Immune Responses to Neisseria gonorrhoeae: Challenges and Opportunities With Respect to Pelvic Inflammatory Disease.

Pelvic inflammatory disease and infertility frequently develop after female genital tract infection with Neisseria gonorrhoeae, but determining their etiology from among various possibilities presents difficulties. Exploitation of serology to identify the causative agent is complicated by numerous factors, and no immunological test currently exists to determine unequivocally whether an individual currently is, or has been, infected with N. gonorrhoeae. The extensive antigenic variability of N. gonorrhoeae and its expression of antigens shared with other Neisseria species commonly carried in humans render problematic an assay that is specific for all gonococcal strains. However, novel conserved gonococcal antigens identified for potential vaccines may find additional application in diagnostic assays. N. gonorrhoeae also interferes with the adaptive immune response, and antibody responses to uncomplicated infection are usually weak. Elucidating the mechanisms whereby N. gonorrhoeae manipulates the human immune system may lead to improved understanding of the pathogenesis of pelvic inflammatory disease and infertility.

The association between subclinical hypothyroidism and TPOAb positivity with infertility in a population-based study: Tehran thyroid study (TTS).

BACKGROUND: Thyroid autoimmunity(TAI) is the most prevalent autoimmune condition in women of fertile age. There are increasing data regarding the association of thyroid dysfunction and thyroid autoimmunity with adverse pregnancy outcomes but there is no consensus regarding infertility and TPOAb positivity; thus we aimed to evaluate the association between thyroid TPOAb positivity and infertility in females and males in a population-based study (TTS). METHODS: Cross-sectional study of 3197 female and male participants in Tehran Thyroid Study (TTS) at the framework of the Tehran Lipid and Glucose Study (TLGS). Data included biochemical measurements and a self-administered questionnaire. RESULTS: A total of 12,823 cases in phase 4, 3719 cases (2108 female and 1611 male) were analyzed. The mean TSH of the infertile female and male was 2.52 ± 2.68 µIU/ml and 3.24 ± 10.26 µIU/ml respectively. The TPO median(IQR) of women with and without a history of infertility were 6.05 (3.30-13.96)and 6.04 (3.17-11.15);(P = 0.613), they were 5.08 (3.20-125.68) and 5.31 (3.93-125.68);(P = 0.490) in male participants, respectively. Results of crude and adjusted logistic regression analysis of the development of infertility by thyroid function and TPOAb, except for fT4 in male subjects, depicted no association between infertility and other variables in both crude and adjusted models. CONCLUSION: Based on the result, thyroid autoimmunity was not associated with infertility in both females and males.

Functional Ambivalence of Dendritic Cells: Tolerogenicity and Immunogenicity.

Dendritic cells (DCs) are the most potent professional antigen-presenting cells (APCs) and inducers of T cell-mediated immunity. Although DCs play a central role in promoting adaptive immune responses against growing tumors, they also establish and maintain peripheral tolerance. DC activity depends on the method of induction and/or the presence of immunosuppressive agents. Tolerogenic dendritic cells (tDCs) induce immune tolerance by activating CD4+CD25+Foxp3+ regulatory T (Treg) cells and/or by producing cytokines that inhibit T cell activation. These findings suggest that tDCs may be an effective treatment for autoimmune diseases, inflammatory diseases, and infertility.

Immunophenotypic Profiles in Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) a long-known endocrinopathy and one of the most common endocrine-reproductive-metabolic disorders in women, which can lead to infertility. Although the precise etiology remains unclear, PCOS is considered as a complex genetic trait, with a high degree of heterogeneity. Besides, hormones and immune cells, including both innate and adaptive immune cells, are reportedly a cross talk in PCOS. Chronic low-grade inflammation increases autoimmune disease risk. This proinflammatory condition may, in turn, affect vital physiological processes that ultimately cause infertility, such as ovulation failure and embryo implantation. Here, we review the accumulating evidence linking PCOS with inflammatory status providing an overview of the underlying hormone-mediated dysregulation of immune cells. We mainly focus on the correlational evidence of associations between immune status in women and the increased prevalence of PCOS, along with the specific changes in immune responses. Further recognition and exploration of these interactions may help elucidate PCOS pathophysiology and highlight targets for its treatment and prevention.

SARS-CoV-2 testing in infertile patients: different recommendations in Europe and America.

The incorporation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing into patient care algorithms has been proposed to mitigate risk. However, the two main professional societies for human reproduction (ESHRE and ASRM) appear divergent on their clinical utility and whether they should be adopted. In this opinion paper, we review the currently available tests and discuss the strengths and weaknesses of the proposed clinical care pathways. Nucleic acid amplification tests are the cornerstone of SARS-CoV-2 testing but test results are largely influenced by viral load, sample site, specimen collection method, and specimen shipment technique, such that a negative result in a symptomatic patient cannot be relied upon. Serological assays for SARS-CoV-2 antibodies exhibit a temporal increase in sensitivity and specificity after symptom onset irrespective of the assay used, with sensitivity estimates ranging from 0 to 50% with the first 3 days of symptoms, to 83 to 88% at 10 days, increasing to almost 100% at ≥ 14 days. These inherent constraints in diagnostics would suggest that at present there is inadequate evidence to utilize SARS-CoV-2 testing to stratify fertility patients and reliably inform clinical decision-making. The failure to appreciate the characteristics and limitations of the diagnostic tests may lead to disastrous consequences for the patient and the multidisciplinary team looking after them.

Effects of treatment with hydroxychloroquine on the modulation of Th17/Treg ratio and pregnancy outcomes in women with recurrent implantation failure: clinical trial.

AIM: The imbalance of Th17/Treg cells has been recently suggested as a new risk factors for recurrent implantation failure (RIF). Furthermore Th17/Treg cells are involved in immune regulation in peripheral blood and endometrial tissue of patients with RIF. In this research, we investigated the effects of Hydroxychloroquine (HCQ) on the level and function of Th17 and Treg cells in women with RIF. It may be possible to improve pregnancy outcomes by modulating high cytokine levels. METHODS: Women with RIF received oral HCQ (n = 60) on day 4 of the menstrual cycle and continued until day 20 of the menstrual cycle and 2 days before embryo transfer and continued until the day of the pregnancy test, for a total of 16 days in another cycle. The serum levels of IL-17 and IL-10, the expression of transcription factors related to Th17 and Treg cells and the immune-reactivity of IL-17, IL-21 as Th17 related cytokines and IL-10, TGF- ß as Treg related cytokines in endometrial tissues were evaluated by ELISA, real-time PCR, and fluorescent immunohistochemistry respectively.Results: Treatment with HCQ down-regulated Th17 related cytokines and function and up-regulated Treg related cytokines and function significantly (p < .001). RORγt, the Th17 transcription factor, expression was down-regulated and FOXP-3, the T-reg transcription factor, expression was up-regulated. The biochemical pregnancy rate was not significantly different in RIF patients before and after treatment. CONCLUSION: Our results demonstrated that the administration of HCQ in RIF women with immune cell disorders during pregnancy could affect the Th17/Treg ratio and enhance Treg and diminish Th17 responses which may be associated with successful pregnancy outcomes. However, significant difference in pregnancy outcomes was not observed in the present study.

Premature ovarian insufficiency (POI) and autoimmunity-an update appraisal.

PURPOSE: Primary ovarian insufficiency (POI) represents ovarian dysfunction related to very early aging of the ovaries. While the cause of POI in a majority of clinical cases remains undefined, autoimmunity is responsible for approximately 4-30% of POI cases. In the present paper, we aim to provide a critical appraisal and update review on the role of autoimmunity in POI patients. METHODS: A literature review was conducted for all relevant articles reporting on POI and autoimmunity. PubMed/MEDLINE and the Cochrane library were searched for the best available evidence on this topic. RESULTS: Patients with POI and coexisting autoimmunity are indistinguishable from those with negative autoimmune screen with regard to age of onset, prevalence of primary amenorrhea, or their endocrine profiles. A specific noninvasive reliable diagnostic test for the diagnosis of an autoimmune etiology is lacking; therefore, patients should be screened for the most common autoantibodies, i.e., steroid cell antibodies, anti-ovarian antibodies, and anti-thyroid antibodies. Moreover, treatment strategies to POI infertility are lacking and controversial. CONCLUSIONS: Nowadays, guidelines for the treatment of autoimmune POI are not available. Moreover, since diagnostic and treatment strategies to POI infertility are still lacking and controversial, further large clinical studies are needed to investigate the true impact of autoimmunity on POI and to identify the selected groups of patients who are most likely to benefit from immunossuprresive treatment.

Transcervical Inoculation with Chlamydia trachomatis Induces Infertility in HLA-DR4 Transgenic and Wild-Type Mice.

Chlamydia trachomatis is the leading cause of infection-induced infertility in women. Attempts to control this epidemic with screening programs and antibiotic therapy have failed. Currently, a vaccine to prevent C. trachomatis infections is not available. In order to develop an animal model for evaluating vaccine antigens that can be applied to humans, we used C. trachomatis serovar D (strain UW-3/Cx) to induce infertility in mice whose major histocompatibility complex class II antigen was replaced with the human leukocyte antigen DR4 (HLA-DR4). Transcervical inoculation of medroxyprogesterone-treated HLA-DR4 transgenic mice with 5 × 105C. trachomatis D inclusion forming units (IFU) induced a significant reduction in fertility, with a mean number of embryos/mouse of 4.4 ± 1.3 compared to 7.8 ± 0.5 for the uninfected control mice (P < 0.05). A similar fertility reduction was elicited in the wild-type (WT) C57BL/6 mice (4.3 ± 1.4 embryos/mouse) compared to the levels of the WT controls (9.1 ± 0.4 embryos/mouse) (P < 0.05). Following infection, WT mice mounted more robust humoral and cellular immune responses than HLA-DR4 mice. As determined by vaginal shedding, HLA-DR4 mice were more susceptible to a transcervical C. trachomatis D infection than WT mice. To assess if HLA-DR4 transgenic and WT mice could be protected by vaccination, 104 IFU of C. trachomatis D was delivered intranasally, and mice were challenged transcervically 6 weeks later with 5 × 105 IFU of C. trachomatis D. As determined by severity and length of vaginal shedding, WT C57BL/6 and HLA-DR4 mice were significantly protected by vaccination. The advantages and limitations of the HLA-DR4 transgenic mouse model for evaluating human C. trachomatis vaccine antigens are discussed.

Homology between cattle bull sperm and bacterial antigenic proteins viz a viz possible role in immunological infertility.

This study was carried out to investigate the possible presence of identical sperm and bacterial antigens which may cause similar antisperm antibody production leading to lower fertility. Cross-reactive antigens of cattle bull spermatozoa and different bacteria including Escherichia coli (E. coli), Bacillus sp., and Staphylococcus sp. were characterized by immunoblotting and mass fingerprinting. Significant cross-reactivity was obtained for 75, 72, 44, 40, 33, 30, 25, 18, 14 kDa proteins with purified IgG of calves, heifers and cows between spermatozoa and the studied bacteria. Significantly (p < 0.05) matched cross-reactive 40/33/30 kDa sperm, 33 kDa Staphylococcus sp/Bacillus sp and 40/25 kDa E. coli proteins were analyzed. Mass fingerprinting of 40/33/30 kDa (spermatozoa); 40/25 kDa (E. coli) and 33 kDa (Bacillus/Staphylococcus) proteins revealed their matching with vitellogenin-1-like/mitochondrial malate dehydrogenase 2, NAD/acrosin-binding protein isoform XI; outer membrane insertion signal domain/spore coat protein and glyceraldehyde-3-phosphate dehydrogenase, respectively. Acrosin-binding protein isoform X1 and mitochondrial malate dehydrogenase 2, NAD contributes to the capacitation of spermatozoa. Spore coat protein; glyceraldehyde-3-phosphate dehydrogenase of E. coli; Bacillus/Staphylococcus are 37.6% and 39.01% identical to acrosin-binding protein isoform X1; mitochondrial malate dehydrogenase 2, NAD of cattle bull spermatozoa. It can be interpreted from these observations that cross-reacting antibodies developed against 33/30 kDa sperm proteins and 25, 33 kDa bacterial proteins in cows may affect the functional activity of spermatozoa leading to delayed fertility in heifers and cows.

Descriptive Study of Rubella Titer Status in Infertility Patients.

INTRODUCTION: There is a 6.4 percent incidence of rubella exposure during pregnancy in the U.S. Given the severe effects rubella can have on a developing fetus, vaccination of women prior to pregnancy is important. Women seeking fertility treatment therefore present a population of patients primed for the vaccination. This study collected and analyzed rubella-specific immunoglobulin G (RV-IgG) titer statuses and corresponding demographics of infertility patients to identify patients at risk of rubella nonimmunity. METHODS: The study consisted of a retrospective review of electronic medial records (EMR) of female patients, ages 18 to 50, who were new patients receiving an infertility workup at a Midwestern reproductive endocrinology clinic from Jan. 1, 2010 through Dec. 31, 2014. Of those patients who had RV-IgG titers noted in their EMR, the following demographics were collected: age, race, gravidity and parity, state of residence, and community size. RESULTS: There were 750 patients included in the study. Rubella titers were drawn on 72.7 percent of the patients. Of those drawn, 90.8 percent had a positive rubella titer. Most of the participants (92.3 percent) were identified as Caucasian/White. Caucasians/Whites, Asians, and African Americans/Blacks had the highest rates of rubella immunity, while American Indians/Alaskan Natives had the lowest rates of immunity (p=0.0006). Nulligravida participants had a positive rubella titer rate of 94.1 percent, while primigravida participants had a rate of 89.8 percent (p=0.04). Participants living in the largest sampled communities had the lowest rates of positive rubella titers, while those living in the smallest communities had the highest rates of positive rubella titers, although these findings were not statistically significant. CONCLUSIONS: Of the infertility patients, 27.3 percent did not have an RV-IgG titer drawn as part of their fertility workup. Of the 72.7 percent of patients for whom titers were checked, nearly 10 percent were not immune to rubella. While there are a couple reasons why a patient may not have a positive titer, lack of immunization is the most common reason. Data analysis identified significance in the difference in titer status only with respect to race and gravidity, and those findings, particularly race, must be viewed critically in light of the study population. While the statistical significance of the study may be limited, there is clinical significance in identifying infertility patients at highest risk of rubella nonimmunity so vaccination education and efforts can be focused accordingly.

Variability in tuberculosis granuloma T cell responses exists, but a balance of pro- and anti-inflammatory cytokines is associated with sterilization.

Lung granulomas are the pathologic hallmark of tuberculosis (TB). T cells are a major cellular component of TB lung granulomas and are known to play an important role in containment of Mycobacterium tuberculosis (Mtb) infection. We used cynomolgus macaques, a non-human primate model that recapitulates human TB with clinically active disease, latent infection or early infection, to understand functional characteristics and dynamics of T cells in individual granulomas. We sought to correlate T cell cytokine response and bacterial burden of each granuloma, as well as granuloma and systemic responses in individual animals. Our results support that each granuloma within an individual host is independent with respect to total cell numbers, proportion of T cells, pattern of cytokine response, and bacterial burden. The spectrum of these components overlaps greatly amongst animals with different clinical status, indicating that a diversity of granulomas exists within an individual host. On average only about 8% of T cells from granulomas respond with cytokine production after stimulation with Mtb specific antigens, and few "multi-functional" T cells were observed. However, granulomas were found to be "multi-functional" with respect to the combinations of functional T cells that were identified among lesions from individual animals. Although the responses generally overlapped, sterile granulomas had modestly higher frequencies of T cells making IL-17, TNF and any of T-1 (IFN-γ, IL-2, or TNF) and/or T-17 (IL-17) cytokines than non-sterile granulomas. An inverse correlation was observed between bacterial burden with TNF and T-1/T-17 responses in individual granulomas, and a combinatorial analysis of pair-wise cytokine responses indicated that granulomas with T cells producing both pro- and anti-inflammatory cytokines (e.g. IL-10 and IL-17) were associated with clearance of Mtb. Preliminary evaluation suggests that systemic responses in the blood do not accurately reflect local T cell responses within granulomas.

Factors in Early-Life Programming of Reproductive Fitness.

Fertility rates have been declining worldwide, with a growing number of young women suffering from infertility. Infectious and inflammatory diseases are important causes of infertility, and recent evidence points to the critical role of the early-life microbial environment in developmental programming of adult reproductive fitness. Our laboratory and others have demonstrated that acute exposure to an immunological challenge early in life has a profound and prolonged impact on male and female reproductive development. This review presents evidence that perinatal exposure to immunological challenge by a bacterial endotoxin, lipopolysaccharide, acts at all levels of the hypothalamic-pituitary-gonadal axis, resulting in long-lasting changes in reproductive function, suggesting that disposition to infertility may begin early in life.

Effect of Endometrial Injury on Secretion of Endometrial Cytokines and IVF Outcomes in Women with Unexplained Subfertility.

In order to determine the effect of endometrial injury (EI) on in vitro fertilization (IVF) outcomes in women with unexplained subfertility and explore the relationship between EI and endometrial inflammatory cytokines, 66 women with unexplained subfertility undergoing IVF treatment were recruited. 38 patients in the EI group underwent EI in the mid-luteal phase of the cycle and 28 patients in the non-EI (NEI) group. According to the pregnancy outcome, the NEI and EI groups were divided into NEI-nonpregnant (NEI-NP), NEI-pregnant (NEI-P), EI-NP, and EI-P. All patients underwent aspiration of endometrial secretions immediately before embryo transfer. The concentrations of ten mediators were measured using Milliplex Magnetic Bead assay. The clinical pregnancy was significantly higher in the EI than in the NEI group. The concentrations of interleukin- (IL-) 6, IL-8, IL-12 (p70), IL-13, interferon- (IFN-) γ, monocyte chemotactic protein- (MCP-) 1, and vascular endothelial growth factor (VEGF) were significantly higher in the EI than the NEI group. The expression of IFN-γ and VEGF in the EI-P was significantly increased compared to the EI-NP group. These findings suggest that, in women with unexplained subfertility, endometrial injury might be a potential method to improve clinical pregnancy rates by promoting the expression of IFN-γ and VEGF.

The Role of Uterine NK Cells in Normal Reproduction and Reproductive Disorders.

The human endometrium contains a substantial population of leucocytes which vary in distribution during the menstrual cycle and pregnancy. An unusual population of natural killer (NK) cells, termed uterine NK (uNK) cells, are the most abundant of these cells in early pregnancy. The increase in number of uNK cells in the mid-secretory phase of the cycle with further increases in early pregnancy has focused attention on the role of uNK cells in early pregnancy. Despite many studies, the in vivo role of these cells is uncertain. This chapter reviews current information regarding the role of uNK cells in healthy human pregnancy and evidence indicating their importance in various reproductive and pregnancy problems. Studies in humans are limited by the availability of suitable tissues and the limitations of extrapolation from animal models.

Luteal cells from functional and regressing bovine corpora lutea differentially alter the function of gamma delta T cells.

The luteal microenvironment is thought to direct the function of resident immune cells to facilitate either luteal function or regression. To determine if luteal cells from functional (Days 10-12) and regressing (8 h after administration of prostaglandin F2alpha) corpora lutea (CL) induce different responses in γδ T cells, luteal cells were cocultured with autologous γδ T cells isolated from peripheral blood. Proliferation, functional phenotypes, and cytokine synthesis were analyzed by flow cytometry. To determine if the luteal cells from functional CL induce hyporesponsiveness in γδ T cells, γδ(+) cells were cocultured with midcycle luteal cells and further stimulated with concanavalin A. Coculture of γδ(+) cells with midcycle luteal cells did not inhibit concanavalin A-induced proliferation. In a proliferation assay, luteal cells from midcycle CL predominantly induced proliferation of γδ(+) WC1(-) cells (P < 0.05), while luteal cells from regressing CL predominantly induced proliferation of γδ(+)WC1(+) cells (P < 0.05). Analysis of intracellular cytokines indicated that midcycle luteal cells increased the proportion of γδ(+) cells containing interleukin 10 (P < 0.05), but reduced the proportion of γδ(+) cells containing interferon gamma (IFNG; P < 0.05). There were no changes in the proportions of γδ(+) cells synthesizing interleukin 4 or tumor necrosis factor. Unexpectedly, coculture of γδ(+) cells with luteal cells from regressing CL had no effect on any of the cytokines analyzed. These data support the hypothesis that the function of resident T cells is differentially modulated depending on the status of the CL.

Evaluation of cytokines in follicular fluid and their effect on fertilization and pregnancy outcome.

Cytokines in follicular fluid (FF) are important for reproduction as they modulate oocyte maturation and ovulation which influence subsequent fertilization, development of early embryo and potential for implantation. We evaluated FF cytokines in women who underwent intracytoplasmic sperm injection (ICSI) and their association with fertilized oocytes, embryo quality and pregnancy outcome. FF belonging to 38 patients including 18 polycystic ovary (PCO) and 20 male/unexplained infertility patients were investigated for granulocyte colony stimulating factor (G-CSF), regulated upon activation normal T cell expressed and presumably secreted (RANTES), tumour necrosis factor (TNFα), interferon gamma (IFNγ) and interleukins (IL-4 and IL-2) by bead-based sandwich immunoassay. Our findings revealed that on the day of oocyte retrieval, G-CSF was positively correlated with the number of fertilized oocytes, while TNFα detection was associated with reduced number of fertilized oocytes. Only G-CSF showed significant positive effect to the pregnancy outcome although the cytokines studied were not associated with embryo quality. PCO as the cause of infertility did not show an association with cytokines in FF. The functions of cytokines in reproduction are likely to be complex, and cytokine evaluation may offer insight to the understanding of the mechanisms leading to success or failure of assisted reproduction.

Human spermatozoa antigens in unexplained infertility.

OBJECTIVE: To determine and compare the immunolocalization of functionally important antigens in human spermatozoa in an unexplained infertility (UI) group. MATERIALS AND METHODS: In this study, the sperm samples of 20 patients undergoing evaluation belonging to normozoospermic group, whose primary reason of infertility was under investigation for this purpose, were screened. CD46, CD55 and CD52, CD69, CD98, fMLP, HI307, and 80280 were stained on the spermatozoa through indirect immunofluorescence technique. RESULTS: In addition to CD46, CD55, and CD52 antigens, which are known to be localized on human spermatozoa, significant immunolocalization of several novel antigens including: CD52, CD69, CD98, fMLP, HI307, and 80280 were determined on the spermatozoa of the unexplained infertility group, possibly reflecting important roles in the pathophysiology of such unresolved clinical situations. CONCLUSION: Identification and characterization of antigens present on sperm cells is crucial for understanding of the diagnosis and treatment of unexplained infertility. Further studies were conducted to evaluate a possible correlation between the expression of these antigens and clinical outcomes in different well-defined infertility groups.

[The role of selenium in endocrine system diseases]. / A szelén szerepe az endokrin betegségekben.

Oxygen derived free radicals, generated by a number of cellular reactions, include superoxide anion, hydrogen peroxide and hydroxyl radicals. They exert their cytotoxic effects mainly via peroxidation of the cell membrane resulting in the loss of membrane integrity. The essential trace element, selenium exerts complex effects on the endocrine systems, partly due to its antioxidant capacity. Well-characterized selenoproteins include iodothyronine deiodinases, glutathione peroxidases and thioredoxin reductases involved in thyroid hormone metabolism and protection from oxidative damage. The value of selenium supplementation in autoimmune thyroid disorders has been investigated and most studies confirmed the beneficial effect of selenium supplementation in Hashimoto's and Graves's diseases. Recently, selenium proved to be effective in mild inflammatory orbitopathy. There are a number of reports about the effect of selenium in diabetes mellitus, but the data are controversial as both insulin-like and diabetes-inducing effects of selenium have been described. Selenium was successfully used in both female and male infertility of autoimmune origin.

Immunological Aspects of Infertility-The Role of KIR Receptors and HLA-C Antigen.

The mechanisms of immune tolerance of a mother against an antigenically foreign fetus without a concomitant loss of defense capabilities against pathogens are the factors underlying the success of a pregnancy. A significant role in human defense is played by killer immunoglobulin-like receptor (KIR) receptors, which regulate the function of the natural killer (NK) cells capable of destroying antigenically foreign cells, virus-infected cells, or tumor-lesioned cells. A special subpopulation of NK cells called uterine NK cells (uNK) is found in the uterus. Disruption of the tolerance process or overactivity of immune-competent cells can lead to immune infertility, a situation in which a woman's immune system attacks her own reproductive cells, making it impossible to conceive or maintain a pregnancy. Since the prominent role of the inflammatory response in infertility, including KIR receptors and NK cells, has been postulated, the process of antigen presentation involving major histocompatibility complex (MHC) molecules (HLA) appears to be crucial for a successful pregnancy. Proper interactions between KIR receptors on female uNK cells and HLA class I molecules, with a predominant role for HLA-C, found on the surface of germ cells, are strategically important during embryo implantation. In addition, maintaining a functional balance between activating and inhibitory KIR receptors is essential for proper placenta formation and embryo implantation in the uterus. A disruption of this balance can lead to complications during pregnancy. The discovery of links between KIR and HLA-C has provided valuable information about the complexity of maternal-fetal immune interactions that determine the success of a pregnancy. The great diversity of maternal KIR and fetal HLA-C ligands is associated with the occurrence of KIR/HLA-C combinations that are more or less favorable for reproductive success.

Pathogenesis of infertility and recurrent pregnancy loss in thyroid autoimmunity.

Thyroid autoimmunity is the most prevalent autoimmune state that affects up to 4% of women during the age of fertility. A growing body of clinical studies links thyroid autoimmunity as a cause of infertility and adverse pregnancy outcomes that includes miscarriage or preterm deliveries. Importantly, these adverse effects are persistent in euthyroid women. In the current review we elaborate on the pathogenesis that underlies infertility and increased pregnancy loss among women with autoimmune thyroid disease. Such mechanisms include thyroid autoantibodies that exert their effect in a TSH-dependent but also in a TSH-independent manner. The later includes quantitative and qualitative changes in the profile of endometrial T cells with reduced secretion of IL-4 and IL-10 along with hypersecretion of interferon-γ. Polyclonal B cells activation is 2-3 time more frequent in thyroid autoimmunity and is associated with increased titers of non-organ specific autoantibodies. Hyperactivity and Increased migration of cytotoxic natural killer cells that alter the immune and hormonal response of the uterus is up to 40% more common in women with thyroid autoimmunity. Lack of vitamin D was suggested as a predisposing factor to autoimmune diseases, and was shown to be reduced in patients with thyroid autoimmunity. In turn, its deficiency is also linked to infertility and pregnancy loss, suggesting a potential interplay with thyroid autoimmunity in the context of infertility. In addition, thyroid autoantibodies were also suggested to alter fertility by targeting zona pellucida, human chorionic gonadotropin receptors and other placental antigens.