CD1c+ immature myeloid dendritic cells are predominant in cord blood of healthy neonates

It has been suggested lately that some types of antigen presenting cells-myeloid dendritic (DC-1) cells can differentiate the immune response towards Th1 type immunity, whereas lymphoid cells (DC-2) can stimulate Th2 type immunity. It has been observed that neonates are deficient in Th1 response. The purpose of our study was to estimate the proportions of immature myeloid (CD1c(+)) and lymphoid (BDCA-2(+), BDCA-4(+)) dendritic cells and the CD1c(+):BDCA-2(+) cell ratio in cord blood of healthy neonates in comparison with dendritic cells of healthy adults. Thirty healthy neonates born from normal pregnancies and 30 healthy adults were included in the study. The dendritic cells were isolated from cord and peripheral blood, stained with anti-CD1c, anti-BDCA-2, anti-BDCA-4, anti-CD123 and anti-CD19 monoclonal antibodies and estimated using flow cytometry. The percentage of CD1c(+) dendritic cells in cord blood of healthy newborns did not differ significantly when compared to those in peripheral blood of healthy adults. The percentages of cord blood BDCA-2(+) and BDCA-4+ dendritic cells of neonates were significantly lower when compared to lymphoid dendritic cells in peripheral blood of adults. The CD1c(+):BDCA-2(+) ratio was significantly higher in cord blood of neonates in comparison with CD1c(+):BDCA-2(+) ratio in adult's blood. Myeloid and lymphoid dendritic cells may be involved in the immune regulation during fetal development. Immature myeloid dendritic cells are predominant in cord blood of healthy neonates. Immature lymphoid dendritic cells are not the major population of dendritic cells in cord blood. (C) 2003 Elsevier B.V. All rights reserved.