TREGS POPULATION IMPAIRMENT IS ASSOCIATED WITH AN INCREASED RISK OF SPONTANEOUS ABORTION
RUMYANA SUSURKOVA1,2, TSVETELINA KUTLEVA1,2, ANDREY VELICHKOV2, NIKOLINA MIHAYLOVA3, ISKRA ANTONOVA4, GEORGI NIKOLOV4, VELISLAVA TERZIEVA2*
1 – Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
2 – Department of Immunobiology of Reproduction, Institute of Biology and Immunology of Reproduction, BAS, Sofia, Bulgaria
3 – Laboratory of Experimental Immunology, Institute of Microbiology, BAS, Sofia, Bulgaria
4 – Centre for Reproductive Biology and Medicine “Reprobiomed”, Sofia, Bulgaria
*Corresponding author: terzieva.velislava@gmail.com
Keywords: regulatory T cells, pregnancy, immune tolerance
Abstract: The regulatory T-cells, both natural (nTregs) and inducible (iTregs) are engaged in the immune tolerance establishment. One of the most intriguing tolerance-depending physiological conditions is the pregnancy where the embryo and placenta are not recognised as foreign. Among the extensively studied mechanisms supposed to ensure the maternal tolerance, Tregs are the object of a particular interest, being still not well characterised. The aim of the present study is to analyse the populations of peripheral regulatory T-cells in women with pregnancy failure in comparison to healthy subjects.
PBMCs from two subject groups – controls - women with history of normal pregnancy and patients with pregnancy failure were isolated and stained with anti-CD3, -CD4, -CD45RA, -CD25, -FOXP3 antibodies. Their expression was evaluated by multicolour flowcytometry.
Our results show that the peripheral Tregs profile in patients with pregnancy failure is impaired. In contrast to the controls, in the patient group the entire CD4+FOXP3+Treg population is significantly decreased. It consists mainly of CD45RA- iTregs, while CD45RA+ nTregs represent a minority. In healthy subjects, both fractions are equally rich in CD25+ cells. Inversely, in the patient group, CD45RA- iTregs, but not CD45RA+ nTregs are more populated with CD25+ cells.
The immune tolerance development during pregnancy is based on a complex cellular network. Therefore, the impaired peripheral Tregs pool could have a significant impact on the tolerance development in patients with pregnancy failure.