Identification of Fetal Inflammatory Cells in Eosinophilic/T-cell Chorionic Vasculitis Using Fluorescent In Situ Hybridization

Occurrence of Eosinophilic Granulocytes in the Decidua of Placentas With Perinatal Clinical Findings

INTRODUCTION

Inflammatory and immunologic homeostasis in the basal plate of the placenta is essential for the fetal development and growth, since the fetus immunologically constitutes a semi-allograft. Bone marrow derived eosinophilic granulocytes are usually not found in the basal plate.

MATERIALS AND METHODS

We retrospectively analyzed the occurrence of eosinophilic granulocytes in the basal plate of singleton placentas and investigated clinical and pathologic-anatomic associations.

RESULTS

In 5 singleton placentas (0.3% of all investigated cases from the archive) eosinophilic granulocytes were detectable. All these cases also displayed chronic deciduitis. Two cases had a clinical history of substitution therapy with methadone, in 2 instances the mothers had a history of atopic diseases, and 1 mother had a SARS-CoV-2-infection during pregnancy.

CONCLUSIONS

The infiltration of eosinophilic granulocytes in the decidua is a rare feature of placentas with perinatal clinical findings. Strikingly, all 5 affected cases also presented with chronic deciduitis. This may hint at a contribution of the eosinophilic infiltrate to a non-infectious pathologic inflammatory process with an increased risk for perinatal complications.

Discordant Eosinophilic/T-Cell Chorionic Vasculitis in a Dichorionic Diamniotic Placenta

Eosinophilic/T-cell chorionic vasculitis (ETCV) is an idiopathic lesion composed of eosinophils, CD3+ T lymphocytes, and histiocytes. In twins, ETCV may affect only one chorionic plate, a feature defined as "discordant". We present a case of ETCV discordance in a diamniotic dichorionic placenta at 38 weeks of gestation, in which the female twin was small for gestational age, weighing 2670 g (25th percentile). The corresponding placental territory presented ETCV in two close chorionic vessels with concordance of the fetal inflammatory response. Immunohistochemistry showed an abundance of CD3+/CD4+/CD25+T lymphocytes, CD68 PG M1+ macrophages, and scattered CD8+ T cells with focal TIA-1 positivity. Granzyme B, CD20 B lymphocytes, and CD56 natural killer cells were negative. High-grade villitis of unknown etiology (VUE) was additionally found and displayed comparable ETCV findings, except for an equivalent ratio of CD4+/CD8+ T cells, but TIA-1 was focally expressed. VUE was associated with chronic histiocytic intervillositis (CHI). The combination of ETCV, VUE, and CHI may have been responsible for reduced fetal growth. Concordance was observed in the ETCV and TIA-1 expression, both in ETCV and in VUE, which is a maternal response. These findings may suggest a common antigen or chemokine pathway to which both mother and fetus accordingly responded.

Eosinophilic/T-cell Chorionic Vasculitis: Its Incidence Is Increasing but It Does Not Appear to Recur in Subsequent Pregnancies

INTRODUCTION

Eosinophilic/T-cell chorionic vasculitis (E/TCV), an incidental finding primarily in third trimester placentas, is characterized by eosinophils and CD3+ T lymphocytes infiltrating at least 1 chorionic and/or stem villous vessels. Its etiology and clinical significance are unclear.

METHODS

Placental pathology reports issued by 8 pediatric-perinatal pathologists at Alberta Children's Hospital were retrieved from the lab information system (2010-2022), and candidate reports were identified using a Perl script searching for "eosinophil." Candidate diagnoses of E/TCV were validated by pathologist review.

RESULTS

38,058 placenta reports from 34,643 patients were reviewed; 328 cases of E/TCV were identified, for an overall incidence of 0.86%. Incidence increased 23% per year, from 0.11% in 2010 to 1.5% in 2021 (P < .01). This temporal change was observed for all pathologists; the incidence of identified multifocality also increased over time (P < .01). Umbilical vascular involvement was exceedingly rare. No variation in incidence was attributable to season. We received more than 1 placenta from 46 mothers with an E/TCV placental diagnosis; examination of >1 placenta did not reveal any mother with >1 E/TCV diagnosis.

CONCLUSIONS

The incidence of E/TCV increased steadily over a ~12-year period and no recurrent cases were observed.

Co-occurrence of Eosinophilic/T-Cell Chorionic Vasculitis and Acute Chorionitis, Acute Chorionic Vasculitis, and Funisitis in a Term Placenta

Eosinophilic/T-cell chorionic vasculitis was initially defined as "a new form of chorionic vasculitis characterized by an infiltrate composed primarily of eosinophils and CD3⁺ T lymphocytes ... [that] occurs in the absence of any evidence of chorioamnionitis." No subsequent reports have directly addressed whether histologic evidence suggestive of amniotic fluid infection should preclude its diagnosis. The case reported here describes a term placenta with mild acute chorionitis, moderate acute subchorionitis, mild acute chorionic vasculitis, and funisitis associated with multifocal eosinophilic/T-cell chorionic vasculitis. It shows unequivocally, with immunohistochemical staining, that eosinophilic/T-cell chorionic vasculitis and acute chorionic vasculitis can be seen and histologically distinguished in the same case. The paper shows how differing interpretations of inclusion and exclusion criteria by investigators have affected estimates of the incidence of this rare lesion. There is a need to harmonize diagnostic criteria; the report describes how cases with both entities can be documented carefully.

Аllergic Basal Deciduitis as a Reason of Recurrent Antenatal Fetal Death

BACKGROUND: Allergic diseases of pregnant women are associated with chronic placental insufficiency and the development of immunopathological conditions of unknown etiology in a child in postnatal life. Pregnancy with bronchial asthma is often complicated by intrauterine growth retardation, preeclampsia, and antenatal fetal death. AIM: The objective was to present a clinical case of recurrent antenatal fetal death in the third trimester in women with bronchial asthma under controlled course. CASE REPORT: Pregnancy proceeded without clinical signs of exacerbation of bronchial asthma and allergic status. However, chronic inflammation with eosinophilia in the intervillous space and the basal lamina was revealed in the placenta tissue. Eosinophilia of the intervillous area was accompanied by obliteration of the intervillous area by fibrin deposits. CONCLUSION: We suppose that immunological inflammation at the fetoplacental unit level can occur regardless of the mother’s allergic status. Moreover, it is likely that the objective state of the mother in the presence of an allergic disease does not reflect the presence/absence of an immunological process in the placenta, as the immunological inflammatory process can develop in different compartments (at the level of the mother’s body and the placental-fetal compartment) with varying degrees of severity.

Maternal-Fetal Inflammation in the Placenta and the Developmental Origins of Health and Disease

Events in fetal life impact long-term health outcomes. The placenta is the first organ to form and is the site of juxtaposition between the maternal and fetal circulations. Most diseases of pregnancy are caused by, impact, or are reflected in the placenta. The purpose of this review is to describe the main inflammatory processes in the placenta, discuss their immunology, and relate their short- and long-term disease associations. Acute placental inflammation (API), including maternal and fetal inflammatory responses corresponds to the clinical diagnosis of chorioamnionitis and is associated with respiratory and neurodevelopmental diseases. The chronic placental inflammatory pathologies (CPI), include chronic villitis of unknown etiology, chronic deciduitis, chronic chorionitis, eosinophilic T-cell vasculitis, and chronic histiocytic intervillositis. These diseases are less-well studied, but have complex immunology and show mechanistic impacts on the fetal immune system. Overall, much work remains to be done in describing the long-term impacts of placental inflammation on offspring health.

Discordance of Twin Placentas for Multifocal Eosinophilic/T-cell Chorionic Vasculitis

Eosinophilic/T-cell chorionic vasculitis (ETCV) is an idiopathic placental lesion characterized by chorionic vasculitis composed predominantly of eosinophils and CD3+ T lymphocytes. It usually presents as a unifocal lesion, but a subset have multifocal involvement. We report 4 Di-Di and 2 Di-Mo twins sharing fused placental discs with discordant circulatory involvement by multifocal ETCV. The findings are difficult to explain by sampling alone. The limitation of ETCV to 1 fetus's vascular territory in monozygotic twin pregnancies is difficult to explain but could provide insights into the fetal immune system and the etiology of ETCV.

Chorionic Histiocytic Hyperplasia is Associated With Chronic Inflammatory Lesions in the Placenta

Background Chorionic histiocytic hyperplasia (CHH) is a cellular proliferation at the base of the chorion that was identified by the authors in examining placentas for chronic chorioamnionitis (CC). This study is a retrospective review of cases diagnosed with CHH, describing its incidence alone and with associated lesions, and the immunophenotype of lesional cells. Design In this retrospective study, a laboratory information system search over a 34-month period using the key phrase "chorionic stromal" was performed. Cases identified were reviewed for presence of the following: CC, chronic villitis (CV), chronic deciduitis (CD), maternal (MIR), and fetal (FIR) acute inflammatory responses, meconium deposition; and whether CD3 immunostaining was performed. Incidences were tabulated and compared with known prevalences in our population. Select cases were stained with various immunostains to identify cell lineage and X and Y fluorescent probes to identify fetal or maternal cell origin in cases with male infants. Results Eighty cases of CHH were identified during the study period. Incidences of inflammatory lesions associated with CHH were: CV (54/80, 68%), CD (32/80, 40%), CC (25/80, 31%), MIR (39/80, 49%), and FIR (9/80, 11%). Only chronic inflammatory lesions had a significant correlation with the co-incidence of CHH. CC was identified alongside CHH in 12 of 22 cases in which a CD3 immunostain was performed. The cell population in CHH was vimentin+, CD68+, CD3-, CD45-, CD56-, hPL-, SMA-, OCT 3/4- and, in some cases, variably mixed with CD3+ lymphocytes. The cells had a male genotype by fluorescent in situ hybridization analysis. Conclusion The association of CHH with acute and chronic inflammatory conditions and its immunophenotype suggest that it may be a reactive process. CD3 immunostaining is helpful to identify concurrent CC.