HIV leucoencephalopathy and TNFα expression in neurones
- 1Tufts Neurology Program, New England Medical Center, 75 Kneeland Street, Boston, MA 02111, USA
- 2Department of Psychiatry, New England Medical Center
- 3Paediatric Neurology, University of Göttingen, Robert-Koch-Str. 40, Göttingen 37073, Germany
- 4Department of Neuroradiology, Massachusettes General Hospital, Boston, MA 02111, USA
- 5Center for Neuroscience and Aging, The Burnham Institute, La Jolla, CA 92037, USA
- Correspondence to: Dr B Navia Laboratories of Research in Psychiatry, Tufts-New England Medical Center, 75 Kneeland Street, Boston, MA 02111, USA; BNaviatufts-nemc.org
- Received 18 January 2004
- Accepted 15 September 2004
- Revised 7 September 2004
Abstract
Background: Human immunodeficiency virus (HIV) leucoencephalopathy (HIVL) is an uncommon and rapidly progressive form of AIDS dementia complex (ADC) that has remained poorly understood. Tumour necrosis factor α (TNFα), which has been implicated in the pathogenesis of ADC, is predominantly localised in macrophages in the HIV infected brain, although in vitro studies indicate that neurones can express this cytokine.
Objective: To examine the clinical/neuroradiological features of HIVL and the expression of TNFα in HIVL.
Methods: Six patients who presented with rapidly progressive dementia within four to 12 weeks of the primary manifestation of their HIV infection were evaluated. Clinical history, treatment regimens, and imaging studies were reviewed, and brain samples from three of the patients were studied by means of immunohistochemistry.
Results: Imaging studies showed diffuse bilateral deep white matter changes in all six patients. Clinical and imaging abnormalities improved in five of the six patients within weeks after initiation of antiretroviral treatment. Brain biopsies of two showed pronounced microglia/macrophage activation, but only scant viral protein (gp41) expression. Staining for TNFα was found in microglia/macrophages, and surprisingly, in neurones also. Postmortem analysis of a third patient also showed TNFα expression in neurones of the frontal cortex and basal ganglia.
Conclusion: This study provides the first demonstration of staining for TNFα in the neurones of the HIV infected brain, and suggests that the process underlying this rapidly progressive form of ADC may reflect indirect mechanisms mediated by host factors, particularly TNFα.
- ADC, AIDS dementia complex
- AZT, 3′-azido-3′-deoxythymidine
- BBB, blood–brain barrier
- CSF, cerebrospinal fluid
- DWM, deep white matter
- HIV, human immunodeficiency virus
- HIVL, human immunodeficiency virus leucoencephalopathy
- MRI, magnetic resonance imaging
- PML, progressive multifocal leucoencephalopathy
- TNFα, tumour necrosis factor α
Footnotes
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Competing interests: none declared
