Sensory neuropeptides induce histamine release from bronchoalveolar lavagecells in both nonasthmatic coughers and cough variant asthmatics

Background Sensory neuropeptides have been suggested to play a role in the pathogenesis of a number of respiratory diseases including asthma and chron ic non-productive cough. Objectives To investigate the action of sensory neuropeptides on airway mas t cells obtained by bronchoalveolar lavage (BAL). Methods BAL was performed on 23 nonasthmatic patients with cough (NAC), 11 patients with cough variant asthma (CVA) and 10 nonatopic controls. Washed lavage cells were stimulated (20 min, 37 degrees C) with calcitonin gene-re lated peptide (CGRP), neurokinin A (NKA) and substance P (25 and 50 mu mol/ L). Results The neuropeptides tested induced histamine release in all groups st udied. Only CGRP (50 mu mol/L) induced significantly more histamine release from both NAC and CVA patients compared with control subjects (P = 0.038 a nd 0.045, respectively). Conclusion Regardless of aetiology, mast cells from patients with chronic c ough appear to have an increased responsiveness to CGRP compared with contr ols. The results of the present study suggest that the role of CGRP in chro nic cough should be further investigated.