IL-5 and IL-13 are TH2 cytokines associated with the development of airway inflammation in mice (23) and humans (24, 25); the observed increase in these proinflammatory cytokines in Cbl-b−/− mice is suggestive of exacerbated TH2 cell responses to aerosol challenge during acute inflammation. The gene discussed is CBLB; the disease is inflammation.