Chorionic Villus Research Articles

Regulation of Immune Checkpoint Antigen CD276 (B7-H3) on Human Placenta-Derived Mesenchymal Stromal Cells in GMP-Compliant Cell Culture Media.

Therapies utilizing autologous mesenchymal cell delivery are being investigated as anti-inflammatory and regenerative treatments for a broad spectrum of age-related diseases, as well as various chronic and acute pathological conditions. Easily available allogeneic full-term human placenta mesenchymal stromal cells (pMSCs) were used as a potential pro-regenerative, cell-based therapy in degenerative diseases, which could be applied also to elderly individuals. To explore the potential of allogeneic pMSCs transplantation for pro-regenerative applications, such cells were isolated from five different term-placentas, obtained from the dissected maternal, endometrial (mpMSCs), and fetal chorion tissues (fpMSCs), respectively. The proliferation rate of the cells in the culture, as well as their shape, in vitro differentiation potential, and the expression of mesenchymal lineage and stem cell markers, were investigated. Moreover, we studied the expression of immune checkpoint antigen CD276 as a possible modulation of the rejection of transplanted non-HLA-matched homologous or even xeno-transplanted pMSCs. The expression of the cell surface markers was also explored in parallel in the cryosections of the relevant intact placenta tissue samples. The expansion of pMSCs in a clinical-grade medium complemented with 5% human platelet lysate and 5% human serum induced a significant expression of CD276 when compared to mpMSCs expanded in a commercial medium. We suggest that the expansion of mpMSCs, especially in a medium containing platelet lysate, elevated the expression of the immune-regulatory cell surface marker CD276. This may contribute to the immune tolerance towards allogeneic pMSC transplantations in clinical situations and even in xenogenic animal models of human diseases. The endurance of the injected comparably young human-term pMSCs may promote prolonged effects in clinical applications employing non-HLA-matched allogeneic cell therapy for various degenerative disorders, especially in aged adults.

Adrenomedullin has a pivotal role in trophoblast differentiation: A promising nanotechnology-based therapeutic target for early-onset preeclampsia.

Early-onset preeclampsia (EOPE) is a severe pregnancy complication associated with defective trophoblast differentiation and functions at implantation, but manifestation of its phenotypes is in late pregnancy. There is no reliable method for early prediction and treatment of EOPE. Adrenomedullin (ADM) is an abundant placental peptide in early pregnancy. Integrated single-cell sequencing and spatial transcriptomics confirm a high ADM expression in the human villous cytotrophoblast and syncytiotrophoblast. The levels of ADM in chorionic villi and serum were lower in first-trimester pregnant women who later developed EOPE than those with normotensive pregnancy. ADM stimulates differentiation of trophoblast stem cells and trophoblast organoids in vitro. In pregnant mice, placenta-specific ADM suppression led to EOPE-like phenotypes. The EOPE-like phenotypes in a mouse PE model were reduced by a placenta-specific nanoparticle-based forced expression of ADM. Our study reveals the roles of trophoblastic ADM in placental development, EOPE pathogenesis, and its potential clinical uses.

MiR-150-5p contributes to unexplained recurrent spontaneous abortion by targeting VEGFA and downregulating the PI3K/AKT/mTOR signaling pathway

PurposeThe purpose of this study is to investigate the function of miR-150-5p in URSA. MethodTwenty-six chorionic villous tissues were collected to examine the expression of miR-150-5p and VEGFA by using quantitative polymerase chain reaction (qPCR) and western blot assay, respectively. Transwell assay was conducted to assess the migration and invasion ability of trophoblast cells. The dual-luciferase reporter assay was applied to determine the relationship between miR-150-5p and VEGFA in vitro. Relevant signaling pathway protein expression level was measured via western blot assay. Signaling transduction inhibitor LY294002 was used to block PI3K/AKT/mTOR signaling pathway. Finally, in vivo the effect of miR-150-5p on embryonic absorption rate was evaluated in mice.ResultsClinical samples revealed that miR-150-5p expression was significantly elevated in the villous tissues and serum of URSA patients. Moreover, the overexpressing of miR-150-5p could inhibit both HTR-8/SVneo cell and JAR cell migration, invasion, and restrained PI3K/AKT/mTOR signaling pathway by targeting VEGFA in vitro. This inhibitory effect of miR-150-5p could be reversed by overexpressing the gene of vascular epithelial growth factor A (VEGFA). In contrary, inhibition of miR-150-5p significantly enhanced migration, invasion ability of both HTR-8/SVneo and JAR cells, and also could stimulate PI3K/AKT/mTOR signaling pathway. This promoting effect of miR-150-5p could be ameliorated by LY294002 (PI3K inhibitor). Finally, after miR-150-5p overexpression in vivo, the embryo resorption rate in pregnant mice was increased significantly.ConclusionsOverall, these findings imply that miR-150-5p is among the key factors that regulate the pathogenesis of URSA.

An analysis of placental chorionic villous and decidual basalis tissue immunoreactivity in patients after cesarean section due to a placenta accreta spectrum disorder and elective cesarean section followed by the depressed mood.

Over the past few years, interest in investigating immune dysfunction in patients with psychiatric disorders has increased. B7-H4 is a molecule with immunosuppressive properties that seems to play a key role in establishing maternal tolerance against fetal antigens. The aim of this study was to compare the B7-H4 immunoreactivity levels in patients after cesarean section. Placental and decidual tissue samples were obtained from 49 women who delivered at Bielański Hospital in Warsaw between 2009 and 2015. Fifteen of the patients developed postpartum depression and 14 had a diagnosis of placenta accreta spectrum. The control group consisted of 20 healthy patients on whom cesarean section was performed due to breech presentation at term. The highest levels of B7-H4 immunoreactivity were found in the placental chorionic villous and decidual basalis tissue samples of the patients who later developed postpartum depression, while the lowest levels were found in the samples of those patients with a placenta accreta spectrum disorder. The difference between the B7-H4 immunoreactivity levels of these two groups was statistically significant. The B7-H4 expression levels were statistically significantly higher in the women in the postpartum depression group than in the control group. Postpartum depression follows a disturbance of the suppressive milieu responsible for rebalancing the maternal immune system after the initial cytotoxic activation during labor.

FOXP3-positive cell infiltration in the chorionic villi is increased in the placenta accreta and decreased in the placental abruption.

Growing data suggest a role of Treg cells in placentation. The aim of the study was to evaluate Treg cells (FOXP3-positive cells) placental bed infiltration in patients with placenta accrete syndrome (PAS) and patients who experienced placental abruption. The study group included 13 patients with PAS and the control group consisted of 66 women who had caesarean (CD) delivery of whom, 44 patients with elective caesarean (EC) delivery, and 22 patients with urgent caesarean (UC) delivery due to placental abruption. FOXP3 cell infiltration was assessed by means of immunohistochemistry in placental chorionic villous (CV) and in the decidua (D) and cumulatively in the placental bed (PB). We observed significant difference in the degree of FOXP3-positive cell CV infiltration between studied groups (p = 0.04). FOXP3-positive cells were the most commonly observed in PAS patients, while, they were the least frequently presented in patients after UC. The immunoreactivity for FOXP3-positive cells in CV were as follows: PAS 5 (38%), urgent CS 1 (5%) and elective CS 8 (18%) subjects. We found no difference in the presence of FOXP3-positive cells in the D (p = 0.35) and in the PB (p = 0.23) of analyzed groups. FOXP3-cell infiltration was not related with patient age, BMI, gestational age and neonatal birth weight. Our study provides further evidence that abnormal invasive placentation is an associated disturbance of the maternal immune response. Accordingly, we have theorized that alteration of the FOXP3-positive Treg cell infiltration into the placental bed allows trophoblast cell invasion.

MRNA and Protein Expression in Human Fetal Membrane Cells: Potential Biomarkers for Preterm Prelabor Rupture of the Fetal Membranes?

Clinically, unique markers in fetal membrane cells may contribute to the search for biomarkers for preterm prelabor rupture of the fetal membranes (pPROM) in maternal blood. pPROM is associated with overwhelming inflammation and premature cellular senescence causing "biological microfractures" of the fetal membranes. We hypothesize that these pathological processes are associated with the shedding of fetal membrane cells into the maternal circulation. The aim of this study was to identify markers expressed exclusively in fetal membrane cells to facilitate their isolation, characterization, and determination of biomarker potential in maternal blood. We have (1), by their transcriptomic profile, identified markers that are upregulated in amnion and chorion tissue compared to maternal white blood cells, and (2), by immunohistochemistry, confirmed the localization of the differentially expressed proteins in fetal membranes, placenta, and the placental bed of the uterus. RNA sequencing revealed 31 transcripts in the amnion and 42 transcripts in the chorion that were upregulated. Among these, 22 proteins were evaluated by immunohistochemistry. All but two transcripts were expressed both on mRNA and protein level in at least one fetal membrane cell type. Among these remaining 20 proteins, 9 proteins were not significantly expressed in the villous and extravillous trophoblasts of the placenta.

Retention of Key Characteristics of Unprocessed Chorion Tissue Resulting in a Robust Scaffold to Support Wound Healing.

Placental membranes have been widely studied and used clinically for wound care applications, but there is limited published information on the benefits of using the chorion membrane. The chorion membrane represents a promising source of placental-derived tissue to support wound healing, with its native composition of extracellular matrix (ECM) proteins and key regulatory proteins. This study examined the impact of hypothermic storage on the structure of chorion membrane, ECM content, and response to degradation in vitro. Hypothermically stored chorion membrane (HSCM) was further characterized for its proteomic content, and for its functionality as a scaffold for cell attachment and proliferation in vitro. HSCM retained the native ECM structure, composition, and integrity of native unprocessed chorion membrane and showed no differences in response to degradation in an in vitro wound model. HSCM retained key regulatory proteins previously shown to be present in placental membranes and promoted the attachment and proliferation of fibroblasts in vitro. These data support the fact that hypothermic storage does not significantly impact the structure and characteristics of the chorion membrane compared to unprocessed tissue or its functionality as a scaffold to support tissue growth.

Beta Thalassemia Mutation Analysis in Fetal Samples for Optimal Mutation Screening Strategy

Objective: To determine the frequency of various beta-thalassemia mutations in the prenatal period and ascertain the spectrum of mutations to optimise mutation analysis with cost reduction in testing. Study Design: Cross-sectional study Place and Duration of Study: Department of Molecular Hematology, Armed Forces Institute of Pathology (AFIP)/National University of Medical Sciences (NUMS), Rawalpindi Pakistan from Jul 2021 to Jan 2022. Methodology: Chorionic villus sampling (CVS) was performed at 12-16 weeks of gestation in target couples where both parents were known β-thalassemia carriers. Deoxyribonucleic acid (DNA) was extracted from fetal tissues, and polymerase chain reaction (PCR) was performed, and mutations were analysed with controls on polyacrylamide gel electrophoresis (PAGE). Results: Out of a total of 87 CVS samples, 17(19.5%) showed no mutation, 25(28.7%) had Beta-thalassemia major, and 45 (51.7%) were beta-thalassemia trait (heterozygous). Eight mutations were detected in the study population, and the three most common mutations were Fr 8/9, IVS 1/5 and Cd 15. Comparatively less common mutations included Cd 5, Fr 41/42, Fr 16, IVS 1/1 and Cap+1. Ethnical distribution of these mutations showed high frequency in Pathans and Punjabis compared to Sindhis, Balochis, Saraikis and Kashmiris. Conclusion: The commonly detected prevalent thalassemia mutations must be tested to provide cost-effective facilities in our resource-constrained country. This study will help in future testing strategies and optimisation of mutation analysis in our country.

Prenatal Evaluation of a Fetal Cystic Hygroma: An Unexpected Finding of a De Novo Fetal BRCA1 Deletion Case Report

This case presents a novel occurrence of a de novo BRCA1 gene deletion in a fetus with a cystic hygroma. Chorionic villus sampling (CVS) was performed for chromosome G-banding analysis, demonstrating a normal karyotype: 46, XX. Chromosome microarray analysis performed as a reflex test revealed an 80 kb deletion on 17q21.31, encompassing the BRCA1 gene. Follow-up FISH analysis performed on parental blood samples yielded negative results, confirming that the deletion was de novo in the fetus. Subsequent anatomic ultrasound evaluation showed no identifiable structural defects, and it was concluded that the microdeletion was unlikely to be the cause of the cystic hygroma. Regardless, it will be imperative that the patient’s daughter be appropriately counseled regarding the implications of carrying a BRCA1 deletion and the need for heightened surveillance in adulthood. As BRCA1 genetic testing is traditionally performed on adult patients with informed consent, this case report highlights the need for ongoing conversations and research in the management of incidental fetal diagnosis discovered during routine prenatal testing, as well as the care and counseling of these patients and their families.

Case Report: A rare case of Fanconi anaemia

Fanconi anaemia (FA) is autosomal recessive but can also be an autosomal dominant or X-linked recessive disease. In India, Fanconi anaemia is a very rarely seen disorder. Clinical findings in FA include pancytopenia, hyperpigmentation or hypopigmentation, skeletal anomalies, small stature or growth retardation, endocrine abnormalities, anal atresia, deafness, malignancy of head and neck, and it has a tendency to run in families. Diagnosis of FA can be made on clinical findings and laboratory examination. Recommended prenatal testing like chorionic villus sampling and amniocentesis. Androgen therapy and hematopoietic stem cell transplantation (HSCT) are treatment modalities recommended for FA. Follow-up of all diagnosed FA patients is essential throughout their lifetime. Having a healthcare team with diverse expertise is vital in preventing anemia and malignancy. A meticulous plan and unwavering support are also crucial. Outcomes of FA patients is desolate due to complications associated with it. Our aim of the study is to increase awareness among physicians about the presence of such rare diseases. Well-timed diagnosis with appropriate treatment is needed to prevent complication.

Optical genome mapping for prenatal diagnosis: A prospective study

PurposeCytogenetic analysis provides important information for prenatal decision-making and genetic counseling. Optical genome mapping (OGM) has demonstrated its performances in retrospective studies. In our prospective study, we assessed the quality of DNA obtained from cultures of amniotic fluid (AF) and chorionic villi (CV) and evaluated the ability of OGM to detect all clinically relevant aberrations identified by standard methods. MethodsA total of 37 prenatal samples from pregnancies with a fetal anomaly on ultrasound were analyzed prospectively by OGM between January 1, 2021 and June 31, 2022. OGM results were interpreted blindly and compared to the results obtained by standard techniques. ResultsOGM results were interpretable in 92% of samples. We observed 100% concordance between OGM and karyotype and/or chromosomal microarray results. In addition, OGM identified a median of 30 small (<100 kb) structural variations per case with the involvement of 12 OMIM genes, of which 3 were OMIM morbid genes. ConclusionThis prospective study showed OGM performed well in detecting genomic alterations in cell cultures from prenatal samples. The place of OGM in relation to CMA or exome sequencing remains to be defined in order to optimize the prenatal diagnostic procedure.

Application of flat-sided culture tubes during prenatal diagnosis

To assess the value of using flat-sided culture tubes for preparing chromosomes through chorionic villi (CV) and amniotic fluid (AF) cell cultures during prenatal diagnosis. From February to March 2020, 157 CV samples and 147 AF samples subjected to prenatal diagnosis at the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region were selected as the study subjects. For each sample, one flat-sided tube and one flask culture were set up by following the standard protocols. The methods were evaluated by comparing the cell growth, experimental process, quality of chromosome preparation and costs. The success rates for the culturing of CV and AF samples by the flat-sided culture tube method were 97.45% (153/157) and 97.96% (144/147), respectively. By contrast, the success rates for the conventional flask method were 98.72% (155/157) for CV and 98.64% (145/147) for AF samples. No significant difference was found between the two methods (P > 0.05). The average harvest time required by the flat-sided culture tube method was 8.45 days for CV and 9.43 days for AF cultures, whilst the average harvest time for conventional flask method was 9.05 days and 9.54 days, respectively. The flat-sided culture tube method for CV had required significantly shorter average harvest time than the conventional method (P < 0.001). No statistical significant difference was found in the average harvest time for AF by the two methods (P > 0.05). The conventional culturing method had required three containers with two sample transfers. By contrast, the flat-sided culture tube method was carried out in one tube without any sample transfer. The average total amount of medium used was 3.91 mL for each flat-sided culture tube and 6.26 mL for each conventional flask. The flat-sided culture tube method can provide a simple, cost-effective and error-reducing procedure for the CV and AF samples culture during prenatal diagnosis.

Late first-trimester ultrasound findings can alter management after high-risk NIPT result.

To evaluate the impact of detailed late first-trimester ultrasound (LFTU) on the positive predictive value (PPV) of a high-risk non-invasive prenatal test (NIPT) result for various chromosomal abnormalities. This was a retrospective study of all cases undergoing invasive prenatal testing from three tertiary providers of obstetric ultrasound over 4 years, each using NIPT as a first-line screening test. Data were collected from pre-NIPT ultrasound, NIPT, LFTU, placental serology and later ultrasound examinations. Prenatal testing for chromosomal abnormalities was performed by microarray, initially using array comparative genomic hybridization and then single nucleotide polymorphism (SNP) array for the last 2 years. Uniparental disomy testing was performed by SNP array during all 4 years. The majority of NIPT tests were analyzed using the Illumina platform, initially confined to the assessment of the common autosomal trisomies, sex chromosome aneuploidies and rare autosomal trisomies (RAT), then extending to genome-wide analysis for the last 2 years. Amniocentesis or chorionic villus sampling (CVS) was performed on 2657 patients, 1352 (51%) of whom had undergone prior NIPT, with 612 (45%) of these returning a high-risk result and meeting the inclusion criteria for the study. LFTU findings significantly affected the PPV of the NIPT result for trisomies 13 (T13), 18 (T18) and 21 (T21), monosomy X (MX) and RAT but not for the other sex chromosomal abnormalities or segmental imbalances (> 7 Mb). Abnormal LFTU increased the PPV close to 100% for T13, T18, T21, MX and RAT. The magnitude of the change in PPV was highest for the most severe chromosomal abnormalities. When LFTU was normal, the incidence of confined placental mosaicism (CPM) was highest in those with a high-risk NIPT result for T13, followed by T18 and T21. After normal LFTU, the PPV for T21, T18, T13 and MX decreased to 68%, 57%, 5% and 25%, respectively. LFTU after a high-risk NIPT result can alter the PPV for many chromosomal abnormalities, assisting counseling regarding invasive prenatal testing and pregnancy management. The high PPVs of NIPT for T21 and T18 are not sufficiently modified by normal LFTU findings to alter management. These at-risk patients should be offered CVS for earlier diagnosis, particularly given the low rate of CPM associated with these aneuploidies. Patients with a high-risk NIPT result for T13 and normal LFTU findings often wait for amniocentesis or avoid invasive testing altogether given the low PPV and higher rate of CPM in this context. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

EP21.03: Volume of chorionic villus sampling and delay in patient care

EP21.03: Volume of chorionic villus sampling and delay in patient care

EP21.07: Impact of patient obesity on chorionic villus sampling volume outcomes

EP21.07: Impact of patient obesity on chorionic villus sampling volume outcomes

The Extent of Beta-Thalassemia Mutations in Couples Referred for Chorionic Villus Sampling: A Collaborative Single Center Cross-Sectional Study

The Extent of Beta-Thalassemia Mutations in Couples Referred for Chorionic Villus Sampling: A Collaborative Single Center Cross-Sectional Study

H19 Promoter DNA Methylation is Lower Among Early Abortion Patients Undergoing IVF Embryo Transfer.

H19 is the first long noncoding RNA (lncRNA) found to be associated with gene imprinting. It is highly expressed in the embryonic stage and may have important regulatory effects on human embryonic development. We investigated the differences between the levels of H19 promoter DNA methylation in the chorionic villi of patients who experienced spontaneous abortion (SA) following in vitro fertilization embryo transfer (IVF-ET) and those of patients with a normal early pregnancy (NEP). We also analyzed the associated DNA methyltransferase (DNMT) activity. Chorionic villus tissue from patients with SA and NEP were collected. The DNA methylation levels of two CpG islands in the promoter region of the H19 gene in the two groups were detected by bisulfite sequencing, and the mRNA expression of DNMTs was analyzed by real-time polymerase chain reaction. The sample size of each group was 32, and there were no significant differences in baseline data, including age, parity, and body mass index, between the two groups. Among the 7 CpG islands measured, the methylation rates of 3 CpG islands (CpG 1, 6, and 7) were significantly lower in the SA group than in the NEP group (P < 0.01). The methylation levels of the other 4 CpG islands were not significantly different between the two groups. There were no differences in the expression of DNMT1 between the two groups (P > 0.05), but DNMT3a and DNMT3b RNA levels were significantly lower in SA group than in the NEP group (P < 0.01). The lower H19 promoter DNA methylation levels found in the chorionic villi of patients with SA patients following IVF-ET may be explained by decreased expression of DNMT3a and DNMT3b.

Transcriptomic analysis of stem cells from chorionic villi uncovers the impact of chromosomes 2, 6 and 22 in the clinical manifestations of Down syndrome

BackgroundDown syndrome (DS) clinical multisystem condition is generally considered the result of a genetic imbalance generated by the extra copy of chromosome 21. Recent discoveries, however, demonstrate that the molecular mechanisms activated in DS compared to euploid individuals are more complex than previously thought. Here, we utilize mesenchymal stem cells from chorionic villi (CV) to uncover the role of comprehensive functional genomics-based understanding of DS complexity.MethodsNext-generation sequencing coupled with bioinformatic analysis was performed on CV obtained from women carrying fetuses with DS (DS-CV) to reveal specific genome-wide transcriptional changes compared to their euploid counterparts. Functional assays were carried out to confirm the biological processes identified as enriched in DS-CV compared to CV (i.e., cell cycle, proliferation features, immunosuppression and ROS production).ResultsGenes located on chromosomes other than the canonical 21 (Ch. 2, 6 and 22) are responsible for the impairment of life-essential pathways, including cell cycle regulation, innate immune response and reaction to external stimuli were found to be differentially expressed in DS-CV. Experimental validation confirmed the key role of the biological pathways regulated by those genes in the etiology of such a multisystem condition.ConclusionsNGS dataset generated in this study highlights the compromised functionality in the proliferative rate and in the innate response of DS-associated clinical conditions and identifies DS-CV as suitable tools for the development of specifically tailored, personalized intervention modalities.

Pregnancy Through Assisted Conception After Radical Trachelectomy: A Case Report

Introduction: Trachelectomy, a conservative surgery in the early stages of cervical cancer, allows young women to keep their fertility. Infertility after such a surgery is frequent, and many couples should opt for assisted reproduction. Objectives: This case report aims to present a successful pregnancy in a woman with a history of cervical cancer and complete removal of the uterine cervix through trachelectomy. Case Presentation: A successful pregnancy is described after two failed attempts of embryo transfer (ET) in a 32-year-old woman with a history of trachelectomy due to stage IA invasive squamous cell carcinoma of the cervix. Before and after radical trachelectomy, she received adjuvant chemotherapy. In her second course of in-vitro fertilization, after a mock transfer at the time of ovum pickup with 11 oocytes and 7-day 3 embryos, her third ET cycle under ultrasound guide was successful. During pregnancy, in the first-trimester screening, nuchal translucency was reported to be 4.5 mm. Therefore, chorionic villous sampling and comparative genomic hybridization CGH-Array were performed before preparing for abdominal cerclage at 14 weeks. Further screening tests were normal. Finally, she delivered a 2430 g healthy baby girl through cesarean section at 37 weeks. Conclusions: The mock transfer and ultrasound-guided ET are suggested for women with a history of trachelectomy.

Mild/asymptomatic COVID-19 in unvaccinated pregnant mothers impairs neonatal immune responses.

Maternal SARS-CoV-2 infection triggers placental inflammation and alters cord blood immune cell composition. However, most studies focus on outcomes of severe maternal infection. Therefore, we analyzed cord blood and chorionic villi from newborns of unvaccinated mothers who experienced mild/asymptomatic SARS-CoV-2 infection during pregnancy. We investigated immune cell rewiring using flow cytometry, single-cell RNA sequencing, and functional readouts using ex vivo stimulation with TLR agonists and pathogens. Maternal infection was associated with increased frequency of memory T and B cells and nonclassical monocytes in cord blood. Ex vivo T and B cell responses to stimulation were attenuated, suggesting a tolerogenic state. Maladaptive responses were also observed in cord blood monocytes, where antiviral responses were dampened but responses to bacterial TLRs were increased. Maternal infection was also associated with expansion and activation of placental Hofbauer cells, secreting elevated levels of myeloid cell-recruiting chemokines. Moreover, we reported increased activation of maternally derived monocytes/macrophages in the fetal placenta that were transcriptionally primed for antiviral responses. Our data indicate that even in the absence of vertical transmission or symptoms in the neonate, mild/asymptomatic maternal COVID-19 altered the transcriptional and functional state in fetal immune cells in circulation and in the placenta.