The Role of HLA-G4 and G5 in Threatened-Abortion Women

Background and Major pathologic cause of abortions is unknown. HLA-G4 and HLA-G5 are two isoforms, membrane (G4) and soluble (G5) of nonclassical molecules of HLA-1b that can induce tolerance between mother and fetus. In this study, expression of two HLA-G isoforms and their effect were evaluated in threatened-abortion women in comparison with controls. In a case-control study, 101 threatened-abortion women and 101 health pregnant women in the age range of 20-32 years were studied for expression level of two HLA-G4 and HLA-G5 isoforms after RNA extraction and cDNA synthesize with use of real-time polymerase chain reaction (Real-time PCR) procedure. The expression of HLA-G4 and G5 were significantly decreased in threatened–abortion women in comparison with controls (P < 0.0001). In addition, HLA-G5 higher than HLA-G4 decreased in threatened- abortion women (P = 0.0001). Furthermore, senile had direct effect in high abortion risk and low expression level of HLA-G4. According to our findings, HLA-G5 is affecting molecule in fetus maintenance in comparison with HLA-G4 during pregnancy. Thus, it is proposed to evaluate this molecule before twenty weeks in pregnancy as a prognosis factor for prevention of fetus loss.