IL4 and asthma: Besides, the pathologic scores of mice in group D were significantly lower than those of mice in group A. Serum IFN-γ levels and the IFN-γ/IL-4 ratio of OVA-induced asthmatic mice in group D were significantly higher than those of mice in group A. Therefore, our results are consistent with previous findings and indicate that early-life exposure to diverse microbial environments may improve the Th1/Th2 balance, and thus reduce airway inflammation in asthma.