The number of CD68(+) (Hofbauer) cells is decreased in placentas with chorioamnionitis and with advancing gestational age.

Hofbauer cells are placental macrophages found in chorionic villous stroma; they express classic monocyte/macrophage markers, such as CD68. Little is known about their participation in placental disease and immunologic interactions at the placental interface. The aim of this study was to quantify the amount of Hofbauer cells in placentas complicated, or not, by chorioamnionitis and in placentas from different gestational ages. Fifty-eight 2nd- and 3rd-trimester placentas with the histologic diagnosis of acute chorioamnionitis were compared with 42 control placentas matched according to gestational age. Immunohistochemistry evaluation was performed with a monoclonal anti-CD68 antibody. Five areas of each placenta were photographed and 5 investigators, with the help of a computerized image analysis program, independently evaluated the number of CD68(+) cells. Our results showed that there are significantly fewer CD68(+) cells per villous area in placentas diagnosed with chorioamnionitis than in those of controls (P < 0.001). Moreover, there was a significant overall decrease in the number of these cells in 3rd as compared with 2nd trimester placentas (P  =  0.02), as well as in placentas from term as compared to preterm pregnancies (P  =  0.004). Our data indicate that CD68(+) Hofbauer cells may be involved in placental infection and possibly associated with the developmental maturation of the fetoplacental unit.