Ask the Doctor: Viruses and Antibodies

Photo of Dr. Barry Hendin
Dr. Barry A. Hendin

By Dr. Barry A. Hendin
MSAA’s Chief Medical Officer

Q: There is a lot of talk about antibodies for COVID-19 after a person has already contracted the coronavirus. I’ve heard that the COVID-19 antibodies don’t stay in the body indefinitely. Why then do the JC virus antibodies stay with us indefinitely once we have them? Also, do the coronavirus and JC virus interact?

A: We are still early in our understanding of this novel coronavirus and its consequence, COVID-19. It’s important to remember that we have only been investigating this new coronavirus since December 2019. We are learning more, but our knowledge is still incomplete. Questions remain regarding the level and the duration of immunity from COVID-19. We have a fuller understanding of the JC virus, which causes progressive multifocal leukoencephalopathy (PML), a serious brain infection. Currently, there is no evidence of an interaction between the JC virus and the virus that causes COVID-19.

JC virus levels can change. A small percentage of JC virus-negative people become positive each year. People with positive JC virus assays may have their level of positivity vary over time. And a small number of people who were designated JC virus-positive, have a drop in their JC virus assay levels and are then designated JC virus-negative. In this case, the virus hasn’t actually disappeared, but the reaction to the virus has diminished.

Q: I would like to know more about contrast agents. Last year, I found that the hospital I went to for a brain MRI no longer uses gadolinium as the contrast agent. Instead, the hospital uses Dotarem, which does not require a blood test beforehand.

Since that time, I started with a new neurologist and a different hospital, and this one only uses gadolinium and thus requires a blood test. I have read some interesting articles about using gadolinium and that its agents can be deposited in the brain for an indeterminate time or maybe forever, and its use is somewhat controversial.

Could you tell me if one contrast agent is preferred over the other, and if one is thought to be safer? Also, can contrast agents increase the risk of blood clots, or could they pose any threat if blood clots are present when administered?

A: Gadolinium has been widely and safely used in patients for many years, however, it does carry increased risks in patients with kidney disease or allergies to gadolinium. Approximately 15 years ago, reports began to appear that a tiny amount of gadolinium could be retained in the brain, particularly in patients who had multiple gadolinium infusions.

Although no evidence has been found to suggest that the tiny amount of retained gadolinium could produce disease or injury, the finding led to the wider use of newer, structurally different forms of gadolinium, such as Dotarem® (gadoterate meglumine), which is not associated with significant retention in the brain. Many MS neurologists have also reduced their gadolinium use for routine follow-up exams.

Regarding blood clots, in general, gadolinium is not associated with an increase in blood clots and has not been shown to worsen existing blood clots. However, as in any medical situation, rare exceptions could possibly occur.

Q: Have you heard about treatments by a Texas group that use stem cells from umbilical cords? They cannot do the procedure in the United States because the FDA has not approved it. Their procedure is done in Panama.

According to testimonials, they have had great success with MS patients. Why can’t these types of trials be approved and started in our own country? The cost is approximately $25,000 and includes treatment, care, hotel, and airfare. Considering the price of MS medications in this country, this treatment is very inexpensive.

A: Stem cell treatments are an interesting and often beneficial intervention for highly active MS that is not currently controlled by approved disease-modifying therapies. Stem cell therapies (SCT) are still investigational in nature and are most safely performed in experienced academic centers with rigorous protocols. These may be performed at an investigational protocol without cost – and in some instances – in North America.

Experimental medications and therapies in this country are tested through the different clinical trial phases as approved and overseen by the United States Food and Drug Administration (FDA). Performing trials under strict supervision ensures the safety of the participants. For more information on FDA-approved SCT trials for the treatment of MS (and possible participation), readers may visit the Clinical Trials Search section of MSAA’s website at

In your question, you mention using stem cells from umbilical cords. Stem cells may be derived from different sources, including: embryonic, amniotic, or umbilical cells; genetically altered adult cells; and adult cells from fat or marrow. With SCT, participants are typically given strong immunosuppressant chemotherapy and/or radiation prior to receiving the stem cells (either taken from the participant or from a donor). All of the steps involved in SCT involve risks to the patient, some of which may be severe and even life-threatening. In unregulated centers, the risks can be significant and the benefits uncertain. Ultimately, cost is not the issue… safety is.

MSAA’s website and publications offer information about stem cell therapy (SCT) for the experimental treatment of MS. Details on some of the newer studies on SCT are featured in the recent editions of MSAA’s MS Research Update, and may be found by going to the Publications section of MSAA’s website at, and scroll down to select one of the two most recent editions of the MS Research Update.

Barry A. Hendin, MD, is a highly accomplished neurologist who specializes in MS. He is the chief medical officer for the Multiple Sclerosis Association of America (MSAA) and has spoken at several of MSAA’s educational programs. After 45 years as a neurologist with Phoenix Neurological Associates, Ltd., Dr. Hendin is now director of the newly created Multiple Sclerosis Center of Arizona. He is also director of the Multiple Sclerosis Clinic at Banner University Medical Center and clinical professor of neurology at the University of Arizona Medical School.

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