Involvement of Hofbauer cells and maternal T cells in villitis of unknown aetiology.
OBJECTIVE
The nature of villitis of unknown aetiology (VUE) is intriguing in terms of its aetiology, origin of inflammatory cells and immunophenotype of T cells involved. The aim was to determine the origin of macrophages and the immunophenotype of T lymphocytes in VUE associated with various complications of pregnancy.


RESULTS
Placentas with VUE (n = 45) were studied by chromogenic in-situ hybridization (CISH) for Y chromosome (DYZ1) and immunohistochemistry for CD14, CD68, Ki67 (n = 10; all from male neonates) and a panel of T-cell antigens (CD3, CD4 and CD8) (n = 35). All of the placentas from male neonates showed CISH+ signals from Y chromosomes in the majority of macrophages, but not in lymphocytes, indicating that the macrophages were of fetal origin. Many macrophages of the affected chorionic villi were Ki67+, suggesting that they are hyperplastic Hofbauer cells. Among the lymphocytes, CD8+ T cells outnumbered CD4+ T cells in all placentas with different obstetrical conditions.


CONCLUSIONS
We define primary components of VUE as maternal CD8+ T cells and hyperplastic Hofbauer cells. We propose that VUE is a unique inflammatory reaction where the leucocytes from two hosts are key partners, analogous to either allograft rejection or graft-versus-host disease.
Kim
J-S
JS
Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, USA.
Romero
R
R
Kim
M R
MR
Kim
Y M
YM
Friel
L
L
Espinoza
J
J
Kim
C J
CJ
D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002824:Chorionic Villi / Q000276:immunology / Q000473:pathology*; D041322:Chromosomes, Human, Y; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005865:Gestational Age; D006084:Graft Rejection; D006086:Graft vs Host Disease; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization / Q000379:methods; D007231:Infant, Newborn; D007249:Inflammation / Q000209:etiology / Q000276:immunology / Q000473:pathology*; D019394:Ki-67 Antigen / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008431:Maternal-Fetal Exchange / Q000235:genetics*; D010922:Placenta Diseases / Q000209:etiology / Q000276:immunology / Q000473:pathology*; D011247:Pregnancy; D011248:Pregnancy Complications
D019394:Ki-67 Antigen