December 5, 2013
News Review From Harvard Medical School -- TB Vaccine May Help Prevent MS
A vaccine used to prevent tuberculosis might also help people at high risk of developing multiple sclerosis, a new study suggests. Multiple sclerosis (MS) occurs when the immune system attacks the sheath that surrounds the body's nerve cells. Some people first are diagnosed with "clinically isolated syndrome." Symptoms include numbing and problems with vision, hearing and balance. About half of those with this syndrome will develop MS within 2 years. The new study included 73 people with this syndrome. They were randomly divided into 2 groups. One group received injections of a vaccine against tuberculosis that contained live but weakened bacteria. The other group received placebo (fake) injections. In the next 6 months, brain scans showed an average of 8 lesions (possible signs of MS) in those who got the placebo and 3 lesions in those who got the vaccine. Both groups also received treatment with an MS drug, interferon beta-a. After 5 years, 70% of those who got the placebo and 42% of those who got the vaccine had developed MS. The journal Neurology published the study online. HealthDay News wrote about it December 4.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Most often, multiple sclerosis (MS) starts with a set of symptoms that usually get better on their own. The symptoms can be scary. They might include:
- Tingling sensations
- Muscle weakness
- Blurred or double vision
Doctors call this "clinically isolated syndrome." Those affected might even have changes on an MRI that look like multiple sclerosis. But it's called "isolated" because some people never have another episode.
You don't make a diagnosis of MS based on one episode only. It's not MS unless symptoms are lasting or keep coming back. While some people with clinically isolated syndrome don't develop MS, about half will within two years of the first symptoms.
When clinically isolated syndrome leads to multiple sclerosis, the cause is an autoimmune reaction. The body's own immune system attacks the layer of fatty tissue that surrounds and protects the nerves of the brain and spinal cord. This layer is called the myelin sheath.
These autoimmune attacks damage the myelin sheath, producing scar tissue (sclerosis). This disrupts signals between the central nervous system and the rest of the body.
Researchers continue to study the best approach to clinically isolated syndrome. Two drugs, interferon-beta and glatiramer, are sometimes given. They may help delay MS and make symptoms less severe. But drug treatment does not need to begin right away.
In this study, researchers looked at whether a vaccine that stimulates the immune system might prevent or delay MS in someone with clinically isolated syndrome. The vaccine is called BCG. It is used in developing countries to help prevent tuberculosis. It's also used to stimulate the immune system as treatment for bladder cancer. And it's being studied in type 1 diabetes, another autoimmune disorder.
It might seem contrary to want to stimulate an immune system that is already attacking the brain and spinal cord. Indeed, some proven therapies for MS act by damping down the immune system.
But, like many autoimmune disorders, MS is not simply caused by an overactive immune system. Something triggered the immune system to attack myelin. And perhaps stimulating the immune system against a vaccine like BCG might trick the immune system so that it does not attack myelin.
This small study compared people with clinically isolated syndrome who received the vaccine or a placebo injection. Those who got the real vaccine were less likely to have symptoms get worse. They also developed fewer brain abnormalities, shown on an MRI, than those who got the placebo.
These results are intriguing and potentially exciting. But it's way too soon for the vaccine to be used in clinical practice.
What Changes Can I Make Now?
Everyone in this study was given interferon-beta, starting six months after the clinically isolated syndrome symptoms. This treatment lasted for one year. After that, the need and type of further treatment was determined by their own doctors.
Interferon-beta used in this study is a very reasonable treatment for clinically isolated syndrome. This should not imply that it's the best. Other treatments may work just as well or even better at helping to help prevent or delay MS.
If you do have multiple sclerosis, there are things other than drugs than can help:
- Make sure you get plenty of rest. Fatigue is a common problem in MS.
- Exercise can ease some common symptoms of MS. This may make day-to-day living easier and improve your mood and quality of life. Yoga, tai chi and strength training can help you move better and boost muscle strength.
- Consider ways to reduce stress. This might include relaxation strategies such as meditation or massage.
- Consider a support group.
What Can I Expect Looking to the Future?
Larger and longer studies will be done to prove the benefits of the BCG vaccination for people with clinically isolated syndrome and MS.