Human pegivirus-1 associated leukoencephalitis: Clinical and molecular features

Area of Science:

• Neurology
• Virology
• Pathology

Background:

• Encephalitis diagnosis remains uncertain in 35-50% of cases globally.
• Human pegivirus-1 (HPgV-1) is a known virus, but its role in neurological disease is not well-established.

Observation:

• Two adult female patients presented with fatal leukoencephalitis.
• Neuroimaging revealed inflammatory white matter changes in the brain.
• Neuropathology confirmed lymphocyte infiltration and gliosis in the brain's white matter.

Findings:

• Brain infection with HPgV-1 was identified as the cause of leukoencephalitis.
• HPgV-1 RNA sequences from the brain showed phylogenetic clustering with other pegiviruses.
• An 87-nucleotide deletion was noted in the viral nonstructural (NS)2 gene.
• HPgV-1 NS5A antigen was detected in brain lymphocytes, astrocytes, and oligodendrocytes.

Implications:

• HPgV-1 neuroadaptation should be considered in the differential diagnosis of progressive leukoencephalitis.
• This study highlights a novel cause of severe neurological disease.
• Further research is needed to understand the mechanisms of HPgV-1 neurotropism and pathogenesis.