Of note, IgE sensitization may be indispensable for histone H1-mediated induction of mast cell degranulation due to the lack of allergic rhinitis in PBS/Alum-sensitized and histone H1-challenged mice (Fig 2A) and the lack of PCA response in PBS/histone H1-injected ear (Fig 4A). Here, IGHE is linked to allergic rhinitis.