New possible biomarkers for diagnosis of infections and diagnostic distinction between bacterial and viral infections in children.

Detailed information about patients with infections is required to ensure appropriate choice of treatment. Although white blood cell (WBC) counts, and C-reactive protein (CRP) levels are useful diagnostic indicators of infections, more rapid and easily assayed indicator(s) could improve diagnosis. Moreover, it is of pivotal importance to distinguish bacteria or viruses as causative pathogens. Overall, TLR2 and TLR4 expression levels in neutrophils derived from individuals (n = 118) with bacterial (n = 37) and viral (n = 34) infections were higher than those in control samples (n = 47). Significant higher levels of TNF-α in patients with both types of the infection were observed, and those of IL-4, IL-8, IL-10, and IL-12 also were observed in the present study. Levels of IL-2, IL-8, and IL-10 on day 1 post-viral infection were significantly higher than those on day 1 post-bacterial infection. Therefore, there is a possibility that IL-4, IL-8, IL-10, IL-12 and TNF-α might be biomarkers for infections, in addition to WBC counts and CRP levels, and that IL-2, IL-8 or IL-10 are potentially able to distinguish between bacterial and viral infections.