SHM Converge Scientific Abstract ePoster Gallery-Progressive Multifocal Leukoencephalopathy Arising in Hiv-Negative Idiopathic Cd4 Lymphocytopenia: A Multidisciplinary Case

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This case report describes a 46-year-old previously healthy HIV-negative woman who developed progressive multifocal leukoencephalopathy (PML), a rare and often fatal demyelinating CNS disease caused by JC virus in the setting of immunosuppression. She presented with one month of left-sided weakness, aphasia, dysarthria, and dysphagia. Brain MRI showed multiple right hemispheric T2 hyperintense lesions, raising concern for a demyelinating process.<br /><br />At the outside hospital, she was found to have leukopenia and profound CD4 lymphopenia (CD4 count 15 cells/μL) despite negative HIV testing. Extensive evaluations by neurology, neurosurgery, hematology-oncology, and infectious disease ruled out malignancy, metastatic disease, common viral causes, HTLV-1, and repeat HIV infection. These findings led to a diagnosis of PML associated with unexplained CD4 lymphocytopenia. She was transferred for further workup and possible pembrolizumab treatment.<br /><br />At the receiving institution, additional testing by allergy/immunology and other teams investigated the cause of her immune deficiency. Genetic and immunologic studies were largely negative, and while T-cell flow cytometry suggested possible autoimmune lymphoproliferative syndrome, confirmatory testing was negative. Overall, results supported preserved humoral immunity but impaired T-cell function, leading to a final diagnosis of PML due to idiopathic CD4 lymphocytopenia (ICL).<br /><br />She received a single dose of pembrolizumab and had modest short-term improvement in speech, but her neurologic condition continued to worsen. She ultimately transitioned to hospice and died.<br /><br />The report emphasizes that PML is usually associated with HIV but can occur in other forms of immunosuppression, including ICL, which is a diagnosis of exclusion. It also highlights the need for broad multidisciplinary evaluation and notes that immune checkpoint inhibitors like pembrolizumab may represent a potential treatment option when no reversible cause is found.

Asset Subtitle

Madeleine Davis

Meta Tag

Author List Kaitlyn Greiner, Madeleine Davis

Category Clinical Vignettes

Concept Progressive Multifocal Leukoencephalopathy

Concept JC Virus

Concept Immunosuppression

Concept Idiopathic CD4 Lymphocytopenia

Concept CD4 Count

Distinguished Non-Finalist

Presenter Organization The Ohio State University College of Medicine

Presenting Author Madeleine Davis

Track Adult

Keywords

progressive multifocal leukoencephalopathy

PML

JC virus

idiopathic CD4 lymphocytopenia

CD4 lymphopenia

immunosuppression

demyelinating CNS disease

pembrolizumab

HIV-negative

brain MRI

Progressive Multifocal Leukoencephalopathy

JC Virus

Immunosuppression

Idiopathic CD4 Lymphocytopenia

CD4 Count