title: Human leukocyte antigen (HLA)-G during pregnancy part I: correlations between maternal soluble HLA-G at midterm, at term, and umbilical cord blood soluble HLA-G at term.
abstract: Human leukocyte antigen (HLA)-G is a class Ib molecule with restricted tissue distribution expressed on trophoblast cells and has been proposed to have immunomodulatory functions during pregnancy. Soluble HLA-G1 (sHLA-G1) can be generated by the shedding of membrane-bound HLA-G molecules; however, three soluble isoforms also exist (HLA-G5 to -G6). During pregnancy, it is unknown whether there is a correlation between sHLA-G levels in maternal and fetal blood. In 246 pregnancies, we have measured the levels of sHLA-G1/-G5 in maternal blood plasma samples from gestational week 20 (GW20) and at term, as well as in umbilical cord blood samples. Soluble HLA-G levels declined by 38.4% in maternal blood from GW20 to term, and sHLA-G levels were significantly lower in maternal blood at term than in GW20 (P<0.001). At term, the sHLA-G levels were significantly higher in maternal blood than in umbilical blood (P<0.001). HLA-G levels in maternal blood in GW20 and at term, and in maternal blood at term and umbilical cord blood, were correlated (P<0.001 and P<0.01, respectively). This is the first large study simultaneously measuring sHLA-G in both maternal and umbilical cord blood. The finding that sHLA-G levels are significantly lower in fetal compared with maternal blood at term documents for the first time that sHLA-G is not freely transferred over the placental barrier. Soluble HLA-G levels in maternal and fetal blood were found to be correlated, which may be due to shared genetic factors of importance for production of sHLA-G in the mother and child, or it may support the theory that sHLA-G in the pregnant woman and the fetus is partly derived from a "shared organ", the placenta.
authors: Department of Obstetrics and Gynecology, Aalborg University Hospital, 9000 Aalborg, Denmark.
authors: Louise
authors: L
authors: Klitkou
authors: Department of Clinical Biochemistry, Centre for Immune Regulation and Reproductive Immunology (CIRRI), Copenhagen University Hospital (Roskilde) and Roskilde Hospital, 7-13 Køgevej, DK-4000 Roskilde, Denmark.
authors: Mette
authors: M
authors: Dahl
authors: Department of Clinical Biochemistry, Centre for Immune Regulation and Reproductive Immunology (CIRRI), Copenhagen University Hospital (Roskilde) and Roskilde Hospital, 7-13 Køgevej, DK-4000 Roskilde, Denmark. Electronic address: tvh@regionsjaelland.dk.
authors: Thomas Vauvert F
authors: TV
authors: Hviid
authors: Department of Clinical Biochemistry, Centre for Immune Regulation and Reproductive Immunology (CIRRI), Copenhagen University Hospital (Roskilde) and Roskilde Hospital, 7-13 Køgevej, DK-4000 Roskilde, Denmark.
authors: Snezana
authors: S
authors: Djurisic
authors: Department of Obstetrics and Gynecology, Aalborg University Hospital, 9000 Aalborg, Denmark.
authors: Zofia Maria
authors: ZM
authors: Piosik
authors: Department of Obstetrics and Gynecology, Aalborg University Hospital, 9000 Aalborg, Denmark.
authors: Peter
authors: P
authors: Skovbo
authors: Department of Obstetrics and Gynecology, Aalborg University Hospital, 9000 Aalborg, Denmark.
authors: Anna Margrethe
authors: AM
authors: Møller
authors: Department of Clinical Immunology, Aalborg University Hospital, 32 Urbansgade, 9000 Aalborg, Denmark.
authors: Rudi
authors: R
authors: Steffensen
authors: Department of Obstetrics and Gynecology, Aalborg University Hospital, 9000 Aalborg, Denmark; Fertility Clinic 4071, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
authors: Ole B
authors: OB
authors: Christiansen
mesh_terms: D015331:Cohort Studies; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005500:Follow-Up Studies; D005865:Gestational Age; D059951:HLA-G Antigens / Q000097:blood / Q000276:immunology*; D006801:Humans; D007112:Immunity, Maternally-Acquired; D021041:Placental Circulation / Q000276:immunology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000276:immunology*
chemical_list: D059951:HLA-G Antigens
keywords: HLA-G; MHC; Pregnancy; Umbilical cord blood; sHLA-G