Progressive multifocal leukoencephalopathy after CAR T therapy.

Area of Science:

• Neuroimmunology
• Oncology
• Infectious Diseases

Background:

• Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system caused by the JC virus.
• PML typically affects immunocompromised individuals, with poor prognoses in patients with hematological malignancies.
• While outcomes improve with immune reconstitution in HIV+ or multiple sclerosis patients, effective treatments for PML in other immunocompromised states remain limited.

Observation:

• A patient with relapsed diffuse large B-cell lymphoma developed PML seven months after lymphodepleting chemotherapy (fludarabine/cyclophosphamide) and anti-CD19 CAR T-cell therapy.
• This represents the first reported case of PML occurring after CAR T-cell therapy.
• The patient had a history of rapid relapse following a prior autologous hematopoietic stem cell transplant.

Findings:

• The patient presented with encephalopathy, a known complication of CAR T-cell therapy, but PML was the underlying cause.
• A combination of antiviral therapies and immunotherapy was administered.
• The patient showed stabilization of symptoms and remained alive 12 months after PML diagnosis.

Implications:

• This case expands the known spectrum of complications associated with CAR T-cell therapy.
• It suggests that PML should be considered in the differential diagnosis of encephalopathy post-CAR T-cell therapy.
• The successful management highlights the potential efficacy of combined antiviral and immunotherapeutic strategies in treating PML in this context.