Immunology of Pregnancy
Pregnancy presents a unique immunological challenge. Usually, your immune system works by fighting off any invading cells that it doesn't recognise because they don't share your genetic code and it is immunologically different. In the case of an embryo, the immune system learns to tolerate it even though it has a different genetic code from the mother.
It has become now known that in some cases of miscarriage or infertility, the mother’s immune system may fail to accept the embryo due to these differences in their genetic codes.
Immunological equilibrium
There is a balance between the activation and tolerance induced by the immune system. This immunological equilibrium is important for protection against autoimmune and alloimmune responses. Any disturbance in this equilibrium will lead to autoimmune or alloimmune disorders.
Fetus is a Semi-allograft
The fetus is 50% from the mother and 50% from the father. So, the fetus is 50% different immunologically from the mother. Hence, fetus is also known as “semi-allograft. In spite of this, the pregnancy continues to grow in the mother’s body without any rejection, as should have happened logically. This is known as “Paradox of pregnancy”. This is possible due to the complex immunological interactions happening at the feto-maternal interface.
Where does it come from?
Role of Protective antibodies (Blocking antibodies)
There are protective antibodies in the mother, that protect the pregnancy against the maternal immune attack.
These antibodies functionally univalent and are called asymmetrical antibody. These asymmetric antibodies are unable to form complexes, thus inhibiting complement fixation and phagocytosis. They competitively inhibit the unmodified symmetric antibody.
These antibodies function as regulators and cover paternal HLA (human leucocyte antigen) molecules on the fetus and protect the fetus from attack of maternal NK cells and T cells.
The Role of the Uterus
The uterus plays a crucial role in promoting immune tolerance. The lining of the uterus, the endometrium, secretes immunosuppressive factors that create a nurturing environment for the embryo. These factors suppress the mother's immune response at the implantation site, allowing the placenta to develop and facilitate nutrient exchange between mother and fetus.
The Role of Regulatory T Cells
Regulatory T cells (Tregs) are a specialized subset of T lymphocytes that play a vital role in suppressing the maternal immune response against the fetus. These cells are particularly enriched at the fetomaternal interface, promoting tolerance to paternal antigens.
LIT: A Potential Solution
LIT, the therapy offered by Dr. Mohan and Dr. Mugdha Raut, aims to address these immunological challenges. By introducing paternal lymphocytes to the mother in a controlled manner, LIT may help her immune system develop tolerance to the paternal antigens present in the fetus. This could potentially improve pregnancy outcomes in women with specific immunological causes of infertility, miscarriages or IVF failures.
