Exploration of Allograft Humoral Rejection in Chronic Histiocytic Intervillositis

Exploration of Allograft Humoral Rejection in Chronic Histiocytic Intervillositis

Chronic histiocytic intervillositis (CHI) is a rare condition with an incidence of 5 in 10,000 pregnancies. This rare condition is associated with placental inflammatory lesions leading to severe and recurrent obstetrical complications: intrauterine growth retardation (IUGR), fetal death in utero and miscarriage. The pathophysiological mechanisms of CHI are poorly understood, while the empirical treatments prescribed to prevent recurrence are cumbersome and of poor efficacy.

Recent findings suggest that an alloimmune response may play a role. In a recent work, the investigators have demonstrated the role of maternal alloantibodies directed against fetal HLA antigens in two patients followed for recurrent IUGR associated with CHI. Their work suggests that a humoral alloimmune response directed against fetal HLA antigens mimics an allograft rejection process.

The investigators propose to extend the preliminary results obtained in these patients to provide new insights into the pathophysiological mechanisms of CHI, and eventually to predict the risks of fetal loss.

Family Inclusion Criteria:

• Mother and father ≥ 18 years old

• For mothers in the CHI group :

  • History of a normal pregnancy (full term, alive child) or IUGR/MFIU or miscarriage(s) or abortion followed by at least 1 obstetrical complication such as IUGR, MFIU, miscarriage
  • Diagnosis of chronic histiocytic intervillitis made by placental anatomopathological examination with CD68+ marking

• For the mothers of the antiphospholipid syndrom group

  • History of miscarriage(s)
  • Having an anti-phospholipid syndrome

• For mothers in the normal pregnancy group:

  • Third consecutive pregnancy of normal course, at term (≥ 36 weeks of amenorrhea) with eutrophic child

For the mother and father:

o Consent to participate in the study and for the participation in the study of at least one child and/or the use of existing samples (placenta / fetal DNA) from at least one previous pregnancy with CHI for the CHI group or at least one previous miscarriage for the APS group

For the father:

o Father of the last pregnancy and of the child(ren) participating in the study

Exlusion criteria :

• For mothers in the normal pregnancy group:

  o Suspected or confirmed intra-amniotic infection

• For all the mothers:

  • History of blood transfusion
  • History of allogeneic organ transplantation

• For the mother and the father:

  • Person under legal protection (guardianship, curatorship)