Reduced CD200 and CD200R1 expression in human chorionic villi contributes to early spontaneous abortion.

Objective: To examine the expression of CD200 and its receptor (CD200R) in human chorionic villi during the first trimester of normal pregnancy and early spontaneous abortion (ESA).

Design: Prospective study.

Methods: Expression of CD200 and CD200R in the chorionic villi was determined using streptavidin-peroxidase immunohistochemistry, confocal laser scanning microscopy and real-time polymerase chain reaction.

Population: Thirty-five women diagnosed with ESA and 30 women experiencing a healthy pregnancy in a medical university hospital in China were enrolled in this study between 2011 and 2013.

Main Outcome Measures: CD200 and CD200R expression.

Results: The expression of CD200 in syncytiotrophoblast cells was significantly higher during normal pregnancy than in ESA (0.51 ± 0.05 vs. 0.35 ± 0.05). In contrast, expression of CD200 in cytotrophoblast cells and CD200R in stromal cells was significantly lower during normal pregnancy when compared with ESA (CD200: 0.16 ± 0.02 vs. 0.32 ± 0.03; CD200R: 0.19 ± 0.03 vs. 0.22 ± 0.02). In villi, the expression of both CD200 protein and CD200R transcripts were significantly higher in healthy first-trimester pregnancy than in ESA (CD200: 156.89 ± 105.65 vs. 37.51 ± 17.62).

Conclusions: There is an increase in inhibitory properties of human chorionic villi during normal pregnancy. The mechanism underlying ESA might be associated with enhanced expression of CD200 and CD200R in the trophoblast, leading to an upregulation of the immune response during the first trimester of pregnancy.