Neutrophil and monocyte β2-integrin expression in maternal and fetal blood

OBJECTIVE: The aim of this study was to investigate fetal and maternal leukocyte β2-integrin expression throughout pregnancy. STUDY DESIGN: In a cross-sectional study of 173 fetuses at 18 to 40 weeksʹ gestation, 114 women with normal singleton pregnancies at 6 to 40 weeks, and 25 adult volunteers, flow cytometry was used to determine neutrophil and monocyte expression of β2-integrins. RESULTS: The surface density of β2-integrins on fetal neutrophils and monocytes increased significantly with gestation, except for the expression of fetal monocyte CD11b, which did not change. There were no significant changes in maternal β2-integrin expression with gestation. During the third trimester fetal expression of CD18, CD11b, and CD11c on neutrophils and CD11b on monocytes was lower, and maternal expression of CD11a on neutrophils and CD18, CD11a and CD11c on monocytes was higher than were the control adult values. CONCLUSIONS: These data demonstrate that pregnancy is associated with changes in the expression of maternal β2-integrins and illustrate the pattern of immunophenotypic maturation of fetal β2-integrins on neutrophils and monocytes.