Correlation Of IL-18 With Tryptase In Atopic Asthma And Induction Of Mast Cell Accumulation By IL-18 And Tryptase

ObjectiveThe current study is to investigate the correlation between IL-18 and tryptase in asthma, and the role of IL-18 and tryptase in mast cell accumulation.MethodsThe expression of IL-18R and PAR-2 on mast cells from OVA-sensitized and nonsensitized mice were determined by flow cytometric analysis, and cytokine and tryptase levels in plasma and PLF were detected by ELISA.ResultsIt was found that IL-18 and tryptase levels in the plasma of moderate and severe asthma were elevated, and they correlated well with each other. Tryptase and agonist peptides of PAR-2 induced substantial quantity of IL-18 release. IL-18 and tryptase provoked mast cell accumulation in peritoneum of OVA-sensitized mice. OVA-sensitization increased number of IL-18R+mast cells. IL-18 and tryptase induced dramatic increase in IL-18R+mast cells, and MFI of IL-18R on mast cells. Moreover, while IL-18 induced an increase in PAR-2+mast cells in nonsensitized mice, IL-18 and tryptase provoked increases in IL-4 and TSLP in the peritoneum of OVA-sensitized mice.ConclusionThe correlation between IL-18 and tryptase in plasma of patients with asthma indicates close interactions between them, which should be considered for development of anti-IL-18 and anti-tryptase therapies. Interactions between IL-18 and tryptase may contribute to mast cell recruitment in asthma.