The Potential Role Of IL-18 In Activate Immunologic Responses In Asthma

Objective In recent years, it has been suggested bronchial asthma was a TH1/TH2 imbanlance disease.Interleukin(IL)-18 is the only cytokine with a unique capacity to regulate not only the TH1 pathway but also the TH2 pathway, and it has been implicated in the pathogenesis of asthma. The aim of the present study was to evaluate how IL-18 is associated with bronchial asthma. Methods Serum IL-18, plasma IFN-γand serum IgE levels were measured in patients with acute asthma (n=21),moderate asthma(n=22),stable asthma(n=24) and healthy subjects(n=20) by enzymelinked immunosorbent assay(ELISA). Results there were significant differences in levels of serum IL-18 between four groups by one-way ANOVA(P<0.001), acute asthma (447.6±64.96 pg/ml),moderate asthma(311.60±48.17 pg/ml), stable asthma (139.63±49.97 pg/ml),control subjects(108.35±30.85 pg/ml). Further analysis was performed for comparisons among groups. There was no significant difference in serum IL-18 between the stable asthma and the control group (P=0.226).We found significant differences in levels of serum IL-18 among other groups(P<0.001). And the serum IL-18 levels of patients tend to increase as the severity of the disease increased. But there were no significant differences in plasma IFN-γlevels in all groups (P=0.634).We also found significant differences in levels of serum IgE among four groups (P<0.001), acute asthma(411.36±113.70 IU/ml ),moderate asthma(237.37±57.36 IU/ml ), stable asthma ( 170.09 ±57.70 IU/ml ) and control subjects ( 15.94 ±19.88 IU/ml).Further total comparisons were performed among all groups. There were all significant differences every two groups(P≤0.01).And the serum IgE levels of patients tend to increase as the severity of the disease increased. And the IL-18 levels significantly correlated with serum IgE levels(R=0.791 P<0.001), but the IFN-γlevels didn't significantly correlated with serum IL-18 levels and IgE levels. Conclusion There is a more complicated pleiotrophic role for IL-18 than simply induction of IFN-γproduction. IL-18 may be a dangerous cytokine for asthma, and it may be associated with the severity bronchial asthma. Serum IL-18 level may reflect disease activity in bronchial asthma exacerbation.