Human polyomavirus 6 DNA in the cerebrospinal fluid of an HIV-positive patient with leukoencephalopathy

BACKGROUND: Leukoencephalopathies in HAART-treated, HIV-positive patients include progressive multifocal leukoencephalopathy (PML), a result of lytic infection oligodendrocytes by JC polyomavirus (JCV), and another form characterized by the absence of JCV genome in cerebrospinal fluid (CSF). OBJECTIVES: To test the potential viral etiology of JCV-negative leukoencephalopathy. STUDY DESIGN: CSF was collected from 43 HIV-positive patients with MRI suggestive of leukoencephalopathies. DNA was isolated and real-time PCR assays for neurotropic viruses (Herpes Simplex Viruses 1/2, Varicella Zoster Virus, Epstein Barr Virus, Human Cytomegalovirus, Human Herpesvirus 6, JCV and HIV) were conducted. CSF from 14 non-reactive cases were subjected to random nucleic acid amplification, deep sequencing, and in silico search for viral sequences. RESULTS: JCV genome was detected in the CSF of 19/43 PML patients, HIV genome in the CSF of 5 PML patients including 2 JCV negative patients, and no viruses were detected in 22 patients. Human Polyomavirus 6 (HPyV6) DNA was detected by deep sequencing in one JCV-negative leukoencephalopathy CSF sample. CONCLUSIONS: HPyV6 DNA was detected in CSF of a case of demyelinating disease. HPyV6 has not been previously reported in CSF or associated with any disease. Demonstrating a causative role will require further studies.