STUDY OBJECTIVES To investigate whether mantle radiotherapy (MRT) for the lung, through its proinflammatory effects, can induce an increase in airway responsiveness. DESIGN: Follow-up of the changes in lung function and methacholine responsiveness in patients 1, 6, 12, and 24 months after they underwent MRT. PATIENTS: Thirteen nonasthmatic patients with bulky Hodgkin's lymphoma who were scheduled for MRT. MEASUREMENTS AND RESULTS: Chest radiographs, lung function tests, methacholine thresholds of the bronchi (the provocative dose of methacholine causing a 10% fall in FEV(1) [PD(10)]) and central airway (the provocative dose of methacholine causing a 25% fall in the maximal mid-inspiratory flow [PD(25)MIF(50)]), and the provocative dose of methacholine causing five or more coughs (PDcough) were serially assessed. One month after patients underwent MRT, there were significant decreases in PD(10) (mean [+/- SEM], 2,583 +/- 414 microg to 1,512 +/- 422 microg, respectively; p