The immune response in babies can be influenced by different environmental exposures. With regards to allergy and asthma, some triggers (severe ower respiratory tract infection) are considered as risk factors for allergic asthma development later in life. Others like growing up in a farming environment, on the opposite side, can strongly protect children So far, nobody knows how exposure to one or the other factor can affect asthma onset. In our lab, we are trying to identify the mechanisms that will put children a higher of asthma development as well as mechanisms that can protect chidren from becoming asthmatic in adulthood. We believe that environmental factors encountered in early life might cause changes in the lung immune cells and/or in the structural cells of infants, that can have long-lasting effects. Understanding how early-life exposures affect responses to allergens later in life is crucial to develop new preventive strategies against allergy and asthma development.