Abstracts

Abstract

INTRODUCTION: One of the characteristics of the beginning of labor in women is the arrival of leukocytes in reproductive tissues. These migrating cells may play a role in the induction of functional and biochemical changes associated with the rupture of fetal membranes during labor. This study was undertaken to assess whether human fetal membranes induce leukocyte chemotaxis during labor as well as to identify and localize chemokines secreted by these tissues. METHODS: Extracts from amnion, chorion and whole fetal membranes were obtained from two groups of women who had full-term pregnancies; 1) with spontaneous active labor and 2) without labor. Leukocyte chemotactic activity of extracts was compared between both groups. The number and phenotype of attracted leukocytes were analyzed by ow cytometry. Chemokines were localized by immuno uorescence histochemistry. RESULTS: Leukocyte chemotactic activity induced by fetal membranes extracts during labor was attributed to the chorion. Polymorphonuclear leukocytes were the most attracted subpopulation. However, their numbers only increased 3-fold when extracts with labor were used as chemoattractant. The same extracts exhibited a major increase of attracted T cells (143-fold) and monocytes (71-fold) as well as NK cells (6-fold) when compared to extracts without labor. This enhanced chemotactic activity was associated with the presence of IL-8, IP-10 and MCP-1, which were localized mainly in the chorion. CONCLUSIONS: Chorion extracts obtained from women during labor exhibited selective chemotaxis for speci c leukocyte subpopulations in vitro. This process may contribute to a microenvironment composed of speci c leukocytes that promotes and ampli es biochemical changes in the fetal membranes during labor.