Abstract
BACKGROUND--The effect of cessation of exposure to pollen on the concentration-response curves to inhaled methacholine was investigated. METHODS--Methacholine inhalation challenges (up to 200 mg/ml) were performed in 13 non-asthmatic patients with grass and/or Parietaria pollen-induced rhinitis during the pollen season, and one and four months after it. Concentration-response curves were characterised by their PC20, position, and plateau. RESULTS--Geometric mean methacholine PC20 increased from 6.4 mg/ml during the pollen season to 28.2 mg/ml and 54.9 mg/ml one and four months after the end of season, respectively. The mean (SE) level of the plateau decreased from 30.5 (4.3%) in the pollen season to 23.3 (3.7)% and 20.1 (3.3)% one and four months after the end of pollen season, respectively. Although the methacholine concentration that produced 50% of the maximal response increased from 2.9 mg/ml to 4.3 mg/ml and 6.0 mg/ml, the differences were not significant. CONCLUSIONS--In non-asthmatic patients with pollen-induced rhinitis cessation of exposure to pollen is associated with significant modifications in the methacholine threshold value and level of plateau, and with a small shift in the concentration-response curves to the right.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Aubier M., Levy J., Clerici C., Neukirch F., Herman D. Different effects of nasal and bronchial glucocorticosteroid administration on bronchial hyperresponsiveness in patients with allergic rhinitis. Am Rev Respir Dis. 1992 Jul;146(1):122–126. doi: 10.1164/ajrccm/146.1.122. [DOI] [PubMed] [Google Scholar]
- Boonsawat W., Salome C. M., Woolcock A. J. Effect of allergen inhalation on the maximal response plateau of the dose-response curve to methacholine. Am Rev Respir Dis. 1992 Sep;146(3):565–569. doi: 10.1164/ajrccm/146.3.565. [DOI] [PubMed] [Google Scholar]
- Boulet L. P., Morin D., Milot J., Turcotte H. Bronchial responsiveness increases after seasonal antigen exposure in non-asthmatic subjects with pollen-induced rhinitis. Ann Allergy. 1989 Aug;63(2):114–119. [PubMed] [Google Scholar]
- Cockcroft D. W., Killian D. N., Mellon J. J., Hargreave F. E. Bronchial reactivity to inhaled histamine: a method and clinical survey. Clin Allergy. 1977 May;7(3):235–243. doi: 10.1111/j.1365-2222.1977.tb01448.x. [DOI] [PubMed] [Google Scholar]
- Moreno R. H., Hogg J. C., Paré P. D. Mechanics of airway narrowing. Am Rev Respir Dis. 1986 Jun;133(6):1171–1180. doi: 10.1164/arrd.1986.133.6.1171. [DOI] [PubMed] [Google Scholar]
- Sterk P. J., Daniel E. E., Zamel N., Hargreave F. E. Limited bronchoconstriction to methacholine using partial flow-volume curves in nonasthmatic subjects. Am Rev Respir Dis. 1985 Aug;132(2):272–277. doi: 10.1164/arrd.1985.132.2.272. [DOI] [PubMed] [Google Scholar]