Reproductive Immunology is the study of all aspects of the system that evolved to protect organisms against potential harmful invaders. Reproductive immunology refers to a field of medicine that studies the phenomenon of immunological tolerance achieved when the mother's immune system accepts the foreign embryo. The concept of lack of achieving immunologic tolerance has been used to explain some cases of recurrent miscarriages and implantation failure after IVF/ET. Recent recognition of the fact that the implanting embryo engages in "cross-talk" with immune cells in the lining of the uterus through secreted proteins known as cytokines has provided evidence for a role of immunologic risk factors leading to recurrent miscarriages and implantation failure after IVF/ET. If this “cross-talk” results in successful alteration of the maternal immune cell response, the embryo can implant and develop unhindered in the uterus If the "cross-talk" is unsuccessful, then the embryo can be rejected. An important cytokine secreted by the embryo that contributes to the “cross-talk” between embryo and endometrium is HLA-G. Soluble HLA-G (sHLA-G) can be measured in the media surrounding each embryo after in vitro fertilization and has been shown to predict subsequent implantation.
Once implantated in the lining of the uterus, the embryo must induce its own blood supply. If this blood supply is clotted off through inflammatory or blood clotting genes, the pregnancy will fail. Laboratory tests are available to identify immunologic and blood clotting problems that can lead to either implantation failure after IVF or recurrent miscarriages.
Immunologic tests include:
Natural killer cells
NK activation assay
Blood clotting tests include:
Treatment for immunologic or blood clotting problems depends on the results of the above testing. Immunologic problems are treated with immunotherapy. If the cause is related to activated immune cells and their cytokines, treatments include: Intravenous Immunoglobulin (IVIg)and Intralipid. If either acquired or inherited thrombophilia is causing clotting of the placental vessel and subsequent pregnancy loss, then heparin and aspirin are the treatments of choice. If the blood clotting is the result of an immune process, then steroids can be used.