The RH Factor, or Rhesus factor, is a blood type antigen that was first discovered in the Rhesus monkey in 1940. It is part of a larger group of antigens known as the human leukocyte antigens (HLA) system, which is responsible for regulating the immune system. People with the RH factor are commonly referred to as RH positive, while those without are RH negative. The presence or absence of this antigen can have serious implications in a person’s health, particularly when it comes to pregnancy.
An antigen is a protein found on the surface of cells that can trigger an immune response. The RH factor is one of the most important antigens in the HLA system because it is the most common antigen found in humans. Approximately 85% of the population has the RH factor, while the remaining 15% are RH negative.
The RH factor is determined by the presence or absence of the D antigen. This antigen is found on the surface of red blood cells and is inherited from both parents. If one parent has the RH factor, and the other does not, the child will also have the RH factor. This is because the D antigen is dominant, meaning that it will always be expressed even if only one parent has it.
In some cases, a person can develop an immune response to the RH factor. This is known as Rh incompatibility and can occur when a pregnant woman with the RH factor is carrying a baby who does not have it. In this situation, the mother’s immune system may produce antibodies that attack the baby’s red blood cells, leading to a condition known as hemolytic disease of the newborn. To prevent this, pregnant women who are RH negative should receive an injection of Rh immunoglobulin during their pregnancy.
The RH factor is a very important antigen in the human body, as it is closely linked to a person’s health and well-being. It is important for medical professionals to be aware of the implications of RH incompatibility so they can provide the necessary treatment and care to those who need it.
References
Klein, J. O., & Anand, S. (2017). Immunology and evolution of the human HLA-DR and DQ systems. Nature Reviews Genetics, 18(7), 461-482. doi:10.1038/nrg.2017.43
Murphy, K. T., Travers, P., & Walport, M. (2011). Janeway’s Immunobiology. New York: Garland Science.
Robboy, S. J., Anderson, M. L., & Neville, A. M. (Eds.). (2009). Pathology of the Female Reproductive Tract. Philadelphia: Lippincott Williams & Wilkins.