Th1 and Th2 cytokine levels in nasopharyngeal aspirates from children with human bocavirus bronchiolitis

BACKGROUND: Human bocavirus (hBoV) is regarded as one of the possible etiologic agents in lower respiratory tract infection and bronchial asthma exacerbation in children despite frequent co-detection with other respiratory viruses. The immunologic response in children with hBoV infection is still not clear. OBJECTIVES: To investigate the profiles of T helper-1 (Th1)/T helper-2 (Th2) cytokines in children with hBoV-associated bronchiolitis. STUDY DESIGN: This study utilized of 59 nasopharyngeal aspirates from 59 infants aged 24 months or younger, including 29 from children with hBoV-related bronchiolitis and 30 with respiratory syncytial virus (RSV)-related bronchiolitis. Eighteen infants hospitalized for elective surgeries were included as controls. Nasopharyngeal aspirates were tested simultaneously for cytokines interleukin (IL)-2, IL-4, IL-5, IL-10, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha using the Cytometric Bead Array. RESULTS: Significantly higher concentrations of IFN-gamma (p=0.0001), IL-2 (0.006), and IL-4 (p=0.0002) were observed in hBoV positive specimens than in controls. The concentration of IL-10 (p=0.04) and TNF-alpha (p=0.006) in the RSV-positive group was significantly higher than in the hBoV-positive group, while there was no difference in other cytokines concentration between the two groups. CONCLUSIONS: These results showed that both of Th1 and Th2 cytokines were increased in children with hBoV-related bronchiolitis compared to normal controls, but Th2-polarized responses were not observed