Yes, we do provide an HLA-G typing service. Most clients include HLA-G in addition to sequencing and typing other Class I and Class II alleles. However, we can type HLA-G alone if this is required.
HLA-G Background
HLA–G is a non–classical human leukocyte antigen (HLA) molecule belonging to the HLA–I class. It is a non–classical HLA molecule because it is not involved in antigen presentation, like the classical HLA molecules, HLA–A, B and C. Rather, HLA–G functions as an immunomodulator, and is involved in immune system regulation and tolerance of the fetus during pregnancy. It is expressed on the surface of extravillous trophoblast cells, which are cells in the implantation site of the placenta that are in contact with the maternal decidua.
HLA–G has four isoforms: membrane–bound (HLA–G1 and HLA–G5), soluble (HLA–G2 and HLA–G6) and a truncated isoform (HLA–G7). The isoforms differ in their glycosylation patterns and their ability to bind to receptors. HLA–G1 binds to the inhibitory receptor ILT2, which has immunosuppressive effects, and the binding of HLA–G1 to ILT2 has been shown to reduce the production of pro–inflammatory cytokines and prevent NK cell activation. HLA–G2 and HLA–G6 have also been shown to inhibit NK cell cytolytic activity and cytokine production. HLA–G7 has been shown to increase the expression of ILT2 and thus have an even greater effect on immune regulation. HLA–G is essential for the maintenance of the maternal–fetal interface and for the development of a healthy pregnancy.
3′-UTR Polymorphisms
There are several well-known polymorphisms in the 3′-UTR region of the HLA-G allele. We describe these polymorphisms in more detail here. Let us know if you want to include this region as part of your sequencing projects. We will generate a separate report from our standard HLA report specifically for this region.
