IFNG and susceptibility to pneumonia measurement: Then, the expressions of 25-OH-VD, VDR, TGFβ, IL-2, IFN-γ, TNFα, IL-1β, Ca2+, PCT, CRP, and IL-6 in mild pneumonia, severe pneumonia, and healthy controls were determined using qRT-PCR, western blot, ELISA, and calcium colorimetry assay.