suggest that cytokine products of the activated T-cells may be involved in regulating cellular processes of endometriosis tissue.

Regulatory roles of IFN-gamma in human endometrium

Available data suggest that several microenvironments exist within the complex structure of human endometrium. Predecidual reaction which is associated with the expression of VLA-1 and alpha 1 PEG first appears in the stromal cells around the spiral arteries. Expression of Ber-EP4 is limited to a distinct group of stromal cells that reside around glands and underneath surface epithelium. A distinctly different group of stromal cells that surround lymphoid cells express HLA-DR molecules. The proliferative activity of endometrial epithelium is markedly higher in the upper functionalis and is gradually diminished towards the basalis. In addition, several proteins, including HLA-DR and some members of the integrin family of molecules are strongly expressed in the basalis epithelium. The expression of these proteins in endometrial epithelium is gradually diminished towards the surface. The gradual rather than abrupt changes in the expression of proteins and proliferative activity across the length of endometrial epithelium argues against separation of endometrium into the distinct regions of basalis and functionalis. Rather, such distribution is in favor of existence of a polarized microenvironment in human endometrium. Emerging evidence suggests that the development of this microenvironment is mediated by T cells activated within lymphoid aggregates with consequent secretion of IFN-gamma. IFN-gamma regulates HLA-DR expression and proliferation of endometrial epithelium. Maximal impact of the cytokine is exerted in regions close to the source of cytokine with a gradual dissipation of the effect distant from this source. Therefore, this cytokine may be the prototype of a group of paracrine factors that induce a polarized microenvironment in human endometrium.

Cytokine regulation of cellular proliferation in endometriosis

OBJECTIVE

This study was designed (1) to characterize the resident leukocyte population in ectopic endometrium (EE), (2) to assess proliferative activity of cellular components in EE, (3) to assess whether resident leukocytes in EE express IFN gamma mRNA and (4) to demonstrate endometrial epithelial cell IFN gamma receptors in EE.

STUDY DESIGN

Biopsies of EE and normal eutopic endometrium (UE) were studied immunocytochemically using monoclonal antibodies specific for CD45 leukocyte common antigen, CD3 (a T cell marker), CD11c (a macrophage marker), and Ki67 (proliferation marker). Leukocyte types were identified immunocytochemically, followed by in situ hybridization to assess expression of IFN gamma mRNA. IFN gamma receptor expression was assessed by immunocytochemistry.

RESULTS

The percentage of scattered stromal cells staining for each CD marker was greater in EE than in UE. The proliferative activity of endometrial stromal cells and epithelial cells was significantly less in EE than in UE. The overall concentration of T cells and macrophages expressing IFN gamma mRNA was significantly greater in EE than in UE. The percentage of each leukocyte type expressing IFN gamma mRNA was also greater in EE than in UE, and IFN gamma receptors were present in glandular epithelium of EE.

CONCLUSIONS

These findings support a possible paracrine role for resident leukocytes and IFN gamma in regulating cell proliferation in endometriosis.

The effect of progesterone on the accumulation of leukocytes in the human endometrium

OBJECTIVE

Our purpose was to determine the role of progesterone on the number and type of leukocytes found in human endometrium.

STUDY DESIGN

Endometrial tissue was obtained from normally cycling women and from women receiving hormone replacement therapy for premature ovarian failure. All tissues were formalin fixed, sectioned, and stained with specific antibodies to leukocytes, T cells, B cells, and macrophages. Each tissue was also dated by means of published techniques. Quantitation was performed by counting all immunopositive cells in five high-powered fields. Data were compared by analysis of variance and Mann-Whitney U test.

RESULTS

Leukocytes increased from 31.1 to 99.1 per high-powered field (p = 0.0001), and T cells increased from 10.9 to 20.4 per high-powered field (p = 0.001) after 12 days of progesterone treatment of women with ovarian failure. Normally menstruating women in the late luteal phase had similar concentrations. Neither B cells nor macrophages were found to increase with progesterone treatment.

CONCLUSIONS

These data indicate that progesterone results in an increased leukocyte and T-cell concentration in human endometrium.

Growth factors and growth modulators in human uterine endometrium: their potential relevance to reproductive medicine

OBJECTIVE

To provide an up-to-date, comprehensive review on the presence and regulation of growth factors (GFs), GF receptors, and GF regulatory proteins in human endometrium in an effort to understand the potential roles of these proteins in endometrial cell mitosis and differentiation and in endometrial-trophoblast interactions.

DESIGN

Relevant studies were identified through a computerized bibliographic search (MEDLINE; BRS Information Technologies, a division of Maxwell Online, Inc., McLean, VA) and through manual scanning of recent relevant journals.

RESULTS

Several GFs, their receptors, and regulatory proteins have been identified in endometrium, and cellular localization and steroid-dependence of these proteins as well as action of several growth modulators on endometrial cell function have been studied. Epidermal growth factor, transforming growth factor (TGF)-alpha, platelet-derived growth factor, insulin-like growth factors (IGFs) and their binding proteins, fibroblast growth factor (FGF), TGF-beta, colony-stimulating factor (CSF)-1, and interferon-gamma regulate mitosis of endometrial cellular components in vitro. Endothelin-1 may participate in vasoconstriction and FGF may participate in angiogenesis in this tissue in vivo. Interleukins-1 and -6 are believed to be involved in endometrial T-cell activation, and TGF-beta, CSF-1, the interleukins, and the IGFs likely mediate endometrial-trophoblast interactions. The role of tumor necrosis factor in endometrium remains uncertain.

CONCLUSIONS

Current evidence supports the thesis that GFs play a central role in cyclic mitosis and differentiation of endometrial cellular components, recruitment of macrophages in decidualizing endometrium, endometrial-trophoblast interactions, early pregnancy maintenance, tissue shedding in the absence of implantation, and endometrial functionalis regeneration.

Enhanced expression of resident leukocyte interferon gamma mRNA in endometriosis

PROBLEM

Previous studies have shown that the endometrial epithelial/stromal cell proliferative activity of endometriosis is significantly less than that of normal endometrium and that the concentration of resident stromal leukocytes is significantly greater in ectopic than in eutopic endometrium. Other work has shown that interferon gamma (IFN gamma), secreted by resident leukocytes, inhibits endometrial cell proliferation in vitro. Accordingly, we hypothesized that the lower proliferative activity of endometriosis may be related to enhanced resident leukocyte IFN gamma production. This study was designed to assess whether resident leukocytes in endometriosis express IFN gamma mRNA and to compare this expression to that of normal endometrium.

METHODS

Biopsies of ectopic endometrium (N = 16) from women in the follicular phase and normal proliferative (N = 9) and secretory (N = 8) endometria were examined for IFN gamma expression. Using monoclonal antibodies specific for CD45 (leukocyte common antigen), CD3 (a T-cell marker) and CD11c (a macrophage marker), leukocyte types were identified immunocytochemically, followed by in situ hybridization to examine expression of IFN gamma mRNA.

RESULTS

Results demonstrated that (1) the overall concentration of T cells and macrophages expressing IFN gamma mRNA is significantly greater in endometriosis as compared to eutopic endometrium, and (2) the percent of each leukocyte type expressing IFN gamma mRNA is greater in endometriosis than in normal endometrium.

CONCLUSIONS

These findings support a possible paracrine role for resident leukocytes in regulating cell proliferation in endometriosis.

Phenotypic characterization of CD7+, CD3+, and CD8+ lymphocytes from first trimester human decidua using two-color flow cytometry

PROBLEM

There is increasing evidence that decidual lymphocytes play a major role in local interactions at the fetomaternal interface.

METHOD

In this paper we use two-color flow cytometry to delineate the phenotype of lymphocytes obtained from human early decidua by mechanical dispersal technique.

RESULTS

The most abundant decidual lymphocytes expressed CD7, CD38, CD56, and CD2 markers, relatively small proportions of CD3+, CD8+, CD4+, CD16+, CD45RA+, CD11b+, and Leu8+ cells were also present. The vast majority of decidual CD7+ lymphocytes expressed CD38, CD2, and CD56 markers and were CD3-, CD8-, CD16-, and CD57-. Decidual CD3+ lymphocytes were weakly staining for TCR alpha/beta, lacked T-cell receptor (TCR) gamma/delta molecules, and approximately 40% of them expressed HLA-DR. All decidual CD8+ lymphocytes were CD2+ and the majority of them expressed CD38, CD56, and CD7 markers and were CD3- at the same time CD8+CD7- lymphocytes were found in decidua. According to the expression of the CD45RA marker, decidual CD8+ lymphocytes could be divided into two subsets: CD8+CD45RA+CD56+ and CD8+CD45RA-.

CONCLUSIONS

These data clearly demonstrate that decidual lymphocytes display phenotypical features different from those of their counterparts in peripheral blood.

The distribution and possible function of gamma interferon-immunoreactive cells in normal endometrium and myometrium

T-lymphocytes are present in normal endometrium, where they may have a role in the control of glandular maturation. T-cell activity could be related to the local secretion of cytokines such as gamma interferon, which has an anti-proliferative effect on endometrial epithelial cells in vitro. We have examined gamma interferon immunoreactivity and T-cell distribution in 24 normal pre-menopausal uteri. Endometrial appearances were representative of all stages of the menstrual cycle. Most cells in the lymphoid aggregates in the stratum basalis were stained by T-cell and gamma interferon antisera. T-lymphocytes were also scattered in glandular epithelium and throughout the stroma of basal and functional layers; immunoreactivity for gamma interferon was less consistent in these cells. There was no alteration in the intensity or distribution of gamma interferon staining in different phases of the menstrual cycle. Endometrial granulocytes (K-cells) present mainly in the late secretory endometria were not reactive with the gamma interferon antiserum. In addition to endometrial staining, T-cells were distributed in all areas of the myometrium in most uteri, and many myometrial lymphocytes were gamma interferon positive. These results support a role for gamma interferon in endometrial physiology, possibly as an inhibitor of epithelial proliferation.

IL-7 and IL-8 inhibit gamete interaction in the zona-free hamster egg sperm penetration assay

Current thought in reproductive endocrinology suggests hat endometriosis-associated subfertility may be the result of an adverse influence of activated immunocompetent cells on fertilization and embryo development. Inflammatory ediators such as interleukin-1 and tumour necrosis actor have been implicated in the pathophysiology of this process. The purpose of this study was to assess the effect of two recently characterized cytokines, interleukin-7 (IL-7 ) and interleukin-8 (IL-8), on gamete interaction in the perm penetration assay (SPA). Donor sperm were preincubated or 4 h with 0.5, 5, 50, or 500 ng ml(-1) of human ecombinant IL-7 or IL-8. Sperm penetration was determined by an experienced gametologist by the presence of decondensed sperm heads or pronuclei formation. A dose-dependent inhibition of gamete interaction was observed following coincubation with either IL-7 or IL-8. These data offer the possibility that IL-7 and IL-8 may play a role in the pathogenesis of immunocompetent cell-associated subfertility.

Cytokine regulation of human endometrial function

Human endometrium undergoes sequences of proliferation, and secretion followed by menstruation in a predictable fashion. The importance of systemic factors, steroid hormones, in driving endometrium through these phases is well known. However, it is becoming increasingly apparent that a group of factors collectively called cytokines may also serve a key role as local modulators of endometrial function. Expression of the receptors for cytokines, production of cytokines and the ability to demonstrate modulation of a host of functions of both endometrial epithelium and stroma indicate that human endometrium is uniquely poised to respond to cytokines.

Human endometrial epithelial cell lines for studying steroid and cytokine actions

Recent studies suggest that the proliferation and expression of HLA-DR molecules in endometrial epithelium may be regulated by systemic steroids and local cytokines. To test the interacting influences of cytokines and steroids on the expression of HLA-DR and proliferation of epithelial cells, an endometrial cell model is required that is sensitive to both signals. In this study, we characterize cells of carcinoma cell lines of endometrial lineage for their responsiveness to cytokines and steroids. Independently developed for its response to steroid hormones from a well-differentiated adenocarcinoma of human endometrium, EnCa101AE cell line is further cloned for the expression of progesterone receptor. Immunohistochemical localization using monoclonal antibodies demonstrates that both EnCa101AE cell line and cloned ECC1 cells are purely epithelial, as evidenced by the expression of cytokeratin and epithelial membrane antigen, express estrogen receptors, and concomitantly exhibit IFN-gamma receptor. Experiments using radioiodinated IL-1 reveal that these cell lines also possess high affinity receptors for IL-1. As indicated by the induction of HLA-DR molecules, and alterations in morphologic characteristics, these cell lines are sensitive to both IFN-gamma and IL-1 action. The class II molecules (HLA-DR, HLA-DP, and HLA-DQ) are differentially induced by IFN-gamma treatment in carcinoma cell lines, with HLA-DR being the prevailing induced molecule. IFN-gamma inhibits and estradiol-17 beta promotes growth of ECC1 cells in a dose- and time-dependent manner. These findings indicate that the interacting effect(s) of the cytokines and steroid hormones on endometrial epithelium may be studied in these unique steroid- and cytokine-sensitive epithelial cell lines.