HLA-G profile of infertile couples who underwent assisted reproduction treatment.

HLA-G codes for a non-classical class I (Ib) protein which is mainly expressed in trophoblast cells. Many pieces of evidence pointed out its essential role conferring immunological tolerance to the fetus. Some HLA-G alleles have been linked to enhanced or reduced HLA-G protein levels expression, which have been associated with reproductive failure. In this study 33 couples undergoing ART (assisted reproduction treatment; n=66) and 120 couples who conceived naturally (controls; n=240) were enrolled in the study. Genotyping was performed by SBT and tagged an 1837bp at 5'URR as well as exons 2, 3 and4 of HLA-G. Alleles, genotypes and haplotypes were compared between infertile and control groups using Fisher Exact Test. The haplotype HLA-G∗ 010101b/HLA-G∗ 01:01:01 showed statistically significant higher frequency in control groups. The immunogenetics of infertility is complex and might be dependent on different genes involved in the establishment of a successful pregnancy. A better understanding of HLA-G alleles and haplotypes structure and how the genetic diversity at their regulatory sites could impact on their level of expression and build up the susceptibility or protection conditions may shed light on the comprehension of immunogenetics mechanisms acting at the fetus-maternal interface.