Multiple sclerosis (MS) is thought by many medical researchers to be an autoimmune disease, which is when the body’s immune system turns against its own tissues. There are a number of diseases that fall into this category, including lupus, rheumatoid arthritis, psoriasis, and Crohn’s disease. In MS, the immune system attacks the fatty myelin coating that surrounds and insulates nerve cells (a process called demyelination), resulting in lesions. Oligodendrocytes, which are myelin-producing cells, and nerve fibers are also damaged. Having another autoimmune disease may also be a slightly higher risk factor for developing MS. Thyroid disease MS has been associated with thyroid disease, although there are only a few studies about this. Thyroid disease has been reported to develop as a consequence of interferon beta and Lemtrada (alemtuzumab) MS therapies, which represents a concern due to the induction of autoimmune diseases. Researchers have found that treatment with the thyroid hormone increases the replacement of myelin in rats with a chronic demyelinating disease, suggesting that the thyroid hormone is needed for the normal development of precursor cells that become myelin-producing cells. Before this study, researchers had found that the thyroid hormone promotes re-myelination during the early phases of the disease. Type 1 diabetes Children and adolescents with type 1 diabetes may have an increased risk of developing MS because the two conditions may share common genetic risk factors, although environmental factors such as low sun exposure and low vitamin D levels may also increase this risk. Irritable bowel disease Irritable bowel disease (IBD) is characterized by a chronic inflammation of the gastrointestinal tract, leading to disruption of the intestinal lining, usually called “leaky gut.” This disruption of the intestinal lining may allow luminal antigens to abnormally activate the host-immune response, leading to a systemic autoimmune response. A study from Sweden reported that disruption of the intestinal lining supports experimental autoimmune encephalomyelitis, the prototypic mouse model of human MS. Recent observations suggest an association between MS and inflammatory bowel disease (IBD), with increased incidence of Crohn’s disease (CD) and ulcerative colitis (UC), the two most common types of IBD among MS patients. Irritable bowel syndrome Irritable bowel syndrome (IBS) also occurs more often than expected in people with MS when compared to the general population. Although it is not considered an autoimmune disease but a functional disorder of the digestive system, people with IBS have been reporting immunological alterations that are consistent with a chronic but low intensity activation of the immune system. It may also be a syndrome associated with stress. Note: Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.