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Updated: Dec 6, 2025
Flow Cytometric Analysis of Lymphocyte Infiltration in Central Nervous System during Experimental Autoimmune Encephalomyelitis
Published on: November 17, 2020
"Borderline" idiopathic CD4+ T-cell lymphocytopenia presenting with atypical progressive multifocal
Clemente Dato1, Andrea Elefante2, Cinzia Coppola1
1Department of Advanced Medical and Surgical Sciences, Second Division of Neurology - University of Campania "Luigi Vanvitelli", via Pansini 5, 80131 Naples, Italy.
Insights
Idiopathic CD4+ lymphocytopenia (ICL) can present with progressive multifocal leukoencephalopathy (PML) even without severe immune suppression. This case suggests current ICL definitions may need reevaluation for PML risk assessment.
Area of Science:
- Neuroimmunology
- Immunodeficiency Disorders
Background:
- Idiopathic CD4+ lymphocytopenia (ICL) is defined by low CD4+ T-cell counts without other causes of immunosuppression.
- Progressive multifocal leukoencephalopathy (PML) is a rare, opportunistic infection of the central nervous system.
Observation:
- A 40-year-old male presented with PML exhibiting a monophasic clinical course.
- Routine immunodeficiency workups were negative, revealing only borderline ICL.
Findings:
- PML can occur in patients with ICL even without profound CD4+ lymphocytopenia.
- The case demonstrates a non-severe form of ICL associated with PML.
Implications:
- Severe immunosuppression may not be an absolute requirement for PML development in ICL patients.
- The findings prompt a reconsideration of the diagnostic criteria and clinical implications of ICL.
Abstract:
Idiopathic CD4+ lymphocytopenia (ICL) is a rare disorder characterized by low counts of CD4+ cells (<300/mm3) in absence of other known causes of immunosuppression. A few cases of progressive multifocal leukoencephalopathy (PML) were reported in association with ICL with variable outcome. We describe the case of a 40 year-old man diagnosed with PML, which showed a monophasic course. Causes of primary and secondary immunodeficiency were ruled out, only a "borderline" ICL was found. This case highlights that a severe immunodepression could not be an absolute prerequisite in developing PML and also points the attention on current definition of ICL.
