Pulmonary physiology, airway responsiveness and asthma.

What we know: Tests that have allowed the measurement of lung function in infants have greatly enhanced our understanding of early pulmonary development and the pathophysiology of early respiratory disease. Airway responsiveness in infancy appears to be an independent determinant of symptoms and lung function later in childhood. New tests of airway responsiveness hold the promise of predicting, with increased specificity, infants at risk of developing asthma. What we need to know: What are the factors that determine airway responsiveness soon after birth? Why does airway responsiveness in the first weeks of life relate to lung function many years later? Do different challenge agents reflect different pathophysiological processes involved in the development of persistent asthma?