The information on this website is not intended for diagnosis or treatment. Please consult your physician for health concerns.

+90 850 321 50 00

Progressive Multifocal Leukoencephalopathy (PML)

JC Virus-Mediated Demyelinating Brain Infection in Immunocompromised Patients

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Nöroloji department. Book Appointment →

What is Progressive Multifocal Leukoencephalopathy (PML)?

Progressive multifocal leukoencephalopathy (PML) is a rare, often fatal demyelinating disease of the central nervous system caused by reactivation of the JC polyomavirus in patients with cellular immunodeficiency.

The pathogen, John Cunningham virus, latently infects 50–80% of healthy adults; reactivation in oligodendrocytes causes lytic infection with progressive demyelination.

Diagnosis requires combination of clinical features, characteristic MRI findings (asymmetric subcortical white matter lesions without mass effect or contrast enhancement in classical PML), and CSF JC virus PCR or brain biopsy showing oligodendroglial inclusions.

Two patterns: classical PML (immune deficiency) and PML-IRIS (immune reconstitution inflammatory syndrome) characterized by gadolinium enhancement and inflammatory infiltrate.

Symptoms

Subacute (weeks to months) progressive focal neurologic deficits without features of encephalitis (no fever, no headache typically)
Cognitive decline, behavioral changes, and apraxia
Motor weakness, hemiparesis, ataxia, and gait disturbance
Visual symptoms: hemianopia, diplopia, cortical blindness
Aphasia and dysarthria from involvement of language areas
Seizures (less common, occurring in 10–20% in late disease)
Death within 6–12 months in untreated classical PML; better prognosis with immune restoration

Risk Factors

HIV/AIDS with CD4 count <200 cells/μL (most common cause historically; now reduced with antiretroviral therapy)
Multiple sclerosis patients on natalizumab (especially with anti-JCV antibody index >1.5, prior immunosuppression, and >2 years of treatment)
Hematologic malignancies treated with rituximab, ocrelizumab, ibrutinib, idelalisib, and other lymphocyte-depleting agents
Solid organ and hematopoietic stem cell transplant recipients on long-term immunosuppression
Inflammatory bowel disease and rheumatologic disease patients on biologics (efalizumab historically associated, now withdrawn)
Idiopathic CD4 lymphocytopenia and primary immunodeficiencies

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Subacute focal neurologic deficits in immunocompromised patient
  • MS patient on natalizumab with new neurologic symptoms
  • Confused or weakened patient with HIV/AIDS or post-transplant
  • Patient on B-cell depleting therapy (rituximab, ocrelizumab) developing new cognitive or motor deficits
  • Known PML with worsening symptoms or new contrast-enhancing lesions (suggest IRIS)

Treatment Methods

01
Immune restoration is the mainstay of therapy: prompt initiation or optimization of antiretroviral therapy in HIV-PML, withdrawal of immunosuppressive agents, plasma exchange or immunoadsorption to remove natalizumab in MS-PML
02
Anti-JCV antibody screening and risk stratification before starting natalizumab; switching to alternative MS therapies (ocrelizumab carries lower but non-zero risk)
03
Immune checkpoint inhibitors: pembrolizumab anti-PD-1 has shown promise in case series for PML, restoring T-cell function and reducing JCV viral load
04
Adoptive T-cell therapy: third-party JCV-specific cytotoxic T-lymphocytes administered as investigational therapy in selected centers
05
Maraviroc and mefloquine have been investigated but lack clear efficacy
06
Corticosteroids for management of PML-IRIS to control inflammatory tissue damage in immune reconstitution
07
Supportive care: physical, occupational, and speech therapy; antiepileptic drugs for seizures; management of dysphagia and aspiration risk
08
Multidisciplinary follow-up with neurology, infectious disease, and rehabilitation; serial MRI and CSF JC virus monitoring; family counseling about prognosis

Which Department to Visit?

You can visit our Nöroloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Nöroloji Department

Let us help you

You can make an appointment with our specialists or contact us for your concerns.

Book AppointmentContact Us

Related Health Topics

Other articles from the same department you may want to explore.

Headache and Migraine

Nöroloji

What you need to know about headache types, migraine attacks, and triggering factors.

Low Back Pain

Nöroloji

Learn about the most common causes of low back pain, risk factors, and appropriate treatment approaches.

Neck Pain and Cervical Disc Herniation

Nöroloji

Learn about the symptoms and treatment options for cervical disc herniation and problems in the neck region.

Epilepsy

Nöroloji

Accurate information about epilepsy, types of seizures, and recommendations for patients and families.

Parkinson Disease

Nöroloji

Parkinson disease is caused by progressive degeneration of dopaminergic neurons and alpha-synuclein accumulation; well-timed therapy substantially improves function and quality of life.

Alzheimer's Disease and Dementia

Nöroloji

Information about early signs, diagnosis, and the care process for Alzheimer's and other types of dementia.

Multiple Sclerosis (MS)

Nöroloji

What is multiple sclerosis, who is at risk, and which treatments are applied?

Stroke

Nöroloji

What is stroke, what are the FAST signs, and why is emergency intervention critical?

Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.