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.