How strange it is that something that exists in the vast majority of the people's bodies can cause a deadly and destructive disease. The JC virus affects almost 90% of the population. The virus is harmless to those who are not immunosuppressed. It "lies dormant in the kidneys and causes no problems" according to Harvard Medical School and the Beth Israel Deaconess Medical Center representatives who conducted a study of 19 MS patients taking Tysabri. The study reveals that using Tysabri, a drug for the treatment of multiple sclerosis, affects T-cells and can lead to a fatal brain condition.
The JC virus infiltrated blood cells on 60% (13) of patients after 18 months and spread to the brain, causing PML, progressive multifocal leukoencephalopathy, a rare condition where the myelin covering nerves becomes damaged in the the white matter. The study shows heightened levels of the virus in the patients' blood and urine. Conditions like AIDS also correlate with the likelihood of PML: 4% of AIDS patients are debilitated by PML.
In 2005, the FDA had ordered Tysabri to be taken off the market because of its link to PML. MS patients objected profusely, citing no direct link and no surefire way to measure the susceptibility to PML in patients. They lobbied successfully and the drug was reintroduced onto the market.
This reminds me of our discussion in class about the qualities of a perfect drug or vaccine. Unfortunately, some of the most effective treatments are laden with damaging side effects. I am interested in seeing what causes some viruses to awaken and attack the cells, and what keeps them in check without this drug's interaction.