The Many Faces of Human Leukocyte Antigen-G: Relevance to the Fate of Pregnancy

Table 1

A comparison of differences in HLA-G gene and protein expression and functional characteristics between the 14 bp deletion and 14 bp insertion alleles. The observed differences may be influenced by other DNA and mRNA polymorphisms in the 3′-untranslated region (3′UTR), especially the +3142 and +3187 SNPs, and/or the 5′-upstream regulatory region of HLA-G that are in linkage disequilibrium with the 14 bp ins/del polymorphism (see the text and Figure 1 for details). (Based on a large number of references listed in the text).

	14 bp; deletion; HLA-G allele	14 bp; insertion; HLA-G allele
Alternative splicing of HLA-G mRNA that includes a deletion of 92 bp of the 3′UTR	No	Yes
Levels of HLA-G mRNA (not including the 92 bp splice variants)	+++	++
Levels of soluble HLA-G1	?	?
Levels of HLA-G5 during pregnancy*	+	++
Levels of soluble HLA-G in blood plasma from healthy nonpregnant donors**	+++	++
Membrane-bound expression of HLA-G1*	++	+++
HLA-G mRNA stability	+	+++
Inhibition of NK cytotoxicity*	+	++

∗Only one or very few studies; needs further verification.
^∗∗𝛽2-microglobulin-associated soluble HLA-G1 and HLA-G5.