title: Correlation between protein expression of FOXP3 and level of FOXP3 promoter methylation in recurrent spontaneous abortion.
abstract: OBJECTIVE
  The aim of this study was to investigate the level of Forkhead box P3 (FOXP3) promoter methylation and protein expression in recurrent spontaneous abortion and to elucidate the pathogenesis of unexplained recurrent spontaneous abortion (URSA).
  
  
  METHODS
  We assessed a total of 56 URSA patients with a normal embryo, 24 recurrent spontaneous abortion (RSA) patients with an abnormal embryo (as control group 1), and 39 normal pregnant women (as control group 2). The expression of FOXP3 protein in deciduas was assessed through Western blot, and the level of FOXP3 promoter methylation was detected using bisulfite-assisted genomic sequencing polymerase chain reaction.
  
  
  RESULTS
  The expressing quantity of FOXP3 protein in the URSA group was significantly lower than that in control groups 1 and 2, both with a P-value < 0.05. By contrast, no statistical difference was observed in the expressing quantity of FOXP3 protein of the two control groups (P = 0.212). The FOXP3 promoter methylation level in the URSA group was significantly higher than that in the two control groups, both of which exhibited a statistical difference of P-values < 0.05. Meanwhile, no statistical difference was observed in the FOXP3 promoter methylation level of the two control groups (P = 0.141). A negative correlation was found between the FOXP3 promoter methylation level and the expressing quantity of FOXP3 protein (r = -0.861, P < 0.05).
  
  
  CONCLUSIONS
  Increasing FOXP3 promoter methylation levels may cause abnormal immune tolerance through the downregulation expression of the FOXP3 protein, which in turn leads to URSA.
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Wenhui
authors: W
authors: Hou
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Zhuyu
authors: Z
authors: Li
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Yinguang
authors: Y
authors: Li
authors: Medical Genetic Centre, Guangdong Women and Children Hospital, Guangzhou, China.
authors: Liyuan
authors: L
authors: Fang
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Jie
authors: J
authors: Li
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Jia
authors: J
authors: Huang
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Xiaoqing
authors: X
authors: Li
authors: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China. youzeshan888@21cn.com.
authors: Zeshan
authors: Z
authors: You
mesh_terms: D000022:Abortion, Spontaneous / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D019175:DNA Methylation; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000378:metabolism; D005865:Gestational Age; D006801:Humans; D059785:Karyotype; D011247:Pregnancy; D011401:Promoter Regions, Genetic
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors
keywords: forkhead box P3; promoter methylation; protein expression; unexplained recurrent spontaneous abortion