Microchimerism is the existence of two genetically distinct and separately derived cell lines within the same individual or organ. However, among the two cell lines, one cell line exists at a much lower concentration than the more dominant cell line. The term is derived from the word ‘chimers’ in Greek mythology where it has been used to describe an awesome fire breathing monsters with the head of a lion, the body of a goat and the tail of a serpent.
How does microchimerism take place?
According to scientists, microchimerism can take place due to different reasons. One commonly accepted fact is that certain cells can traverse the placenta from the mother into the baby and may end up being part of the baby’s system. A transfer of cells from one twin to the other has also been cited as a reason for giving rise to microchimerism. In addition, blood transfusions, in-vitro fertilization and transplantations have also been recognized as potential causes for microchimerism.
How do twins become ‘blood chimeras’?
One recognized fact in the science of ‘chimerism’ is that around 8% of non-identical twins can become chimeras. It is postulated that as certain percentage of twin embryos share the blood supply from the placenta, stem cells from one twin can enter the blood circulation of the other twin and are deposited within the bone marrow. In some instances, even when one of the twins die early in the gestation, the other twin could become a chimera.
How long can ‘microchimerism’ last?
Scientists believe that microchimerism can last for many decades and sometimes even a lifetime. However, the exact mechanisms of its survival and depletion have not been recognized.
What is the importance of knowing the existence of microchimerism?
With the detection of higher concentration of microchimerism in a patient with Scleroderma in the year 1998, scientists have ventured into many areas seeking the truth behind the role played by microchimerism in relation to certain disease process, cell repair and damage and therapeutic procedures. It has been studies in relation to primary biliary cirrhosis, thyroiditis, rheumatoid arthritis…etc. In addition, microchimerism has also been studied in relation to breast cancer protection, its role in the progression or non-progression of HIV and AIDS as well as in relation to graft rejections in tissue transplantations.
How ‘microchimerism’ opens up a new paradigm?
With the advent of microchimerism, the popular belief of ‘self’ could be challenged. The presence of natural chimerism could lead to the occurrence of certain disease states and in some instances protect the individual from unwarranted health issues. Harnessing this knowledge could be the key to many discovering in the field of medicine in the future although to embrace the full potential of microchimerism, it is necessary to embrace a new notion of ‘self’ than what it was believed to be.