rhTSLP and trophoblast cells induce decidual DCs to produce high levels of IL-10 and CCL17. The peripheral monocytes from normal early pregnant women were cultured with rhIL-4 (100 U/mL) and granulocyte-macrophage colony-stimulating factor (100 U/mL) for 5 to 9 days. At day 7, the cells became star-like morphologically. The CD1c⁺ dDCs or peripheral moDCs from the early pregnancy were treated with rhTSLP (15 ng/mL) or LPS (10 μg/mL) respectively, for 48 hours. The rhTSLP significantly stimulates dDCs to release higher levels of T_H2 cell-attractive CCL17 and IL-10. TNF-α production by dDCs remains at a lower level, except for LPS-dDCs, whereas the rhTSLP-treated moDCs secrete lower levels of TNF-α and IL-10. The dCD1c⁺ DCs or moDCs from the early pregnancy were cocultured with trophoblast cells, with or without 10 μg/mL antihuman TSLP neutralizing antibody (trophoblasts + α-TSLP) for 48 hours. Human trophoblast cells stimulate the decidual DCs to secrete high levels of IL-10 and CCL-17, which can be effectively inhibited by neutralizing anti-TSLP antibody. The amount of TNF-α secreted by the trophoblast-regulated moDCs is not significantly different from that of the trophoblast-regulated dDCs, and α-TSLP has no significant effect on them. Data are from 4 independently conducted experiments with 4 cases. Data are mean ± SD.