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Age distribution of progressive multifocal leukoencephalopathy
G L Stoner1, D L Walker, H D Webster
1NIH/NINCDS Laboratory of Experimental Neuropathology, Bethesda, Maryland.
Abstract:
The age distribution is given of 79 cases of progressive multifocal leukoencephalopathy confirmed as JC virus infection. The data are compared with a published age distribution of multiple sclerosis onset in Vestfold County, Norway, and with published data from Rochester, Minnesota of the age distribution of viral encephalitis. In contrast to viral encephalitis, 61% of which occurs in children under the age of 10, PML has been identified only once in this age group. PML, like MS, is a disease of adult onset, peaking in the sixth decade of life. The reason for this late onset of a CNS disease caused by a ubiquitous childhood infection is still uncertain, but it may be related to maturation of susceptible cells in the brain, as well as to declining immunity associated with chronic disease and age.
Insights
Progressive multifocal leukoencephalopathy (PML) primarily affects adults, peaking in the sixth decade. Unlike viral encephalitis, PML rarely occurs in children, suggesting delayed onset mechanisms possibly linked to brain cell maturation and immune decline.
Area of Science:
- Neuroscience
- Virology
- Epidemiology
Background:
- Progressive multifocal leukoencephalopathy (PML) is a rare, demyelinating disease of the central nervous system.
- PML is caused by the JC virus, a ubiquitous virus that typically infects individuals in childhood.
- The age distribution of PML cases is not well-characterized, particularly in comparison to other neurological diseases.
Purpose of the Study:
- To determine the age distribution of progressive multifocal leukoencephalopathy (PML) cases.
- To compare the age distribution of PML with multiple sclerosis (MS) and viral encephalitis.
- To explore potential reasons for the late onset of PML despite childhood JC virus infection.
Main Methods:
- Analysis of age distribution data from 79 confirmed PML cases.
- Comparison with published age distribution data for MS onset in Norway.
- Comparison with published age distribution data for viral encephalitis in Rochester, Minnesota.
Main Results:
- PML predominantly affects adults, with a peak incidence in the sixth decade of life.
- In contrast to viral encephalitis (61% in children <10 years), PML was identified only once in this age group.
- PML exhibits an adult onset pattern similar to multiple sclerosis.
Conclusions:
- PML is a disease of adult onset, distinct from viral encephalitis which commonly affects children.
- The late onset of PML, despite ubiquitous childhood JC virus infection, remains uncertain.
- Potential factors for late onset include brain cell maturation and age-related or chronic disease-associated immune decline.