PHOSPHORILATED STAT5 IS ASSOCIATED WITH DIFFERENTIAL ACTIVATION CAPACITY OF T REGULATORY CELLS IN WOMEN WITH REPRODUCTIVE FAILURE

The population of regulatory T-cells (Tregs) is associated with the immune tolerance. Tregs have a significant impact in preservation of self-tolerance and the control of pregnancy development, tumour immunology, etc. Deviations in their percentage and/or function result in recurrent pregnancy loss (RPL), autoimmunity, etc. Tregs functionality is strongly dependent on IL-2 signalling pathway. As a part of this pathway, pSTAT5 interacts directly with the foxp3 gene which is specific for the Tregs function. We studied pSTAT5 expression in the light of regulatory and non-regulatory T cells (Teff) by 6 colour FAGS analysis. The comparison between healthy controls and patients with RPL was done by nonparametric statistical methods. Results showed decreased percentage of pSTAT5+ cells in patients' Tregs, but not in controls' Tregs. In vitro stimulation of isolated PBMCs demonstrated a trend of pSTAT5+ change in Tregs and Teff that differed between patients and healthy controls. Our results indicate that variations in pSTAT5 expression might be associated with ineffective activation of Tregs in patients with RPL.