RESUMEN
From an immunological point of view during pregnancy the interactions between the steroid sex hormones and immunocompetent cells as a part of the dynamic local and peripheral immune response is of a particular interest. The aim of our study is to investigate the expression of the early activation marker CD69 in T-lymphocytes subpopulation: CD4+ and CD8+ in peripheral blood from pregnant and non-pregnant women. Our data clearly demonstrate an increase of the percentage of activated CD4+ lymphocytes in pregnant women in comparison to non-pregnant and this difference is statistically significant. A similar but not statistically significant dependency is observed in CD8+ and CD69+ lymphocytes. From the obtained results we conclude that during pregnancy the activation of CD4+ lymphocytes is increased, which probably leads to an increased production of cytokines that shifts the immune response to Th2 type which is protective for pregnancy. This could be partly due to the increased levels of progesterone.