Iinuma T, et al. – By focusing on ST2, which is an IL–33 receptor, the relationship between pathogenic Th2 (Tpath2) cells and the stages of allergic rhinitis was investigated. The pathogenicity of memory Th2 cells exhibited a link with sensitization and the stage of allergic rhinitis. Results revealed that Tpath2 cells seemed to provide useful insights into the mechanism of the onset and progression of allergic rhinitis.