Epub 1: Huppke et al. JC virus antibody status in a paediatric multiple sclerosis cohort: Prevalence, conversion rate and influence on disease severity. Mult Scler. 2014 Jul.
BACKGROUND: Because of the emergence of novel therapies for MS and the associated increased risk of progressive multifocal leukoencephalopathy (PML), John Cunningham (JC) virus infection has become a focus of interest for neurologists. However, little is known about JC virus infection in paediatric MS to date.
OBJECTIVE: We aimed to analyze the prevalence of anti-JC virus antibodies, the conversion rate and the influence of the anti-JC virus antibody status on the clinical course in a large pediatric MS cohort.
METHODS: Anti-JC virus antibodies were analyzed in serum samples within six months of disease onset and during the course of the disease. Clinical data were extracted from a pediatric MS databank.
RESULTS: A total of 51.6% of 256 MSers were found to be positive for anti-JC virus antibodies at onset of disease. No correlation between antibody status and clinical course was seen. Analyzing 693 follow-up serum samples revealed high titer stability, and an annual conversion rate of 4.37% was seen.
CONCLUSION: No evidence was found that seropositivity for anti-JC virus antibodies influences the clinical course. Surprisingly, seroprevalence for anti-JC virus antibodies was more than twice as high as anticipated in this age group, raising the question of whether the infection increases the risk of MS development.
Epub 2: Delbue et al. JC virus urinary excretion and seroprevalence in natalizumab-treated multiple sclerosis patients. J Neurovirol. 2014 Jul 23.
Background: The risk of developing PML, as a consequence of infection/reactivation with JC virus (JCV), is consistent in natalizumab-treated MSers, with 430 cases of PML reported so far. The risk of PML is higher in JCV seropositive MSers, and it is recommended that only MSers without JCV antibodies should be enrolled in the treatment postulating that they do not have JCV infection.
Methods: We have studied 42 natalizumab-treated MSers, and urine and blood were collected monthly for up to 60 months. JCV and BK virus (BKV) DNA presence was verified using quantitative real-time PCR assays, and serum anti-JCV antibodies were measured with the Stratify and/or Stratify DxSelect tests.
Results: JCV and BKV DNA were not found in the blood samples, whereas they were found at least once in the urine of 21 of 42 (50 %) and of 25/42 (59.5 %) MSers, respectively. JCV DNA urinary shedding increased up to month 24 of natalizumab treatment (45.2 %), and the effect of time was significant for JCV (pā=ā0.04), but not for BKV (pā=ā0.39). JCV viruria and seropositivity did not completely correlate, since three MSers shedding JCV DNA in the urine were seronegative according to the serological tests.
Conclusion: The results indicated that natalizumab therapy may increase the rate of JCV urinary shedding. Additionally, we confirmed that the identification of JCV carriers cannot solely rely on serological tests, but sensitive methods for viral DNA detection should be adopted to more precisely identify the truly JCV uninfected cases.