Related Experiment Video

Updated: Aug 11, 2026

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture
11:14

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture

Published on: October 12, 2018

Human herpesvirus 6-meningoencephalitis in an HIV patient with progressive multifocal leukoencephalopathy

M Ito1, J V Baker, D J Mock

  • 1Department of Pathology, University of Rochester School of Medicine and Dentistry, NY 14642, USA.

Acta Neuropathologica
|August 31, 2000
PubMed

Insights

Human herpesvirus 6 (HHV6) can cause brain inflammation in HIV patients, leading to meningoencephalitis and progressive multifocal leukoencephalopathy (PML). This study found HHV6 directly infecting neurons in an HIV-positive patient with both conditions.

Area of Science:

  • Neurovirology
  • Infectious Diseases
  • Immunology

Background:

  • Human herpesvirus 6 (HHV6) is a common virus, typically causing mild illness but rarely associated with severe neurological conditions like meningoencephalitis and leukoencephalitis.
  • Progressive multifocal leukoencephalopathy (PML) is a serious demyelinating disease affecting the brain, often seen in immunocompromised individuals.

Observation:

  • This study details a case of an HIV-infected patient presenting with lesions characteristic of PML.
  • The patient also exhibited meningoencephalitis, with diagnostic investigations strongly implicating HHV6 as the causative agent.
  • Immunohistochemistry and in situ PCR confirmed the presence of HHV6 antigens and genome within meningeal and cortical lesions.

Findings:

  • Microglia and lymphocytes within the lesions tested positive for HHV6.
  • Crucially, infected neurons were observed, with many showing signs of damage, including neuronophagia (phagocytosis of neurons by other cells).
  • Evidence suggests direct HHV6 infection of neurons, contributing to the observed neuropathology.

Implications:

  • This case highlights HHV6 as a potential pathogen in inflammatory brain diseases, even in the context of PML in HIV patients.
  • The findings suggest that HHV6 may play a more significant role in causing neuronal damage and encephalitis than previously recognized.
  • Further research is warranted to understand the pathogenic mechanisms of HHV6 in the central nervous system and its interaction with opportunistic infections like PML.

More Related Videos

A Rat Model of EcoHIV Brain Infection08:48

A Rat Model of EcoHIV Brain Infection

Published on: January 21, 2021

Identification of EcoHIV-Infected Cells in Microglia-Manipulated Transgenic Mice07:23

Identification of EcoHIV-Infected Cells in Microglia-Manipulated Transgenic Mice

Published on: December 20, 2024

Related Concept Videos

Herpes01:28

Herpes

Herpes simplex type 1 (HSV‑1) is a widespread pathogen responsible for orolabial lesions. It is an enveloped, double-stranded DNA (dsDNA) virus belonging to the family Herpesviridae. Once the virus infects a host cell, its double‑stranded DNA genome is delivered into the nucleus, where a coordinated cascade of immediate‑early, early, and late gene expression directs viral DNA replication, structural protein synthesis, and virion assembly. After primary infection of epithelial cells, HSV-1...
Cytomegalovirus Disease01:27

Cytomegalovirus Disease

Cytomegalovirus (CMV) disease is caused by human cytomegalovirus, a double-stranded DNA virus of the Herpesviridae family. While primary CMV infection is often asymptomatic in immunocompetent individuals, the virus can cause severe disease in neonates and immunocompromised patients. CMV is the most common cause of congenital viral infection in the United States, and a major pathogen in solid organ and hematopoietic stem cell transplant recipients.CMV is transmitted via bodily fluids, sexual...
Genital Herpes01:23

Genital Herpes

Genital herpes is a sexually transmitted infection primarily caused by herpes simplex virus type 2 (HSV-2), though herpes simplex virus type 1 (HSV-1) is increasingly implicated in genital infections, particularly among younger populations. Transmission occurs mainly through sexual contact, with asymptomatic viral shedding serving as a major route of spread. This characteristic makes HSV-2 difficult to control at a population level, as individuals may unknowingly transmit the virus even in the...
Cryptococcal Meningitis01:27

Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...
Encephalitis l: Introduction01:19

Encephalitis l: Introduction

Encephalitis is inflammation of the brain parenchyma, most often due to infections or autoimmune processes. It presents with neuropsychiatric features such as fever, altered mental status, behavioral changes, cognitive dysfunction, seizures, focal deficits, and sometimes autonomic instability. In some cases, the meninges are also involved, resulting in meningoencephalitis.Infectious CausesInfectious encephalitis is most commonly viral but can also result from bacterial, fungal, or parasitic...
Encephalitis ll: Pathophysiology01:26

Encephalitis ll: Pathophysiology

Encephalitis is inflammation of the brain parenchyma caused by direct viral invasion or immune-mediated mechanisms triggered by infections or tumors. Both processes lead to neuronal injury, disrupted neurotransmission, and diverse neurological symptoms, often with overlapping clinical and pathological features.Autoimmune EncephalitisIn autoimmune encephalitis, antibodies target neuronal antigens on cell surfaces, synapses, or within neurons. A key example is anti-NMDAR encephalitis, which can...