In this study, we will explore mechanisms of exacerbation in asthma by careful characterization studies in asthmatics presenting in acute severe exacerbation. Specifically, we will determine the frequency of secretor status in these subjects by blood and saliva testing, and we will also perform a detailed cellular and biochemical analysis of their airway secretions. We will collect airway secretions using two methods. One method will be to have subjects cough sputum into a clean plastic container. The other method only applies to asthmatics with near-fatal asthma requiring intubation and mechanical ventilation. In these asthmatics, we will collect airway secretions by tracheal aspirate using methods normally applied in their clinical care.