The Role of Platelets in the Formation of Immunological Tolerance in Recurrent Miscarriage

Objective of the Review: Аnalysis of literature and summarizing of data on the participation of platelets in the formation of immunological tolerance during the physiological pregnancy and recurrent miscarriage. Key points. Platelet-derived soluble factors determine their involvement in the endocrine regulation of the placenta, initiate and maintain trophoblast invasion. Platelets are able to influence the balance of M1 and M2 macrophages, inhibit the cytotoxic potential of NK cells and the antigen-presenting ability of dendritic cells. The interaction of platelets with regulatory T cells initiates the recruitment of lymphocyte cells to the site of inflammation and their activation. It has been shown that the differentiation of immune cells and changes in their functional activity, aimed at creating conditions favorable for prolonging pregnancy, are largely determined by both platelet-derived soluble factors and the formation of platelet-leukocyte complexes. Conclusion. Platelets and products of their activation play an important role in creating the conditions necessary for the onset of pregnancy and its prolongation to full term. The functional state of platelets determines the success of placentation both directly (through the control of hemodynamic parameters in the placental vessels, increased invasiveness of the extracellular trophoblast, the effect on the endocrine background) and indirectly by modulating the functions of decidual immune cells, which determines their contribution in the implementation of idiopathic pregnancy loss. Keywords: platelets, platelet-leukocyte interaction, immunoregulation, recurrent abortion, pregnancy loss.