HLA‐G polymorphism in a Chinese Han population with recurrent spontaneous abortion

Abstract

Reproduction is an important biological phenomenon posing an immunological paradox because the semiallogeneic fetus survives by evading maternal immune recognition. The detailed mechanisms behind this maternal-fetal immunotolerance remain elusive. Human leucocyte antigen (HLA)-G, a non-classical HLA class I antigen, initially identified as a molecule selectively expressed on extravillous cytotrophoblasts and first studied in the context of pregnancy, has long been supposed to play a critical role in fetal-maternal immunotolerance. To investigate the role of HLA-G polymorphism in this process and whether the HLA-G genotype is associated with an increased risk for a subsequent miscarriage, 69 women with three or more recurrent spontaneous abortions (RSA) and 146 fertile control women were genotyped for the HLA-G locus in this study. To our knowledge, this is the first report on HLA-G polymorphism in RSA and in normal fertile women from a Chinese Han population. Nine HLA-G alleles were detected in the fertile control group; however, the allele HLA-G*0103 was absent in the RSA group. No statistical significance was observed in the distribution of HLA-G alleles between the two groups. The frequency of the null allele HLA-G*0105 N in the RSA group and in normal fertile women is 0.7% and 1.4%, respectively. Our data suggested that there was no association of HLA-G polymorphism with RSA.

Human leukocyte antigen-G polymorphism in relation to expression, function, and disease

“…A similar Chinese study reported the same results [67]. Other studies have not reported significant associations between the 14-bp HLA-G polymorphism (or other HLA-G alleles) and RSA or in vitro fertilization [25,68]. Two studies have investigated the hypothesis of HLA-G histoincompatibility or sharing of alleles between a woman and her partner, and thus the fetus, but reported no support for this [62,69].…”

Role of 14-bp deletion/insertion polymorphism in exon 8 of the HLA-G gene in recurrent spontaneous abortion patients

“…Furthermore, the +14 bp/+14 bp genotype was found in RSA patients with abortions greater than 3 as observed byAbbas et al .,[11] Tripathi et al .,[12] and Yan et al . [13] They showed an increase in the frequency of 14-bp insertion alleles in the RSA group as compared to controls whereas in contrast, Hviid et al . [19] observed more number of heterozygotes in controls.…”

Role of HLA-G and other immune mechanisms in pregnancy

“…Some studies did not find any association between HLA-G and recurrent spontaneous abortion [65,[85][86][87][88][89] or preeclampsia [90][91][92]. However, significant associations between HLA-G*01:05N, HLA-G*01:01:03 and HLA-G*01:04 alleles and recurrent spontaneous abortion have been documented in Caucasian populations [79,93], and in French and Chinese populations, the HLA-G*01:06 allele has been associated with preeclampsia [94,95].…”

“…Yan et al, [87] recurrent spontaneous abortion PCR significantlyincreasedfrequencyof-14bp/+14bp heterozygotes in RSA patients compared to normal fertile controls of Chinese ethnicity…”