Sand in Your Eyes

June 28, 2013

By Medical Discovery News

First the eyes feel dry, so dry the sensation is like having sand in them. Then the mouth dries out so that it’s hard to swallow. While the symptoms come on slowly, the disease is usually diagnosed after it’s too late. By then, the patients’ salivary glands and tear glands are already destroyed and there is little that can be done. But researchers are trying to change that by developing a test that could diagnose Sjogren’s Syndrome (SS) earlier.

As the third most common autoimmune disorder in the U.S., SS affects about 4 million Americans, most of them women and over 40. Autoimmune disorders result from a person’s own immune system attacking the body. The worst part is that there is no cure for SS.

The disease first attacks the mucous membranes and moisture secreting glands, causing dry eyes and mouth which are treated with over-the-counter and prescription medications. However, this disease is systemic, affecting many parts of the body including the brain, kidneys, liver, lungs, skin, and nerves among others. A person with SS can end up seeing a host of specialists including rheumatologists and dentists to come up with an individualized treatment plan using immunosuppressive therapies to treat this complex disease. They also face a 5-15 percent chance of developing lymphomas as the disease progresses.

Diagnosis of SS includes blood tests to measure antibodies frequently associated with autoimmune disorders, ophthalmological tests for tear production and dryness of the surface of the eye, additional tests to measure salivary gland function, and a biopsy to check for signs of inflammation may also be done. Diagnosis is based on having a combination of symptoms and results of the various lab tests. Currently, there is no known test to definitively diagnose it.

But now researchers have developed a test that could diagnose SS much sooner, before the damage sets in. Since it is very rare to diagnose humans in the early stages of SS, researchers had to first develop an animal model of SS in mice that closely resembles the disease in humans. This allowed researchers to look for markers of the disease as it progressed. They discovered elevated levels of messenger RNAs that code for three salivary gland proteins in SS mice. They also found that the SS mice were making antibodies against these three proteins, in effect attacking themselves, the hallmark of an autoimmune disorder.

They then detected the same autoantibodies in human SS patients. So, the new test works by measuring the levels of these three types of unique antibodies in the blood.  Antibodies, Y-shaped proteins produced by the immune system, recognize and bind to antigens, substances that the body flags as foreign and/or harmful, like bacteria and viruses.

These newly identified autoantibodies appear much earlier, providing an opportunity for earlier and more definitive diagnosis. Earlier diagnosis may allow doctors to start therapies that may save SS patients’ salivary and tear glands, alleviating their symptoms and slowing the progression of SS.

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New Hope for MS

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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