The JC Virus: A New Variant of MS?
A new variant of multiple sclerosis (MS) called “JC” was recently discovered in a patient with relapsing-remitting type (RRM), which is one of the most common forms of MS. RRM patients have a higher risk for developing other types of MS such as secondary progressive or mixed form. There are currently no effective treatments for these other forms.
In addition, there is growing evidence that the immune system may play a role in causing some cases of MS. For example, studies show that certain proteins produced by B cells from the bone marrow can trigger autoimmune reactions in the brain and spinal cord. These include inflammation and demyelination (nerve damage) in areas where neurons are located.
Researchers believe that these autoantibodies may contribute to the development of MS.
Researchers at Johns Hopkins University School of Medicine found that two genes, CCR5 and CD40L, were involved in triggering these autoantibody responses. They found that mice lacking either gene had increased levels of antibodies against their own nerve cells and a greater number of them than normal mice. They also showed that the presence of both genes in humans increases the risk for developing MS.
These genes are involved in immune regulation.
The discovery of this new variant of MS will increase the number of known types from 2 to 3. It is not clear whether the presence of these genes causes the disease or only increases susceptibility. Regardless, the presence of certain genes may be a more accurate way to predict who is at risk or already developing this form of disease.
The discovery of this new type of disease is an exciting one, and scientists hope that it will lead to the development of new drugs and therapies for treating all types of multiple sclerosis.
What Is The JC Virus?
The JC virus (JCV) is a very common virus that infects people worldwide. In most people, the immune system keeps the virus from causing harm. However, it can cause a rare and usually fatal type of brain disease in people with poor immune systems. It can also lead to a rare type of cancer called non-Hodgkin’s lymphoma.
The virus spreads through contact with the saliva of an infected person. This can occur through kissing, or sharing eating utensils, toothbrushes, or cigarettes. The virus can also be passed from a mother to baby during pregnancy or around the time of birth.
The virus isn’t spread through the air, and people can’t get it by touching you. You can’t get it from animals either.
The virus is common in children, and most of them have it at some time. Normally, the infection causes no symptoms at all. When symptoms do occur they tend to be mild and flu-like and usually last less than a week.
The most common ones are
® Sore throat and swollen glands
® Fatigue (tiredness)
Infection happens once the virus reaches the nervous system, which usually occurs in people with severely weakened immune systems. For example, people with inherited disorders that reduce immunity are at risk, as are those who have AIDS or have received an organ transplant. Infection can also happen to people taking certain medications after an organ transplant.
Once inside the nervous system, the virus typically travels along the nerve fibers until it reaches the brain and spinal cord. There it causes inflammation that affects the normal functioning of these vital organs.
The inflammation caused by the virus is the main cause of most symptoms. The virus itself, however, doesn’t usually cause permanent damage to the nervous system. Most people recover completely once the infection has run its course.
Even though most people have no symptoms, the virus is still present in their saliva at low levels for years after infection.
In a few cases, the virus can enter the brain and spinal cord and cause inflammation that affects the nervous system’s ability to function normally. The most serious of these conditions is progressive multifocal leukoencephalopathy (PML). PML is a rare but often rapidly progressing disease of the central nervous system that can lead to physical disability and death.
PML most commonly occurs in people with severely weakened immune systems. People with AIDS and those who have undergone an organ transplant are at greatest risk for developing PML. In AIDS patients, the risk of getting PML is around 50 percent after 10 years of infection with HIV.
Although it’s less common, the virus can also cause PML in people with healthy immune systems.
“The JCV is probably involved in multiple sclerosis, a debilitating disease of the central nervous system. It is also strongly suspected to play a role in Alzheimer’s disease, another neurological disorder.”
The good news is that, with proper treatment, most people survive infection and go on to make a full recovery. The bad news is that there is no vaccine currently available to prevent the disease. The virus is also never eliminated from your body after infection.
It remains in the nerve cells of your body for the rest of your life. If your immune system ever weakens, the virus can again become active and start destroying your nervous system. Even people who have no symptoms can have the virus making copies of itself in their nerve cells.
Vaccines are being developed to protect against this virus. These vaccines would be given to anyone receiving an organ transplant or a bone marrow transplant to prevent them from getting the infection. There are also efforts underway to create a HIV vaccine that would protect people against both viruses.
The good news is that, with proper medical treatment, most people can recover from infection. The bad news is that there is no vaccine to prevent the disease. Since there is always some virus in your system, the virus can become active again and start destroying your nervous system whenever your immune system weakens.
Infection with the JC virus is very common. Most people have no symptoms, while others experience only mild symptoms that go away on their own. Still others have more severe symptoms that are treated with medication that suppresses the immune system.
A small number of people have the virus become active again when their immune system becomes suppressed for some other reason, such as an organ transplant or AIDS.
For those with a weakened immune system, this virus can be very dangerous and even deadly.
Most people with an active case of the virus have no symptoms and never know they were infected. For those who do have symptoms, they tend to be fairly mild. The most common of these are fever and extreme tiredness, occurring in more than half of all cases.
Headaches, skin rashes, and muscle pains also occur occasionally. Less common symptoms can include vomiting, diarrhea, dizziness, and trouble seeing.
The JCV can remain inactive in your body for many years. Most people never experience any problems at all and don’t even know they ever had the virus.
The JC virus most often becomes a problem when the immune system is weakened in some way, such as from another infection, cancer treatments, or an organ transplant. At this point, the virus can become active again and start to reproduce out of control. Symptoms of PML typically occur within one to six months after the immune system is suppressed.
Within your body, the JCV silently multiplies, spreading from your brain to the spinal cord. The virus is very specific, infecting only certain nerve cells in the brain and spinal cord. These infected cells build up scar tissue that causes them to swell.
Eventually these infected cells interfere with the normal functioning of your nervous system.
Once in the brain or spinal cord, the virus begins to reproduce, eventually killing the cells it is infecting. This causes the brain or spinal cord to begin to swell inside your skull or spinal column. The swelling from just a few infected cells can grow to be large enough that you can feel it pushing against your skull or back.
These tumors can grow to be quite large before you experience any symptoms. As the tumor grows, the space inside your skull or spinal column becomes smaller and smaller. This press on or damage nerves, causing numbness, weakness, or pain in parts of your body.
The virus can also spread from your brain or spinal cord to other parts of your body, including bone marrow, blood vessels within your brain, and the skin and muscles around your spinal column.
This secondary spread of the virus is what causes most of the symptoms of PML.
The most common initial symptom is a general headache, which may be severe and may occur with neck stiffness. This is often followed by gradual paralysis in one half of your body as the tumor grows. The virus tends to attack the part of your spinal cord that controls the muscles on the opposite side of your body, so symptoms often begin with weakness in your face, arms, and one leg.
As the tumor continues to grow, you experience numbness or paralysis in the other half of your body. Many people are unable to walk or feel anything below their chest. The numbness or paralysis will continue to spread until you are unable to control any muscles at all.
Other symptoms can include problems with your vision, swallowing, and other functions controlled by your brain. As the tumor grows, it may put pressure on and damage parts of your brain. This can cause you to have difficulty speaking, swallowing, or seeing.
PML is a relentless disease, attacking and destroying your body’s nervous system until it takes your life.
There is no treatment for PML because there is no known way to get rid of the virus once it has infected someone. Even if the virus could be eliminated, the damage it has done to your nervous system can’t be repaired.
The only treatment that may help is a high dose of corticosteroids, which may reduce the swelling in your brain and spinal cord.
Even with medication, most people still die from the swelling, or they become so paralyzed that they are dependent on others for everything. The average time between when symptoms begin and death is three to six months.
Even though there is no cure, supportive treatment can extend your life a few months. Treatment usually begins in the hospital, but may continue at home once you are no longer able to move or breathe on your own. During this time, you and your family will need to make decisions about whether or not extraordinary measures should be used to keep you alive, such as breathing machines.
Once your breathing and heart are no longer supported, death will be imminent.
There is currently no vaccine to prevent PML. It’s important to know that there is a small but significant risk of developing PML each time you take the vaccine. This risk is highest in people over 60 years old, particularly those who have a history of diseases such as multiple sclerosis or cancer.
If you are in this category, you should discuss the benefits and risks of vaccination with your doctor before getting the vaccine.
If you do get the vaccine but don’t develop measles, MMR or MMRV, you will still develop immunity to those specific viruses and won’t be susceptible to them in the future. This means that you won’t be able to pass them on to others who may be more likely to develop severe symptoms.
It’s also important for people who may come into contact with someone who has measles, such as health care workers or relatives of an infected person, to get vaccinated. They should also avoid being in contact with the individual, so that they don’t contract measles and possibly develop PML.
If you think you may have been exposed to the measles virus, it is very important that you contact your doctor immediately.
A Word From Verywell
PML is a rare but very serious complication of measles. If you have already had measles in the past and have no other risk factors, your chance of getting PML is extremely low. Even if you are at higher risk, this doesn’t mean that you will definitely get it.
Talk to your doctor about the benefits and risks of getting the vaccine.
Sources & references used in this article:
Reactivation of JC virus and development of PML in patients with multiple sclerosis by K Khalili, MK White, F Lublin, P Ferrante, JR Berger – Neurology, 2007 – AAN Enterprises
Anti‐JC virus antibodies: implications for PML risk stratification by L Gorelik, M Lerner, S Bixler, M Crossman… – Annals of …, 2010 – Wiley Online Library
Anti‐John Cunnigham virus antibody prevalence in multiple sclerosis patients: Baseline results of STRATIFY‐1 by C Bozic, S Richman, T Plavina, A Natarajan… – Annals of …, 2011 – Wiley Online Library