New insights into the world of eosinophils in allergic diseases

Since their discovery by Paul Ehrlich in 1879, eosinophils have been regarded as a central player in the pathogenesis of allergic diseases such as atopic dermatitis, bronchial asthma, and allergic rhinoconjunctivitis. Eosinophils have a thousand disguises - including beneficial, detrimental, regulatory, hemostatic, and complementary effects - on inflammation and immunity. The present issue of Allergology International features four outstanding reviews presenting new insights into the eosinophil world in allergic diseases. Eosinophils are basically defined morphologically like other immune cells such as lymphocytes and dendritic cells. Lymphocytes are classified into several subpopulations such as T cells, B cells, and innate lymphoid cells (ILCs) by cell surface markers and genes.