Is Multiple Sclerosis Mainly an Autoimmune Disease?
Among the many factors that scientists cannot agree upon concerning multiple sclerosis is its cause. Although a popular belief is that multiple sclerosis is an autoimmune disease, some scientists, clinicians, and patients believe its origins lie elsewhere.
A new report from researchers at Yale, the University of California-San Francisco, and the Broad Institute of MIT and Harvard claims the answer to the question about whether MS is an autoimmune disease is in the affirmative. To support their claim, the authors developed a complex mathematical model and maps that allowed them to pinpoint which variants of cells cause the immune system to dysfunction and result in 21 specific autoimmune diseases.
Multiple sclerosis, as well as Crohn’s disease, diabetes, and rheumatoid arthritis, are among those diseases. According to David A. Hafler, professor of immunobiology, the article’s co-senior author, and chair of the Department of Neurology at Yale, the team revealed findings that “give new insight into the cause of multiple sclerosis and other autoimmune diseases.”
In simple terms, the model the scientists developed allowed them to analyze genetic data and to discover that minute variations in DNA exist near substances that are key in regulating immune system responses. The experts used this information to create tools that ultimately allowed them to identify exactly which cell type causes each of the different autoimmune conditions and how the DNA variations cause the immune cells to dysfunction.
According to Hafler, the findings strongly link the cause of multiple sclerosis to the immune system and provides evidence that the disease is primarily autoimmune in nature. However, all experts don’t agree with this idea.
Other opinions on MS and autoimmunity
At the 5th Cooperative Meeting of the Consortium of Multiple Sclerosis Centers and the Americas Committee for Treatment and Research in Multiple Sclerosis in 2013, the several researchers argued whether multiple sclerosis is an autoimmune disorder or a neurodegenerative condition. Peter Stys, MD, professor of neurology at the University of Calgary, Alberta, believes MS is an autoimmune disease but questioned whether it is primarily so, while Richard Ransohoff, MD, director of the Neuroinflammation Research Center in Cleveland, Ohio, believes MS is mainly an inflammatory condition. So the question becomes, which comes first, the immune system dysfunction or the inflammation?
That is, does cytodegeneration (destruction of the myelin sheaths) trigger the immune system response or does inflammation lead to an immune response that results in the body attacking myelin and cytodegeneration? The answer can be instrumental in developing new preventive and treatment strategies.
Disagreement within the medical research community remains although there is some give and take. Ransohoff himself noted that while he doesn’t eliminate the possibility that cytodegeneration is involved, he supports the notion that MS is mainly an inflammatory condition. As a case in point, he pointed out that multiple sclerosis shares many allelic variants (alterations in the normal sequence of genes) with other autoimmune inflammatory diseases such as lupus, rheumatoid arthritis, and psoriasis.
Stys also questioned the idea that multiple sclerosis is primarily an immunologic condition even though he supports that view in general. In fact, Stys proposes a somewhat radical idea. He has suggested that “maybe the real MS is primary progressive disease, and relapsing-remitting MS, which curiously represents the vast majority of our patients, is actually a reaction, a distraction if you will, to the primary root cause.”
Researchers also need to consider the strong evidence showing how multiple sclerosis is associated with environmental factors such as vitamin D, sun exposure, and smoking. And according to Ransohoff, “It seems as if it’s almost impossible to get MS unless a person has been infected with the Epstein-Barr virus.”
Thus, the debate over the primary cause of multiple sclerosis does not appear to be over. While such ongoing discussions certainly can be productive, they also are frustrating for those who live with this disease.
5th Cooperative Meeting of the Consortium of Multiple Sclerosis Centers and the Americas Committee for Treatment and Research in Multiple Sclerosis Debate. Presented 2013 June 1
Chaudhuri A et al. MS is not an autoimmune disease. Archives of Neurology 2004; 61(10): 1610-12
Yale University. Molecular map reveals genetic origins of 21 autoimmune diseases