Feb. 22, 2013

By Medical Discovery News

Pictures from the 2012 presidential campaign depict Ann Romney, wife of Republican candidate Mitt Romney, as a woman with bright eyes, a luminous smile, and a dancer’s posture. But beneath the polished business suit of a potential first lady another battle raged.

Ann Romney was diagnosed with multiple sclerosis (MS) many years ago and experienced a flare up of her symptoms that forced her to curtail her campaign efforts. There is no known cause or cure for MS, although medications are available to slow the progression of the disease. However, researchers at the National Institutes of Health discovered the drug daclizumab appears to tone down the autoimmune response in MS patients, providing hope for those like Ann Romney who are trying to overcome the obstacles of living with MS.

MS is a type of autoimmune disorder, meaning cells in the body’s own immune system that are supposed to provide protection from invading infections instead attack the body’s own healthy tissues. In the case of MS, the immune system attacks the myelin sheath that covers nerve cells. Myelin is crucial in the conduction of electrical impulses to and from the brain. The loss of myelin, called demyelination, causes hardened scars in areas of the nerves and brain affected. The name multiple sclerosis actually means “many scars.” MS is the most common disease of the central nervous system in young adults, affecting 400,000 Americans. 

In the NIH study, researchers identified a unique type of immune cell called lymphoid tissue inducer (LTi) cells, which promote the development of lymph nodes and similar tissues in a fetus. While it is unclear what LTi cells do in adults, they appear to play a role in the immunity in the gastrointestinal tract. This study implicates these cells may contribute to MS, although they have not previously been linked to any autoimmune disorder.

MS patients in the study receiving daclizumab had reduced levels of LTi cells and reduced signs of inflammation in the cerebrospinal fluid, which surrounds the brain and spinal column, when compared to a control group that didn’t receive the drug. This drug is an engineered antibody that interferes with the signals produced by a molecule called interleukin 2 (IL-2) that promotes inflammation. Antibodies are specialized proteins made by the immune system that target and bind to antigens, in this case the IL-2 protein, to eliminate or block their actions.

By blocking IL-2 action, it seems like daclizumab reduces inflammation and the damage that happens in MS. More studies will have to confirm the role of LTi cells in MS before the development of drugs to selectively target LTi cells can begin in earnest. But one day, such drugs may become part of the treatment for MS and hopefully slow the progression of this disease more effectively. 

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