The disease course in MS and the response to therapy vary from person to person, and there is currently no reliable means to tell early on how active any individual’s MS is likely to be. A team led by Philip L. De Jager, MD, a Harry Weaver Scholar of the National MS Society (Harvard’s Brigham and Women’s Hospital, Boston) has discovered that differences in active genes – detectable in blood samples – has the potential to be used to group people with MS into categories that predict disease course and response to therapy. Further research is needed to verify and refine this approach before it becomes a tool that can benefit treatment decisions made by people with MS and their health care providers. This study was recently published in Science Translational Medicine
[4, 153ra131 (2012)].
MS is known to be affected by both genetics and environmental factors. Doctors have a hard time predicting which people with MS will respond to the different drug therapies that are available and what their disease course is likely to be. Although brain imaging can help predict additional disease events, physicians still lack effective tools to predict the course of the disease. One idea to try to predict the outcome in MS is to look for clues to patterns in the blood that will show which genes are switched on or off, and try to relate those patterns to disease activity and other characteristics.
Dr. De Jager and colleagues collected blood samples from 141 people who were newly diagnosed with MS and who had not yet been treated. The blood samples contain immune cells known to be important in the disease activity involved in MS. From these cells, the team extracted a type of molecule called RNA, which shows what genes are turned on in the immune cells. They used powerful mathematical tools to study the many groups of genes that were switched on.
This analysis showed that the 141 people with MS could be divided into two groups according to whether particular sets of genes involved in immune function were active or inactive. They then tested the importance of their groupings further by examining blood from 222 people who were being treated with two types of first-line therapy used in MS, interferon beta and glatiramer acetate
. The group of people with MS whose immune system genes were more active were significantly more likely to experience a relapse or show other evidence of disease activity, such as on MRI, compared to the group whose immune system genes were less active, regardless of which treatment they were on. In this way, the team was able to find a “signature” by looking at the blood that could predict, early on at least, the likelihood of active disease.
In the paper reporting the study, the authors discuss the need for future studies to examine in more detail the type of cells that are responsible for the differences they have found. It is also unknown whether such a classification will remain stable as the disease progresses, or whether people’s types change or switch to the other group. They also don’t know yet if this classification system can predict if or when a given person will enter the progressive stage of MS.
This study provides an early step that could eventually contribute towards “personalized medicine” in MS, which aims to be able to predict the course of an individual’s disease and the best treatment options to stop their type of disease activity. Further research is needed to verify and refine this approach before it becomes a tool that can benefit treatment decisions made by people with MS and their health care providers. In the future, this type of approach may enable more aggressive treatment for people predicted to be more likely to experience a relapse or to respond poorly to a specific therapy.