Abstract: Objective To detect changes of Foxp3 expression in the decidua in patients with preeclampsia and investigate the
correlation of Foxp3-924 (rs2232365) polymorphisms with preeclampsia. Methods From October 2011 to December 2012, 252
normal pregnant women and 156 preeclampsia patients of Han nationality from the same geographic region were tested for
Foxp3-924 genotypes by polymerase chain reaction with sequence-specific primer (PCR-SSP). Sixty-eight of the patients with
preeclampsia (33 with mild and 35 with severe preeclampsia) and 30 of the normal pregnant women were also examined for
Foxp3 expression in the decidua using immunohistochemical method. Results Foxp3 positive expression rates in the decidua
was 51.52% in mild preeclampsia and 28.57% in severe preeclampsia cases, significantly lower than that in the control group
(86.67%, P<0.05). In preeclampsia patients, the frequencies of Foxp3-924G/G, G/A, and A/A genotypes were 0.1346, 0.4615 and
0.4038, respectively, and the frequencies of Foxp3-924A and Foxp3-924 G were 0.6346 and 0.3654, respectively. The genotype
frequencies of Foxp3-924G/G, G/A and A/A in the control group were 0.1508, 0.4087 and 0.4405, respectively, and the
frequencies of Foxp3-924 A and Foxp3-924 G were 0.6448 and 0.3552, respectively. No significant differences were found in the
gene frequencies of Foxp3-924G/A between preeclampsia patients and the control group (P>0.05). Conclusion The expression
level of Foxp3 in the placental tissue of preeclampsia patients is significantly lower than that in normal pregnant women,
suggesting that lowered Foxp3 expression decreases the immunosuppressive function and causes imbalance of immune
tolerance between maternal-fetal to induce preeclampsia. Foxp3-924 polymorphisms is not significantly correlated with the
occurrence of preeclampsia.