An illustration showing the damage multiple sclerosis can cause to neurons. (Image credit: JUAN GAERTNER/SCIENCE PHOTO LIBRARY via Getty Images)
Researchers say a new study has found genetic characteristics that may indicate the onset of multiple sclerosis (MS) long before a person shows any symptoms of the disease.
Multiple sclerosis is an autoimmune disorder that causes inflammation in the brain and spinal cord. This inflammation damages the myelin sheaths — the insulation that covers the long “wires” of nerve cells — and causes symptoms such as pain, fatigue, numbness or weakness, and vision or movement problems.
People with MS are known to have elevated levels of immune cells known as cytotoxic T cells, which normally help destroy cancer cells and cells infected with germs. However, in MS, these cells accumulate in areas with significant myelin damage, but their role in the disease’s pathology has remained largely unclear – until now.
In a study published Sept. 27 in the journal Science Immunology, scientists looked at T cells from 12 pairs of identical twins. In each pair, one twin had MS and the other did not. If one twin is diagnosed with MS, the other twin has about a 1 in 4 chance of developing the disease later in life. So the T cells from the other twin provide information about the immune systems of those people who are most likely to eventually develop full-blown MS.
“We currently have very effective treatments for multiple sclerosis,” study author Dr. Lisa Ann Gerdes, a neuroimmunologist at Ludwig Maximilian University of Munich, told Live Science. However, patients cannot be treated until they are diagnosed, and the risk factors, triggers, and earliest signs of multiple sclerosis are still poorly understood.
“Studying twins with MS gives us a unique opportunity to study patients at the prodromal [very early] stage of the disease, which is not possible in routine clinical practice,” Gerdes said. “Usually, by the time a patient develops symptoms, the immune system has already begun to attack the brain, so we are late in discovering the key players that cause early inflammation.”
Notably, six of the twins without MS had some inflammation in the central nervous system (CNS) that could be detected by tests but did not yet cause any obvious symptoms.
The researchers analyzed the genes that were activated in the twins’ T cells by measuring levels of RNA, a molecule that helps cells make proteins following DNA’s instructions. The results showed that the T cells from people with multiple sclerosis or central nervous system inflammation were more active and produced more immune signals than T cells from people without the disease. In simple terms, these T cells were especially reactive. The researchers also noted increased activation of genes that help keep T cells working.
The sooner we intervene in the process of inflammation and damage to the nervous system, the more significant our effect will be.
Dr. David Duncan, Hackensack Meridian Health
By classifying the overactive genes by stage of the disease, the scientists showed that genes associated with T-cell activation were most expressed in people with CNS inflammation, but not in those with full-blown MS. Those with MS had higher activity in genes associated with keeping T-cells alive, moving them around the body, and recruiting other parts of the immune system to attack.
Overall, the more advanced a person's disease was, the more T cells showed these genetic changes, lending further support to the hypothesis that these T cells contribute to inflammation in MS.
“Research shows again and again that the earlier we intervene in the process of inflammation and damage to the nervous system, the more
Sourse: www.livescience.com
