Study of Prevalence and Risk Factors for JCV Antibody Seroconversion in Multiple Sclerosis Patients from the UMass Memorial MS Center

Background: Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS) that is a leading cause of disability in young adults.  Treatment directed at the rapid, aggressive progressive phase of MS is typically difficult.  Natalizumab is an effective drug for the treatment of relapsing-remitting multiple sclerosis (RRMS).  However, in rare cases, its use is associated with the development of progressive multifocal leukoencephalopathy (PML), a potentially fatal complication caused by the John Cunningham virus (JCV).  It is estimated that the majority of adults are positive for JCV antibodies.  Risk factors for infection with this virus are unknown.  Environmental factors may play a role.

Objectives: To identify environmental factors associated with JCV antibody status.

Methods: We identified patients who have been tested for antibodies to JCV and performed chart review to determine if there is a difference in terms of gender, age, area of residence, or marital status between patients who tested positive and those who tested negative for JCV antibodies.  The R statistical programming language was used to analyze the data.  We  developed a questionnaire asking about environmental exposures.  This questionnaire will be administered to patients with available JCV serology results to determine if there is a difference in exposures between groups.  Family members will be tested for JCV antibodies to determine if there is an association between family member JCV antibody status and patient JCV antibody status.

Results: 144 patients with JCV serology results were identified.  76.4% were female and 23.6% were male, with a mean age of 46.7.  49.3% were positive for JCV antibodies and 50.7% were negative.  55.8% and 54.2% of the women were negative and positive, respectively.  32.4% and 67.6% of the men were negative and positive, respectively (p=0.01).  The mean age in the negative and positive groups were 45.7 and 47.6, respectively (p>0.05).  Patients came from various locations in MA, RI, CT, NH, TN, and British Columbia.  There were differences in JCV seropositivity among the different areas of residence (p<0.01).  54.1% of patients were married and 45.9% were single, divorced, widowed, or other (p>0.05).  We expect to report results from our exposures questionnaire at the conference.

Conclusions: The 49.3% prevalence of JCV antibodies in this patient population is consistent with that of other studies.  In our study, gender and area of residence were associated with JCV antibody status, whereas age and marital status were not.  It is theorized that JCV infection occurs through an environmental exposure, so it stands to reason that area of residence may influence JCV antibody status.  A greater number of men were positive for JCV.  It is possible that occupational exposures are a factor in this result.  We hope to elucidate this further with our questionnaire.