Detection of human respiratory syncytial virus sequences in peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMC) obtained from patients with lower respiratory infections were examined for the detection of human respiratory syncytial virus (RSV) sequences in the N region using the reverse transcription polymerase chain reaction (RT-PCR). RSV infection was confirmed by at least one method, i.e., virus isolation, enzyme immunoassay for viral antigen, and RT-PCR of nasopharyngeal secretions (NPS) samples. The detection rate for RSV RNA in PBMC obtained from RSV-infected patients was 40% (38/94), compared to 5% (1/20) in controls (P = 0.002). Between the groups positive (38) and negative (56) for RSV RNA in PBMC, there was no significant difference in clinical parameters. Seven patients had eight episodes of reinfection and RSV RNA was detected in 50% (4/8) during consecutive infections. Sequences of their PBMC samples were distinct from those of prototype strains of subgroup A and B. However, they were not always consistent with those of paired NPS samples. The findings suggested that RSV RNA could be detected in PBMC even during reinfection and as might have the possibility of quasispecies dynamics, reflecting the nature of RNA viruses.