Phagocytosis of chorion laeve trophoblasts in patients with chorioamnionitis-associated preterm delivery: ultrastructural and enzyme-histochemical observations.

The purpose of the present study was to examine morphological evidence for the presence of phagocytosing chorion laeve trophoblasts in fetal membranes from patients who had undergone chorioamnionitis-related preterm delivery. Chorion laeve trophoblasts from six patients, who underwent preterm delivery (28-34 weeks of gestation) complicated with chorioamnionitis, were analysed using transmission electron microscopy and ultrastructural enzyme-histochemistry for acid phosphatase, and compared with those from gestational age-matched chorioamnionitis-negative controls. Cytosomal cell projections, phagosomes, phagocytosis of degenerated cells and cell debris, attachment or fusion of lysosomes to the phagosomal membranes and phagosomal membranes positive for acid phosphatase staining were characteristically observed much more frequently in trophoblasts with chorioamnionitis than those without. The results indicated that chorion laeve trophoblasts in fetal membranes from patients having undergone chorioamnionitis-related preterm delivery underwent phagocytosis. Such phagocytosing trophoblasts may play a role in the pathophysiology or pathogenesis of infection-related preterm delivery.