Obstetrical History and Anti-HLA Antibodies Level

Study Overview
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Brief Summary
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Chronic histiocytic intervillositis (CHI) is associated with severe and recurrent obstetrical complications. A link between anti-HLA Antibodies (Ab) and CHI has recently been established. At the Etablissement Français du Sang (EFS), donors who have already given birth once and have high levels of anti-HLA are excluded from donating apheresis platelets and therapeutic plasma to prevent TRALI (Transfusion Related Acute Lung Injury). No studies have examined the obstetrical history of these donors. The question is: is there an association between anti-HLA levels and obstetrical complications?

Detailed Description
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Chronic histiocytic intervillositis (CHI) is a rare condition with an incidence of around 5 in 10,000 pregnancies. It is defined by major infiltration of the intervillous cavity by CD68+ maternal histiocytes, associated with fibrin deposition on the villous surface. CHI is associated with severe obstetrical complications and a very high recurrence rate, estimated at between 70% and 100%. These complications include early and late miscarriage, fetal death, severe growth retardation in surviving fetuses, and premature delivery. The survival rate reported in the literature varies between 30% and 50%. Anti-HLA antibodies are present in 54% of pregnant women at the end of pregnancy, and their rate increases towards the end of pregnancy. The presence of HLA antibodies also increases with the number of pregnancies, and is found in up to 74% of cases after more than 2 deliveries. The research question concerns the existence of a statistically significant association between the presence of high levels of anti-HLA antibodies and the occurrence of one or more obstetric complications.

Official Title
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Obstetrical History and Anti-HLA Antibodies Level

Conditions
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Blood Donors, Anti-HLA Antibody

Intervention / Treatment
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* Other: Obstetrical history
* Other: Anti-HLA Antibody tests


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female blood donors who have been tested for anti-HLA antibodies in the context of TRALI prevention between 2010 and 2020 at EFS Nouvelle Aquitaine [The donors meet the conditions of the Order of December 17, 2019 establishing the selection criteria for blood donors and are over 18 years old, are not protected persons and understand French well] Women who have already given birth at least once (non-nulliparous women) Women who have not expressed their opposition at the time of donation to participating in a research project and to be contacted Exclusion Criteria: None [Donors meet the conditions of the Order of December 17, 2019 establishing the selection criteria for blood donors and are over 18 years old, are not protected persons and understand French well]

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Blood donors tested for anti-HLA Antibody<br>Blood donors tested for anti-HLA Antibody between 2010 and 2020 as part of TRALI prevention program. | Other: Obstetrical history<br>* Selection of donors by EFS retrospectively on the basis of inclusion criteria. Information note sent by e-mail, non-opposition as well as a questionnaire to be completed online to obtain data on obstetrical history.<br>Other: Anti-HLA Antibody tests<br>* Analyze responses in relation to the results of the anti-HLA Antibody tests performed at the time of donation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To measure the association between the occurrence of obstetrical complications and the level of anti-HLA Ab measured during the screening test performed by the EFS. | Obstetrical complications are defined as (binomial qualitative variable) : Preterm delivery < 37 WA Fetal death in utero whatever the term Early or late miscarriage Early or late pre-eclampsia Medical termination of pregnancy Intrauterine growth retardation <3rd percentile | 2 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Type and precocity of obstetrical complication (multinomial qualitative variable) | Preterm deliveries < 37 WA and ≥ 34 WA Premature deliveries < 34 WA Fetal death in utero regardless of term Late miscarriage < 22 WA and ≥ 14 WA Early miscarriage < 14 WA Late pre-eclampsia > 37 WA and ≥ 34 WA Early pre-eclampsia < 34 WA Medical termination of pregnancy Intrauterine growth retardation <3rd percentile | 2 months | 
| Measure the association between the type and precocity of obstetrical complications according to the type of anti-HLA Ab (class I and/or class II), when these Ab are found during the screening test performed by the EFS | Preterm deliveries < 37 WA and ≥ 34 WA Premature deliveries < 34 WA Fetal death in utero regardless of term Late miscarriage < 22 WA and ≥ 14 WA Early miscarriage < 14 WA Late pre-eclampsia > 37 WA and ≥ 34 WA Early pre-eclampsia < 34 WA Medical termination of pregnancy Intrauterine growth retardation <3rd percentile | 2 months | 
| Verify the absence of response bias by comparing the HLA Ab levels of responding versus non-responding donors. | Anti-HLA antibody rate (median) | 2 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obstetrical complications, Levels of anti-HLA antibody, Chronic histiocytic intervillositis