Impact of fetal-maternal microchimerism on women's health--a review.

Microchimerism is defined by the presence of circulating cells, bi-directionally transferred from one genetically distinct individual to another. It occurs either physiologically during pregnancy, or iatrogenically after blood transfusion and organ transplants. The migrated cells may persist for decades. Much controversy exists around the role of microchimeric cells in the pathogenesis of various diseases and around their role in tissue repair. Microchimerism has been investigated in different autoimmune disorders, such as systemic sclerosis, systemic lupus erythematosus, autoimmune thyroid diseases, primary biliary cirrhosis and juvenile inflammatory myopathies. Recent data have demonstrated the promising role of microchimeric cells in the maternal response to tissue injuries by differentiating into many lineages. Therefore, further understanding of fetal-maternal microchimerism may help in anticipating its implications in disease as well as in more general women's health issues.