Phenotypic and metabolic characteristics of maternal monocytes and granulocytes in preterm labor with intact membranes

OBJECTIVE: Experimental and clinical, studies support a role for the fetus in the control of the onset of labor. Fetal systemic Inflammation, but not a maternal inflammatory response, has been linked to the onset of preterm l abor and delivery on the basis of the determination of inflammatory cytokin es in fetal and maternal blood. We propose that parturition requires fetoma ternal cooperation and that inflammation is an integral part of the parturi tional process. This study used flow cytometry a sensitive technique for th e detection of intravascular inflammation, to assess whether maternal infla mmation is present in preterm labor. STUDY DESIGN: A prospective cross-sectional study was performed including p atients with preterm labor (n = 55) and women with normal pregnancy (n = 50 ). Intravascular inflammation was studied by using flow cytometry. Maternal blood was assayed to determine granulocyte and monocyte phenotype by using monoclonal antibodies, which included the following cluster of differentia tion (CD) markers: CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b , and HLA-DR. Oxidative burst and generation of basal intracellular oxygen radical species were assessed. Statistical analysis was conducted with the use of nonparametric methods. A P value of <0.1 was considered statisticall y significant. RESULTS: Preterm labor was associated with a significant increase in the me dian mean channel brightness of CD11b, CD15, and CD66b on granulocytes and median mean channel brightness of CD11b and CD15 on monocytes. The ratio of oxidative burst over basal intracellular oxygen radical species in both gr anulocytes and monocytes was increased in preterm labor (P <. 01). CONCLUSION: Preterm labor with intact membranes is associated with phenotyp ic and metabolic changes of maternal granulocytes and monocytes.