AbstractsBiology & Animal Science

Th2 immunity was evolved for the immune response against parasites. Basophils, eosinophils, mast cells and Th2 cells are characteristic cell types in Th2 immunity. Furthermore Th2 immunity is characterized by IgE antibody production by B cells. Recently a new innate cell type was identified and found to be involved in Th2 immunity. These cells were called group 2 innate lymphoid cells (ILC2s). Group 1 and 3 ILCs are other ILC subsets derived from the same progenitor cells, but with different functions in the immune system. ILC2s contribute to the immune response against parasites, but also to allergic diseases. Their role in allergic asthma and chronic rhinitis has already been described. Very recently, ILC2s were found to contribute to the inflammatory response in atopic dermatitis (AD). AD is characterized by skin lesions with a thickened epidermis and lymphocyte infiltration. Various factors contribute to the pathogenesis: skin barrier dysfunction, IgE sensitization and both Th2 and Th1 immune responses. Acute lesions are mediated by a Th2 immune response, while chronic lesions are mediated by a Th1 immune response. It was shown that depletion of ILC2s reduced the inflammatory response in mice eczema lesions. However the importance of ILC2s in the development of AD remains to be examined. It is suggested that ILC2s cause the initial Th2 response in acute lesions. More research on ILC2s and their role in AD could lead to a better understanding of the pathogenesis of AD and might improve treatment of AD.