P-164: Human Leukocyte Antigen Class Ib and Pregnancy Success

Background: During pregnancy, the maternal immune system is in close contact with cells and tissue from the semiallogenic fetus .The Human Leucocyte Antigen (HLA) class Ib molecules, HLA-E, -F and -G, are expressed at the materno-fetal interface. Because of the apparent immunoregulatory functions of these proteins, they may be involved in successful acceptance of the semi-allogenic fetus during pregnancy.In this presentation we have reviewed studies regarding role of hla class Ib in pregnancy success and gathered their results in order to gain a better understanding of the relationship of these molecule and pregnancy success. Materials and Methods: We have conducted a thorough literature search using search engines in the medical databases and collected the data and research results regarding these molecules and pregnancy.We focused on polymorphisms of the three genes, expression patterns of the proteins, and interactions with immune cells and the have been evaluated to elucidate whether HLA-E, -F and -G are involved in the pathogenesis recurrent miscarriages. Results: Non-classical antigens such as Human leukocyte Antigen class Ib may interact with receptors of NK cells ,Macrophage, CD8+ T cell, CD4+ T cell and monocyte such as Killer Inhibitory Receptor,Leukocyte Ig Like Receptor which results into limit activity of these immune cells and downregulation of immune response and helps in the maintenance of pregnancy and any changes in pattern of expression of these HLA molecules because of polymorphisms or other reasons may cause misscarriage. Conclusion: The HLA class Ib molecules seem to induce suppression of the maternal immune system. Evidences show changes in expression pattern and function of these molecules are associated with miscarriage . To clarify the functions of HLA-E, -F and -G, future studies need to link investigations of the polymorphisms in these genes to measurements of protein levels, and examine the role of these proteins in the complex interplay of immune cells and cytokines at the materno-fetal interface.