Choriodecidua and amnion exhibit selective leukocyte chemotaxis during term human labor

OBJECTIVE: The purpose of this study was to compare the chemotactic activity of the choriodecidua and amnion, and to identify the phenotype of the leukocytes chemoattracted by each tissue. STUDY DESIGN: Amnion, choriodecidua and whole fetal membranes extracts were obtained from women at term (>37 weeks of gestation) with or without labor (n = 5 each). Extracts were assayed for leukocyte chemotactic activity, and the number and phenotype of the chemoattracted leukocytes were characterized by flow cytometry. RESULTS: Although all of the extracts exhibited chemotactic activity, more leukocytes were chemoattracted by the choriodecidua and the whole fetal membranes during labor compared with no labor (P = .010, .008). During labor the choriodecidua is responsible for granulocyte, T-lymphocyte, monocyte, and natural killer-cell chemoattraction, and the amnion is responsible for B-lymphocyte chemoattraction. CONCLUSION: Choriodecidua and amnion exhibit chemotactic activity for selective leukocytes and thus, each fetal membrane differentially regulates leukocyte chemotactic activity during labor.