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.