Comparison of cytokine responses in nasopharyngeal aspirates from children with viral lower respiratory tract infections

Aim: To determine whether nasopharyngeal aspirates (NPAs) cytokine response is different according to the causative viruses in children with lower respiratory tract infections (LRTI). Methods: NPAs from 277 children with LRTI caused by respiratory virus were evaluated. Based on the proven viral agents, LRTI patients were divided into four groups. Levels of IL-4, IL-5 and IFN-γ were determined by ELISA. Results: Patients with influenza virus infection demonstrated significantly lower IL-4 and IL-5 levels than those with other three groups. Patients with respiratory syncytial virus (RSV) infection showed an increase in production of IL-4 and IL-5, and a decrease in the IFN-γ level when compared to patients with influenza virus infection. Interestingly, a similar Th2 response was seen in patients with parainfluenza virus or adenovirus infection. Conclusion: These results demonstrate that respiratory viruses can induce different local cytokine responses. However, Th2 biased responses are not unique for RSV but seem to be predominant in respiratory viruses of young children.