March 5, 2025

Snika Gupta

11th Grade

Brooklyn Technical High School

Autoimmune disorders are disorders in which the body’s immune system attacks the body. In most cases, symptoms can be managed, but typically, there is no cure. Cells in the immune system are T-lymphocytes or T-cells—these cells use the receptors on their surface to recognize foreign microbes such as bacteria and viruses. Usually, T-cells that react to the body's own tissues, the thymus, an organ in the immune system located behind the breastbone, remove those T-cells. The ones that aren't caught may be activated by a trigger. Triggers could be hormones or a viral infection. Once activated, the T-cells that attack the body tell the B-cells to create antibodies against the tissues it is attacking. These antibodies are called autoantibodies—antibodies that attack their own body. 

The exact causes of autoimmune disorders are unknown and often vary with each case. Some risk factors though can include genetics, gender, hormones, the environment, and infections. Autoimmune disorders may run in the family, or offspring may be genetically predisposed to have a risk of developing one. Because of the variability in the disorders, there are also other factors that affect the risk. Certain environmental factors contribute as well to triggering autoimmune disorders. Some disorders can be triggered or worsened by infections. Hormonal changes in women during pregnancy, childbirth, and menopause can also trigger or affect the autoimmune response. 

Gender also increases the risk factor; about ¾ of people with autoimmune diseases are women. As mentioned before, sex hormones and changes during pregnancy, childbirth, and menopause can be classified as triggers. Because there are two X chromosomes in women, one must be shut down to allow the other to create and balance the right amount of proteins. Shutting down, however, creates unfamiliar molecular structures that trigger antibodies to attack.

The gene for the molecule Xist exists on all X chromosomes, but it is only expressed when it is in a XX pair. Then only one of the chromosomes produces Xist as it is used to suppress the extra X chromosomes. Xist is made up of RNA—a messenger that gives organelles genetic instructions. There are many noncoding RNA (lncRNA) and these molecules rest on chromosomes to change the way the DNA is being transcribed. Xist is one of the lncRNA that prevents X chromosomes from producing proteins. Xist on the chromosome creates “odd combinations of lncRNA, proteins that bind to it, other proteins that bind to those proteins and DNA some of those proteins cling to.” (Stanford) This can cause an increased immune response. Many of the proteins that allow the molecule to rest upon regions of the X chromosomes are proteins that are associated with autoimmune disorders. 

In a Stanford experiment, researchers observed male mice with the activated Xist gene developed autoimmune disorders at a close rate to females. Furthermore, a close examination of blood with these disorders showed many autoantibodies to complications associated with Xist. The identification of these autoantibodies can be used to recognize and anticipate the development of autoimmune disorders. In addition to this, females also have significantly higher immunoglobulin and number of T-cells than males. 

However, the experiment also suggested that appropriate genetic background and tissue-damaging stress play a part in the development of autoimmunity. One such example could be the theory of molecular mimicry. The way this works is that bacteria infect someone, and the body reacts and produces T-cells and antibodies against a protein in the bacteria, a similar protein structure lies on an organ and the immune response will attack the organ as well.