Abstract
Microchimerism - the phenomenon of the presence of genetically foreign cells within the body - holds significant interest for endocrinology. It develops as a result of transplacental cell exchange during pregnancy (fetal and maternal microchimeric cells) or iatrogenic interventions and may play an important role in the development of autoimmune endocrine diseases. The greatest amount of data has been accumulated regarding thyroid diseases: fetal microchimeric cells are detected in 38-83% of cases of autoimmune thyroiditis and Graves' disease, with their levels correlating with the activity of the autoimmune process. Three main hypotheses have been proposed regarding their involvement in pathogenesis: initiation of a "graft-versus-host" reaction postpartum, molecular mimicry with thyroid antigens, or passive accumulation in inflammatory foci.In type 1 diabetes mellitus, studies focus on maternal microchimeric cells, which are found in the pancreas of patients and can differentiate into β-cells; however, their pathogenic role remains controversial. Modern methods for detecting microchimeric cells - such as polymerase chain reaction (PCR) and immunofluorescent hybridization in situ (FISH) - are highly sensitive but require standardization. Promising research directions include studying the influence of HLA compatibility, long-term dynamics of microchimeric cells, and their potential therapeutic applications. Addressing these issues could lead to a revision of current understanding of the pathogenesis of endocrine diseases and the development of new treatment approaches.