Microparticles and immunomodulation in pregnancy and pre-eclampsia.
Cellular microparticles are ubiquitously shed from cell membranes or secreted as endocytic vesicles called exosomes. Shed microparticles are >/=100nm in size and are generated during apoptosis or necrosis. In contrast, exosomes are smaller (<100nm), express more limited protein content and are released from late endosomes. Both membrane particles and exosomes can be detected in the circulation in non-pregnant and pregnant women. In the former, they are increased in conditions associated with systemic inflammation such as sepsis or metabolic syndrome. During pregnancy, they are also associated with pre-eclampsia and include not only particles derived from platelets, endothelium and various leukocytes but also syncytiotrophoblast-derived microparticles. Syncytiotrophoblast membrane microparticles (often called STBMs) interact with both immune and endothelial cells. They may contribute to the systemic inflammatory response of both normal and pre-eclamptic pregnancies, although inhibitory activity has also been described. Moreover, trophoblast-derived exosomes may contribute to or cause the downregulation of T cell activity that has been repeatedly observed during pregnancy. Deletion of activate T cells which express Fas ligand by Fas-expressing exosomes derived from trophoblast may contribute to immunoregulation necessary for normal pregnancy.
Redman
C W G
CW
University of Oxford, Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford OX3 9DU, UK. christopher.redman@obs-gyn.ox.ac.uk
Sargent
I L
IL
D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D011992:Endosomes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D007155:Immunologic Factors / Q000276:immunology* / Q000378:metabolism; D007249:Inflammation; D010316:Particle Size; D011225:Pre-Eclampsia / Q000276:immunology* / Q000378:metabolism; D011247:Pregnancy; D013601:T-Lymphocytes / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology* / Q000378:metabolism
D016207:Cytokines; D007155:Immunologic Factors