From Arthritis to Zoster

Progressive multifocal leukoencephalopathy (PML)…it’s a mouthful of technical jargon that describes a frightening problem.

We humans are an interesting stew composed of organs, connective tissues, fluids, cells, and microbes. Some of the bugs we carry around aren’t particularly friendly, but our immune systems keep them in check…until something goes awry.

Whenever our immune system weakens, latent viruses (viruses acquired earlier in an individual’s life that have been suppressed by a healthy immune system) have a chance to reactivate and make us sick. Shingles is one example of a reactivated latent virus; so is a cold sore (caused by Herpes simplex). These viruses hide out in our nervous system until a transient weakness appears in our immune defenses; they then erupt for a time–causing unpleasant symptoms–until our immune system recognizes them as unfriendly foreigners and chases them into hiding once again.

PML occurs when a latent virus reactivates due to loss of normal immune protection. The organism that causes PML is called polyomavirus JC (JC virus). In many cases, drugs designed to deliberately suppress immune function are responsible for allowing the virus to awaken.

When the JC virus reactivates, it damages the myelin, or white matter, in our brains. Myelin is the insulation that surrounds the neurons that make up the “wiring” of our nervous system. Without healthy myelin, messages that are carried along the neurons get scrambled or interrupted.

The symptoms of PML are variable. Depending on where the damage occurs–and how extensive that damage is–victims may exhibit weakness, clumsiness, problems with vision or speech, or personality changes. These deficits progress rapidly, usually over several weeks to months, leading to severe disability and death.

Individuals with HIV-AIDS are often affected by PML; around 5% developed the condition prior to effective anti-retroviral therapy. With the return of improved immune function that is afforded by modern anti-retroviral drugs, many AIDS patients are now surviving PML (mortality previously approached 90%).

For victims of PML whose immune suppression is not caused by HIV-AIDS, the prognosis is still quite poor–approximately 80% die within six months of disease onset. Their only hope lies in reversing the immune-deficient state, and even survivors are usually left with significant neurological disabilities (myelin heals poorly within the central nervous system).

PML has recently become newsworthy because new medications designed to deal with autoimmune diseases–diseases like rheumatoid arthritis, multiple sclerosis, and psoriasis–have been associated with PML. While the manufacturers of these medications are quick to point out the unlikelihood of acquiring PML as the result of taking their drugs, it should also be pointed out that PML is a serious and often fatal disease; for those who develop this condition, statistics mean very little.

Since it is seemingly the unalterable way of our health care system to fire a “silver bullet” at whatever symptom or sign that walks through its portals (rather than seeing patients as complex organisms that only thrive when all of their parts are in balance), each person’s primary response to the knee-jerk tendencies of medical professionals to prescribe the latest wonder drug should be heartfelt, digging-in-your-heels, knock-down-drag-out, kicking-and-screaming resistance.

Sure, your doc doesn’t have all the time in the world to answer those pointed and probing questions about Raptiva, Rituxan, Tysabri, et al…

…but whose brain and life are we talking about here?  

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