A significant decrease in the expression of the Th1 polarization factor IFN-γ and a significant increase in the expression of the Th2 polarization factors IL-4 and GATA-3 in Spp1−/−+OVA mice, which suggests a lack of OPN, increases the Th2-polarized environment in asthma. The gene discussed is IFNG; the disease is asthma.