What is Chronic Histiocytic Intervillositis (CHI)?
This condition is a placental lesion associated with recurrent pregnancy loss at any stage of pregnancy. The pathology report does not always mention CHI as a possible pathology and may include other names which more or less represent the same thing. These include Chronic (histiocytic) intervillositis of unknown etiology (CIUE), Massive Chronic Intervillositis, Nonspecific Chronic Macrophagic Intervillositis, Histiocytic Intervillositis, Chronic Villitis or Chronic Villitis of unknown etiology (CVUE)
The diagnosis is a histopathology one and include idiopathic inflammatory lesion, intervillous space location, extensive maternal infiltration of inflammatory mononuclear cells (monocytes, lymphocytes, histiocytes) in particular CD68, intervillous fibrinoid deposits and trophoblast erosions of varying degree, diffuse (massive) or multifocal infiltration.
In a study by Boyd and Redline (“Chronic histiocytic intervillositis: a placental lesion associated with recurrent reproductive loss” Human Pathology 2000 Nov 31(11):1389-96) recurrent rate was 67% for patients with more than one specimen reviewed. Overall perinatal mortality rate was 77%, and only 18% of pregnancies reached 37 weeks. Severe intrauterine growth restriction was seen in 5 of 8 second- and third-trimester patients.
Another study by Marchaudon et al. also examined the placentas from 69 pregnancies with CHIV in 50 women (“Chronic histiocytic intervillositis of unknown aetiology: clinical features in a consecutive series of 69 cases”; Placenta 2011 Feb 32(2): 140-5). Of 39 fetuses surviving to at least 22 weeks, 24 had severe intrauterine growth restriction (61.5%) and 18 died in utero (46.2%).
Autoimmune or allergic phenomena were identified in 11 out of 19 of Boyd and Redline’s patients. In addition, Reus et al. (“An immunological basis for chronic histiocytic intervillositiis in recurrent fetal loss” Am J Reprod Immunol 2013 Sep; 70(3): 230-7) demonstrated higher cytotoxic T-lymphocyte precursor frequencies CTLpf against their partner in CHIV patients compared to non-complicated pregnancies (P=0.03). Antipaternal HLA antibodies were present in 75%of the CHIV patients compared to none of the controls.