Detection of JC virus DNA in CSF of pediatric patients with non-PML neurological disorders.

BACKGROUND

JC virus (JCV) is a human polyomavirus classically associated with progressive multifocal leukoencephalopathy (PML). Its role in other central nervous system (CNS) disorders - and the contribution of related polyomaviruses such as BK virus (BKV) and simian virus 40 (SV40) - remains poorly defined in pediatric populations, especially among immunocompromised patients.

METHODS

We analysed 64 cerebrospinal fluid (CSF) specimens collected from children evaluated for suspected viral encephalitis or meningoencephalitis between March and October 2024. Broad-range and virus-specific PCR assays targeting conserved regions of the large T antigen (LT-ag) and VP1 genes were performed. Positive amplicons were confirmed by bidirectional Sanger sequencing and phylogenetic analysis. Associations with HIV status were assessed using chi-square tests.

RESULTS

JCV DNA was detected in 4 of 64 samples (4/64; 6.3%), BKV DNA in 5 of 64 samples (5/64; 7.8%), and both viruses were co-detected in 3 samples (3/64; 4.7%). All positive detections occurred in HIV-positive patients (JCV: 4/19 HIV+; BKV: 5/19 HIV+), yielding statistically significant associations with HIV status (JCV p = 0.006; BKV p = 0.002). No SV40 DNA was identified. Phylogenetic reconstruction grouped patient sequences tightly with reference JCV and BKV strains, supporting authentic detection rather than laboratory contamination.

CONCLUSIONS

These results provide molecular evidence that JCV and BKV can be detected in the CSF of pediatric patients with suspected CNS infection - predominantly in the setting of HIV-associated immunosuppression - and may represent underrecognized contributors to non-PML neurological disease. Larger, longitudinal studies integrating clinical, radiological and quantitative viral-load data are required to define causality and clinical impact.