CXCL8 and susceptibility to pneumonia measurement: In the present study, the cytokines, TNF, IL-1β, IL-6, IL-8, IL-12p70, IFN-γ, IL-17A, IL-10 and IL-5, were detected in the serum of children with pneumonia and severe pneumonia at hospital admission, and IL-6 was the only cytokine associated with disease severity.