TY - JOUR
T1 - Associations between fetal HLA-G genotype and birth weight and placental weight in a large cohort of pregnant women
T2 - Possible implications for HLA diversity
AU - Emmery, Johanne
AU - Christiansen, Ole B
AU - Nilsson, Line Lynge
AU - Dahl, Mette
AU - Skovbo, Peter
AU - Møller, Anna Margrethe
AU - Steffensen, Rudi
AU - Hviid, Thomas Vauvert F
N1 - Copyright © 2017 Elsevier B.V. All rights reserved.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Birth weight and placental weight are crucial parameters for the survival of fetuses and newborns in mammals. High variation in the MHC is important for an effective adaptive immune response. The maternal immune system must be controlled in relation to the semi-allogenic fetus. The immunoregulatory HLA/MHC class Ib gene, HLA-G, is strongly expressed on extravillous trophoblast cells. We investigated birth weight and placental weight of the newborns in mothers heterozygous for an HLA-G 14bp insertion (Ins)/deletion (Del) gene polymorphism. Separate analyses for pregnancies without preeclampsia (n=185), pregnancies complicated by preeclampsia (n=101), and both groups combined, were performed. Interestingly, we observed the highest mean birth weight and placental weight in homozygous 14bp Del/Del newborns, and the lowest in 14bp Ins/Ins newborns (P=0.008 and P=0.009). The 14bp Del/Del genotype is also associated with high expression of HLA-G on the trophoblast membrane. In theory, fetuses and newborns with intermediate weights and sizes would be an optimal compromise for both the fetus/father and the mother compared with very high and low weights. If such fetuses/newborns more often are heterozygous at the HLA-G gene locus, then newborns with two distinct HLA haplotypes are favored, leading to a higher degree of HLA diversity. The results of the study may indicate that a compromise between an intermediate birth weight and placental weight, induction of maternal tolerance by a fetal-derived non-polymorphic HLA class Ib molecule, and favoring of HLA heterozygous offspring, have evolved in humans.
AB - Birth weight and placental weight are crucial parameters for the survival of fetuses and newborns in mammals. High variation in the MHC is important for an effective adaptive immune response. The maternal immune system must be controlled in relation to the semi-allogenic fetus. The immunoregulatory HLA/MHC class Ib gene, HLA-G, is strongly expressed on extravillous trophoblast cells. We investigated birth weight and placental weight of the newborns in mothers heterozygous for an HLA-G 14bp insertion (Ins)/deletion (Del) gene polymorphism. Separate analyses for pregnancies without preeclampsia (n=185), pregnancies complicated by preeclampsia (n=101), and both groups combined, were performed. Interestingly, we observed the highest mean birth weight and placental weight in homozygous 14bp Del/Del newborns, and the lowest in 14bp Ins/Ins newborns (P=0.008 and P=0.009). The 14bp Del/Del genotype is also associated with high expression of HLA-G on the trophoblast membrane. In theory, fetuses and newborns with intermediate weights and sizes would be an optimal compromise for both the fetus/father and the mother compared with very high and low weights. If such fetuses/newborns more often are heterozygous at the HLA-G gene locus, then newborns with two distinct HLA haplotypes are favored, leading to a higher degree of HLA diversity. The results of the study may indicate that a compromise between an intermediate birth weight and placental weight, induction of maternal tolerance by a fetal-derived non-polymorphic HLA class Ib molecule, and favoring of HLA heterozygous offspring, have evolved in humans.
KW - Journal Article
U2 - 10.1016/j.jri.2017.02.002
DO - 10.1016/j.jri.2017.02.002
M3 - Journal article
C2 - 28267635
SN - 0165-0378
VL - 120
SP - 8
EP - 14
JO - Journal of Reproductive Immunology
JF - Journal of Reproductive Immunology
ER -