Microbiology
A virus.
Epidemiologic Risks
Part of life, most are seropositive by age 14. Found in high concentrations in urban sewage, so maybe contaminated water is the route of spread. It is mostly found in the GI tract but it can also infect brains and kidneys.
The majority of PML patients have a predisposing disease (HIV, hematologic malignancy) or immunosuppressive or monoclonal antibody therapy (PubMed).
It can be transmitted in the donated kidney (Pubmed).
Syndromes
Progressive Multifocal Leukoencephalopathy in AIDS and transplant patients. The 5-year survival rate is less than 10%.
A variety of biologics like natalizumab and other mabs (not Queen Mab (PubMed)) however are associated with PML as well.
Granule cell neuronopathy leading to cerebellar ataxia (PubMed), at least in patients with immunosuppression and chronic lymphopenia.
Diagnose with PCR on CSF but those on natalizumab may have small lesions and a false negative PCR (PubMed).
Also, blood PCR is occasionally positive when the CSF is negative and not all CSF is readily available for testing (PubMed).
Treatment
None.
Notes
Named after a patient with PML, John Cunningham.
Curious Cases
Relevant links to my Medscape blog
Last update: 09/23/19