title: Low levels of naturally occurring regulatory T lymphocytes in blood of mares with early pregnancy loss.
abstract: Early pregnancy loss is a major reason for low reproductive efficiency in the horse. In humans and mice, low numbers of regulatory T cells (Treg cells) are linked to miscarriage. The percentage of Treg cells in oestrous mares at the start of the breeding season was evaluated in relation to the outcome of subsequent pregnancy. For identification and quantification of Treg cells, a highly sensitive and specific qPCR assay targeting the Treg-specific demethylated region in the equine forkhead box transcription factor (FOXP3) gene was established. In a total of 108 mares, pregnancy was followed until detection of early pregnancy loss (n=17), abortion without identification of an infectious or apparent cause (n=9) or birth of a viable foal (n=82). Measured Treg-cell levels did not significantly differ between mares that conceived (82%; 1.50±0.04%) or did not get pregnant (18%; 1.45±0.10%). The Treg-cell percentage at oestrus before breeding was significantly different (P<0.05) between mares that either underwent early pregnancy loss up to Day 40 of pregnancy (1.29±0.07%) and mares that aborted (1.61±0.15%) or gave birth to a live foal (1.52±0.05%). These results suggest that low levels of Treg cells in mares can contribute to pregnancy loss up to Day 40 after ovulation.
authors.affiliation: Centre for Artificial Insemination and Embryo Transfer, University for Veterinary Sciences, 1210 Vienna, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Aurich
authors.affiliation: Certagen GmbH, D-53359 Rheinbach, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Weber
authors.affiliation: Graf Lehndorff-Institute for Equine Science, University for Veterinary Sciences, 16845 Neustadt (Dosse), Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Nagel
authors.affiliation: Clinic for Obstetrics, Gynaecology and Andrology, University for Veterinary Sciences, 1210 Vienna, Austria.
authors.forename: Maximiliane
authors.initials: M
authors.lastname: Merkl
authors.affiliation: Certagen GmbH, D-53359 Rheinbach, Germany.
authors.forename: Rony
authors.initials: R
authors.lastname: Jude
authors.affiliation: Certagen GmbH, D-53359 Rheinbach, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Wostmann
authors.affiliation: Ivana Türbachova Laboratory for Epigenetics, Epiontis GmbH, D-12489 Berlin, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Ollech
authors.affiliation: Ivana Türbachova Laboratory for Epigenetics, Epiontis GmbH, D-12489 Berlin, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Baron
authors.affiliation: Ivana Türbachova Laboratory for Epigenetics, Epiontis GmbH, D-12489 Berlin, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Olek
authors.affiliation: Certagen GmbH, D-53359 Rheinbach, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jansen
mesh_terms: D000818:Animals; D001947:Breeding; D020964:Embryo Loss / Q000097:blood* / Q000276:immunology / Q000473:pathology*; D005260:Female; D005298:Fertility / Q000276:immunology; D005865:Gestational Age; D006736:Horses / Q000097:blood / Q000276:immunology; D007315:Insemination, Artificial / Q000662:veterinary; D018655:Lymphocyte Count; D010298:Parity; D011247:Pregnancy; D050378:T-Lymphocytes, Regulatory / Q000473:pathology*