Rôle des différentes populations de cellules dendritiques dans l'asthme allergique

Tolerance is the normal immune response to inhalation of antigen, yet type 2 T helper cell (Th2) sensitization to inhaled allergens activating dendritic cells (DCs) is possible in some individuals. Here, we were able to show that both myeloid (m) and plasmacytoid (p) DCs are present in the lung and have distinct functions. The depletion of pDCs during allergen sensitization led to development of allergic asthma characterized by production of IgE antibody, airway inflammation with eosinophilia and cytokine production by Th2 cells. Adoptive transfer of pDCs before sensitization prevented the development of the disease. On the other hand, intra-tracheal administration of mDCs induced all the features of asthma while depletion of mDCs prevented the mice from developing pulmonary inflammation. These results show that mDCs contribute to the induction and maintenance of asthma, while pDCs protect against the development of allergic asthma. Therapies aimed at exploiting the protective function of pDcs might be clinically effective in preventing the development of asthma.