HLA-G regulatory haplotypes and implantation outcome in couples who underwent assisted reproduction treatment

The role of HLA-G in several clinical conditions related to reproduction has been investigated. Important polymorphisms have been found within the 5′URR and 3′UTR regions of the HLA-G promoter. The aim of the present study was to investigate 16 SNPs in the 5′URR and 14-bp insertion/deletion (ins/del) polymorphism located in the 3′UTR region of the HLA-G gene and its possible association with the implantation outcome in couples who underwent assisted reproduction treatments (ART). The case group was composed of 25 ART couples. Ninety-four couples with two or more term pregnancies composed the control group. Polymorphism haplotype frequencies of the HLA-G were determined for both groups. The Haplotype 5, Haplotype 8 and Haplotype 11 were absolute absence in ART couples. The HLA-G*01:01:02a, HLA-G*01:01:02b alleles and the 14-bp ins polymorphism, Haplotype 2, showed an increased frequency in case women and similar distribution between case and control men. However, this susceptibility haplotype is significantly presented in case women and in couple with failure implantation after treatment, which led us to suggest a maternal effect, associated with this haplotype, once their presence in women is related to a higher number of couples who underwent ART.