Naturally acquired microchimerism: clinical, scientific and ethical issues

Microchimerism (MC) is understood as the presence in the body of cells genetically different from the population of the individual, capable of existence and persistence, that is, reproduction and differentiation. This process is associated with the exchange of cellular material between mother and fetus. The consequences of the intrauterine acquisition of maternal MC (MMC) by the fetus are essentially different from the acquisition by the mother of fetal CM (FMC) in the mature state of the organism. Microchimerism has been implicated in the development of autoimmune diseases, but it also helps the body limit a particular disease. Since all these processes take place during the early development of the fetal immune system, the initial response of the immune system is the development of specific tolerance to maternal antigens. MMС can modify immune functions and reactivity through the nongenetic acquisition of cellular and subcellular material. Both FMС and MMС are quite common phenomena, which affects the body of the child and mother, the differentiation and functionality of the host cells. All this allows us to consider foreign cells as a potential target for drugs in the fight against autoimmune diseases or, conversely, stimulation of regeneration processes of damaged tissues. Issues of evolution and prospects for the prevention of various pathological conditions are considered from the standpoint of taking into account maternal and fetal chimerism syndrome.