CD11b Expression on circulating leukocytes increases in preparation for parturition

Abstract

Problem: Initiation of parturition is associated with migration of leukocytes to the reproductive tract. This migration is controlled in part by expression of adhesion molecules on the surface of leukocytes and vascular endothelial cells. Within the reproductive tract, certain endothelial adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), are up-regulated at the end of gestation. ICAM-1 binds to the beta(2) integrin CD11b on the leukocytes. In this study, we wanted to investigate whether complementary changes occur in expression of adhesion molecules on maternal leukocytes in preparation for parturition.

Method of study: We used flow cytometry to ascertain changes in adhesion molecules expression on leukocytes throughout third trimester and labor.

Results: We found a significant increase in the expression of CD11b on monocytes and granulocytes in women at >37 weeks of gestation.

Conclusions: CD11b may be a key molecule for leukocyte trafficking to the reproductive tract at the end of pregnancy.