Chronic Intervillositis of Unknown Etiology (CIUE): Prevalence, patterns and reproductive outcomes at a tertiary referral institution

CD163 Expression in Chronic Intervillositis of Unknown Etiology and SARS-CoV-2 Placentitis

Chronic intervillositis of unknown etiology (CIUE) is an aberrant maternal inflammatory infiltrate comprised primarily of macrophages that collect in the intervillus space and is associated with poor outcomes including recurrent pregnancy loss. An abnormal maternal Th1-type response to pregnancy may be the basis for pathogenesis of CIUE but macrophage in the maternal infiltrate of CIUE have been reported to have an anti-inflammatory M2 phenotype characterized by increased expression of CD163. This study assesses expression of CD163 in CIUE and SARS-CoV-2 placentitis, which has a similar histopathological presentation, using an automated approach to minimize observer-related variability. The data show that the maternal inflammatory infiltrate of CIUE contains a blended population of high and low CD163 expressing macrophage with a prominent bias towards an anti-inflammatory M2 phenotype when compared to normal control tissue. A similar pattern is seen in SARS-CoV-2 placentitis, suggesting pathophysiologic similarity with CIUE, although SARS-CoV-2 also appears to promote decreased CD163 expression in Hofbauer cells, which is not seen in CIUE.

Inflammasome-targeted therapy might prevent adverse perinatal outcomes of recurrent chronic intervillositis of unknown etiology

Chronic histiocytic intervillositis of unknown origin (CHI) is a rare placental disorder associated with adverse pregnancy outcomes, frequent recurrence, and a lack of effective preventive strategies. Recent insights indicate a potential link between CHI-associated inflammatory lesions and the inflammasome pathway, suggesting innovative therapeutic avenues. Here we show a potential role of the inflammasome pathway in CHI through comprehensive transcriptomic analysis of grade 2 or 3 histopathologic CHI samples, paired with placental controls. Additionally, we present case studies of three individuals with recurrent CHI, who have undergone treatment with anakinra and colchicine throughout pregnancy, resulting in improved perinatal outcomes. Notably, all cases are characterized by the birth of healthy, full-term infants, with reduced or absent intervillositis recurrence. Placental assessment unveils heightened activation of the NLRP3-PYCARD inflammasome pathway and IL-1β processing in CHI samples, with downregulation observed in treated pregnancy samples, devoid of intervillositis. Collectively, these findings suggest a potential therapeutic role for targeting the inflammasome pathway in preventing recurrent CHI in pregnant individuals.

Prevalence and association of placental lesions with obstetrical features and outcome: data from French prospective study

Purpose

Since the Consensus Statement diffused by the Amsterdam Placental Workshop Group, knowledge of the meaning of placental vascular malperfusion has become essential in the unavoidable analysis of obstetrical history in a patient followed for autoimmune disease or any other maternal comorbidity. We aimed to analyse the prevalence of various placental lesions from a 6-months prospective observational study and to correlate the various placental profiles to obstetrical outcome, maternal diseases and pregnancy treatments. The frequency of foetal vascular malperfusion lesion could be estimated at 8.7%, in our population and to understand its neonatal associations.

Methods

The study groups consisted of 208 consecutive women which ended the pregnancy and have placental analysis during the period of the study.

Results

From December 2015 to October 2017, from overall 4398 delivered pregnancies in university obstetrical department, 208 (4.7%) placental analysis have been done and included in the study. The placental analysis have been done for vascular obstetrical complications during the pregnancy (n = 106; 51%), unexplained abnormal foetal heart rate tracings (n = 59; 28,3%), suspicion of intra-amniotic infection (n = 12; 5,7%%), term new-borns Apgar score <7 or arterial cord blood pH ≤ 7 (n = 7; 3,5%), spontaneous preterm delivery (n = 19; 9,1%), intrahepatic cholestasis of pregnancy (n = 5; 2,4%). An adverse obstetrical event was noted in 87 cases (42%): preeclampsia or HELLP syndrome (n = 15; 7%), FGR (n = 59; 28%), gestational diabetes (n = 33; 16%) and gestational hypertension (n = 19; 9%). Placental histological analysis showed abnormal vascular features in 159 cases (76%), inflammatory features in 16 placentas (8%), vascular and inflammatory features in 10 cases (4%), chorioamnionitis in 38 cases (18%) and absence of any abnormality in 43 cases (21%). A cluster analysis of histological features allowed distinguishing three placental patterns: a normal pattern characterised by the absence of any placental lesions, an inflammatory pattern characterised by the presence of villitis and/or chronic intervillositis; a vascular pattern with the presence of thrombosis, maternal floor infarct with massive perivillous fibrin deposition, infarction and chronic villositis hypoxia. Women with inflammatory placental profile have significantly increased frequencies of tobacco use (50% vs. 9%; P = 0.03), pathological vascular Doppler (50% vs. 5%; P = 0.001), FGR (100% vs. 14%; P = 0.0001) and oligohydramnios (67% vs. 5%; P = 0.0001) than those with normal placentas. A higher rate of vascular or inflammatory lesion were observed in women with Hypertensive disorder of pregnancy, where as those with inflammatory pattern have significantly more frequent FGR (100% vs 34%; P = 0.02) and oligohydramnios (67% vs 5%; P = 0.0002).

Conclusion

The placenta analysis is important to understand the origin of adverse obstetrical outcome and the risk for subsequent pregnancy.

Reproductive and treatment outcomes in chronic intervillositis of unknown etiology: A systematic review and meta-analysis

Chronic Intervillositis of Unknown Etiology (CIUE) is a rare idiopathic inflammatory disorder of the placenta. The evidence suggests an increased risk for poor obstetrical outcomes and a risk of recurrence as high as 100 %. This meta-analysis examined CIUE prevalence, recurrence, association with autoimmune disorders, reproductive outcomes, pregnancy complications, and the benefits of medical treatments. A systematic review, following PRISMA guidelines, involved a thorough search across multiple databases including Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Evidence Based Medical Reviews, and Scopus. Out of 590 initially identified studies, 19 studies were included for both qualitative synthesis and meta-analysis after full-text review. Risk of bias was assessed using appropriate tools: The Risk Of Bias In Non-randomized Studies of Interventions tool was applied to twelve studies, while the Joanna Briggs Institute case series critical appraisal tool was used for seven studies. Our findings confirm that CIUE is a rare condition (0.7 %). CIUE is associated with decreased live birth rates (53 %), increased recurrent pregnancy loss (23 %), fetal loss beyond 22 weeks gestation (25 %), a higher prevalence of autoimmune diseases (14 %), and a recurrence rate of 30 % in subsequent pregnancies. Moreover, individuals with CIUE had higher rates of pregnancy complications, including gestational hypertension (19 %), intrauterine growth restriction (45 %), and preterm births (43 %). No significant improvement in live birth rate was observed among treated CIUE patients; however, caution is warranted when interpreting these findings due to the limited sample size. Future research in CIUE is crucial given its rarity and complexity.

Intravenous Immunoglobulins for Recurrent Chronic Histiocytic Intervillositis: A Series of Case Studies

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a rare inflammatory placental disease characterized by diffuse infiltration of monocytes into the intervillous space and is associated with adverse pregnancy outcomes. No treatment is currently validated and although in some small reports, steroids with hydroxychloroquine have been described. There are no data for other therapies in refractory cases.

PATIENTS AND METHODS

We here report four cases of patients with a history of CHI treated with immunoglobulins during a subsequent pregnancy. The four patients with recurrent CHI had failed to previous immunomodulatory therapies with steroids and hydroxychloroquine. All patients had at least four pregnancy losses with histopathological confirmation of CHI for at least one pregnancy loss. The usual pregnancy-loss etiology screening and immunological screening were negative for all the patients.

RESULTS

For three patients, intravenous immunoglobulins were initiated at the βHCG positivity at 1 g/kg every 15 days until delivery. In one case with combined therapy since the beginning of the pregnancy, intravenous immunoglobulins were introduced at 20 WG because of severe growth restriction. Two patients had live births at 36 WG and one patient at 39 WG. One patient, who presented early first-trimester hypertension and severe placental lesions, failed to intravenous immunoglobulins and had a pregnancy loss at 15 WG.

CONCLUSION

This is the first report demonstrating the potential benefit of intravenous immunoglobulins in recurrent chronic intervillositis. Larger studies are needed to confirm this potential benefit for patients presenting severe cases of recurrent CHI.

Characterizing Histopathologic Features in Pregnancies With Chronic Histiocytic Intervillositis Using Computerized Image Analysis

CONTEXT.—

Chronic histiocytic intervillositis (CHI) is a rare condition characterized by maternal immune cell infiltration into the human placenta. CHI is strongly associated with fetal growth restriction, miscarriage, and stillbirth, and knowledge of its etiology, and consequently effective treatment, is limited. Currently, diagnosis is largely subjective and varies between centers, making comparison between studies challenging.

OBJECTIVE.—

To objectively quantify and interrelate inflammatory cells and fibrin in placentas with CHI compared with controls and determine how pathology may be altered in subsequent pregnancies following diagnosis. Macrophage phenotype was also investigated in untreated cases of CHI.

DESIGN.—

Computerized analysis was applied to immunohistochemically stained untreated (index) cases of CHI, subsequent pregnancies, and controls. Index placentas were additionally stained by immunofluorescence for M1 (CD80 and CD86) and M2 macrophage markers (CD163 and CD206).

RESULTS.—

Quantification revealed a median 32-fold increase in macrophage infiltration in index cases versus controls, with CHI recurring in 2 of 11 (18.2%) subsequent pregnancies. A total of 4 of 14 placentas (28.6%) with a diagnosis of CHI did not exhibit infiltration above controls. Macrophages in index pregnancies strongly expressed CD163. There was no significant difference in fibrin deposition between index cases and controls, although subsequent pregnancies displayed a 2-fold decrease compared with index pregnancies. CD3+ T cells were significantly elevated in index pregnancies; however, they returned to normal levels in subsequent pregnancies.

CONCLUSIONS.—

In CHI, intervillous macrophages expressed CD163, possibly representing an attempt to resolve inflammation. Computerized analysis of inflammation in CHI may be useful in determining how treatment affects recurrence, and alongside pathologist expertise in grading lesion severity.

Patterns of Interferon γ Expression and C4d Deposition in Chronic Intervillositis of Unknown Etiology

The pathogenesis of chronic intervillositis of unknown etiology (CIUE) may involve IFNγ overexpression. This study assesses the extent of IFNγ expression in CIUE by immunohistochemistry and compares it to spontaneous pregnancy losses. C4d deposition is also assessed to see whether IFNγ and C4d might represent separate diagnostic categories. Placenta from first to early second trimester with high grade CIUE (CHG; 17 cases) and low grade CIUE (CLG; 12 cases) is compared to euploid (SPLN; 18 cases), aneuploid spontaneous pregnancy losses (SPLA, 17 cases), normal placenta (NP, 13 cases). Protein level expression of IFNγ and C4d is assessed on whole tissue sections by immunohistochemistry. 35% of CHG and 42% of CLG show some level of IFNγ expression localized to the luminal surface of syncytiotrophoblast. 12% of SPLA and no SPLN or NP cases are IFNγ positive. C4d deposition is seen in 100% of CIUE, 88% of SPLA, 83% of SPLN, and 46% of NP samples. IFNγ overexpression occurs in approximately 40% of CIUE-related pregnancy losses. IFNγ expression restricted to a subgroup of CIUE implies that IFNγ may define a distinct disease process. The non-discriminatory pattern of C4d deposition suggests it is a non-specific phenomenon possibly related to placental damage.

The severity of chronic histiocytic intervillositis is associated with gestational age and fetal weight

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a rare histopathological lesion in the placenta that is associated with poor reproductive outcomes. The intervillous infiltrate consists mostly of maternal mononuclear cells and fibrin depositions, which are both indicators for the severity of the intervillous infiltrate. The severity of the intervillous infiltrate as well as the clinical outcomes of pregnancy differ between cases. Our objective is to determine the relation between the severity of the intervillous infiltrate and the clinical outcomes of CHI.

METHODS

Cases of CHI were semi-quantitatively graded based on histopathological severity scores. Hereto, CD68 positive mononuclear cells were quantified, fibrin depositions visualized by both a PTAH stain and an immuohistochemical staining, and placental dysfunction was assessed via thrombomodulin staining.

RESULTS

This study included 36 women with CHI. A higher CD68 score was significantly associated with a lower birthweight. Loss of placental thrombomodulin was associated with lower gestational age, lower birthweight, and a lower placenta weight. The combined severity score based on CD68 and PTAH was significantly associated with fetal growth restriction, and the joint score of CD68 and fibrin was associated with birthweight and placental weight.

DISCUSSION

More severe intervillous infiltrates in CHI placentas is associated with a lower birth weight and placental weight. Furthermore, this study proposes thrombomodulin as a possible new severity marker of placental damage. More research is needed to better understand the pathophysiology of CHI.

Chronic Inflammatory Placental Disorders Associated With Recurrent Adverse Pregnancy Outcome

Chronic inflammatory placental disorders are a group of rare but devastating gestational syndromes associated with adverse pregnancy outcome. This review focuses on three related conditions: villitis of unknown etiology (VUE), chronic histiocytic intervillositis (CHI) and massive perivillous fibrin deposition (MPFD). The hallmark of these disorders is infiltration of the placental architecture by maternal immune cells and disruption of the intervillous space, where gas exchange between the mother and fetus occurs. Currently, they can only be detected through histopathological examination of the placenta after a pregnancy has ended. All three are associated with a significant risk of recurrence in subsequent pregnancies. Villitis of unknown etiology is characterised by a destructive infiltrate of maternal CD8+ T lymphocytes invading into the chorionic villi, combined with activation of fetal villous macrophages. The diagnosis can only be made when an infectious aetiology has been excluded. VUE becomes more common as pregnancy progresses and is frequently seen with normal pregnancy outcome. However, severe early-onset villitis is usually associated with fetal growth restriction and recurrent pregnancy loss. Chronic histiocytic intervillositis is characterised by excessive accumulation of maternal CD68+ histiocytes in the intervillous space. It is associated with a wide spectrum of adverse pregnancy outcomes including high rates of first-trimester miscarriage, severe fetal growth restriction and late intrauterine fetal death. Intervillous histiocytes can also accumulate due to infection, including SARS-CoV-2, although this infection-induced intervillositis does not appear to recur. As with VUE, the diagnosis of CHI requires exclusion of an infectious cause. Women with recurrent CHI and their families are predisposed to autoimmune diseases, suggesting CHI may have an alloimmune pathology. This observation has driven attempts to prevent CHI with a wide range of maternal immunosuppression. Massive perivillous fibrin deposition is diagnosed when >25% of the intervillous space is occupied by fibrin, and is associated with fetal growth restriction and late intrauterine fetal death. Although not an inflammatory disorder per se, MPFD is frequently seen in association with both VUE and CHI. This review summarises current understanding of the prevalence, diagnostic features, clinical consequences, immune pathology and potential prophylaxis against recurrence in these three chronic inflammatory placental syndromes.

The Potential Benefit of Hydroxychloroquine in Chronic Placental Inflammation of Unknown Etiology Associated with Adverse Pregnancy Outcomes

The placenta is the site of connection between maternal and fetal circulation, and the liaison is established early in pregnancy. A large variety of pregnancy complications such as preterm birth, fetal growth restriction, or pregnancy loss have placental expression and can be accompanied in some cases of acute or chronic identifiable placental inflamatory lesions. Chronic placental inflammatory (CPI) lesions include chronic villitis of unknow etiology (CVUE), chronic intervillositis of unknown etiology, CIUE (also described as chronic histiocytic intervillositis, CHI), and chronic deciduits. Hydroxychloroquine (HCQ) has been prescribed with good results during pregnancy to prevent adverse perinatal outcomes in maternal autoimmune conditions. Its success has paved the way to its use in CPI as CIUE/CHI; however, to date, there are no prospective, informatively designed, controlled studies on its value in these setting. This review aims to explore the potential role of HCQ in CPI of unknown etiology. Ideally, properly designed, probably multicentric studies should be undertaken to fully understand HCQ's role for prevention of adverse pregnancy outcomes after a chronic placental inflammation.

Chronic histiocytic intervillositis (CHI): current treatments and perinatal outcomes, a systematic review and a meta-analysis

BACKGROUND

Chronic histiocytic intervillositis (CHI) is a rare placental lesion with a high recurrence rate and poor perinatal outcomes. There are currently limited guidelines regarding the diagnosis of this condition in the index pregnancy and treatment where recurrence is suspected.

OBJECTIVE

The primary objective of this systematic review and meta-analysis was to determine the perinatal outcomes of pregnancies affected by chronic histiocytic intervillositis and to what extent they can be improved with treatment. The secondary objective was to assess the relationship between CHI lesion severity and pregnancy loss.

METHODS

A systematic search of Ovid Embase, Web of Science, Science Direct, PubMed, Ovid Medline, Google Scholar and CINAHL was carried out. Case reports, cohort, case-control and randomised controlled trials (RCT) detailing the perinatal outcomes of CHI pregnancies, both treated and untreated, were included.

RESULTS

No RCTs were identified. However, in a review population of 659 pregnancies, with additional 7 in case reports, CHI treatments included aspirin, prednisone, prednisolone, low molecular weight heparin (LMWH), hydroxychloroquine and adalimumab. A descriptive synthesis of data found mixed results for treatments in relation to live birth, miscarriage and fetal growth restriction outcomes. Furthermore, quantitative synthesis of 38 pregnancies revealed a non-significant improvement in live birth rate with CHI targeted treatment (OR 1.79 [95% CI 0.33-9.61] (p=0.50), while meta-analysis of CHI severity in line with pregnancy loss, in a sample of 231 pregnancies, revealed lower odds of pregnancy loss with less severe lesions (OR: 0.17 [0.03-0.80], p=0.03).

CONCLUSIONS

This systematic review and meta-analysis reinforce notions surrounding the insufficient evidence for CHI treatment. It also strengthens previous hypotheses detailing the positive association between CHI lesion severity and odds of pregnancy loss. Aspirin, LMWH, prednisolone, hydroxychloroquine and adalimumab are candidates with varying levels of weak to moderate evidence supporting their use. Further prospective research is required to obtain robust evidence pertaining to treatment safety and efficacy and optimal drug regimes.

SYSTEMATIC REVIEW REGISTRATION

[website], identifier CRD42021237604.

Platelet alloimmunization is associated with low grade chronic histiocytic intervillositis - A new link to a rare placental lesion?

INTRODUCTION

Maternal alloimmunization against human platelet antigen (HPA)-1a has been implied to mediate both reduced birth weight and chronic placental inflammation. Fetal growth restriction is associated with different types of chronic inflammation in the placenta, mainly chronic histiocytic intervillositis and chronic villitis. The aim of this prospective study was to do a systematic examination of placentas from HPA-1a alloimmunized pregnancies, with focus on the histopathological and immunohistochemical diagnosis of variants of chronic inflammation.

MATERIAL AND METHODS

In a Polish-Norwegian study, 48 placentas were examined. The histopathology of placentas from 27 HPA-1a immunized women was compared with 21 placentas from non-immunized HPA-1a negative women (controls). In the group of alloimmunized women, ten received antenatal intravenous immunoglobulin G (IVIg). Tissue sections from formalin fixed paraffin embedded placental tissue were stained with hematoxylin and eosin and microscopically examined with focus on various types of chronic placental inflammations.

RESULTS

Chronic histiocytic intervillositis was observed in 40.7% of placentas from HPA-1a alloimmunized pregnancies, compared to none in the control group (p = 0.001). Chronic villitis of unknown etiology was more frequently found in the alloimmunized group, however this difference was not statistically significant. Maternal administration of IVIg did not seem to protect against chronic inflammatory lesions.

DISCUSSION

Placentas with detectable maternal anti-HPA-1a antibodies are associated with highly increased risk of low-grade chronic histiocytic intervillositis.