Ask the Doctor: PML Risk and JC Virus

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Dr. Jack Burks

By Dr. Jack Burks
Chief Medical Officer for MSAA

Learning about PML Risk when Testing Positive for JC Virus

Q: I was diagnosed with relapsing-remitting multiple sclerosis in 1987. I am a 67-yearold female who is mobile, independent, and able to take care of myself without assistance.

Initially, I was placed on methotrexate for about four years. I was then placed on Avonex and tolerated the weekly intramuscular injections for about 13 years. The only side effect I experienced was the flu-like symptoms.

I have moderate kidney disease and was instructed not to take any over-the-counter pain relievers. I finally persuaded my neurologist to let me try Tecfidera. I began this new oral drug in August 2014. So far I have had no major side effects and all of my visits to the neurologist reveal normal follow-up exams.

In May 2015, my neurologist ordered a lab test to check for the JC virus. The result was positive for PML. I did not have lab work drawn to check for this virus prior to starting Tecfidera. At the present time, my CBC levels are within normal range and these will be checked monthly to see if the levels have decreased.

My questions and concerns are:

  1. Is it possible that the JC virus was already in my body?
  2. How will the virus affect my relapsing form of MS?
  3. At what point in time will the virus affect my brain and my ability to live independently?

A: I am pleased that you are doing so well with your MS, are continuing to do well on Tecfidera® (dimethyl fumarate), and that your blood counts (CBC) are in the normal range. Your questions are all in reference to the JC virus and progressive multifocal leukoencephalopathy (PML), which if not discovered early, is a potentially fatal brain infection. PML is caused by an activation of the JC virus in people with weakened immune systems.

I will address each of your questions, but I first want to clear up a possible misperception. I doubt that your test result was “positive for PML.” I suspect your test result was “positive for antibodies to the JC virus,” which means you have been previously exposed to the JC virus. More than 50 percent of middle-aged adults are JC-virus antibody positive.

Therefore, the answer to your first question is yes, the JC virus was most likely already in your body.

For the second question, the JC virus will not likely affect your MS. For your third question, the JC virus is unlikely to ever affect your brain, because it will likely continue to lie dormant in your body, in places such as the bone marrow, where it is unlikely to cause harm. To cause PML damage, the JC virus must be activated and must get into the brain.

Certain diseases and drugs are associated with the activation of the JC virus – such as HIV/AIDS and the types of drugs used to treat cancer, which greatly suppress the immune system. These types of medications include Tysabri® (natalizumab), a disease-modifying therapy for MS approved by the United States Food and Drug Administration (FDA), as well as methotrexate, one of several medications approved for other conditions by the FDA, but still considered experimental in the treatment of MS.

In MS, we measure the JC virus antibody to help determine the risk of PML in people considering Tysabri. Your previous exposure to methotrexate would increase your risk of Tysabri-associated PML. As for Tecfidera, the risk of JC virus antibody-positive individuals getting PML while taking Tecfidera is very low, but not zero. Only two MS patients have been reported to develop PML while taking this medication. This risk may be increased if your white-blood cell count is low for a prolonged period of time. As you stated, your CBC is normal so far.

As more people with MS are treated over longer periods of time, we will know more about the risks of PML. For now, we do not have enough information to know the true risk, but generally speaking, your risk to develop PML is relatively low. However, continuing with blood tests and watching for symptoms is vital to an early diagnosis in the rare instances that PML does occur. Your neurologist or a specialist from an MS center can provide specific advice for your situation.

Q: I need bowel resolutions! I experience the loss of sensation of having a movement. My gastroenterologist doesn’t seem to understand how this can affect me every day, physically and mentally. It’s not constipation; it’s just not knowing if or when I need to go and then knowing when I’m done. This is so confusing and overwhelming! Do you have any suggestions to help with my situation?

A: Over the years of caring for people with MS, I have become distressed by the numerous misunderstood issues related to problems with bowel, bladder, and sexual problems. Lack of sensation related to bowel movements is one of the most challenging issues to manage. While you have sought help from your gastroenterologist (GI specialist), this has not provided any help to you. On a positive note, you do not presently have to cope with constipation, which is a good thing. My thoughts are:

  1. Get a second opinion from another GI specialist.
  2. Seek out a rehabilitation nurse who specializes in bowel issues for MS and/or trauma-induced paraplegics with bowel issues.
  3. Train your bowels by establishing a bowel routine. For example, eat a healthy breakfast with hot tea or coffee each morning. About 30 minutes later, sit on a commode and concentrate on moving your bowels. The breakfast will hopefully stimulate your gastrocolic reflex, which may produce a more regular bowel movement (BM).
  4. Ask the GI specialist about taking probiotics, stool softeners, or other medications, such as glycerin suppositories. These can help to stimulate bowel movements at regular intervals. I would use laxatives very sparingly.

Again, I am not a GI expert, but I have found that bowel rehabilitation nurses have many techniques that may help people with MS, often employing strategies found to be successful with patients who have suffered spinal-cord injuries. The common denominator is the loss of sensation and reduced control of bowel function. While bowel problems are a challenging symptom in MS, looking to experts such as bowel rehabilitation nurses and specialists at MS centers, can yield positive results and help to improve your quality of life.

Jack Burks, MD is the chief medical officer for MSAA. He is an international MS neurologist, writer, lecturer, and researcher, who assists with the development of new MS therapies and advises patients, families, MS organizations, and healthcare groups. Dr. Burks is a clinical professor of neurology at the Florida International University in Miami and has authored textbooks, chapters, and articles on MS.


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