Role of CCL17 and CCL22 Expression in Dendritic Cells in Maternal- Fetal Immune Tolerance

Background: Unexplained recurrent spontaneous abortion ( URSA ) is a major concern issues of reproductive health, the incidence is increasing. Some scholars point out, the maternal-fetal immune balance in establishing and maintaining is closely related to the dendritic cells (DC) from human decidua and endometrial. Objective: To determine the expression of CCL17 and CCL22 in dendritic cells (DC) from human decidua and endometrial. METHODS: The decidua were collected from normal pregnant women undergoing induced abortion and recurrent spontaneous abortion (RSA)women undergoing early abortion after being approved by the ethics committee. The endometria were collected from non-pregnant women undergoing abdominal hysterectomy. The mononuelear cells in the decidua and endometria were isolated. DC were induced by GM-CSF and IL-4，cultured in vitro and identified. The expression of CCL17 and CCL22 in DC at mRNA an d protein levels was analyzed by real-time PCR and ELISA.

Results: The mRNA levels of CCL17 and CCL22 in decidual DC in normal pregnancy group were 3.04 4-0.40 and 1.83±0.24, respectively, significantly higher than those in endometrial DC in non-pregnancy group(0.85±0.24 and 0.31±0.08, respectively, P<0.01)and those in decidual DC in RSA group(1.65±0.14 and 0.96士0.09, respectively, P<0.01). Decidual DC continually and strongly secreted CCL17 and CCL22. The levels of CCLI7 and CCL22 in norm al pregnancy group were significantly higher than those in non-pregnancy group and RSA group at the same culture time point (P<0.01). CONCLUSION: The expression of CCL17 and CCL22 in decidual DC in pregnant woman increases. This may attract more CD4 CD25 regulatory T cells to decidua and play an important role in the establishment of maternal - fetal immune tolerance.