Autoimmune disorders occur when the body's immune system, which normally helps protect you against infections, instead turns against your organs and tissues. It’s not yet clear exactly what causes autoimmune disorders, but a number of factors appear to play a role.
Some researchers believe that people who have had certain infections may be at higher risk of developing several types of autoimmune disorders. In fact, scientific evidence has linked autoimmune disorders with infection for well over a century.
Infection and Autoimmune Disorders: What's the Connection?
If you have an autoimmune disorder, your immune system has essentially malfunctioned. And because it will no longer recognize your body's own tissues as healthy "self" tissues, it will begin to produce an immune response against them. This immune response involves the production of a type of antibody known as an auto-antibody, which causes the body to attack its own organs and tissues.
Since bacteria and viruses trigger a similar immune response, some researchers have suggested that antibodies produced in response to certain infections may also attack some of normal cells because they somehow resemble the bacteria or virus that caused the infection. Others say that infections may actually damage your immune system, leading to the development of autoimmune disorders.
What the Research Says
Some research has supported this idea of a connection between infection and the development of autoimmune disorders. When researchers have studied the development of autoimmune disorders in identical twins, they have found that in many cases, both a genetic susceptibility and an environmental trigger (for example, infection) must be present for autoimmune disorders to develop.
And in one animal study, mice that were exposed to a certain virus (coxsackie virus B3, or CB3) were at increased risk of an autoimmune heart infection known as myocarditis. Similarly, researchers have experimentally linked the development of rheumatoid arthritis, multiple sclerosis, type 1 diabetes, and other autoimmune disorders, to infections.
No single infection has been found to be responsible for the development of autoimmune disorders. In fact, researchers have found that many different infections may be linked to a single autoimmune disorder. Some of the infections and their potential related autoimmune disorders include:
- Multiple sclerosis: Epstein-Barr virus (EBV) and measles virus
- Type 1 diabetes: coxsackievirus B4, cytomegalovirus (CMV), mumps virus, and rubella virus
- Rheumatoid arthritis: EBV, hepatitis C virus, Escherichia coli bacteria, mycobacteria
- Lupus: EBV
- Myocarditis: CB3, CMV, Chlamydia
- Myasthenia gravis: hepatitis C virus, herpes simplex virus
- Guillain-Barré syndrome: EBV, CMV, Campylobacter bacteria.
Of course, not everyone who gets these infections will develop an autoimmune disorder, since it seems that in addition to the infection, some sort of genetic predisposition is involved in the development of such conditions.
Many other infections may also be related to the development of autoimmune disorders. Because these infections usually occur well before any autoimmune disorder-associated symptoms develop, it can be difficult to determine a definitive link between one infection and a specific autoimmune disorder.
It is important to note that while the evidence is certainly mounting, researchers don't yet know for certain that previous infections increase the risk of developing autoimmune. But current studies are looking at exactly how infections may lead to the development of autoimmune disorders, and which specific infections may be responsible. The hope is that this research will one day lead to new strategies for preventing and treating autoimmune disorders.