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Changing Clinical and Laboratory Characteristics of Progressive Multifocal Leukoencephalopathy: A Retrospective
Ilaria Mainardi1,2, Simonetta Gerevini3, Andrea Tarantino4
1Unit of Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Background:
Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease caused by JC polyomavirus (JCV), affecting immunocompromised individuals. We describe PML demographic, clinical, radiological, and laboratory characteristics and survival over time and according to underlying condition in a large retrospective patient cohort.
Methods:
This is a retrospective cohort including Italian PML patients observed between 1987 and 2024, with known year of diagnosis and underlying disease.
Results:
We included 456 cases with either a definite (n = 376, 82.4%) or clinico-radiological (n = 80, 17.6%) PML diagnosis. The relative frequency of human immunodeficiency virus (HIV)-associated cases decreased through four time periods (1987-1996; 1997-2004; 2005-2012; 2013-2024) from 99% to 43%, in parallel with increasing age (P < .0001), proportion of women (P < .001) and CD4+ counts (P < .001) but not cerebrospinal fluid (CSF) or plasma JCV-DNA levels at diagnosis. One-year survival probability increased from 23.8% in 1987-1996 to 59.2% in 2013-2024, with highest values in natalizumab-treated multiple sclerosis (93.8%), followed by combination antiretroviral treatment (cART)-treated HIV infection (55%), hematological malignancies (50.8%), primary immunodeficiencies (41.3%), and cART-untreated HIV infection (11.9%). At multivariate analysis excluding cART-untreated people with HIV, JCV-DNA levels in both CSF and plasma were independently associated with an increased mortality risk of 2.9% and 7.2%, respectively, for each Log increase in JCV-DNA.
Conclusions:
This observational study showed a changing epidemiological context over 37 years. Although survival improved over time, it remained poor even in the last decade, with a one-year survival probability of 59.2%.
Insights
Progressive Multifocal Leukoencephalopathy (PML) survival has improved over 37 years, but remains poor. This study details PML characteristics and survival trends in immunocompromised patients.
Area of Science:
- Neuroscience
- Virology
- Immunology
Background:
- Progressive Multifocal Leukoencephalopathy (PML) is a severe demyelinating disease caused by JC polyomavirus (JCV).
- PML primarily affects immunocompromised individuals.
- Understanding PML's epidemiology and survival is crucial for patient management.
Purpose of the Study:
- To describe the demographic, clinical, radiological, and laboratory characteristics of PML patients.
- To analyze PML survival trends over time and by underlying condition.
- To identify factors influencing PML mortality.
Main Methods:
- Retrospective cohort study of Italian PML patients diagnosed between 1987 and 2024.
- Inclusion of 456 patients with definite or clinico-radiological PML diagnosis.
- Analysis of demographic data, underlying conditions, and JC polyomavirus (JCV) DNA levels.
Main Results:
- The proportion of HIV-associated PML cases decreased significantly from 99% to 43% between 1987-2024.
- One-year survival probability increased from 23.8% to 59.2% over the study period.
- JC polyomavirus (JCV) DNA levels in CSF and plasma were independently associated with increased mortality risk.
Conclusions:
- The epidemiological landscape of PML has evolved over 37 years.
- While survival has improved, it remains suboptimal, with a one-year survival rate of 59.2% in the most recent decade.
- Further research is needed to improve PML outcomes in immunocompromised populations.
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