In the present study, we have investigated the immune regulatory role of Ncf1 in asthma, and found that mice with the Ncf1m1j mutation, with a dysfunctional ROS response, were protected from ovalbumin (OVA)-induced lung inflammation in an alveolar macrophage dependent manner, with reduced inflammatory cell infiltration in airways and an increased Th1 cytokine expression in the lungs. Here, NCF1 is linked to asthma.