Detection of WU polyomavirus in cerebrospinal fluid specimen from a patient with AIDS and suspected progressive multifocal leukoencephalopathy.

To the Editor—We read with interest the article recently published in the Journal of Infectious Diseases by Sharp et al. [1], who investigated whether the newly discovered KI, WU, and Merkel cell poly-omaviruses could persist and reactivate in immunodeficient patients. To this aim, the authors screened for the presence of ge-nomic sequences of KI, WU, and Merkel cell polyomaviruses, in addition to BK and JC polyomaviruses, in a series of lymphoid tissue autopsy samples from immuno-compromised patients with AIDS but without signs or symptoms suggestive of polyomavirus-associated diseases, such as polyomavirus-associated nephropathy or progressive multifocal leukoencephalopa-thy (PML), and from control subjects without AIDS. The authors demonstrated that, overall, polyomaviruses were significantly more frequently detected in im-munosuppressed patients than in non-immunosuppressed persons. In particular, with regard to the new polyomaviruses, KI polyomavirus was detected in 3 (7.1%) of 42 patients with AIDS and in 1 (1.8%) of 55 control subjects, WU polyomavirus was detected in 4 (9.5%) patients with AIDS, and Merkel cell polyomavirus was identified in only a human immunodeficiency virus (HIV)–infected injection drug user in the control group. Moreover, a higher viral load and a higher rate of mutations in the transcription control region of the viral genome were observed in immuno-suppressed patients than in nonimmu-nosuppressed individuals with KI or WU polyomavirus infection. We would like to support the findings of Sharp et al. [1] of a higher risk of re-activation of KI and WU polyomaviruses in immunosuppressed patients with AIDS and their hypothesis that these viruses might be responsible for disease in such patients [1], by reporting a case of WU polyomavirus DNA detection in a cere-brospinal fluid (CSF) specimen from a patient with AIDS who showed signs of PML but did not have JC polyomavirus infection. The case was identified among a series of CSF samples from patients with suspected viral encephalitis that were retrospectively analyzed for the presence of WU, KI, and Merkel cell polyomavirus ge-nome sequences. In particular, the study was performed using 60 CSF samples collected from Jan-uary through June 2008 at the Microbiology and Virology Unit of Padova University Hospital (Padova, Italy) from patients (26 female and 34 male patients; median age, 44 years [range, 4–88 years]) with neurological signs and symptoms suggestive of acute or chronic viral en-cephalitis; results of polymerase chain reaction (PCR) testing for genome sequences of herpes simplex virus types 1 and 2, varicella zoster virus, and entero-viruses were …