New serum and nasal immunological biomarkers in pediatric infection caused by respiratory syncytial virus

Respiratory syncytial virus (RSV) is the major etiological agent accounted for acute respiratory infection in children aged under 2 years, including bronchiolitis. Worldwide, RSV leads to 60 million infections and 160,000 deaths per year. Although some immunological biomarkers have been proposed for monitoring the severity and prognosis by RSV, new proteins may be also involved. Thus, this study presents new possible systemic and nasal biomarkers [adenosine triphosphate (ATP), IL-1beta, IL-1ra, IL-5, IL-8, IL-10, IL-13, IL-17, IL-23, IGF-1, VEGF, TSLP, Relaxin-1 and Relaxin-3] for RSV positive versus RSV negative and its clinical correlations with bronchiolitis. Upon informed consent, blood and nasal aspirates were collected in 28 children under 2 years of life. 11 showed clinical symptoms of bronchiolitis and were positive for RSV. 17 RSV negative age-matched controls were also analyzed. We observed in patients with bronchiolitis the presence of a positive correlation between plasma and nasal IL-10 levels (p<0.05). The ROC curve analysis revealed that patients with bronchiolitis presenting area greater than 0.7, greater sensitivity of 39% and greater specificity of 60% for IL-1beta, IL-1ra and IL-8 in nasal aspirates and for IL-23 in plasma. Therefore, this study shows for the first time that IL-1beta, IL-1ra, IL-8, IL-10 and IL-23 may play a role in the pathophysiology of RSV infection serving as a possible markers of prognosis for children evolving to bronchiolitis, since that no correlations were found in non-bronchiolitis children.