Intervillites chroniques histiocytaires : bilan et prise en charge

Controversies in chronic histiocytic intervillositis

Understanding the"paradox" of pregnancy remains a challenging field of investigation especially when immunological dysregulation is suspected in pathological pregnancies. Chronic histiocytic intervillositis (CHI) is an example of a rare placental inflammatory disease that can occur during any trimester of pregnancy. The pathogenesis of CHI involves an abnormal immune response characterized by an inflammatory infiltrate of maternal CD68+ mononuclear immune cells in the intervillous space. CHI may be associated with villous and intervillous fibrinoid deposits. The precise immunological mechanism is not yet fully understood; it probably relies on an allo-immune of graft rejection rather than an auto-immune mechanism, although it has been described in several autoimmune diseases. CHI has also been described in COVID19 infected pregnant women. The recurrence rate is high and complications are severe: CHI is strongly associated with fetal growth restriction, miscarriage and stillbirth. The management of these patients remains an issue lacking of -standardized guidelines. The aim of this narrative review is to focus on the knowledge, pathogenesis, diagnosis and treatment of CHI over the last 5 years.

[Use of hydroxychloroquine in recurrent immune-mediated obstetric diseases (excluding systemic lupus): Scientific basis and evidence]

Hydroxychloroquine (HCQ), a synthetic antimalarial, is recognized for its immunomodulatory, anti-inflammatory and vascular-protective effects. In 20-30% of cases of primary obstetrical antiphospholipid syndrome (APS), the combination of antiplatelet aggregation and prophylactic anticoagulation fails to prevent obstetrical complications, a situation referred to as refractory obstetrical APS. This is partly due to the pro-inflammatory effects of antiphospholipid antibodies (aPL) binding to decidual and trophoblastic cells, which compromise embryonic implantation and placentation. Experimental studies in vitro and in mouse models have shown that HCQ can inhibit the detrimental effect of aPLs on trophoblastic invasion, findings corroborated by retrospective observational clinical studies. However, no randomized controlled trial has evaluated the addition of HCQ to conventional therapy for refractory obstetric APS. The hypothesis of allo-immune and/or autoimmune mechanisms involved in cases of recurrent pregnancy loss (RPL) with no identified cause and in chronic intervillositis of unknown etiology (CIUE) has led to the empirical use of HCQ in these indications. However, current evidence does not support its use in unexplained RPL. A few clinical studies of low scientific evidence suggest a benefit of HCQ in CIUE, but further data are needed. Finally, pre-eclampsia (PE) is another pregnancy-related condition at risk of recurrence, and its pathogenesis also seems to involve an imbalance in immune responses. HCQ's antioxidant properties could have a positive effect on endothelial dysfunction, a key component of PE.

[Which workup should be performed after a pregnancy complicated with vasculo-placental disorder?]

Vasculo-placental disorders include pregnancy complications resulting from placental dysfunction of vascular origin, i.e. pre-eclampsia, HELLP syndrome, intrauterine growth retardation (IUGR), placental abruption and stillbirth of vascular origin. Pre-eclampsia should be investigated for antiphospholipid syndrome (APS) in case of severe pre-eclampsia and premature delivery before 34 weeks of gestation. In addition to testing for APS, pathological report of the placenta can identify some anatomical predispositions to placental vascular malperfusion, as well as chronic placental inflammatory lesions and excess fibrin deposits. The latter two are associated with IUGR and recurrent stillbirth, reflecting a dysimmune process of maternal origin. The internal medicine and obstetrics consultation, organized two months after delivery, combines the postnatal visit with an assessment of the causes of vasculo-placental disorders, and enables to inform patients about the management of future pregnancies and their cardiovascular health.

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.

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.

Chronic Villitis of unknown etiology (VUE): Obstetrical features, outcome and treatment

Villitis of unknown etiology (VUE) is characterized by lympho-histiocytic infiltrates, which are predominant within the villous stroma. VUE can be of low grade i.e. affecting less than 10 contiguous villi or high grade with either patchy or diffuse subgroups (the later concerning more than 30 % of distal villi). Several other placental lesions could be associated with VUE, in particular in diffuse subgroups, such as diffuse perivillous fibrin deposition and chronic intervillositis. One of the most characteristic features of VUE is the late onset of fetal growth restriction after 32 weeks of gestation, and earlier detection of villitis should first raise an infectious origin. High grade VUE has been associated with fetal growth restriction, prematurity, fetal deaths, recurrent pregnancy loss, central nervous system injury and is characterized by relatively high risk of recurrence (25-50 %). Prospective and well-designed studies are necessary to determine the real prevalence of these adverse pregnancy events associated with VUE. Data about the management of VUE are extremely scarce and thus no recommendation based on the literature review could be actually done.

Is chronic histiocytic intervillositis a severe placental disease? A case-control study

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a placental disease that has been associated with unfavorable obstetric outcomes in small, noncomparative series. The objective was to measure the excess risk of adverse obstetric outcomes associated with the discovery of CHI after birth.

METHODS

Retrospective single-center case-control study from 2000 through 2016. The case patients had a CHI diagnosis after a pathology analysis of the placenta. Two types of controls were defined for each case: low-risk control women were those who gave birth in our hospital immediately before each case patient, and the high-risk controls were the next women after each case for whom microscopic examination of the placenta was indicated.

RESULTS

We observed 111 cases of CHI during the study period. Compared with the 111 low-risk controls, the cases had a significantly higher frequency of late miscarriages (5.4 vs 0.0%, p < .03), small for gestational age (SGA) babies <3rd centile (70.4 vs 0.9%, p < .001, OR 140, 95% CI, 19.9-2800), and in utero deaths (35.1 vs 0.9%, p < .001, OR 59.6, 95% CI 8.5-1192), with significantly fewer children surviving to discharge (54.9 vs 99.1%, p < .001, OR 0.01, 95% CI, 0.00-0.08). All of these factors also differed significantly compared with the high-risk women (severe SGA: OR 3.7, 95% CI 1.9-7.0; in utero death: OR 4.1, 95% CI 1.9-8.7; children surviving to discharge: OR 0.27, 95% CI, 0.14-0.52).

DISCUSSION

Even compared with high-risk pregnancies, CHI is a severe placental disease associated with a substantial excess rate of late miscarriages, severe SGA and in utero death.