ABSTRACT
OBJECTIVE: Habitual abortion(HA) is postulated to be due to several factors including immunogenetic mechanisms. Many studies have been conducted on the effect of the major histocompatibility(MHC) region in the reproductive phenomena suggesting an immunological or genetic involvement in HA. HLA-G is a nonclassical class I MHC molecule, with evidence of protecting cells against natural killer cell lysis and not stimulating an allogeneic response by peripheral blood T cells. These features suggest that expression of HLA-G could be a crucial factor for fetal survival in the face of a potentially hostile maternal immune system. The goal of this study was to investigate the immunogenetic role of HLA-G gene in the early pregnancy loss. This is the first report in Korea about the HLA-G gene in the patients of habitual abortion. METHODS: Twenty-one chorionic villi (study group) in the women with habitual abortion (at least 3 spontaneous abortion) and 10 normal chorionic villi (control group) in the women with therapeutic abortion were included in this study. The expression of HLA-G gene in placental extravillous cytotrophoblasts were made by reverse transcription-polymerase chain reaction(RT-PCR) and chromosomal analysis was done by ordinary GTG-banding method. Chi-square and Fisher's exact tests were used for the statistical analysis. RESULT: As a result, HLA-G mRNA was expressed in 52.4%(11/21) of study group, in 70%(7/10) of control group and there was no statistical significance. In study group, positive rate of HLA-G mRNA was 57.1%(4/7) in the patients with normal chromosome, and 50.0%(7/14) in the patients with abnormal chromosome and there was no statistical significance. CONCLUSION: Thus, these results suggest that HLA-G gene might not be a immunogentic marker of early pregnancy loss. But further large scale of study would be needed to reveal the role of HLA-G in habitual abortion.