title: Placental histological lesions in fetal and neonatal alloimmune thrombocytopenia: A retrospective cohort study of 21 cases.
abstract: Alloimmunization against human platelet antigens (HPAs) can occur prenatally and induce fetal/neonatal alloimmune thrombocytopenia (FNAIT). The aim of this study was to identify placental histological features associated with platelet alloimmunization and their clinical significance.
  
  
  
  This study examined 21 placentas from FNAIT-affected pregnancies and 42 age-matched control cases, all collected from pathology departments in the Rhône-Alpes region. Clinical and laboratory findings were collected for each FNAIT case. Two pathologists reviewed the placental slides of each FNAIT and control case. Histological features, with special emphasis on chronic inflammatory lesions, were evaluated. Differences between the two groups were calculated with odds ratios (ORs) and assessed with Wald's chi-square.
  
  
  
  FNAIT was associated with a significantly higher frequency of chronic chorioamnionitis (CC) (OR 14, 95%CI 1.7-113.8), basal chronic villitis (BCV) (OR 17, 95%CI 2-145.6) and chronic intervillositis (CIV). Chronic villitis (CV) (OR 3.7, 95%CI 0.9-15.2) and chronic deciduitis (CD) (OR 4.7, 95%CI 0.79-28.2) were also more frequent in the FNAIT than the control group, but these differences were not statistically significant.
  
  
  
  FNAIT is significantly associated with CC, BCV, and CIV. This chronic inflammatory reaction is preferentially localized on the maternofetal interface. Anti-HPA alloimmunization may trigger an immunological conflict similar to graft-versus-host disease.
authors.affiliation: Centre de pathologie Nord, Hôpital de la Croix-Rousse, 103 Grande Rue de la Croix-Rousse, 69317 Lyon Cedex 04, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Dubruc
authors.affiliation: Centre de pathologie Nord, Hôpital de la Croix-Rousse, 103 Grande Rue de la Croix-Rousse, 69317 Lyon Cedex 04, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Lebreton
authors.affiliation: Laboratoire HLA/HPA, EFS Lyon-Gerland, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Giannoli
authors.affiliation: Service de Biostatistique, Hospices Civils de Lyon, F-69003 Lyon, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Rabilloud
authors.affiliation: Service d'Obstétrique, Hôpital de la Croix-Rousse, 103 Grande Rue de la Croix-Rousse, 69317 Lyon Cedex 04, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Huissoud
authors.affiliation: Centre de pathologie Nord, Hôpital de la Croix-Rousse, 103 Grande Rue de la Croix-Rousse, 69317 Lyon Cedex 04, France.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Devouassoux-Shisheboran
authors.affiliation: Centre de pathologie Nord, Hôpital de la Croix-Rousse, 103 Grande Rue de la Croix-Rousse, 69317 Lyon Cedex 04, France. Electronic address: fabienne.allias@chu-lyon.fr.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Allias
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010920:Placenta / Q000473:pathology*; D011247:Pregnancy; D012189:Retrospective Studies; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000473:pathology*
keywords: Anti-HPA antibodies; Basal chronic villitis; Chronic inflammatory lesions; Fetal/neonatal alloimmune thrombocytopenia; Placenta; Platelet alloimmunization