Immune cells in normal pregnancy and gestational trophoblastic diseases.

A healthy pregnancy requires the development of maternal-fetal immune tolerance against the semi-allogeneic fetus. The interactions between the trophoblastic cells and the maternal immune cells (p.e., natural killer cells, T cells, macrophages, dendritic cells and B-cells) are important for the development of the maternal-fetal immune tolerance and the placental growth and function. These interactions are mediated by cell to cell contact and secreted molecules such as cytokines, chemokines, angiogenic factors and growth factors. The maternal immune cells are present in normal non-pregnant and pregnant endometrium and there are several lines of evidence based on immunohistochemical and RNA sequencing data that the decidual immune cells and immune-related pathways display alterations in GTD, which may have pathogenetic and clinical significance. The present review focuses on the usefulness of the immunohistochemical analysis which provides multiparametric in situ information regarding the numbers, the immunophenotypes and the immunotopographical distributions of the decidual immune cells in tissue sections from normal pregnancy and GTD. We also discuss the significance of the immunohistochemical information in order to gain insight in the putative mechanisms explaining the alterations of the decidual immune cells in GTD and the potential implications of these alterations in the pathogenesis and the clinical behavior of GTD.

Type I interferons modulate methotrexate resistance in gestational trophoblastic neoplasia.

PROBLEM: Resistance to methotrexate is a leading clinical problem in gestational trophoblastic neoplasia (GTN), but there are limited laboratory models for this condition. METHOD OF STUDY: We created isogenic trophoblastic cell lines resistant to methotrexate and compared these to the parent cell lines using gene expression microarrays and qRT-PCR followed by mechanistic studies using recombinant cytokines, pathway inhibitors, and patient sera. RESULTS: Gene expression microarrays and focused analysis by qRT-PCR revealed methotrexate led to type I interferon upregulation, in particular interferon alpha 2 (IFNA2), and methotrexate resistance was associated with chronic low level increases in type I interferon expression. Recombinant IFNA2 imparted chemosensitive choriocarcinoma cells with partial resistance to methotrexate, while chemoresistant choriocarcinoma cells were uniquely sensitive to fludarabine, a STAT1 inhibitor. In pre-treatment patient sera, IFNA2 levels correlated with subsequent resistance to methotrexate chemotherapy. CONCLUSION: Methotrexate resistance is influenced by type I interferon signaling with prognostic and therapeutic implications for treating women with GTN.

PD-L1 Expression in Premalignant and Malignant Trophoblasts From Gestational Trophoblastic Diseases Is Ubiquitous and Independent of Clinical Outcomes.

OBJECTIVE: Recently reported expression of programmed cell death 1 ligand 1 (PD-L1) in gestational trophoblastic diseases (GTDs) suggests that the immune tolerance of pregnancy might be hijacked during neoplastic process. We assessed PD-L1 protein expression in premalignant and malignant GTD lesions and analyzed associations with disease severity and chemotherapy outcomes. METHODS: We included 83 GTD whole-tissue sections from 76 patients in different treatment settings. PD-L1 protein expression was assessed with immunohistochemistry in each trophoblast subtype with the Allred total score (ATS), which combines intensity and proportion expression on a 0- to 8-point scale. Peritumoral immune infiltrate was scored on hematoxylin-eosin-safran-stained slides. RESULTS: PD-L1 expression was ubiquitous and strong in all GTD trophoblast subtypes. For invasive moles, ATS scores were maximal at 8 in 100%, 100%, and 75% of syncytiotrophoblast, villous cytotrophoblast, and extravillous cytotrophoblast specimens, respectively. For choriocarcinomas, ATS was 8 in 80% of specimens. Immune infiltrates were moderate to severe in 61%, 100%, and 100% of peritumoral zones of choriocarcinoma, epithelioid trophoblastic tumor, and invasive moles, respectively. Because of the homogeneous pathological findings, no significant differences in PD-L1 expression profiles or peritumoral immune infiltrates were found regarding FIGO (International Federation of Gynecology Obstetrics) prognostic score, fatal outcome, or chemosensitivity. CONCLUSIONS: We confirm that PD-L1 is constitutively expressed in all GTD premalignant and malignant trophoblast subtypes, independently from FIGO score, chemoresistance, or fatal outcomes, thereby suggesting a crucial role for PD-L1 in the development and tolerance of GTD. Assessment of anti-PD-L1 drug in GTD patients has been activated.

IgG expression in trophoblasts derived from placenta and gestational trophoblastic disease and its role in regulating invasion.

Immunoglobulin G (IgG) is an important humoral immune factor, which plays a role in innate immunity of the fetus. IgG immunoreactivity was often seen in trophoblasts of placenta. Traditionally, IgG in trophoblasts was believed to be transported from the maternal blood through neonatal Fc receptor (FcRn). Here, we explored the phenomenon of IgG expression and its role in regulating invasion in trophoblasts derived from normal placenta and gestational trophoblastic disease (GTD). IgG expression was detected with an emphasis on mRNA transcripts by using reverse transcription-polymerase chain reaction and hybridization in situ, besides evaluated at the protein level with immunohistochemistry and immunofluorescence. The migration and attachment of normal trophoblast cell line (TEV-1) and choriocarcinoma cell line (JAR) were inhibited with down-regulation of IgG expression. Methotrexate promoted the differentiation of JAR cell line; however, it had little effect on the differentiation of TEV-1 cell line. IgG expression, migration, and attachment of JAR and TEV-1 cell lines were decreased in the presence of methotrexate. Furthermore, statistical analysis showed that the differences in migration and attachment were significant (P < 0.05) for JAR cell line, while no significant difference was found for TEV-1 cell line. Collectively, these results confirmed that with the progression from normal placenta to GTD, the expression of IgG was increased in trophoblasts, which might actively promote the migration and attachment of trophoblasts as an important regulating factor.

Role of mast cells in gynecological neoplasms.

Mast cells are of paramount importance in allergic reactions, pathogen immune responses during infection, and angiogenesis, as well as innate and adaptive immune regulation. Beyond all these roles, mast cells are now increasingly being recognized as modulators of tumor biology and fate. Notwithstanding mounting evidence of mast cell accumulation in tumors, their exact role in tumorigenesis and tumor progression is still incompletely understood. Although some evidence suggests that mast cells can promote tumorigenesis, there are some clinical sets as well as experimental tumor models in which mast cells seem to have functions that favor the host. This article focuses on the significant roles of mast cells in the mechanism, early diagnosis, differential diagnosis and evaluation of prognosis of gynecological neoplasms, with particular emphasis on the capacity of these cells to stimulate tumor growth by promoting angiogenesis, and highlight recent findings on the integral roles of mast cells in gynecological neoplasm growth, such as cervical and breast cancer. Information to be presented suggests that mast cells may become useful tools for future anticancer therapies.

Immunobiology of gestational trophoblastic diseases.

Gestational trophoblastic diseases (GTDs) comprise a group of interrelated diseases characterized by development after gestation, widespread metastases, and high curability with chemotherapy. The good prognosis of GTDs is considered partly a result of the host immune response to paternal antigens expressed on trophoblastic cells. In this study, we review current understanding of the immunobiology of GTDs. First of all, we describe the microenvironment between trophoblastic cells and subpopulation of immune cells. Second, immunogenetics, immune microenvironment around abnormal trophoblast, and mechanism of GTDs escaping from maternal immune system surveillance were also discussed. Third, we propose the possible immunotherapy for persistent GTDs, particularly the vaccine designed on human chorionic gonadotrophin, which is generally accepted as a tumor marker for GTDs diagnosis. Due to the low incidence of GTDs and high response to chemotherapy, there have been few literatures about immunobiologic characteristics of GTDs compared with the other gynecologic malignancies, such as ovarian cancer, but the immunologic behavior of GTDs should be explored for further understanding of the etiology of these diseases and to help designing immunotherapeutic strategies for persistent GTDs.

Diagnostic and prognostic significance of circulating tumor suppressor gene p53 autoantibodies in patients with gestational trophoblastic tumors.

Seventy-two patients with gestational trophoblastic tumors (GTTs) and 20 first-trimester healthy pregnant women (controls) participated in this study. According to the WHO scoring system, GTTs were subgrouped into 24 hydatiform mole spontaneous regression (HMSR), 18 postmolar high-risk (PMHR) and 16 low- and 14 high-risk cases of choriocarcinoma. Patients with choriocarcinoma were treated with hysterectomy and methotrexate chemotherapy, whereas molar pregnancy was managed by either oxytocin infusion followed by suction evacuation or by hysterectomy. Serum p53 autoantibodies were determined by enzyme-linked immunosorbant assay and serum hCGbeta was determined by radioimmunoassay before and throughout the 12 months after treatment. p53 autoantibodies were not detected in normal pregnancy and cases of HMSR but were detected in all cases of PMHR and choriocarcinoma. Concentrations of p53 autoantibodies were higher in choriocarcinoma than in PMHR cases. Serial measurements of p53 autoantibodies dropped to an undetectable level within 1 and 6 months after treatment in cases of PMHR and low-risk choriocarcinoma, respectively. Decreasing values of p53 autoantibodies in high-risk choriocarcinoma remained higher than the cut-off level of controls. There was a significant positive correlation between p53 autoantibodies and serum hCGbeta concentration in GTTs. In conclusion, detection of p53 autoantibodies has a high potential for the differential diagnosis of GTTs and their serial measurements are clinically useful to monitor disease progression and to assess response to therapy in GTTs.

Co-expression of Fas (APO-1, CD95)/Fas ligand by BeWo and NJG choriocarcinoma cell lines.

OBJECTIVE: Fas (CD95) is a transmembrane protein of the tumor necrosis factor receptor superfamily that induces apoptosis in susceptible cells on crosslinking by its ligand (FasL). The Fas loss of function and concurrent expression of its ligand (FasL) have been associated with malignant phenotype. In this study, we sought to investigate the hitherto undescribed expression of Fas and FasL on the immortalized human choriocarcinoma cell lines BeWo and NJG. METHODS: Receptor and ligand expression was demonstrated using specific antibodies and multiple techniques including immunocytochemistry, confocal immunofluorescence microscopy, flow cytometry, immunoblots, and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Data from this study indicate that human choriocarcinoma cell subtypes co-express both Fas and FasL. A specific cytoplasmic and membranous pattern of immunoreactivity was noted that was further confirmed at mRNA transcripts by RT-PCR. In addition, we provide evidence using flow cytometry that the Fas receptors are downregulated. The mean fluorescence intensities for NJG and BeWo were 1.47 +/- 0.5 and 1.59 +/- 0.4, while that for Fas-positive Jurkat cells was 25.6 +/- 3.1. CONCLUSIONS: To our knowledge, this is the first report on the identification and constitutive co-expression of Fas and FasL in BeWo and NJG choriocarcinoma cells. Choriocarcinoma cells evade immune attack by downregulating the Fas receptor and by killing lymphocytes through expression of FasL. Taken together, our investigations suggest that the Fas/FasL system may represent a mechanism by which malignant trophoblasts become resistant to apoptosis, escape immune surveillance, and metastasize.

Persistent low levels of human chorionic gonadotropin: A premalignant gestational trophoblastic disease.

OBJECTIVE: This study was undertaken to evaluate the significance of persistent low-level human chorionic gonadotropin (hCG) titers (usually <50 IU/L) in the absence of clinical evidence of pregnancy or gestational trophoblastic disease. STUDY DESIGN: The USA hCG Reference Service consulted on 114 cases with persistent low levels of hCG; 51 had false-positive hCG results. The remaining 63 cases had real hCG results and are presented here. RESULTS: Antecedent gestational events included hydatidiform mole (27), pregnancy (35), and gestational trophoblastic neoplasm (1). Forty of the 63 (64%) cases received therapy, including chemotherapy (38), hysterectomy (2), or both (10). Despite treatment, in all cases, low hCG titers persisted. After 1 to 4.5 years of low titers, four women had a sudden rapid increase in hCG levels, and malignant disease was confirmed or clearly suggested (gestational trophoblastic neoplasm [3] and placental site trophoblastic tumor [1]). Invasive trophoblast antigen (ITA) is a marker of invasive cytotrophoblast cells. ITA was measured in 38 of the cases with persistent low hCG, in all cases ITA accounted for less than 25% of the hCG concentration. It was also determined in the 4 cases indicated with malignant disease, accounting for more than 80% of the hCG. CONCLUSION: The presence of persistent low-level hCG titers defines a subset of women with preinvasive or quiescent gestational trophoblastic disease. ITA effectively detected the presence or absence of invasive cells in these cases. The recommended management of the quiescent disease is close surveillance without therapy until malignant disease detected.