Expression of Toll-Like Receptors in Chronic Histiocytic Intervillositis of the Placenta

<div><p>Chronic histiocytic intervillositis of the placenta (CHI) shows monocytic/histiocytic infiltration of the intervillous space. Placental malaria has a CHI-like histopathology and induces an aberrant expression of Toll-like receptors (TLR) 3, 7–9. We hypothesized that, similar to placental malaria, CHI could be associated with increased TLR expression. TLR1-10 and other inflammation-associated factors were analyzed by real-time PCR and immunohistochemistry. A total of 31 formalin-fixed and paraffin–embedded placenta samples were evaluated: CHI (<i>n</i> = 9), and for control purposes, villitis of unknown etiology (VUE, <i>n</i> = 8) and placentas without inflammation (<i>n</i> = 14). CHI shows increased expression of monocytic TLR1, a receptor which is involved in bacterial lipopolysaccharide (LPS)-induced inflammation. This could indicate a TLR1-mediated immune mechanism in the placenta (e.g. triggered by transient, clinically inapparent maternal bacteraemia) which leads to massive monocytic/histiocytic accumulation in the intervillous space. The increased expression of TLR1 with no increased expression of TLR3 and TLR7-9 is different from that in malaria.</p></div

Complement receptor-associated CD163(+)/CD18(+)/CD11c(+)/CD206(-)/CD209(-) expression profile in chronic histiocytic intervillositis of the placenta

Introduction: Chronic histiocytic intervillositis of unknown etiology (CIUE) is a non-infectious, most probably immunologic placenta lesion. CIUE is associated with recurrent miscarriage, intrauterine growth restriction and stillbirth. Among the pathologic-anatomic defined placental lesions this entity displays the highest risk of recurrence in following pregnancies (about 67-100%). The histiocytic cells accumulate in the placental blood space but do not infiltrate into the villi or decidua. Sparsely known is the expression profile of these intervillous cells regarding histiocytic markers. Methods: We analysed 5-22 markers by immunohistochemistry in a total of 41 placenta samples and evaluated decidual, villous and intervillous histiocytic cells. Results: In CIUE, intervillous CD163(+) histiocytes over-express CD11c/CD18 and down-regulate CD206/CD209, while CD163(+) decidual and Hofbauer cells show low CD11c/CD18 and higher CD206/CD209 protein expressions. Discussion: CD163 expression indicates a M2-like polarisation. CD11c and CD18 form the complement receptor 4 which could be related to a complement mediated trigger for aberrant cell accumulation in CIUE